My mentor told me once.. "You may have been mowin your own grass for 40 years, does not mean you were doing it right" ... ya know that stuck with me for 50+ years
I stumbled across your video by accident really. But, I'm glad i watched. Ive been a mechanic pretty much my whole life. Couple years ago i got into ls building, tuning with hp tuners, and took my first stab at porting. I followed a particular person that seemed to have a good reputation. After building the vehicle i noticed a small misfire on a couple of cylinders that couldn't be tuned around. Almost felt like an injector was clogged. Now I believe I opened the throat too much
Hey Eric This video hit home. I have seen what guys do to there heads, Then when they re install think they took all the material off, the motor does not pull like it use to . Well you example is out stand. Makes so much sense. I have never done any porting at all just some little clean ups. Great video. These kind of jobs should always be done from someone like yourself that know the physics of head porting. Thank you so much Fred
Thank you for this informative video. Porting heads is a difficult subject to teach and I appreciate all those who make the effort to share their knowledge.
so many sharp angles inside that combustion chamber, and between the valves, talk about detonation points lol. i love your info about the valves such good info thanks!
Best quote this week: "They just assaulted the head" I was chuckling at that one, because this science/ machining /craftsmanship is your passion. I felt that
Great video Bud. Yup we specialize in Honda Big Block (V6 J-Series engines) and offer PnP parts, with our great gaining Venturi Stage 2 PnP Throttle Body...people doubted gains and we literally had to educate people of what a Venturi does..😎
I was always told the reason not to hog the throat on a 'street' engine was to preserve the venturi effect and maintain flow velocity. What you're saying is it's the necessity to maintain a smooth angle transition. I think this is an excellent video.
So I'm sure I won't get a response to this and I am not sure If this is covered in another video but how do you measure the throat for your 90% are you using a special pair of micrometers or something. Since this accuracy is very important then it has to be measured and ported very carefully. Kind if have to sneak up on it.
@@chrislangdell117 Chris, you don't need any expensive tools. It can be done with just a rule (if your using a tape measure you probably don't have tools to do porting anyway!) The easiest thing to do is just measure the valve and use calculator to get (my preference from what I've learned and read in last 50+years)) 88% for intakes and no more than 90% exhaust. Couple of fender washers and 1/4"(or ~6mm) longish bolts and nuts (to use as 'handles') file them down to the diameter you came up with from valve head diameter (electric drill and bench grinder is quicker ) One 'secret' I found out early on, air, at the velocity in ports (or anywhere else) doesn't want to change direction more than about 7 degrees ( I think you can still look it up in old (1940's) NACA documentation. There is a 'mountain' of information available, problem is finding time to go through it all (pretty sure it's impossible?)
Best video I have seen so far for people just getting started in head porting!!! Your video really helped me understand what David Vizard video meant by hip the port. Subscribed
This is so much better than watching David Vizard on 2x speed 😂 Great vids! Thank you! The clarity was good, it's harder than people think to get the shot and explain too lol
I do it inadvertently when I have a weak signal. Page is jumping around and you hit it by accident. So you hit it again and it doesn't change (so you thought) then hit it again 5x because it's irritating the crap out of you. Then close the window. I can't say for sure, but I can gather that is how most of the dislikes get there.
