I had a friend/mentor that raced through the 70-80's. He confirmed all of the things you state about quench. I built a 450 cubic inch Pontiac with 12:1 CR for the street, using his advice. dual plane, 750 cfm Holley, 72 cc Edelbrock heads, portmatched intake. It made about 580 lb/ft on 93 octane. 4400# Catalina ran a 12.76 at 108 mph. He taught me about suspension, too. He has since passed to cancer, but I will never forget the lessons. I found David Vizard teaching the same theories.
I've watched this video more than I've care to admit to. I have a built 632 for the street and track. I checked the filling station in my area. So, I built my engine with 13.5 compression. When I had to find a e85 station and can't I turn down the advance. If I could I would go with a 14.1 compression. If I was again building my own motors. I would would check the squish to make sure the math was spot on. It makes a huge difference. Listen to Ben. He knows what what he is talking about.
Steve, when I was also doing serious street engines I kept the quench on the tight side as you found out the response is so much better by a big margin compared to normal quench clearance or none at all!
It's interesting to hear this all explained in this way. My mentor Clif Winters Kolostow who worked for Ed Miller Racing Enterprises back in the late 60's early 70's taught me how to build my little 340 Dodge to make a very mild package that made substantially more power than most factory big blocks. The foundation was a 340 block that was decked about .010", then we milled .060" off the cylinder head deck, presumably to bring the combustion chamber down to the 63.3cc factory spec, or so I thought, lol. I actually ended up with combustion chamber volumes in the 58-59cc range. We also used the .018" steel shim head gasket and the factory 1968-1970 10.5 to 1 flat top pistons with four valve reliefs. That little 340 was a monster that loved to eat big block cars. In 1979, when I built this engine, I did not know how to check the actual compression. The car ran fine with 37° total on 93 octane pump premium. It was in a 3300lb Dart Swinger with a 4 speed and 3.91 gears. I put about 30,000 miles on that 340 before I pulled it out. When I took the heads off I noticed that the top of the piston and the cylinder head were nearly clean in the area where they nearly contacted each other. In fact some areas were absolutely clean. You see by milling the heads .060" I had turned an open chamber head into a closed chamber head . The flat area of the combustion chamber was reduced to the point that the "high" points of the rough casting surface were milled off, indicating if I had gone another couple thousandths the rough casting would have been milled smooth. All these years later I did the math and discovered that way back when, I had been running over 13.2 to 1 compression in that little "Stock" looking 340! It never rattled even with that much total timing. I did a little more math and conservatively, that 340 was easily making 1 horsepower per cubic inch. There were quite a few other "Little" tricks done to it, but the real key was that "Quench" area that I didn't realize I had created with that much milling. I never even heard of quench area at that time. So this video reveals a lot to me. Thank you for uploading this!
Exact same thing happened with my first engine rebuild when I had pistons from a Honda engine swapped into Suzuki for higher comp but unexpectedly came out to be 0.6mm out of deck / overdeck , compressed gasket thickness being 1mm. The pistons came out to be taller than mentioned on spec sheet and made 13:1 instead of 11:1. At that time I had to make a call whether to mill the pistons on deck or let them be as is . I took the leap of faith thinking as long as I keep the revs under 6.5k rpm , the rod stretch won’t exceed 0.4mm. And went ahead with the 0.6mm overdeck pistons with a functional quench of 0.4mm . The engine ran of 97 Ron without any knock on stock ecu map which was meant for stock 9:1cr spec motor. With loads of torque and 25% improvement in fuel efficiency.
In cold weather conditions that 13:1 motor would even run on 91 ron pump gas for daily use and out of station trips, all on stock ecu fuel and iginition map meant for 9:1 cr. This Suzuki engine was a 1.6L SOHC G16b , running taller Honda d16 pistons , making 290psi cranking compression on STOCK CAM, but ported head.
Thank you Ben for an easy to understand explanation about Quench/Squish, 3 yrs ago I built a 10.8:1 489, 4.25 stroke 4.28 bore -22 cc or -24cc pistons (forged Racetec) forget now with Brodix 294 R port 115cc CNC option heads, Eddy rpm AG with a Holley 1000HP carb that dynoed 590hp 600tq at crank, before that I threw together a 454 with small golf ball dish pistons .018 down the hole, .027 mls gaskets 1969 “063” heads, Eddy O port rpm AG and a 3310 Holley that really screamed, by going with Proper Quench/Squish absolutely NO Detonation issues in a 3800-4000 lbs 1968 Chevelle, I’m Subscribed and thanks again
Great to hear you talk about quench. Being in Australia and being primarily a Cleveland builder back in the 80's and 90's, I almost always used the 302, small port, closed chamber heads. Cheap, and plentiful to get at the time. I'd run pistons up to 0.010 above the deck. The cylinder heads were always clean in the quench areas, and the pistons would erode the machining marks off the tops of the pistons across the life of the motor. I did this because I was trying to achieve exactly what you described. Being country based, information wasn't as readily accessible back then as is is today, so a lot of what I did was simply based on best guess, and break it engineering. But even though I haven't built a customer engine for over 20 years now, I still get people asking me to build for them. Thank you for sharing your knowledge. It confirms for me what I thought I was doing was right, but also tells me where I wasn't. Great stuff Ben. Regards Greg
Thanks for confirming what I have said many times over and you are testament to this technique of building a better engine and it does not take a rocket scientists but good technique will do it everytime! This is the reason I tell people when they bring me the engine not to tear it down but have us together take it apart because it has a story to tell... You sir know your stuff as well and thanks again!
Thanks Robert! I try to answer but there is so much going my way and I have to make time to respond. It is worth it from my side to engage my viewers in exchanging ideas and comments.
Ben, I predict within the next two years your channel will be so much bigger than you can imagine. I have followed your racing career since your white ‘67 coupe in the late ‘80s lol. Best UA-cam wishes my friend, and thanks for sharing so much knowledge. #MustangTown #MuscleCarTimeMachine
This video is very good, and true. Modern fuel doesn't burn the same as old fuel from the muscle car era. You can run high compression on pump gas with modern cylinder heads, you just have to get your A/F ratio right and then your timing. Old specs for A/F and timing apply to old tech. It's all in the tune. Make it proper.
Another great video from the best teacher anywhere!! I've built many race engines with 11 to 1 to 11.5 to 1 with closed chamber iron heads or open chamber milled. 36 degrees total on 91 pump gas. I always picked a cam profile with 106 lobe and a minimum of 230 degrees duration at .050. Overlap and Quench is your friend!
I had a chev 283 that had 11.25 compression ratio in the late 70's. It ran decent on 91 0ctane lead free pump gas but when I mixed it with 100 LL av gas the temperature went down, the idle came up and it turned into a monster. It tended to run hot on the 91. It was in a 4 speed 69 Chevelle stock chassis. It did ping a little on the 91 at low rpm. 327 camel back heads. Thanks Ben
My 351w pinged a little with stock ported cast iron heads with 10.8 compression, but after changing to AFR 195 aluminum heads (smaller chamber bumped compression even higher) it never pinged again. It was in a 71 F100 with a built C4 and 3.89 gears
Glad I came across your channel. I've tried explaining this ro my wife and friends and you made it easy for me. F open chamber heads and dish pistons! That's why a 305 I built destroyed a factory 350 in the same vehicle. Shameful. I'm building my 347 and need my heads ported before I can even pick my cam...but soon she will be together. Thank you sir for your time!
Invaluable knowledge, OGs like you and I walk aound with this stuff in our heads. We can hear if the combo Is right or wrong. You can't order this type of magic from Summit, And you can't fix a bad combo with a laptop and FuelTech. Keep it coming
Dave, you are correct and yes experience proceeds to wisdom and knowledge. Unfortunately some people have very hard heads and no matter how you explain things they just never listen! lol
I'm old now. I learned like a lot of others by the passion of engines and cars in high school - Beeline Dragway 70's and cruising Mesa. Well, my kids are high school now, and my plan is to have them learn with what they got! So, got another 66 Galaxie 500 for them. They're touching mine - yet Lol. Straight car no rust but gutted. Got a 76' 460 closed chamber cast heads D3VE. I'm going to show them how to make a decent 400hp car (all they need) on the cheap, avoiding all the mistakes I made. I'm purposely going to put solid roller in it and have lashing frequently, keeping them "tuned in." 600 lift cam or smaller matched to cheap KB hyper Flat top. D3VE heads have 97-100 cc chambers. They're gonna do the porting and to match. They're gonna measure the final chamber size. They're going to calculate compression, required decks, (block, heads or both). 3800lb car so CR is going to sacrifice, but I'd hope it's 9:5:1 not sure yet - perhaps more. Yes, 4 SPEED with gears. Manual brakes! They're football players - it'll be fine. The lesson... Build and learn on basic junk that's cool looking on 28's with a decent paint and classic interior. When they can afford stroker and Kasse products - they'll be well schooled with their own money. I'm just kicking it off with basic steel rods and balancing. Ya know, it's awesome being the Dad. I'm their wrestling coach / mentor. Go to all the football games and track events - hunting, fishing now cars! Great life! Thanks for the video above. Gets me motivated!
By your name sir I feel you serve our country very well and thank you! You are teaching your kids the basics and that will lead them in the proper direction and will yield good to excellent results! Try a tad higher on the compression like 10.5 and will give you a lot more which will make everyone happy! 4speed toploader is the the greatest for a street machine anytime anyday! Good luck.
@benalamedaracing2765 Hi Ben. Yea, Top Loaders are very cool! But, this is save $$ project. I've looked recently... Shocked to learn a used TKO or Jerico after getting the proper spline, shafts and bell-hsg w/shifter are cheaper than a 4 Top-Loader. The TL is a prize but very much desired by everybody. What happened to the days when Top Loaders were everywhere Lol. David Kees in TX doesn't even offer whole units for sale hardly anymore. Anyway, we'll figure it out. We're not picky purists. Cheap is our vernacular Lol. Really enjoy your videos. My Son's watch them too.
great video. I am amazed at what a proper quench and combustion chamber can do. I run a 355 sbc on the street with iron Bowtie heads (64cc closed chamber design), a 0.015 steel shim head gasket, small domed pistons 0.025 in the hole, and my static compression ratio is 11.6:1, dynamic is 9.9:1, and I run 39° of total timing, small solid roller cam with 234 I and 242 E duration (@0.050 lift) 108° LSA, and I installed it advanced 3° so my intake valve closes at 39° ABDC (0.050). So my quench is 0.040 and I run 93 unleaded pump gas- no ping, no kickback on hot restarts, it's great!
Well it shows you have the good balance of compression and camshaft working out for you running pump gas! I despair when I see people run 9:1 or somewhere close to this and run a juice camshaft and it does not respond or it has a soggy bottom and mid range! Thanks for your input.
Hi, I would like to know where you got the .015 head gasket. Brand and who sells it if you have that info. I have a similar setup and need a thin head gasket to get the quench that I want. Thinnest I have found is .027. Also would like to know what your cylinder cranking pressure is. I am trying to pick a cam and it is really cool to hear what other engines are running. Thanks for the post.