I watch many videos before I decide there are different ways to to the but can get a person teaching that give you wrong way to do things I will watch this and expand my knowledge before I go hog wild. 90% is safe any more is dangerous...true...,good job nice teaching g
I'll bowl hog the piss out of my head because I know what works in the real world. But Im not gonna be stupid and go so far its unrealistic I just feel im waisting my time on this video with no proof that I can see as to why he states we shouldn't do this or that. The point of the matter is a flow bench is the wrong tool if your using only that to teach others because nothing the flow bench shows you is present in the real world and allot of what effects flow on a bench may not affect flow on a running engine take for instance pulse flow how can you determine how and what rpm this will change or what rpm will be effected with what your doing as far as im concerned when you tell me the air NATURALLY will flow around a valve as in thats what it wants to do then your a joke. Becuase in the real world the intake port flows into the chamber with the valve completely in the way the air will take the least path of resistance so it inevitably will go around the valve. If you take metal away air will fill that spot this can be bad but it can be good . But as far as im concerned I find massive flow (in the real world) cutting off the third angle on the intake port gaining 4-6mm without a bigger valve. Then rounding the edge on the back cut "on the intake valve" The exhaust is another story instead of an average "angle cut" ill do a radius and polish the last angle into the port he says this will effect reversion I find this vary minimal and could car less about reversion because this is something a good cam can take care of and in most circumstances isn't even a big issue if you help reversion if you are gaining more with flowing the proper direction. In my opinion i think we got a couple people on here that are a little stuck in there ways and like to point the finger at who is doing it wrong for 30 years and bashing others that have studied and learned a bit about flow dynamics. Its a toss up.. I say just do what you want but don't tell people they are wrong if you don't have a way to prove it because its all words and no proof
@@bigboatben That's hilarious 😂. People are out there so sour their face hurts. Definitely not the brain trust. Still haven't figured out that shyting on someone else only makes you feel worse over time lol. A grade school lesson.
It's basically dealing fluid pressure head, the angles and flow cross-section area determines the fluid velocities and pressure heads. On a more critical examples are the design of wind tunnels and nozzles.
Great video. Back in mid 90s I was in my 20s I bought a set of "performance GM iron heads" from Aerohead, they were the best of the worst 993 76cc heads with screw in studs .525 springs and 3 angle valve job. I payed for optional 2.02/1.60 s/s undercut stem valves (aeromaxx?) And a $100 "bowl port special" when I delved into porting about 10 years ago I did all the staple mild porting procedures with full exhaust polish, I left the bowls alone I figured where I heard Areohead was a division of INDY Cylinder head they knew more about a bowl port than me. You must remember seeing adds for Aerohead in the lower tier car magazines back in the day. I think the base price was $250 +/- not terrible with the options back in 93ish. And my 355 with a Howard's .480/.480- 232° @.050, 108lsa, (max torque 112031-08 best SBC cam I've ever used and I've tried a pile most underwhelming was crane 450 lift Saturday night special) Torker 1 intake (with 2" spacer) and flat tops it actually runs surprisingly lively for mild smallblock in a pickup. That cam is magical tho, I recommend it to practically everyone with a warmed over 350 and wants a nice broad power band and nice roudy idle with no power brake issues and stock converter will work fine, a 2500 stall was bit un necessary.
Very good points...I might add that an easy mistake is to hog into the short side radius with a porting tool (Specially on the intake port) which will cause major turbulence across the valve. New Guys, Read Smokey's book for the basics.
I like to show folks pouring water out of a bottle, and that spinning it, can make it flow faster than the glug...then dump out a glass, and see that it runs to 1 side. That the air has to spin to be as efficient as possible. For beginners, just clean the flash and make the surface finish uniform for your application, dont change the geometry , and youll do just fine.
I started grinding and polishing valve seats on small bl chevs. at 14 years old. I never changed any of the flow dynamics. Only cleaned up small casting imperfections. That is all it takes to improve the flow where the valves are concerned. To finish waking up the engine, best bang for buck is tuned exhaust. DIY port matching is kind of the same concept. Just grind the very top of the port to match. Don't get crazy on removing a lot of materiel and again, clean up casting imperfections. If you need particular track race heads, go purchase them from the pros. Basically to wake up a stock engine, simply clean up the manufacture's slop. Their numbers are close enough to perfect.
There's work to do relieving the intake to combustion chamber clearance which improves flow at ALL valve positions. Some castings can shift around so every valve needs to be checked.
I’m new to the game. I tried doing some head work on some Honda’s I must say that you make a lot of sense and I know what your talking about Bc I lost a ton of low rpm power but I am able to rev higher, 2000 rpm’s higher but the engine has to stay up in the high revvems for that power. Again, it is just a 4 banger anyway! I learned a lot, thanks for sharing 💪🏼🔥👍🏻🤣
Good video. I have used 90% on the intake ( with a back cut on the valve) and 85% on the exhaust for years and years (motorcycle heads) with excellent results. Bored on a Serdi for uniformity. Low lift #'s at .100 and .200 are very good (bike cams have .300 to .400 lift in general). Low lift #'s are critical as the event happens twice during the opening/closing cycle.....I am glad you made that point about them being important.