Hi Ben, one other aspect to consider that many don't when building their street engine is elevation. If a person lives in Denver (5,000 ft + elevation) and does the majority of his driving locally (like most do),he will be able to get away with a much higher static compression ratio than a person living in L.A. or San Diego (500 ft elevation). His engine will be much more responsive at 12.5-1 versus 9.5-1. And will run virtually zero risk of detonation because of the reduced atmospheric conditions. Keep the good info coming. 🍻
You are right about that elevation relationship with compression! Many miss this scenario and builds a 9.1 compression living at high altitude and wondering why his car is a dog! lol
I'm sharing this with my student, so he can hear the same things from more than one source. I speak more in terms of flame front propagation and sonic boom to inertia of the air column, but we are essentially teaching the same things. Good job.
ive been reading your articles on facebook. and im applying it on small engine.. and now on youtube w/ all the illustrations it is really much easier to understand. it realy helped me a lot.. thank you sir
What was your name? How is Rick and does he still have his auto parts store? I am in Vegas now 4 years and miss Cali but it is getting expensive so I left!
@benalamedaracing2765 Martin. Rick's dad passed away a few years ago. Rick sold the shop. He got married and moved to La Mirada. Cesar (the cop), Rick, and I were talking about you yesterday (good things). We all live within 3 miles of each other. I hope you are well.
Sir I appreciate your videos . I glad I ran onto your web sight . I alway was told 200 ccp on a street engine. I run a bit more on my Harley but you have to be careful on not heat soaking or lugging . At any rate I was told a long time ago I could run a half point more compression with aluminum heads . I don't remember what I was told but way back when the aluminum heads they poured something through them to help with the heat loss .. most will say no way but I ran 12.5 in a 302 chev engine I built in I think 80 and I ran a 600 isky roller sold..that a a decent set of cast iron angle plug heads off a g gas car .. seems like I ran super unleaded and regular gas mix . I kept the engine at 160 also . I never as far as I know had problems . The engine had a 0 deck . I had help building the engine from a dirt track shop in Dallas and a fellow from my home town..since I found your channel I tried to watch all of them a great teaching opportunity. Thanks again
Thanks Jim. I feel 160* is too cold and you will have premature cylinder bore wear. If you can move that higher to 180*f the engine should run better and longer. Cast iron heads are not a laughing matter as you found out and at 12:5 it is at an advantage and you probably know that and I am not telling you anything you do not already know. Obtw thanks for supporting my channel.
Thank you sir for the recommendation appreciate it very much. I checked your channel as well and you gave a lot of thoughtful comments and sound advice to all from the novice to the true enthusiasts!
Thank you Ben! I just had a 363 SBF built and was worried because my engine builder insisted that 11:1 CR was just fine for 93 octane on the street. (Sniper Stealth EFI on an Edelbrock RPM Airgap) The engine is going into my '85 Foxbody with a Magnum 6 speed. The Mahle flat top pistons sat .002 in the hole with a .041 MLS head gasket = .043 quench with AFR 195 Renegade heads. I feel so much better now about running 11:1 CR on pump gas!
Thank you sir and it seems like you got it right on this build and more power to you! The quench is good but you can gain more it you kept it a little bit more tighter and it will respond big time!
U better be running a cam in the mid 240's or more if you're planning on 11:1. Maximum compression is totally based off duration and overlap.... nothing else, except maybe a high octane fuel like e85.😅
Well a few yeas ago I sold my 1970 351C Mustang, it had flat top pistons & 4V quench heads, the new owner put 4V open chamber heads on it, he could not run it with out it pinging, now I understand. My 10.7 :1 quench heads were great. Thx for sharing
Dwayne, thank you for clarifying what I have been saying all along that open chamber heads with lower compression does not mean less detonation. Appreciate the feedback!
What metal your heads are made out of has a whole lot to do with how much compression you can run, typically with aluminum heads you can run quite a bit higher compression without detonation when compared to cast iron heads of the same specs.
Very interesting and quite good timing. They engine builder who Does my valve job suggested I should go with atleast 11:1 on my 3.4 v6 build for my Fiero. After seeing this I might just have to follow his advice, and yours to buy other pistons to replace the bowled ones I bought 😅
Tolerance to detonation is increased as well when you install a somewhat hotter street cam from stock so that will give you a little bit more power and response! Gas mileage too.
It makes sense doesn't it whenever I go inside an empty room the sound travels and bounces on the walls like an echo chamber! Or perhaps an open chamber.
Great video Mr. Alameda-love this topic! Your comment on CR vs load (vehicle weight) was thought provoking. I understand an engine works harder under load, however, I can't visualize how the combustion process is affected by load. What's got me stumped is, if an engine runs fine (no detonation) under light load, why would it change with load. Cylinder filling is what it is-at any giving RPM, at wide open throttle, and should not change based on load. What causes detonation-Is it CR, or is it the total psi within the cylinder? What say you? I'm in agreement with you on maximizing squish/quench to create turbulence/mixture motion within a cylinder. However, many moons ago, I believe it was a Circle Track article, where the engine builder had an opposing point of view. The engine builder's theory was to slow the motion in the chamber prior to ignition, to avoid extinguishing the flame front-was this the early stages of chamber softening? Thank you, Tony
Ts, what you will find and realize is the load vs. non load conditions within the combustion chambers! Under free revving the engine does not meet rpm resistance or slowing down of the rpms. When under load the rpm rise is stunted/delayed significantly while the FLAME FRONT SPEED DOES NOT SLOW DOWN. This situation of slower piston speed towards and after TDC will affect the "unburned" sections of the combustion chambers! Mainly around the intake valve relief @ the piston closest to the cylinder wall. ON THIS AREA IT SEE'S A RAPID RISE IN TEMPERATURES AND PRESSURES elevated to a point that auto- ignition emanates from this area. A secondary auto ignition is also present at the exhaust valve relief at the piston closest to the cylinder wall as well. Lean conditions at the intake valve pocket is exacerbated by the slower piston speed and the expansion of the ignited gases is still progressing at the same rate! Here the dangerous situation rears its ugly head and continues on towards pre-ignition! Like wise, the RICH CONDITIONS @ THE EXHAUST RELIEF results in a slower than normal ignition flame speed at this area because the richer mixture progression is slower BUT DOES NOT EXEMPT THIS AREA FROM THE SAME PRESSURE AND TEMPERATURE SPIKES SIMILAR TO THE INTAKE SIDE! Therefore a loaded engine's RPM RISE IS SLOWER. AN UNLOADED ENGINE RPMS IS FASTER! BOTH PRESENTS TWO DIFFERENT SCENARIOS AS PISTON SPEEDS SLOWS WHILE THE IGNITION FLAME SPEED STAYS THE SAME. Remember: Lean areas burn "slower" because the fuel molecules are farther apart. Rich areas also burn slower/cooler because rich mixtures are lazy and burns at a lower rate! In short if loaded or unloaded does not make a difference on chamber performance and conditions? Then why do we dyno an engine and tune ignition and air fuel ratios under load??? If load is unconsequential then we will just free rev the engine and set our tuning tables! But that would not work anywhere. The scenario above points to increase probability of detonation first from the intake side then the exhaust side if the conditions get progressively worse. The same loading conditions exist in 1st gear and the probability of detonation gets progressively worse the more you get to 2nd, 3rd and final 4th gear! The difference here is the slower rpm rise as you go thru the gears because the engine sees ever increasing "load" as you lose gear reduction thereby making the rpm rise much slower and here is where the problem starts! Big difference. I hope it is clear with you and thanks because it is an excellent and worthwhile question to answer. Lastly, an engine with no load does not build "boost" and the only way you can achieve it is to hold reverse and low gear/some 2nd gear on a transbrake! This will excite the combustion pressure to a higher level and the turbo will get a blast of exhaust pressures absent from a no load/light load situation. Proof that the combustion conditions are indeed different between load (added-weight) and no load/light load. Ben.
You just know when you are listening too a pro. Nothing to rehearsed if at all, all the numbers straight of the top of his head and they always run out of time. Mate you could have talked for an hour and I would have listened to every word. Just stumbled across this just now and subbed!
Salamat and thanks for your support on my channel! I just wish I can break in the social media there in motorcycles and cars! Many know me here but not there!
Many years past Diamond Pistons provided a video on pouring their mold material into a combustion chamber which they would then use to build your pistons.. this was done on an engine stand with head mounted, mold goop then poured in from bottom of cylinder
Great info! I built a supercharged 377 Chevy. 9.23:1 on pump gas. Not huge cubic inch. But keeping quench tight. 400 block 4.155 bore 3.48 stroke. .035 quench with a semi flat/dished piston to get the 9.23CR. Cometic mls gaskets Everything I read says 7.5-8 to 1 with a weiand blower. Granted I have only ran about 6.5psi but so far so good.
Another thing to add, try to get forged pistons made from 2618 alloy, and not 4032. 4032 alloy may fragment from the effects of detonation and if this happens, it can be very destructive of the engine. The forged 2618 alloy piston is much more resistant to the effects of detonation and heat.
Also, as a form of 'insurance'... although we have 93 octane here in Texas, I am lucky enough to have stations nearby that sell E85. I usually get a few Jerry cans full of E85 and add a couple of gallons to my tank before topping it off w/ 93 octane. E85 is 108 octane... and it also cools the burn of the fuel. With just a couple of gallons, you don't need to retune anything or get E85-specific equipment. Definitely see a difference, especially during these 105+ degree Texas summers.
AWESOME CAN NOT BEAT YOU OLD TIMERS GOT ALOT OF KNOWLEDGE AND EXPERIENCE AND SCHOOLS CAN NOT TEACH EXPERIENCE AND COMMON CENSE THANK YOU SO MUCH NOW I HAVE A VERY GOOD UNDERSTANDINGOF HOW IMPORTANT QUEENCH IS FLAT TOP PREFERED THANKS FOR TEACHINGS ME FOR FREE AND IM 66 FIX CARS ALL MY LIFE BUILDING A LA360 MOPAR 4.000STROKE BORED 4.030 408 CIDAND AM LEARNING ALOT AS I GO BEFORE I EVEN ORDER PARTS THANK YOU SO MUCH GODBLESS YOU
I always felt the dish pistons suck. Compression 10.5 to 11 with decent gas and 3000 pounds works well as you say. Torque rules on the street. High RPM power not realistic on the street. Gotta love 331 SBC, smooth and efficient. Keep camshaft 224 degrees/ 110 separation or slightly less on both.
A childhood friend of mine with me doing the engines and running his 65 corvette we were cleaning the streets! lol LOve it with that much rpm potential!
I have a good way to extract power from the dish piston no quench motors, with a cam and intake, use a Edelbrock Performer or an old SP-2P intake, not an RPM or anything, it has to have the tall narrow opening at the exit into the head. Then use a 108 LSA moderate lift cam, the scavenging of the cam and the high velocity of the intake creates a swirl/turbulence in the chamber of epic proportions, the engine acts like a 2 stroke at high RPM almost. This is for the guys who don't want to pull the motor and change pistons.
Jeff, sounds like it might work? Usually when you have high velocity ports combined with swirl/tumble, there is a big possibility you will centrifuge your fuel and separate from the airflow. There is an ideal port air speed street or racing and this is what we have to achieve in order for everything to work together and combust properly. Even high ram velocity into the chambers will lead to lean conditions like I explained on the piston intake valve relief breaking off or melting...