You say a lot here that makes sense regarding the venturi effect and make sure that you do not exceed 15 degree angles so that the air does not detach and cavitate, which is well known in the aircraft industry. with such large valves and so little mass left between them, I would be worried about cracks between the valves, and maybe a lot of sharp edges for detonation. but now I'm not an expert on this, I've been an engine mechanic for 30 years for boat engines + various hobby tuning projects on the side of this. but in terms of porting, I have limited this to minor fixing in casting errors and port matching
I love it man… I apparently ruined a set of heads 6 years ago, but man they were crap when I started. I want to clean up some 5.3 heads but I know better than to do more than clean em up a little.
Great video. Love your comment about people saying "I've been doing like this for 30 years". I've been responding to them by saying they've been doing it wrong for 30 years for awhile. Great minds think alike I suppose 😂
I've always used 85 percent fwiw. I've found that Japanese bike heads are 85 percent as well. I used a new way style cutter as a boring tool. Worked in a pinch
Does increasing the throat on a stock head to a safe, maybe 85-87% help top end power or bottom? I'm thinking it would only help top end, because you said at low lift, if it's too big it hurts. I think of rpm and lift being the same things at times but that's a mistake. But the only time you're using all your flow at high lift is at wot, probably on the top end of your power curve? Am I correct or confused?
Thanks for sharing your knowledge. That aluminum head looks maxed out since there appears to be no room between the intake and exhaust valve to go with a larger intake valve. Am I correct? Some people don't think to do any research before they start hogging out their heads. Even if you were get one of the intake and exhaust ports correct is that novice person going to be able to repeat the same dimensions with seven more intake and exhaust ports? They don't think about that factor. If I've invested several thousand dollars in a set of heads, you can bet that I'm going to take them to a reputable head shop for porting. If head work was as easy as some folks think, it's obvious that you wouldn't be in business. Personally, I can do a lot of engine work in my small garage, but I'm just not set up to do anything to those heads but some flash and rough casting clean up, plus I'd have a real problem living with a dumbass, (myself) if I screwed them up. Thanks again for the video.
The seat angles help the air/fuel charge to stay closer to the seat and curl around it due to molecular cohesion, rather than it coming away from the sides of the throat and seat and slamming into the valve which causes bad turbulence and a high pressure area. It is for the same reason that the short side radius is very critical for flow.
If you have the earlier 'boxer' motors there is an awful lot that can be done. Most difficult but dramatic is angling carbs outwards so you no longer have air doing 110+ degrees to get into cylinder I don't know if you ever saw the twin plug modification that gave around 11bhp due to high dome pistons being used in race motors? (probably around 1979~80)
I was taught entire point of porting is to move most air possible with least restrictions. Now I’m a water well driller pump installer by trade and have a ton of experience understanding how water flows and restricts so it only makes sense to me how air moves and small restrictions with water make tons of splashing etc so a tiny turn making a restriction will definitely cause tons of air turbulence.
Interesting. I read somewhere about fluid dynamics and water can be a good substitute for air/fuel mix but is around 1,600 times denser (and not about 1000 times as is mostly quoted) so you can use a much slower flow but high volume. I had a friend who sold his flow-bench (he stopped professional porting) He had a 55 gallon drum on top of shed to see where and how fluid discharged through valve. (he 'invented' measuring devices to use it as well) He said it was real handy if a customer wanted to 'see' where his money had gone plus it extrapolated very well with Superflow' bench results This was a long time before any 'wet flow' flow benches came into being (early 1970's through to mid 90's) He also told me, the biggest issue was waiting for the water drum to fill up though
Least restrictions, yes. But the limitation is keeping fuel droplets in suspension. There's always some that drops out/finds the floor, and as mentioned, enough people have done enough work to show that 15 degree changes is a very good guideline - a pure radius does worse. Things get weird in the 4 valve world regarding throats - numbers in the 85 to 87% suggest there is a minimum step change [throat vs valve diameter] needed to flash fuel back into suspension during early intake opening event.