Like always. Thank you for all the knowledge. I wish you would have been doing these videos years ago. Now I want to change up my set up. Good job. Thanks again
Ben, I just found your videos haaa at 73 I have tried to tell people the same thing as you since the 60’s and they just didn’t get it. So I just stopped my life being too short. So glad your still trying nice job good luck! M
Good video Ben! I never really understood how piston shape affects the quench, you described it very well. I learned years ago from Tom Nelson of Nelson Racing Engines, to zero deck the block and use the head gasket to adjust the quench. Of course with a stock type steel head gasket this wouldn't work, you would have to put the piston further down in the hole.
With most engine if you are zero deck a .045 head gasket thickness or even tighter would work really good on a small block. What kind of engine do you have?
Very good video and reaches most of the street audience like you said. Like your perspective on compression ratio too - tske all thats there for pump gas. On point wotg tq vs RPM too. Subscribed. I have a 430W just built and dyno'd on my channel. Definitely a fan of the 8.2/9.5 deck Windsors.
i prefer the Windsor 9.5" deck over a chevy 350 deck, but its still not enough. i need 10 or 11 inch deck hieght at least with a 4" bore, even more with a 4.185" bore. That is why i am build my ford and chevy small block head using engines with custom DIY engine block with molecular iron. One day i hope to build a nano-molecular auto orbital quantum particle arranger and 'multi-D print' the son a bitch the way its supposed to be done. Then form for myself and others brand new bodies to live in for that matter.
Had a 351 flat-top pistons with 289 HP heads (46 cc chambers) in a 67 Cougar, Nash 5-spd and 3.4 gears. Effectively 12.5:1 compression. No knocks on premium pump gas
I truly enjoy your theory application/ explanation videos. Guess it's my engineering mindset. Everyone loves horsepower, but don't understand the science involved. How does reverse dome pistons for boosted applications react? How do you increase/control combustion efficiency?
F&F, excellent question and makes me think this is why I love being asked about these scenarios! Reverse dome pistons for boosted applications is not a net negative and I will explain why. 1. Boost as part of the intake function in itself creates its own mixing by the mere presence of dense atmospheres inside the port! Boost does not happen if there are no rpms in the scenario given and with rpms comes the rapid stop n go of the charge column making it a very effective mixture motion assisting! 2. Boost comes with heat. Heat tends to excite the molecules and keep them from sticking to the port walls! These is the reason we have heated intake manifolds to keep the fuel from sticking to the cold port or manifold walls! A reason for the choke on ancient carburetors and the close loop function in modern EFI's. Purpose is to richen the mixture to compensate for fuel wetting and lean conditions inside the combustion chambers when it is cold! 3. Therefore with boost creating heat making the fuel particles more engage and active in the mixing process, and rpms obvious shaking and mixing prowess, the combustion chamber/reverse dome negatives are negated to a lesser role and we have a net horsepower increase!
@@benalamedaracing2765 Thank you for the lesson. Now it makes sense as to why at throttle response at idle (w/ reverse dome pistons) will not be as crisp as a NA motor. Of course important off the line. That's an interesting point in regards to heat and its' relation to making horsepower. Knowing the thermal efficient crossover point when heat is maximized for horsepower, versus causing detonations from heat of excessive compressed air (boost). I'm truly enjoy this! Thank you for broadcasting in a video platform. It's a bit easier for me to digest (understand) versus reading lol. Happy Holidays my friend!
Great presentation. My 12.5/1 boss 302 after sitting all winter just blew two spark plugs out of the heads. Just the porcelain came out not the steel part.
Excellent content!! It sometimes becomes difficult to run a flat top with a large 500+ ci stroker, because if you do you'll have like 15:1 compression!
I think you have it backwards. With a bigger bore, such as in a 540 BBC, you need less of a dome to achieve the same compression. With a 454, you need a bigger dome to get a good compression ratio.
@@ekitchingany time you increase the cylinder volume you increase the CR if the closed volume stay the same. 540 has 1/4 more bore and 1/4” more stroke than a 454 also.
I'm a rookie trying to piece together a Buick 350. I just watched a video about compression in a boosted 4-cylinder application that made me think I should still buy heads but keep my dished 8.5:1 pistons for cooler temperatures and compatibility with lower octane. But the information here makes me think that without the better quench of a "10:1" piston I won't see the benefits of the better heads nearly as well, and the engine may be closer to mid-grade friendly than I thought.
You got my point on compression and now just follow on and you will have impressive engine on pump gas or otherwise! Just watch the videos I posted and it should apply just about for all makes.
Rarely do i hear builders recommend any more than 11-11.5:1 compression for pump gas... I built my 438W 14 years ago with 12.42:1 comp. and 218# cyl. press. w/ 240 Hi-Ports, Zero detonation, 93 octane (ethanol free) with 30° total timing, idles at 850 rpm, makes an honest 740 horse at 6900rpm and 618 ft lbs tq. single carb, budget pump gas build, daily driver runs 190° in FL summer heat. The cam timing is critical with this amount of compression and a custom Comp. cam to my specifications, built in advance... provides its streetability. 3270# C4 5200 stall street car all motor 9.52 @141.80
You got it big time and that is moving no doubt! People and many of them do not realized the 351W configuration is plenty stout and even the factory block is light compared to other blocks with big mains.
BBC heads really suffer with their design... They're severely "undervalved" because of it and require some real trickery to get good numbers, from my experience. One thing I saw my friend do on a few different castings, was sink the exhaust valve (50 thou or more) so the incoming intake charge flows over top of the exhaust valve face (instead of finding it's way right out through the short side, where then it REALLY can't breathe) in the low lift/over lap phase. That was pretty much how my buddy, Nick, said it... I just tried to put it more simply... He ported heads for living, and always had some wild looking stuff over there. Anyways! Thanks a million for the wisdom, Ben!
engines without quench give mushy performance & require more spark advance to make mean best torque. more spark for power = loss of compression pressure because you have lit the charge early. The more excited the charge is because of quench the easier it is to ignite..
This makes sense. years ago I had a decked 283 with flat tops, closed camber camel hump heads, and a cam in a 3500# car. It ran great on 87 octane. Pretty quick, high 12 second car, good power, never detonated. I now daily a 4800# square body suburban, with a stock, low compression, open chamber 882 smog headed 350. Its a turd, and it detonates on 87..
This is only relevant for two valve heads where the intake charge creates a centrifuge spinning fuel outwards, but pretty much every engine for the last 30 years has been four valve which creates a tumble so a flat or dished piston is preferred. The most efficient pistons for a modern engine are flat or dished with a perimeter quench area.
I agree with your last statement but your introduction is really off base, "only?" and let me explain to you why. Check frames 55:20 of this video and it will explain "tumble" motion and how the fuel molecules has to almost travel a full 360* turn to return some fuel to the 4V's intake short side! I have worked from 1250rwhp turbo six street engines to Mercedes Benz 24hrs of Daytona & 12hrs of Sebring endurance engines (pls check my 2JZ build on FB Ben Alameda Racing) which I go thru the details of cylinder heads and block design. Almost ALL 4v's do not have a short side to influence some kind of radius entry to the short sides enabling fuel to go to this lean areas! Almost ALL depends on tumble motions that slams the fuel to the opposite side of the cylinder walls under the exhaust valves. Piston movement shoves most of these fuel droplets to the exhaust pads/valves and hardly anything that somersaulted inside and on top of the pistons ended up on the intake valve/pads! These are the reality of endurance engines and it gets worse on drag application which entails much higher boost levels shoving the fuel stream to the extreme end of the cylinders (opposite the intake valves). Anyway, the saving grace is 4V's predominant mostly "small bore configuration" wherein the flame front can easily spread to the intake area due to the "centrally" located spark plugs compared to domestic 2V's having bore sizes way past 4 inch diameters, spark plug located on 1 side and below or mostly below the combustion chambers. Remember small bore engines have less chances of detonation compared to its bigger bore counterparts wherein the flame front, farther away from its ignition source increasing chances of secondaries by a wide margin due to temp./press. spikes before it is consumed by the expanding flame front.
I see a lot of people build a big Windsor with 9:1 compression and not even making 400 rwhp. I always ask them why they are building blower motor and they say the same thing pump gas.
I run 12 to 1 in my 6.4 hemi 2500 ram with a stock cam. I run tight quench, milled heads srt8 pistons, zero deck block... no knocking showing on the knock sensors. You can get away with it in a heavy vehicle also and it really helps mpg but I bet my NOX is pretty high...
BMW and Mercedes have engines 11.5:1 from the factory. For coyote gen 2 is 11:1 and gen 3 is 12:1. All will run 93 octane and reduce octane with decreased timing advance. Each pt of compression is about 4% torque increase across the curve. So its certainly worth being concerned with.
I was running 10.5:1 back in 1992 using IRON Ported Windsor jr heads, we polished the chambers and i ran 93 octane with a "normal" 5.0 stang base type timing. No ping problems, just power. With aluminum head I would have run 11.5:1 back then. What inspired me was David Vizard "How to build horsepower" book.
My builder is currently working on my original 69 corvette 427 390hp .070 over with 4.25 stroker kit making it a 498 ci. Flat top pistons are .020 down and plan to use .040 mls head gasket making quench .060. Due to matching numbers block we cannot mill for a zero deck to tighten quench. Builder doing 9.75 compression due to using factory BB iron heads and modern 93 pump gas. Factory heads have been ported 2.19 1.72 valves, titanium retainers. Comp solid roller cam 11-770-8 .639 .646 lift, 236 242 duration, 110 LSA. Tremec TKX 5-speed with 3:55 rear. Corvette will only see the street. I wanted a high torque street motor but wanted as much out of it as possible and look totally stock on the outside. Using original Rochester, intake and exhaust manifolds. Engine will be dyno’d before being put back in the Vette. Not sure under the circumstances what more could be done or changed? Thanks for your video!!
Could you tighten up the quench a little bit more? I feel everything looks good and would like it a little closer even -010 would work. Perhaps a cometic thinner gasket would work.
@@benalamedaracing2765Using a compression calc and a .040 MLS head gasket final compression will be 9.7522 to 1. Today I tried asking for a thinner gasket but he doesn’t want to increase compression with todays 93 gas using my original iron 290 heads. The heads have 99 cc’s 🤷🏻♂️
Get a mls .030 like Ben just explained, it’s not going to put you over 11.5:1 and the gains will be more than worth it. I run .027 mls gaskets with pistons.005 in the hole with no problems. Iron headed bbc. You could drop down to a .015 and still be at .035 quench and plenty safe. I too dealt with a machine shop that said 9:5.1 max for 93octane and iron heads.. Some shops just don’t understand quench. Going tight is key but .032 is as tight as I’ve gone myself.
@@phildo39645thanks for your reply. I was never able to convince builder to tighten up the quench. He kept saying if I used a .030 mls compression would be 9.9:1 and I’d ping with iron heads and today’s gas. The engine dyno’d 540hp 628tq using factory aluminum intake and Rochester carb.