Thank you for the great video . I want to port my Chevrolet Camel Hump heads and I have a question. Can more porting be done, basically at the beginning and at the ending of the throat and maybe taking a half of a millimeter off the throat ? ( and of course, not touching the valve seat ).I am a beginner at this but I know , when I get it figured out , I'll do it right .
I honestly believe while the flow would hurt, it's still a good tool in some cases. If you remove those angles, the mixture has to go straight, the valve is in its straight path. And a big thing in combustion is when the fuel hits that hot valve, it vaporizes and you get a better burn, so if more fuel HAS to hit the valve... it's good for trucks and street/drag cars
You are Amazing and HILARIOUS 😆 I just died when u told your joke because I'm married and going through a divorce.. I know there's a level of truth to that. I have 3 Mustangs and 3 Chevy trucks. Mine would def do it😉😆🙏😇💪😎👍
well the felpro 1266 did not work i have deeper issues.. Great Vid. I have a fresh 355 with Dart heads that were from a circle track car. Heads were milled and i can see light on #8 intake through my victor Jr intake. My machine shop said to use washers on all 4 corners that equal gasket I'd. Then mold BB` model clay on all runners top and bottom. Slice in half and measure depth. Going to try tomorrow. Also china wall close but not hitting yet. Anything else i can try? Thanks. John
What is the effect of reversion pulses when the valve closes? Would deep bowels act as accumulators and have pressurized air for the next opening cycle?
What if I think the following when I try this for the first time: I first make the valve seat cuts and the undercuts, and make sure the undercuts are not touched. Can that be a starting point, and not do too much damage?
I have really enjoyed your channel Eric. Do you have a video on what us cheapskates 'should' do? Should we leave the dimensions intact but smooth out original castings? I am asking for us that are running oddball heads that don't fit the domestic realm but want to make improvements while our heads are off the engine. Again, love & respect your insight.
I been watching your videos trying to learn how to port heads, but then it darn on me. What if you running turbo engines like I do, is the porting method the same for forced induction heads and on 4-valve heads? Cheers from Sweden :-)
Eric have you ever tested a valve with multiple back cuts ? I was messing around at work. Took a 460 stock valve and put a 15°, 30°, 45° and 50°. Then reversed my cuts from 50, 40, 30, 20 and that blended into the 15. With .070 width. Just curious what you or anyone who's actually flowed something like this (surely its been done a million times) ill get the flow bench at work going and see. Vs a few other used valves with different angles
Glad you clarified that it applies to the intake only. I did a set of turbo Buick heads that are 92% intake and 91% exhaust. Flow numbers are excellent and the exhaust side is the highest I've seen on a 8445 Buick head. 91% on a 1.5 valve forced a very narrow 45 which is not ideal but everything is a compromise. Your doing a great job.
@@mr.know_it_all Always remember... a huge amount of the gasses are expelled the instant the exhaust valve lifts at all. Right before the exhaust valve even opens there can be between 50 and 100 psi, and this is more than plenty to spool the turbo. If work on the exhaust port leads to more flow, then the cam doesnt need to start lifting the exhaust valve as soon, and more of this excess pressure can be used to continue pushing down on the piston, making more power that way. The turbo is always supposed to be the exhaust restriction and nothing else, and is easiest to change, via a different exhaust housing. If the exhaust port flows better, then all of a sudden perhaps the turbo exhaust housing doesnt need to be so small for best spooling. This is how a higher exhaust flow % can help the boosted engine.
I seriously doubt it matters on the intake having those angle because the flow is in the opposite direction which those angles ate of little help. This is why the tesla valve works so well at restricting flow in one direction and not the other. I believe the opposite of what this guy is stating in his video. I say prove it (on the intake side)
@@Engine_biulds, When compared to those with experience, your position is the minority. The burden of proof falls to you. Also, remember there is a great big restriction in the way for most of the intake cycle (valve). In fact even for a fairly hot street engine, the valve is never out of the way. Pretty sure David Vizard has some #s in some of his books if you want someone else to do the testing for you.
@@Engine_biulds The boundary layer of the air flow coming out of the intake port will widen as it exits. Remember the boundary layer barely moves any air. The harder the turn the air must make the less of degrees the boundary layer moves. This creates a false wall that the velocity must overcome. the reason you see long slow sweeping "trunk" areas on very fast vehicles is the accommodate this principle, allowing the boundary layer to transition to the chamber surface as fast as possible.
On point Eric, way too many heads are butchered by people that don't have a flow bench and if they do they dwell on full lift flow only ignoring the mid to low lift numbers which you know is in a way almost more important than total lift because the valve passes through those lower lifts twice!
How much would it help if I just smooth the rough casting in the throat area and not cut much. I have a pair of #13 Pontiac cylinder heads. I noticed on the Pontiac heads the exhaust bowl has the outlet port offset. Is that to create a swirling action? I would like to learn as much as I can about #13 Pontiac heads thanks
Polishing up casting errrors and scratches is way less material removed than porting and is therefore “safer” if you can have the discipline to not do more
Thanks for the great video. The reasoning for throat ratio not being critical for exhaust make sense but it begs the question: would the poor flow characteristics of the throat being cut too wide be lessened with an increase in pressure of the intake charge (i.e. forced induction)? Thanks for the informative videos!
The point is with forced induction you no longer need skill. Just boost and more boost. If you blow fuel straight through it doesn't matter as you can brag the dyno results. Normally aspirated is like a musician in perfect tune across the spectrum. 250bhp per litre was achieved in the 1960s. Many turbo engines can't get close now. Except F1... £1000000 engine, 250 miles Now that's a bargain.
i always like to make the bowl a little egg shaped near the short side. then you dont need such a big throat. Eric you are doing a great job on the videos!
Whenever I do porting, I typically just try to remove all the rough edges. I’m not looking for 800hp on anything I build. So a gasket match and a de-burring is all you need. Unless it’s a Chevy inline 6, then you have a little work to do.
The crux of the 250 is that the head bolts run straight through the middle of the intake ports. You don’t even need to port a 250 to boost power. Just cut out the head bolt pillars and add a short bolt instead. Use the “lump port kit” for even more power. It’s how you can turn 200hp into 250hp with no other modifications.
I'm a Ford engine builder. 40 years. Don't like chevy engines. I have my reasons. But the 250 is a great engine. I have one in my boat. Good on gas mileage and power.
I work in a machine shop mainly doing street stuff not much for performance. Often I'm cutting three angle seats on stock heads with replacement seat inserts, I'll set the cutter up on the valve as normal. Most of the time I'll end up with next to next to no bottom angle. I always aim to have the seat in the middle of the valve face usually an 060 or 080 width for street use. Does this mean stock heads will flow like crap until you fit a bigger valve and you're able to increase the venturi effect? What's your take? I'd be interested to know what you think.
On a wedge head how do you keep all the valves in a straight line ? If I take a straight edge and place them across the valve stems no shop ever gets them straight.
So what You're saying is instead of Directing the Air down into the Combustion Chamber, the Air goes Straight over top of the Valve hits the back of the port and then goes through the Valve?
I really like the 2 "booster ports" that aluminum head has now! Talk about thinking outside of the box. They look super trick and will become craze of the future no doubt.
Can you do a video on a ford "C" head as far as fixing the valve guide problem from overheating and porting correctlly. Oh and it will have a twin screw added
If anything in that case I usually try make the throat larger as long as I don’t compromise the angles of the valve job too much. Radius valve job should only be used on exhaust because you need that angle on the intake to help with atomization.
on the exhaust they weld up the botttom of the port build up a tonsel looking likr floor of thhe port aka e port head and they have a flat bottom of port caled a d port head they also have port stuffer plates to put on exhaust port
I always enjoy seeing the holes into the head bolt. I have to try this myself. 93% throat on a 2.3 valve becomes 91% when using av 2.35 valve so it should work ok I guess.
In my realm of 4 link suspension I tell my customers real data and numbers is what you go by. Never so and so said this, or dude runs that and bla bla. No facts, no data, no using of components or services. Good video man.