My street engine in my Sonoma was dynoed on 89 pump and features 47cc chambers and custom Ross piston's for 10.7 to 1 which i'll be running on 91 pump. 399ci. 1st gen stroker.
and here I am... Just bought a 2004 6.0 ls lq4 engine, stripped it down... no unusual bearing wear, cross hatching still visible in the cylinders... Going in a lowered 2005 2500 hd, in search of tire squealing torque.. scrapping the stock heads and dish pistons for a forged rotating assembly..... trying to get a plan together...
a few years back I acquired a 1990 Suburban with a 350. It would not pull a 5% grade on the interstate without down shifting and losing 20mph. SO, I pulled the engine. The engine wasn't factory colors so I assumed it had received a long black at some point. Compressions were factory fresh so I decided to leave the bottom end stock. SBC aluminum heads raise dcompression to 10.5 to 1. I aded a cam that was just shy of an idle gallop. A high rise intake, headers and an Edlebrock 1400 series carb. It dyno=d at 400hp and 390ft/lbs and ran everywhere on 87 octane without detonation
Gen 3 Coyote ( 2018 up in Mustang) runs 12 to 1 stock with Hyper pistons, usually check 220+ psi cranking...just fine on pump gas...however they have nice active knock sensors they will even ADD timing not just pull it ( DI and Port injection blended )
This video and presentation is extremely informative and helpful.... Ive been chewing tums for indigestion caused by me worrying about the Ford 300 inline six im building on a budget. I knew at 8.0.1 compression it wasnt going to make anything resembling power....itd be a lazy pig. So im having the block bored .050 over to accept a 360FE piston so i can have a true flat top piston and get a higher compression height, and we are decking the block and milling the head. Havent found any real info on it other than "people used to do this back in the day" , but i was hoping for something close to 10.1, and the camshaft is a custom grind 206/212 @.050 447/460 lift with stock 1.6 ratio rocker arms. Stayed mild on the cam since this engine will be limited by its rotating assembly to under 5000rpm. But now im being warned about a high dynamic compression ratio thatd make it too high for pump gas in the 4400 pound van the engine is going in. Any thoughts?
Yes it seems the cam is way too small! You have a lot of weight you are moving and adding duration even in the 214-218 range should not do any damaged.
I realized this when I looked at supersport street bikes. They have over 12.5 to 1 compression ratios and run on 91 octane gas. Modern 200 HP 1000 cc bikes are over 13 to 1 compression and weigh around 450 pounds. Not much load under normal operation.
Light weight with good gearing helps the engine big time! But most of all, a smaller bore diameter isn't as prone to detonation as a big bore engine combination.
Your taking about static compression. The Dynamic Compression is what counts. Dynamic has to do with valve timing events. If they are running 93 octane your dynamic will/should not be beyond 8.5:1 compression.
I explained that in detail on Part II of this video. A more simple technique is the cranking pressure not exceeding 200# and advancing or retarding the camshaft will increase or lower this number so further running pump gas without detonation. All explained in it.
@@benalamedaracing2765 Oh! Okay. I paid not see that vid. My apologies. Yes, cranking pressure would be a solid indicator also as you mentioned. Do you explain the tolerances needed for proper quench? How do you calculate the stretch of the rods so the piston doesn’t make contact with the head?
I had a smogger 454 with 8.5 to 1 compression. Oval port heads with a rectangular port intake and a mild cam. It did mid 13's and would probably have run on hobo piss. I don't trust the consistency of gas stations, keep the compression reasonable and you will have a more enjoyable ride, and a heavier wallet.
@@benalamedaracing2765 Nope. We had the intake and threw it on to see what would happen. It was fun in town and actually got decent highway mileage. I have a theory that fuel puddled at the step at normal rpm's and got sucked in when there was enough air flow acting like an accelerator pump. It was the perfect street set up as far as I'm concerned.
Thanks Ben. I'm build for my buddy and he won't know till he find out powerful enough lol.. I'll keep quiet. Thank gave me tip.. 11:1 compression ratio lol..
Great lessons Ben. Low compression not good in the combustion chamber. Aluminum heads, high compression (10.5-11.1), quench, proper carburetor size, light car, 3.42- 3.73 gears and correct total timing. All on pump gas (93,94) street car. Makes excellent power and quick reaction off the line. What more could i add?
I've got a 1971 383 with 906 heads and got about 9-1ratio. The cam is a factory Chrysler cheater cam which has a little over 300 duration I believe but stock lift of .450. since I have zero deck height pistons, I'm going to run a set of 1966 383 closed chamber heads. -9.5cc compared to the open chambers. .020 head gasket. I think closed chamber with flat top pistons pings less than open a chamber with a raised dome on the same octane of fuel. Chrysler called those heads "fast burn" and that's why they are expelling a lot of unburdened hydrocarbons. For a clean burn exhaust you can't go much above 8.5 compression. Open chamber heads are nothing but smog heads for their slower burn. No quenching here and no performance, but cleaner and less hydrocarbons for the catalytic converter to reburn.
Good video for sure. Surprised the Cobra engine builders didn't know that about pump gas. I had JBA out of California build me an engine to go vintage racing in the early 90's, 351w about the same cam lift. J302 heads 11.5 to 1 and raced it with nothing but 93 octane pump gas. Ran perfectly fine. 30 to 40 minute races and practices. Engine is still in the car. I forgot total timing but probably around 34 degrees max.
@@benalamedaracing2765 They were the only company at that time using the new J302 head. The real brains for the engine build was Doug Baker. I don't know what happened to him. I talked to him personally a few times. He was pretty sharp when it came to building engines and figuring out what the customer wanted. I still wanted to drive the car on the street so we ended up with a crane cam originally ground for a Cleveland motor. Had 400 ft lbs. of flat torque curve. and still achieve 425 hp at around 6500. 1.7 rockers to get .580 to .590 lift. Speed pro pop up pistons, to do exactly what you described in the video. Great motor with longevity in mind. With the technology in head design that engine would probably be close to 500hp now, changing nothing else but head. J302 only flowed stock right around 210 cfm intake side.
awesome! Hey. 355 c.i. 5.7" scat stroker rods. 9" deck height. 4 bolt 010 block. 4.032" bore size.180cc Dart heads 63cc chambers milled from 64cc. 10.3:01 static compression. Performer EPS edelbrock intake. 7CC piston tops. custom crank scraper kickout pan. 800 rpm idle 14" vacuum. Schnieder racing cams hydraulic roller cam# 27684H 112*LSA/ 106* ICL. Nylon cam button. 7.4" pushrods. 36* total timing. 175 cranking PSI. O.028" Head gasket. O.009" down the hole. HEI. 750 cfm Holley on 1/2" phenolic spacer. Running 90 octane. Made 410HP @ 5700 RPM peak. And 465 TQ. @ 3600 RPM peak. Next i want to try this with an aluminum AFR or TFS head or DART 180-190cc ports or even larger on an efficient AFR head. Competition ported. Or BRODIX. And slightly more compression. 10.75:01 with same cam and see what it does. Then a 383 with a Mike Jones Cam Designs EHS Hydraulic Roller 282 with the correct lifters from them.
Looks like you already got it close to being the best it can be! Going slightly higher on the compression will improve from here and stepping up perhaps to a 195cc heads with smaller chambers and higher lifts perhaps with running a 1.6 ratio on the intake should yield more power. Good luck!
Dead stock LS2 are 10.9:1 Suprized people haven't noticed. With modern heads and efi its so easy, especially when a big cam profile is added even 12:1 isnt too hard.
One thing with the LS is they come with good compression and great cylinder heads (fr. the factory) not too big and not small for the streets and high performance.
I bought a 2004 5.3l out of a tahoe and put it in my 71 Monte Carlo and when I turned the motor to bolt the flexplate up the motor was as hard to turn as my 11.1 compression SS Chevelle 396/375. I was surprised.
I had a friend/mentor that raced through the 70-80's. He confirmed all of the things you state about quench. I built a 450 cubic inch Pontiac with 12:1 CR for the street, using his advice. dual plane, 750 cfm Holley, 72 cc Edelbrock heads, portmatched intake. It made about 580 lb/ft on 93 octane. 4400# Catalina ran a 12.76 at 108 mph. He taught me about suspension, too. He has since passed to cancer, but I will never forget the lessons. I found David Vizard teaching the same theories.
Were you running the 3310 vacuum secondaries on that holley? That is a hard running pontiac!
Would that be Roger helgenson 🤔
Meticulously prepared F/Stock 389 Catalinas were running mid-Twelves at 106-108 mph in the late 60’s. NHRA stock on 7”tires.
Thx for sharing.. I love listening to the previous generations talk about autos!
It's like listening to Yoda's wisdom....
I think oil companies are behind the dis- information of making people build low efficiency / high fuel consumption engines..
I've watched this video more than I've care to admit to.
I have a built 632 for the street and track. I checked the filling station in my area. So, I built my engine with 13.5 compression. When I had to find a e85 station and can't I turn down the advance. If I could I would go with a 14.1 compression. If I was again building my own motors. I would would check the squish to make sure the math was spot on. It makes a huge difference. Listen to Ben. He knows what what he is talking about.
Steve, when I was also doing serious street engines I kept the quench on the tight side as you found out the response is so much better by a big margin compared to normal quench clearance or none at all!
This man is pure gold
Thanks !
It's interesting to hear this all explained in this way. My mentor Clif Winters Kolostow who worked for Ed Miller Racing Enterprises back in the late 60's early 70's taught me how to build my little 340 Dodge to make a very mild package that made substantially more power than most factory big blocks. The foundation was a 340 block that was decked about .010", then we milled .060" off the cylinder head deck, presumably to bring the combustion chamber down to the 63.3cc factory spec, or so I thought, lol. I actually ended up with combustion chamber volumes in the 58-59cc range. We also used the .018" steel shim head gasket and the factory 1968-1970 10.5 to 1 flat top pistons with four valve reliefs. That little 340 was a monster that loved to eat big block cars.
In 1979, when I built this engine, I did not know how to check the actual compression. The car ran fine with 37° total on 93 octane pump premium. It was in a 3300lb Dart Swinger with a 4 speed and 3.91 gears. I put about 30,000 miles on that 340 before I pulled it out. When I took the heads off I noticed that the top of the piston and the cylinder head were nearly clean in the area where they nearly contacted each other. In fact some areas were absolutely clean. You see by milling the heads .060" I had turned an open chamber head into a closed chamber head . The flat area of the combustion chamber was reduced to the point that the "high" points of the rough casting surface were milled off, indicating if I had gone another couple thousandths the rough casting would have been milled smooth.
All these years later I did the math and discovered that way back when, I had been running over 13.2 to 1 compression in that little "Stock" looking 340! It never rattled even with that much total timing. I did a little more math and conservatively, that 340 was easily making 1 horsepower per cubic inch. There were quite a few other "Little" tricks done to it, but the real key was that "Quench" area that I didn't realize I had created with that much milling. I never even heard of quench area at that time.
So this video reveals a lot to me. Thank you for uploading this!
Thanks for confirming my video and glad you forwarded this comment for others to see and we all learn as well!
Exact same thing happened with my first engine rebuild when I had pistons from a Honda engine swapped into Suzuki for higher comp but unexpectedly came out to be 0.6mm out of deck / overdeck , compressed gasket thickness being 1mm. The pistons came out to be taller than mentioned on spec sheet and made 13:1 instead of 11:1.
At that time I had to make a call whether to mill the pistons on deck or let them be as is . I took the leap of faith thinking as long as I keep the revs under 6.5k rpm , the rod stretch won’t exceed 0.4mm. And went ahead with the 0.6mm overdeck pistons with a functional quench of 0.4mm . The engine ran of 97 Ron without any knock on stock ecu map which was meant for stock 9:1cr spec motor. With loads of torque and 25% improvement in fuel efficiency.
In cold weather conditions that 13:1 motor would even run on 91 ron pump gas for daily use and out of station trips, all on stock ecu fuel and iginition map meant for 9:1 cr. This Suzuki engine was a 1.6L SOHC G16b , running taller Honda d16 pistons , making 290psi cranking compression on STOCK CAM, but ported head.
Thank you Ben for an easy to understand explanation about Quench/Squish, 3 yrs ago I built a 10.8:1 489, 4.25 stroke 4.28 bore -22 cc or -24cc pistons (forged Racetec) forget now with Brodix 294 R port 115cc CNC option heads, Eddy rpm AG with a Holley 1000HP carb that dynoed 590hp 600tq at crank, before that I threw together a 454 with small golf ball dish pistons .018 down the hole, .027 mls gaskets 1969 “063” heads, Eddy O port rpm AG and a 3310 Holley that really screamed, by going with Proper Quench/Squish absolutely NO Detonation issues in a 3800-4000 lbs 1968 Chevelle, I’m Subscribed and thanks again
Thanks for the clarification of what you were able to accomplish! Please spread the channel to gearhead friends!
We’re fortunate to have someone like you to pass on knowledge that most of us could never have the resources too. Great content as always.
I appreciate that!
Great to hear you talk about quench. Being in Australia and being primarily a Cleveland builder back in the 80's and 90's, I almost always used the 302, small port, closed chamber heads. Cheap, and plentiful to get at the time. I'd run pistons up to 0.010 above the deck. The cylinder heads were always clean in the quench areas, and the pistons would erode the machining marks off the tops of the pistons across the life of the motor. I did this because I was trying to achieve exactly what you described. Being country based, information wasn't as readily accessible back then as is is today, so a lot of what I did was simply based on best guess, and break it engineering. But even though I haven't built a customer engine for over 20 years now, I still get people asking me to build for them. Thank you for sharing your knowledge. It confirms for me what I thought I was doing was right, but also tells me where I wasn't. Great stuff Ben. Regards Greg
Thanks for confirming what I have said many times over and you are testament to this technique of building a better engine and it does not take a rocket scientists but good technique will do it everytime! This is the reason I tell people when they bring me the engine not to tear it down but have us together take it apart because it has a story to tell...
You sir know your stuff as well and thanks again!
Thx for being the ONLY UA-cam motor/racer guy who answers my questions.
Thanks Robert! I try to answer but there is so much going my way and I have to make time to respond. It is worth it from my side to engage my viewers in exchanging ideas and comments.
@Ben Alameda Racing ....
You're a blessing to us gearheads and motor building guys, I can't thank you enough sir!
Ben, I predict within the next two years your channel will be so much bigger than you can imagine. I have followed your racing career since your white ‘67 coupe in the late ‘80s lol. Best UA-cam wishes my friend, and thanks for sharing so much knowledge. #MustangTown #MuscleCarTimeMachine
Thank you and you have been one of the earliest supporters of mine. Grateful for all the years you have been there and appreciate it very much friend.
i need your email so we can chat
i need some knowledge 👍🏽 love ur content
I legit learned something! That's why you'll see 2 different style pistons for the same motor. It's because of chamber design. Thank you!
Thanks TT for your support of my channel!
A wealth of excellent information right their, thank you Mr Alameda.
Thanks as well!
This video is very good, and true. Modern fuel doesn't burn the same as old fuel from the muscle car era. You can run high compression on pump gas with modern cylinder heads, you just have to get your A/F ratio right and then your timing. Old specs for A/F and timing apply to old tech. It's all in the tune. Make it proper.
Another great video from the best teacher anywhere!!
I've built many race engines with 11 to 1 to 11.5 to 1 with closed chamber iron heads or open chamber milled.
36 degrees total on 91 pump gas. I always picked a cam profile with 106 lobe and a minimum of 230 degrees duration at .050. Overlap and Quench is your friend!
Mike, glad your on board watching and looks like you have a strong runner there!
Ping much ?
I had a chev 283 that had 11.25 compression ratio in the late 70's. It ran decent on 91 0ctane lead free pump gas but when I mixed it with 100 LL av gas the temperature went down, the idle came up and it turned into a monster. It tended to run hot on the 91. It was in a 4 speed 69 Chevelle stock chassis. It did ping a little on the 91 at low rpm. 327 camel back heads. Thanks Ben
I hope after prolonged usage your aviation fuel did not eat the gaskets for lunch! With the camel back heads did you have a decent quench clearance?
My 351w pinged a little with stock ported cast iron heads with 10.8 compression, but after changing to AFR 195 aluminum heads (smaller chamber bumped compression even higher) it never pinged again. It was in a 71 F100 with a built C4 and 3.89 gears
Glad I came across your channel. I've tried explaining this ro my wife and friends and you made it easy for me. F open chamber heads and dish pistons! That's why a 305 I built destroyed a factory 350 in the same vehicle. Shameful. I'm building my 347 and need my heads ported before I can even pick my cam...but soon she will be together. Thank you sir for your time!
Glad I could help. Thanks as well!
Invaluable knowledge, OGs like you and I walk aound with this stuff in our heads.
We can hear if the combo Is right or wrong.
You can't order this type of magic from Summit,
And you can't fix a bad combo with a laptop and FuelTech. Keep it coming
Dave, you are correct and yes experience proceeds to wisdom and knowledge. Unfortunately some people have very hard heads and no matter how you explain things they just never listen! lol
Awsome video some people need to here this
I'm old now. I learned like a lot of others by the passion of engines and cars in high school - Beeline Dragway 70's and cruising Mesa. Well, my kids are high school now, and my plan is to have them learn with what they got! So, got another 66 Galaxie 500 for them. They're touching mine - yet Lol. Straight car no rust but gutted. Got a 76' 460 closed chamber cast heads D3VE. I'm going to show them how to make a decent 400hp car (all they need) on the cheap, avoiding all the mistakes I made. I'm purposely going to put solid roller in it and have lashing frequently, keeping them "tuned in." 600 lift cam or smaller matched to cheap KB hyper Flat top. D3VE heads have 97-100 cc chambers. They're gonna do the porting and to match. They're gonna measure the final chamber size. They're going to calculate compression, required decks, (block, heads or both). 3800lb car so CR is going to sacrifice, but I'd hope it's 9:5:1 not sure yet - perhaps more. Yes, 4 SPEED with gears. Manual brakes! They're football players - it'll be fine. The lesson... Build and learn on basic junk that's cool looking on 28's with a decent paint and classic interior. When they can afford stroker and Kasse products - they'll be well schooled with their own money. I'm just kicking it off with basic steel rods and balancing. Ya know, it's awesome being the Dad. I'm their wrestling coach / mentor. Go to all the football games and track events - hunting, fishing now cars! Great life! Thanks for the video above. Gets me motivated!
By your name sir I feel you serve our country very well and thank you! You are teaching your kids the basics and that will lead them in the proper direction and will yield good to excellent results! Try a tad higher on the compression like 10.5 and will give you a lot more which will make everyone happy! 4speed toploader is the the greatest for a street machine anytime anyday! Good luck.
@benalamedaracing2765 Hi Ben. Yea, Top Loaders are very cool! But, this is save $$ project. I've looked recently... Shocked to learn a used TKO or Jerico after getting the proper spline, shafts and bell-hsg w/shifter are cheaper than a 4 Top-Loader. The TL is a prize but very much desired by everybody. What happened to the days when Top Loaders were everywhere Lol. David Kees in TX doesn't even offer whole units for sale hardly anymore. Anyway, we'll figure it out. We're not picky purists. Cheap is our vernacular Lol. Really enjoy your videos. My Son's watch them too.
Your videos are fantastic, Mr. Alameda! Been building and racing for decades and it's fascinating to see how much I still don't know.
Thanks and glad to help sir.
great video. I am amazed at what a proper quench and combustion chamber can do. I run a 355 sbc on the street with iron Bowtie heads (64cc closed chamber design), a 0.015 steel shim head gasket, small domed pistons 0.025 in the hole, and my static compression ratio is 11.6:1, dynamic is 9.9:1, and I run 39° of total timing, small solid roller cam with 234 I and 242 E duration (@0.050 lift) 108° LSA, and I installed it advanced 3° so my intake valve closes at 39° ABDC (0.050). So my quench is 0.040 and I run 93 unleaded pump gas- no ping, no kickback on hot restarts, it's great!
Well it shows you have the good balance of compression and camshaft working out for you running pump gas! I despair when I see people run 9:1 or somewhere close to this and run a juice camshaft and it does not respond or it has a soggy bottom and mid range! Thanks for your input.
@@benalamedaracing2765ad no idea you could run 9.9 dynamic compression on pump 93. Especially with iron heads.
Hi, I would like to know where you got the .015 head gasket. Brand and who sells it if you have that info. I have a similar setup and need a thin head gasket to get the quench that I want. Thinnest I have found is .027. Also would like to know what your cylinder cranking pressure is. I am trying to pick a cam and it is really cool to hear what other engines are running. Thanks for the post.
@@PatrickLee-y5r sure thing- I got the 0.015 gasket from EBay, it was a FelPro brand. The cranking psi is 220.
@@PatrickLee-y5r the gasket is a Fel Pro that I found on EBay. The cranking pressure is 220psi
Hi Ben, one other aspect to consider that many don't when building their street engine is elevation. If a person lives in Denver (5,000 ft + elevation) and does the majority of his driving locally (like most do),he will be able to get away with a much higher static compression ratio than a person living in L.A. or San Diego (500 ft elevation). His engine will be much more responsive at 12.5-1 versus 9.5-1. And will run virtually zero risk of detonation because of the reduced atmospheric conditions. Keep the good info coming. 🍻
You are right about that elevation relationship with compression! Many miss this scenario and builds a 9.1 compression living at high altitude and wondering why his car is a dog! lol
Very few accept this information as accurate... It's very true.
But if sell it and it goes the sea level the new owner has a problem.
I'm sharing this with my student, so he can hear the same things from more than one source. I speak more in terms of flame front propagation and sonic boom to inertia of the air column, but we are essentially teaching the same things. Good job.
Glad you tuned in because I like people in the know for the proper feedback and response to whatever I posted! Thanks
ive been reading your articles on facebook. and im applying it on small engine.. and now on youtube w/ all the illustrations it is really much easier to understand. it realy helped me a lot.. thank you sir
Thanks Tora-tora!
Hey Ben, I became a fan of yours when Rick (Progreso Auto Parts) and I went to Pomona to watch your street Mustang run in the 9s.
What was your name? How is Rick and does he still have his auto parts store? I am in Vegas now 4 years and miss Cali but it is getting expensive so I left!
@benalamedaracing2765 Martin. Rick's dad passed away a few years ago. Rick sold the shop. He got married and moved to La Mirada. Cesar (the cop), Rick, and I were talking about you yesterday (good things). We all live within 3 miles of each other. I hope you are well.
Very educational Ben some things you mentioned, I had forgotten about, let's get together and design a piston.