I used to think the throat is more of a restriction than anything in some heads, then it occurred to me that it might be there for Venturi effect and to help direct airflow toward the seat, then I realized I shouldn’t attempt my own port work. 😄
If you hunt around, here on UA-cam, you'll find some pieces on how to build yourself a flowbench on a budget. I built one around forty years ago, inspired by an article in Car Craft magazine. It proved a real aid to my engine building, along with articles on cylinder head modification written by the genius David Vizard.
Hi mate from Australia! What is your opinion on valve guides that protrude into the port past the guide boss that is cast into the head . I have a set of edelbrock performer rpm heads for a big block chev and believe that they should be removed as I think they reduce air flow. Your opinion is very important. Thanks.
That is great question. No doubt they hurt flow but you have to leave them in there. If not the guides and valve job wear out fast. I know from experience.
Just put together a small black Chevy 355 with iron eagle dart heads that were ported really horribly and they put apoxy to cover up that mistake. I have to reput the heads on noticed oil and number 8 cylinder a lot.. Took the manifold back off found number 8 cylinder runner have a small hole in the casting. Where would it be sucking oil from somewhere in the middle of the casting?
@@WeingartnerRacing Was not the intake it was the head cracked on the headbolt. down deep before threads.runner sucked oil out into #8 cylinder. Heads are junk. ugg. i now have 1200 paper weights.
Does this apply to turbocharged engines at boost, or will the turbo flow enough air into it to negate the difference? Or will the difference still exist at higher pressure than atmosphere? Of course it will matter with spool up at low boost.
@EricWeingartner Where can I purchase the cutter your using? Same with the the 5 angle blade? Any videos of you using it? Doing port work on a la1 with a lx9 head and intake swap. 12:1 comp w/turbo here I come lol
'Anyone' can buy SERDI cutters, they are not cheap though. Last time I priced them, (around 2009) the cutter blades were about $90.00 (US) and the most basic SERDI set up cost $160,0 although you could go for fully automatic (industrial head production) for around $3~500,000
Hello from Greece. I have one question regarding the area below the valve guide. Its better to leave that line parallel with the flow? Or it doesn't matter to grid it away and make an overall cylindrical port?
You do NOT want the port to be shaped like a perfect cylinder…. It needs the center of the port to have an ‘hourglass’ shape by creating a bottleneck half way up , that’s why he mentions 91% ratio of the valve seat ( large hole at top of port ) when compared to narrowest point of the throat.
@@Pwnulolumad thank you for the answer But i was mean the area exactly below the valve guide.in this video there is guide line in the cast of cylinder head. Some others grid it away.
There is 2 things a flow bench are worthless for. One is a rotary engine. Complete an utter waist of time with trying to flow test the ports on a rotary. Those engines are all about volume and timing not the amount of flow. One can also argue this with 2 stroke. And the second is boost application. Especially on small displacement high rpm engines. Granted there is more usable information with the flow bench on a boost head then an iron of a rotary but one can argue your theory about bowl size and choke points when you put pressure behind that valve above atmospheric at any given lift point. Object is volume at that point not creating a Venturi to speed up air flow. I come from rotary. Both na and boost. One thing I have learned with them is it does not take psi to make power but a massive charger at a lower boost level will make power and at a safer level. Example take a 13b with a gt35 . That engine will and has made north of 600bhp but at above 28 psi on pump gas and will stop producing tq at about 5500 rpm . Now take that same engine bolt a gt4202 to it now to make north of the 600 bhp you only need 18psi an tq production does not fall off and exceeds what the 35r did at all rpm points and is just as responsive . Same can be said to a point on a 2.3lt turbo 4 cylinder engine head port. Not the turbo size but volume of air flow being forced into the cylinder. I recently did one with taking the port bowl to full square to the seat. Much like you explained in this vid and said was wrecked. The results with the same turbo was about 500 rpm sooner spool gained about 50 to 70 tq depending on rpm point and gained about 25 whp and the power curve pulled 2000 rpm further out as this particular engine was always a lower rpm power peak from the get go now seems corrected. Explain that
With the exhaust. Can you flow it like an intake port then reverse the flow and get a foward to reverse flow ratio? If you could the higher the ratio but the more exhaust overall flow you would think would be better.