Sir I appreciate your videos . I glad I ran onto your web sight . I alway was told 200 ccp on a street engine. I run a bit more on my Harley but you have to be careful on not heat soaking or lugging . At any rate I was told a long time ago I could run a half point more compression with aluminum heads . I don't remember what I was told but way back when the aluminum heads they poured something through them to help with the heat loss .. most will say no way but I ran 12.5 in a 302 chev engine I built in I think 80 and I ran a 600 isky roller sold..that a a decent set of cast iron angle plug heads off a g gas car .. seems like I ran super unleaded and regular gas mix . I kept the engine at 160 also . I never as far as I know had problems . The engine had a 0 deck . I had help building the engine from a dirt track shop in Dallas and a fellow from my home town..since I found your channel I tried to watch all of them a great teaching opportunity. Thanks again
Thanks Jim. I feel 160* is too cold and you will have premature cylinder bore wear. If you can move that higher to 180*f the engine should run better and longer. Cast iron heads are not a laughing matter as you found out and at 12:5 it is at an advantage and you probably know that and I am not telling you anything you do not already know. Obtw thanks for supporting my channel.
Hello Ben. I just recommended this video on my channel. Similar topic. Lots of good comments. AG
Thank you sir for the recommendation appreciate it very much. I checked your channel as well and you gave a lot of thoughtful comments and sound advice to all from the novice to the true enthusiasts!
Thank you Ben!
I just had a 363 SBF built and was worried because my engine builder insisted that 11:1 CR was just fine for 93 octane on the street.
(Sniper Stealth EFI on an Edelbrock RPM Airgap)
The engine is going into my '85 Foxbody with a Magnum 6 speed.
The Mahle flat top pistons sat .002 in the hole with a .041 MLS head gasket = .043 quench with AFR 195 Renegade heads.
I feel so much better now about running 11:1 CR on pump gas!
Thank you sir and it seems like you got it right on this build and more power to you! The quench is good but you can gain more it you kept it a little bit more tighter and it will respond big time!
U better be running a cam in the mid 240's or more if you're planning on 11:1. Maximum compression is totally based off duration and overlap.... nothing else, except maybe a high octane fuel like e85.😅
@@parkerracing7374
Custom grind Comp Cams 243 degree/.601 lift/112 lobe
Well a few yeas ago I sold my 1970 351C Mustang, it had flat top pistons & 4V quench heads, the new owner put 4V open chamber heads on it, he could not run it with out it pinging, now I understand. My 10.7 :1 quench heads were great. Thx for sharing
Dwayne, thank you for clarifying what I have been saying all along that open chamber heads with lower compression does not mean less detonation. Appreciate the feedback!
What metal your heads are made out of has a whole lot to do with how much compression you can run, typically with aluminum heads you can run quite a bit higher compression without detonation when compared to cast iron heads of the same specs.
Very interesting and quite good timing.
They engine builder who Does my valve job suggested I should go with atleast 11:1 on my 3.4 v6 build for my Fiero.
After seeing this I might just have to follow his advice, and yours to buy other pistons to replace the bowled ones I bought 😅
Tolerance to detonation is increased as well when you install a somewhat hotter street cam from stock so that will give you a little bit more power and response! Gas mileage too.
I like the furniture analogy.
It makes sense doesn't it whenever I go inside an empty room the sound travels and bounces on the walls like an echo chamber! Or perhaps an open chamber.
Great video Mr. Alameda-love this topic! Your comment on CR vs load (vehicle weight) was thought provoking. I understand an engine works harder under load, however, I can't visualize how the combustion process is affected by load. What's got me stumped is, if an engine runs fine (no detonation) under light load, why would it change with load. Cylinder filling is what it is-at any giving RPM, at wide open throttle, and should not change based on load. What causes detonation-Is it CR, or is it the total psi within the cylinder? What say you?
I'm in agreement with you on maximizing squish/quench to create turbulence/mixture motion within a cylinder. However, many moons ago, I believe it was a Circle Track article, where the engine builder had an opposing point of view. The engine builder's theory was to slow the motion in the chamber prior to ignition, to avoid extinguishing the flame front-was this the early stages of chamber softening? Thank you, Tony
Ts, what you will find and realize is the load vs. non load conditions within the combustion chambers! Under free revving the engine does not meet rpm resistance or slowing down of the rpms. When under load the rpm rise is stunted/delayed significantly while the FLAME FRONT SPEED DOES NOT SLOW DOWN. This situation of slower piston speed towards and after TDC will affect the "unburned" sections of the combustion chambers! Mainly around the intake valve relief @ the piston closest to the cylinder wall. ON THIS AREA IT SEE'S A RAPID RISE IN TEMPERATURES AND PRESSURES elevated to a point that auto- ignition emanates from this area. A secondary auto ignition is also present at the exhaust valve relief at the piston closest to the cylinder wall as well. Lean conditions at the intake valve pocket is exacerbated by the slower piston speed and the expansion of the ignited gases is still progressing at the same rate! Here the dangerous situation rears its ugly head and continues on towards pre-ignition!
Like wise, the RICH CONDITIONS @ THE EXHAUST RELIEF results in a slower than normal ignition flame speed at this area because the richer mixture progression is slower BUT DOES NOT EXEMPT THIS AREA FROM THE SAME PRESSURE AND TEMPERATURE SPIKES SIMILAR TO THE INTAKE SIDE! Therefore a loaded engine's RPM RISE IS SLOWER. AN UNLOADED ENGINE RPMS IS FASTER!
BOTH PRESENTS TWO DIFFERENT SCENARIOS AS PISTON SPEEDS SLOWS WHILE THE IGNITION FLAME SPEED STAYS THE SAME.
Remember: Lean areas burn "slower" because the fuel molecules are farther apart.
Rich areas also burn slower/cooler because rich mixtures are lazy and burns at a lower rate!
In short if loaded or unloaded does not make a difference on chamber performance and conditions? Then why do we dyno an engine and tune ignition and air fuel ratios under load???
If load is unconsequential then we will just free rev the engine and set our tuning tables!
But that would not work anywhere.
The scenario above points to increase probability of detonation first from the intake side then the exhaust side if the conditions get progressively worse.
The same loading conditions exist in 1st gear and the probability of detonation gets progressively worse the more you get to 2nd, 3rd and final 4th gear!
The difference here is the slower rpm rise as you go thru the gears because the engine sees ever increasing "load" as you lose gear reduction thereby making the rpm rise much slower and here is where the problem starts!
Big difference. I hope it is clear with you and thanks because it is an excellent and worthwhile question to answer.
Lastly, an engine with no load does not build "boost" and the only way you can achieve it is to hold reverse and low gear/some 2nd gear on a transbrake! This will excite the combustion pressure to a higher level and the turbo will get a blast of exhaust pressures absent from a no load/light load situation. Proof that the combustion conditions are indeed different between load (added-weight) and no load/light load.
Ben.
25:38 A ton of info in such a short video. Wow! Thank you!!!
Subbed!
You just know when you are listening too a pro. Nothing to rehearsed if at all, all the numbers straight of the top of his head and they always run out of time. Mate you could have talked for an hour and I would have listened to every word. Just stumbled across this just now and subbed!
Thank you sir and appreciate the feedback!
Kuya Ben is hands down one of the Best in the Bizz!!🤜🤛💪💪💪❤️
Salamat and thanks for your support on my channel! I just wish I can break in the social media there in motorcycles and cars! Many know me here but not there!
You are an incredible wealth of knowledge, and severely underrated.
Motor Trend, got nothing on you.
Thank you sir appreciate the support.
Many years past Diamond Pistons provided a video on pouring their mold material into a combustion chamber which they would then use to build your pistons.. this was done on an engine stand with head mounted, mold goop then poured in from bottom of cylinder
They did that then and today they use a computer and digitized the whole chamber and feeds that to the computer to make the piston dome.
Great info! I built a supercharged 377 Chevy. 9.23:1 on pump gas. Not huge cubic inch. But keeping quench tight. 400 block 4.155 bore 3.48 stroke. .035 quench with a semi flat/dished piston to get the 9.23CR. Cometic mls gaskets Everything I read says 7.5-8 to 1 with a weiand blower. Granted I have only ran about 6.5psi but so far so good.
What you have is workable and seen it with of course the Chevy's and Ford's running low boosts without issues.
Dished pistons are made for a purpose. You're definitely right on NA applications, boosted is a different thing
Yes absolutely sir.
Thanks for sharing your knowledge.....
You bet and thanks for your support!
Thanks! awesome. Keep these videos coming.
Thanks for Sharing..
Thanks as well Kabayans!
Another thing to add, try to get forged pistons made from 2618 alloy, and not 4032. 4032 alloy may fragment from the effects of detonation and if this happens, it can be very destructive of the engine. The forged 2618 alloy piston is much more resistant to the effects of detonation and heat.
Also, as a form of 'insurance'... although we have 93 octane here in Texas, I am lucky enough to have stations nearby that sell E85. I usually get a few Jerry cans full of E85 and add a couple of gallons to my tank before topping it off w/ 93 octane. E85 is 108 octane... and it also cools the burn of the fuel. With just a couple of gallons, you don't need to retune anything or get E85-specific equipment. Definitely see a difference, especially during these 105+ degree Texas summers.
What is your mixing ratio with pump gas to e85? Thanks for your insight.
I'm a new subscriber found you today I like the way you explain technical concepts of the engine got my Bell on thanks for sharing your information
Thanks for supporting my channel MIke and appreciate it greatly!
AWESOME CAN NOT BEAT YOU OLD TIMERS GOT ALOT OF KNOWLEDGE AND EXPERIENCE AND SCHOOLS CAN NOT TEACH EXPERIENCE AND COMMON CENSE THANK YOU SO MUCH NOW I HAVE A VERY GOOD UNDERSTANDINGOF HOW IMPORTANT QUEENCH IS FLAT TOP PREFERED THANKS FOR TEACHINGS ME FOR FREE AND IM 66 FIX CARS ALL MY LIFE BUILDING A LA360 MOPAR 4.000STROKE BORED 4.030 408 CIDAND AM LEARNING ALOT AS I GO BEFORE I EVEN ORDER PARTS THANK YOU SO MUCH GODBLESS YOU
I always felt the dish pistons suck. Compression 10.5 to 11 with decent gas and 3000 pounds works well as you say. Torque rules on the street. High RPM power not realistic on the street. Gotta love 331 SBC, smooth and efficient. Keep camshaft 224 degrees/ 110 separation or slightly less on both.
A childhood friend of mine with me doing the engines and running his 65 corvette we were cleaning the streets! lol LOve it with that much rpm potential!
I have a good way to extract power from the dish piston no quench motors, with a cam and intake, use a Edelbrock Performer or an old SP-2P intake, not an RPM or anything, it has to have the tall narrow opening at the exit into the head. Then use a 108 LSA moderate lift cam, the scavenging of the cam and the high velocity of the intake creates a swirl/turbulence in the chamber of epic proportions, the engine acts like a 2 stroke at high RPM almost. This is for the guys who don't want to pull the motor and change pistons.
Jeff, sounds like it might work? Usually when you have high velocity ports combined with swirl/tumble, there is a big possibility you will centrifuge your fuel and separate from the airflow. There is an ideal port air speed street or racing and this is what we have to achieve in order for everything to work together and combust properly. Even high ram velocity into the chambers will lead to lean conditions like I explained on the piston intake valve relief breaking off or melting...
Like always. Thank you for all the knowledge. I wish you would have been doing these videos years ago. Now I want to change up my set up.
Good job. Thanks again
Ben, I just found your videos haaa at 73 I have tried to tell people the same thing as you since the 60’s and they just didn’t get it. So I just stopped my life being too short.
So glad your still trying nice job good luck!
M
Part of life and we can say and prove things and there are critics which will always disagree! lol What do we do?
Good video Ben! I never really understood how piston shape affects the quench, you described it very well. I learned years ago from Tom Nelson of Nelson Racing Engines, to zero deck the block and use the head gasket to adjust the quench. Of course with a stock type steel head gasket this wouldn't work, you would have to put the piston further down in the hole.
With most engine if you are zero deck a .045 head gasket thickness or even tighter would work really good on a small block. What kind of engine do you have?
@@benalamedaracing2765 454 big block chevy....piston will be about .003 to .005 in the hole and using a felpro .039 gasket.
Very good video and reaches most of the street audience like you said. Like your perspective on compression ratio too - tske all thats there for pump gas. On point wotg tq vs RPM too. Subscribed. I have a 430W just built and dyno'd on my channel. Definitely a fan of the 8.2/9.5 deck Windsors.
i prefer the Windsor 9.5" deck over a chevy 350 deck, but its still not enough. i need 10 or 11 inch deck hieght at least with a 4" bore, even more with a 4.185" bore. That is why i am build my ford and chevy small block head using engines with custom DIY engine block with molecular iron. One day i hope to build a nano-molecular auto orbital quantum particle arranger and 'multi-D print' the son a bitch the way its supposed to be done. Then form for myself and others brand new bodies to live in for that matter.
You are the best teacher, so easy to understand , thanks from Calgary , Canada.
Thank you! 😃
Had a 351 flat-top pistons with 289 HP heads (46 cc chambers) in a 67 Cougar, Nash 5-spd and 3.4 gears. Effectively 12.5:1 compression. No knocks on premium pump gas
You must have run that quench tight and you are getting away with it on pump fuel. That is good and how big or small is the cam?
I truly enjoy your theory application/ explanation videos. Guess it's my engineering mindset. Everyone loves horsepower, but don't understand the science involved. How does reverse dome pistons for boosted applications react? How do you increase/control combustion efficiency?
F&F, excellent question and makes me think this is why I love being asked about these scenarios! Reverse dome pistons for boosted applications is not a net negative and I will explain why.
1. Boost as part of the intake function in itself creates its own mixing by the mere presence of dense atmospheres inside the port! Boost does not happen if there are no rpms in the scenario given and with rpms comes the rapid stop n go of the charge column making it a very effective mixture motion assisting!
2. Boost comes with heat. Heat tends to excite the molecules and keep them from sticking to the port walls! These is the reason we have heated intake manifolds to keep the fuel from sticking to the cold port or manifold walls! A reason for the choke on ancient carburetors and the close loop function in modern EFI's. Purpose is to richen the mixture to compensate for fuel wetting and lean conditions inside the combustion chambers when it is cold!
3. Therefore with boost creating heat making the fuel particles more engage and active in the mixing process, and rpms obvious shaking and mixing prowess, the combustion chamber/reverse dome negatives are negated to a lesser role and we have a net horsepower increase!
@@benalamedaracing2765 Thank you for the lesson. Now it makes sense as to why at throttle response at idle (w/ reverse dome pistons) will not be as crisp as a NA motor. Of course important off the line. That's an interesting point in regards to heat and its' relation to making horsepower. Knowing the thermal efficient crossover point when heat is maximized for horsepower, versus causing detonations from heat of excessive compressed air (boost). I'm truly enjoy this! Thank you for broadcasting in a video platform. It's a bit easier for me to digest (understand) versus reading lol.
Happy Holidays my friend!
Great presentation. My 12.5/1 boss 302 after sitting all winter just blew two spark plugs out of the heads. Just the porcelain came out not the steel part.
Wow I hope it did not scratch the cylinder walls. ? That i bet is one strong Boss engine!
Awesome as always Ben
Great stuff, love your lessons! Thanks for the Bob Glidden history tid bit.
Excellent content!! It sometimes becomes difficult to run a flat top with a large 500+ ci stroker, because if you do you'll have like 15:1 compression!
Big strokes more than a big bore will yield the higher compression ratios. It is very hard to build low compression with huge displacements.
I think you have it backwards. With a bigger bore, such as in a 540 BBC, you need less of a dome to achieve the same compression. With a 454, you need a bigger dome to get a good compression ratio.
@@ekitchingany time you increase the cylinder volume you increase the CR if the closed volume stay the same. 540 has 1/4 more bore and 1/4” more stroke than a 454 also.
Very simplistic randomly came acrossed this and glad i did
Thanks for watching and please spread it around!
Use to drive the grapevine in a big truck. hauling Harbor freight.
I'm a rookie trying to piece together a Buick 350. I just watched a video about compression in a boosted 4-cylinder application that made me think I should still buy heads but keep my dished 8.5:1 pistons for cooler temperatures and compatibility with lower octane. But the information here makes me think that without the better quench of a "10:1" piston I won't see the benefits of the better heads nearly as well, and the engine may be closer to mid-grade friendly than I thought.
You got my point on compression and now just follow on and you will have impressive engine on pump gas or otherwise! Just watch the videos I posted and it should apply just about for all makes.
Thanks Sir! T.C Big Help as Always.......
Thanks as well sir.
Rarely do i hear builders recommend any more than 11-11.5:1 compression for pump gas...
I built my 438W 14 years ago with 12.42:1 comp. and 218# cyl. press. w/ 240 Hi-Ports, Zero detonation, 93 octane (ethanol free) with 30° total timing, idles at 850 rpm, makes an honest 740 horse at 6900rpm and 618 ft lbs tq. single carb, budget pump gas build, daily driver runs 190° in FL summer heat. The cam timing is critical with this amount of compression and a custom Comp. cam to my specifications, built in advance... provides its streetability.
3270# C4 5200 stall street car all motor 9.52 @141.80
You got it big time and that is moving no doubt! People and many of them do not realized the 351W configuration is plenty stout and even the factory block is light compared to other blocks with big mains.
Great video in a subject that i am very interested in, I am a subscriber. AG
Thank you sir and appreciate your interest in the subject. I will check you out as well and exchange ideas and opinions.
Thanks Ben. I have recommended your video on my channel. @@benalamedaracing2765
I am glad I found you. I have learned some good stuff from just two videos. You remind me of David Vizard.
Vizard is the man!
BBC heads really suffer with their design... They're severely "undervalved" because of it and require some real trickery to get good numbers, from my experience. One thing I saw my friend do on a few different castings, was sink the exhaust valve (50 thou or more) so the incoming intake charge flows over top of the exhaust valve face (instead of finding it's way right out through the short side, where then it REALLY can't breathe) in the low lift/over lap phase. That was pretty much how my buddy, Nick, said it... I just tried to put it more simply... He ported heads for living, and always had some wild looking stuff over there.
Anyways! Thanks a million for the wisdom, Ben!
Thank you and you have a good friend there with obvious good skills!
engines without quench give mushy performance & require more spark advance to make mean best torque. more spark for power = loss of compression pressure because you have lit the charge early. The more excited the charge is because of quench the easier it is to ignite..
You got it right on point sir!
Finally some great info,have a 355 with pop ups at 12:1 running on pump gas,jetting and timing were fun but it runs like a champ…2400 s10 with th400
3 speed auto with that kind of engine should be one strong street engine!
Seen too many good running engines strap down by a 2 speed powerglide...
This makes sense.
years ago I had a decked 283 with flat tops, closed camber camel hump heads, and a cam in a 3500# car.
It ran great on 87 octane. Pretty quick, high 12 second car, good power, never detonated.
I now daily a 4800# square body suburban, with a stock, low compression, open chamber 882 smog headed 350.
Its a turd, and it detonates on 87..
Now you realize the importance of quench and close chamber heads. Glad you read and understood where I am coming from.
This is only relevant for two valve heads where the intake charge creates a centrifuge spinning fuel outwards, but pretty much every engine for the last 30 years has been four valve which creates a tumble so a flat or dished piston is preferred. The most efficient pistons for a modern engine are flat or dished with a perimeter quench area.
I agree with your last statement but your introduction is really off base, "only?" and let me explain to you why. Check frames 55:20 of this video and it will explain "tumble" motion and how the fuel molecules has to almost travel a full 360* turn to return some fuel to the 4V's intake short side! I have worked from 1250rwhp turbo six street engines to Mercedes Benz 24hrs of Daytona & 12hrs of Sebring endurance engines (pls check my 2JZ build on FB Ben Alameda Racing) which I go thru the details of cylinder heads and block design. Almost ALL 4v's do not have a short side to influence some kind of radius entry to the short sides enabling fuel to go to this lean areas! Almost ALL depends on tumble motions that slams the fuel to the opposite side of the cylinder walls under the exhaust valves. Piston movement shoves most of these fuel droplets to the exhaust pads/valves and hardly anything that somersaulted inside and on top of the pistons ended up on the intake valve/pads! These are the reality of endurance engines and it gets worse on drag application which entails much higher boost levels shoving the fuel stream to the extreme end of the cylinders (opposite the intake valves).
Anyway, the saving grace is 4V's predominant mostly "small bore configuration" wherein the flame front can easily spread to the intake area due to the "centrally" located spark plugs compared to domestic 2V's having bore sizes way past 4 inch diameters, spark plug located on 1 side and below or mostly below the combustion chambers. Remember small bore engines have less chances of detonation compared to its bigger bore counterparts wherein the flame front, farther away from its ignition source increasing chances of secondaries by a wide margin due to temp./press. spikes before it is consumed by the expanding flame front.
I see a lot of people build a big Windsor with 9:1 compression and not even making 400 rwhp. I always ask them why they are building blower motor and they say the same thing pump gas.
These is why big inch small blocks burns rubber good and fade on the top end with low compression!
I run 12 to 1 in my 6.4 hemi 2500 ram with a stock cam. I run tight quench, milled heads srt8 pistons, zero deck block... no knocking showing on the knock sensors. You can get away with it in a heavy vehicle also and it really helps mpg but I bet my NOX is pretty high...
The gearing on the trans with the rear axle does wonder as well so that may be a factor.
BMW and Mercedes have engines 11.5:1 from the factory. For coyote gen 2 is 11:1 and gen 3 is 12:1. All will run 93 octane and reduce octane with decreased timing advance. Each pt of compression is about 4% torque increase across the curve. So its certainly worth being concerned with.
I was running 10.5:1 back in 1992 using IRON Ported Windsor jr heads, we polished the chambers and i ran 93 octane with a "normal" 5.0 stang base type timing. No ping problems, just power. With aluminum head I would have run 11.5:1 back then. What inspired me was David Vizard "How to build horsepower" book.
If you would have added 3-4* from base timing, you would still been safe from detonation with more power and torque to really enjoy your ride!
@@benalamedaracing2765 We certainly bumped the timing as far as we could and backed up a degree or two...
Wow ! I learned something. This guy knows his science. !
Thank you sir Mike.
My builder is currently working on my original 69 corvette 427 390hp .070 over with 4.25 stroker kit making it a 498 ci. Flat top pistons are .020 down and plan to use .040 mls head gasket making quench .060. Due to matching numbers block we cannot mill for a zero deck to tighten quench. Builder doing 9.75 compression due to using factory BB iron heads and modern 93 pump gas. Factory heads have been ported 2.19 1.72 valves, titanium retainers. Comp solid roller cam 11-770-8 .639 .646 lift, 236 242 duration, 110 LSA. Tremec TKX 5-speed with 3:55 rear. Corvette will only see the street. I wanted a high torque street motor but wanted as much out of it as possible and look totally stock on the outside. Using original Rochester, intake and exhaust manifolds. Engine will be dyno’d before being put back in the Vette. Not sure under the circumstances what more could be done or changed? Thanks for your video!!
Could you tighten up the quench a little bit more? I feel everything looks good and would like it a little closer even -010 would work. Perhaps a cometic thinner gasket would work.
@@benalamedaracing2765Using a compression calc and a .040 MLS head gasket final compression will be 9.7522 to 1. Today I tried asking for a thinner gasket but he doesn’t want to increase compression with todays 93 gas using my original iron 290 heads. The heads have 99 cc’s 🤷🏻♂️
Get a mls .030 like Ben just explained, it’s not going to put you over 11.5:1 and the gains will be more than worth it. I run .027 mls gaskets with pistons.005 in the hole with no problems. Iron headed bbc. You could drop down to a .015 and still be at .035 quench and plenty safe. I too dealt with a machine shop that said 9:5.1 max for 93octane and iron heads.. Some shops just don’t understand quench. Going tight is key but .032 is as tight as I’ve gone myself.
@@phildo39645thanks for your reply. I was never able to convince builder to tighten up the quench. He kept saying if I used a .030 mls compression would be 9.9:1 and I’d ping with iron heads and today’s gas. The engine dyno’d 540hp 628tq using factory aluminum intake and Rochester carb.
My street engine in my Sonoma was dynoed on 89 pump and features 47cc chambers and custom Ross piston's for 10.7 to 1 which i'll be running on 91 pump. 399ci. 1st gen stroker.
That should work great for the street!
@@benalamedaracing2765 400 ft lbs@3500..........513 ft lbs@4500.......shows over @6400 still over 525 ft lbs, at 63 i'm old school.
and here I am... Just bought a 2004 6.0 ls lq4 engine, stripped it down... no unusual bearing wear, cross hatching still visible in the cylinders... Going in a lowered 2005 2500 hd, in search of tire squealing torque.. scrapping the stock heads and dish pistons for a forged rotating assembly..... trying to get a plan together...
Great video thanks for sharing
Thanks as well Matt!
This guy is incredible,where have you been all of this time. Love you videos, please continue.
Thank you for the kind words...
a few years back I acquired a 1990 Suburban with a 350. It would not pull a 5% grade on the interstate without down shifting and losing 20mph. SO, I pulled the engine. The engine wasn't factory colors so I assumed it had received a long black at some point. Compressions were factory fresh so I decided to leave the bottom end stock. SBC aluminum heads raise dcompression to 10.5 to 1. I aded a cam that was just shy of an idle gallop. A high rise intake, headers and an Edlebrock 1400 series carb. It dyno=d at 400hp and 390ft/lbs and ran everywhere on 87 octane without detonation
400hp is a good number and is no slouch!
Gen 3 Coyote ( 2018 up in Mustang) runs 12 to 1 stock with Hyper pistons, usually check 220+ psi cranking...just fine on pump gas...however they have nice active knock sensors they will even ADD timing not just pull it ( DI and Port injection blended )
This is absolute GOLD......gonna incorporate this into my 350 build
Thanks and I should always say these things apply to most engines as well as the SBC-BBC!
Believe me, if the information makes us more horsepower or makes us win races, we will listen no matter how long it takes.😊
Thanks sir and I have that problem @ the track when people want to chat and I got to go make a pass! lol
This video and presentation is extremely informative and helpful.... Ive been chewing tums for indigestion caused by me worrying about the Ford 300 inline six im building on a budget. I knew at 8.0.1 compression it wasnt going to make anything resembling power....itd be a lazy pig. So im having the block bored .050 over to accept a 360FE piston so i can have a true flat top piston and get a higher compression height, and we are decking the block and milling the head. Havent found any real info on it other than "people used to do this back in the day" , but i was hoping for something close to 10.1, and the camshaft is a custom grind 206/212 @.050 447/460 lift with stock 1.6 ratio rocker arms. Stayed mild on the cam since this engine will be limited by its rotating assembly to under 5000rpm. But now im being warned about a high dynamic compression ratio thatd make it too high for pump gas in the 4400 pound van the engine is going in. Any thoughts?
Yes it seems the cam is way too small! You have a lot of weight you are moving and adding duration even in the 214-218 range should not do any damaged.
@@benalamedaracing2765 thank you!
I agree. Great info
Thanks!
I realized this when I looked at supersport street bikes. They have over 12.5 to 1 compression ratios and run on 91 octane gas. Modern 200 HP 1000 cc bikes are over 13 to 1 compression and weigh around 450 pounds. Not much load under normal operation.
Light weight with good gearing helps the engine big time! But most of all, a smaller bore diameter isn't as prone to detonation as a big bore engine combination.
Your taking about static compression. The Dynamic Compression is what counts. Dynamic has to do with valve timing events. If they are running 93 octane your dynamic will/should not be beyond 8.5:1 compression.
I explained that in detail on Part II of this video. A more simple technique is the cranking pressure not exceeding 200# and advancing or retarding the camshaft will increase or lower this number so further running pump gas without detonation. All explained in it.
@@benalamedaracing2765 Oh! Okay. I paid not see that vid. My apologies. Yes, cranking pressure would be a solid indicator also as you mentioned. Do you explain the tolerances needed for proper quench? How do you calculate the stretch of the rods so the piston doesn’t make contact with the head?
Subbed! Building a SBC400 soon and will use this info!
It should work big time applying most of what I suggest here for a strong Chevy street or strip engine.
Love your explanations. Very valuable information. Thank you
Glad it was helpful!
Run on is more a thing with cast iron heads due to heat. Aluminum heads don’t do it anywhere near as much.
Correct.
I had a smogger 454 with 8.5 to 1 compression. Oval port heads with a rectangular port intake and a mild cam. It did mid 13's and would probably have run on hobo piss. I don't trust the consistency of gas stations, keep the compression reasonable and you will have a more enjoyable ride, and a heavier wallet.
Did you match the intake ports on the manifold and head?
@@benalamedaracing2765 Nope. We had the intake and threw it on to see what would happen. It was fun in town and actually got decent highway mileage. I have a theory that fuel puddled at the step at normal rpm's and got sucked in when there was enough air flow acting like an accelerator pump. It was the perfect street set up as far as I'm concerned.
Thanks Ben. I'm build for my buddy and he won't know till he find out powerful enough lol.. I'll keep quiet. Thank gave me tip.. 11:1 compression ratio lol..
Should be a surprise big time if he was used to too low a compression engine! lol
Great lessons Ben.
Low compression not good in the combustion chamber.
Aluminum heads, high compression (10.5-11.1), quench, proper carburetor size, light car, 3.42- 3.73 gears and correct total timing.
All on pump gas (93,94) street car.
Makes excellent power and quick reaction off the line.
What more could i add?
Did you install underdrive pulleys? They are good for power and a little mileage addition.
I've got a 1971 383 with 906 heads and got about 9-1ratio. The cam is a factory Chrysler cheater cam which has a little over 300 duration I believe but stock lift of .450. since I have zero deck height pistons, I'm going to run a set of 1966 383 closed chamber heads. -9.5cc compared to the open chambers. .020 head gasket. I think closed chamber with flat top pistons pings less than open a chamber with a raised dome on the same octane of fuel. Chrysler called those heads "fast burn" and that's why they are expelling a lot of unburdened hydrocarbons. For a clean burn exhaust you can't go much above 8.5 compression. Open chamber heads are nothing but smog heads for their slower burn. No quenching here and no performance, but cleaner and less hydrocarbons for the catalytic converter to reburn.
Watch your quench clearance and i suggest you go minimum .035 on that because the weight of the piston and rod with a big block.
Good video for sure. Surprised the Cobra engine builders didn't know that about pump gas. I had JBA out of California build me an engine to go vintage racing in the early 90's, 351w about the same cam lift. J302 heads 11.5 to 1 and raced it with nothing but 93 octane pump gas. Ran perfectly fine. 30 to 40 minute races and practices. Engine is still in the car. I forgot total timing but probably around 34 degrees max.
You went to the right guys @ JBA. James Bittle is a good friend from years ago and one of the nicest guys you will ever meet.
@@benalamedaracing2765 They were the only company at that time using the new J302 head. The real brains for the engine build was Doug Baker. I don't know what happened to him. I talked to him personally a few times. He was pretty sharp when it came to building engines and figuring out what the customer wanted. I still wanted to drive the car on the street so we ended up with a crane cam originally ground for a Cleveland motor. Had 400 ft lbs. of flat torque curve. and still achieve 425 hp at around 6500. 1.7 rockers to get .580 to .590 lift. Speed pro pop up pistons, to do exactly what you described in the video. Great motor with longevity in mind. With the technology in head design that engine would probably be close to 500hp now, changing nothing else but head. J302 only flowed stock right around 210 cfm intake side.
Excellent explanation that most will be able to comprehend.
Thanks sir!
awesome! Hey.
355 c.i. 5.7" scat stroker rods. 9" deck height. 4 bolt 010 block.
4.032" bore size.180cc Dart heads 63cc chambers milled from 64cc. 10.3:01 static compression. Performer EPS edelbrock intake. 7CC piston tops. custom crank scraper kickout pan. 800 rpm idle 14" vacuum. Schnieder racing cams hydraulic roller cam# 27684H 112*LSA/ 106* ICL. Nylon cam button. 7.4" pushrods. 36* total timing. 175 cranking PSI. O.028" Head gasket. O.009" down the hole. HEI. 750 cfm Holley on 1/2" phenolic spacer. Running 90 octane. Made 410HP @ 5700 RPM peak. And 465 TQ. @ 3600 RPM peak. Next i want to try this with an aluminum AFR or TFS head or DART 180-190cc ports or even larger on an efficient AFR head. Competition ported. Or BRODIX. And slightly more compression. 10.75:01 with same cam and see what it does. Then a 383 with a Mike Jones Cam Designs EHS Hydraulic Roller 282 with the correct lifters from them.
Looks like you already got it close to being the best it can be! Going slightly higher on the compression will improve from here and stepping up perhaps to a 195cc heads with smaller chambers and higher lifts perhaps with running a 1.6 ratio on the intake should yield more power. Good luck!
Love the vid mate! ...subscribed
Im happy with my pistons now and will never buy dish again ...
Thanks as well for watching!
Dead stock LS2 are 10.9:1 Suprized people haven't noticed. With modern heads and efi its so easy, especially when a big cam profile is added even 12:1 isnt too hard.
One thing with the LS is they come with good compression and great cylinder heads (fr. the factory) not too big and not small for the streets and high performance.
I bought a 2004 5.3l out of a tahoe and put it in my 71 Monte Carlo and when I turned the motor to bolt the flexplate up the motor was as hard to turn as my 11.1 compression SS Chevelle 396/375.
I was surprised.