Thanks for the tip. Why do you leave a peak on both sides of the guides. Please explain. This is all new to me. Also what about the holes in the chambers, and could you epoxy the throat back or weld it. Ronnie.
My mentor told me once.. "You may have been mowin your own grass for 40 years, does not mean you were doing it right" ... ya know that stuck with me for 50+ years
watching some people mow, that hits home :)
lol, just revived memories of some of the most random mowing i ever seen...
I have always said “you can do something wrong for 50 years if you just believe it’s right
As a professional grass cutter, I appreciate, and approve of your comment ☺️
I stumbled across your video by accident really. But, I'm glad i watched. Ive been a mechanic pretty much my whole life. Couple years ago i got into ls building, tuning with hp tuners, and took my first stab at porting. I followed a particular person that seemed to have a good reputation. After building the vehicle i noticed a small misfire on a couple of cylinders that couldn't be tuned around. Almost felt like an injector was clogged. Now I believe I opened the throat too much
Hey Eric This video hit home. I have seen what guys do to there heads, Then when they re install think they took all the material off, the motor does not pull like it use to . Well you example is out stand. Makes so much sense. I have never done any porting at all just some little clean ups. Great video. These kind of jobs should always be done from someone like yourself that know the physics of head porting.
Thank you so much Fred
Thank you for this informative video. Porting heads is a difficult subject to teach and I appreciate all those who make the effort to share their knowledge.
so many sharp angles inside that combustion chamber, and between the valves, talk about detonation points lol. i love your info about the valves such good info thanks!
Best quote this week: "They just assaulted the head"
I was chuckling at that one, because this science/ machining /craftsmanship is your passion. I felt that
Great video Bud. Yup we specialize in Honda Big Block (V6 J-Series engines) and offer PnP parts, with our great gaining Venturi Stage 2 PnP Throttle Body...people doubted gains and we literally had to educate people of what a Venturi does..😎
I was always told the reason not to hog the throat on a 'street' engine was to preserve the venturi effect and maintain flow velocity. What you're saying is it's the necessity to maintain a smooth angle transition. I think this is an excellent video.
It’s both things. Thanks for watching.
@@WeingartnerRacing hello can i ask. i dont get the hog and bigger throat. do u mean i dont need to touch the throat part? only the bowl partv
So I'm sure I won't get a response to this and I am not sure If this is covered in another video but how do you measure the throat for your 90% are you using a special pair of micrometers or something. Since this accuracy is very important then it has to be measured and ported very carefully. Kind if have to sneak up on it.
@@chrislangdell117 Chris, you don't need any expensive tools.
It can be done with just a rule (if your using a tape measure you probably don't have tools to do porting anyway!)
The easiest thing to do is just measure the valve and use calculator to get (my preference from what I've learned and read in last 50+years)) 88% for intakes and no more than 90% exhaust. Couple of fender washers and 1/4"(or ~6mm) longish bolts and nuts (to use as 'handles') file them down to the diameter you came up with from valve head diameter (electric drill and bench grinder is quicker )
One 'secret' I found out early on, air, at the velocity in ports (or anywhere else) doesn't want to change direction more than about 7 degrees ( I think you can still look it up in old (1940's) NACA documentation.
There is a 'mountain' of information available, problem is finding time to go through it all (pretty sure it's impossible?)
@@stoosee just open throat to 99% and you'll be fine on any street engine.
Even F1 with 18,000rpm engines doesn't go over 90%
Best video I have seen so far for people just getting started in head porting!!! Your video really helped me understand what David Vizard video meant by hip the port. Subscribed
True. Good for beginners.
This is so much better than watching David Vizard on 2x speed 😂 Great vids! Thank you! The clarity was good, it's harder than people think to get the shot and explain too lol
To funny someone disliked the video, must have been Eric's wife or one of those bowl hog guys. Great video Eric very insightful.
I do it inadvertently when I have a weak signal. Page is jumping around and you hit it by accident. So you hit it again and it doesn't change (so you thought) then hit it again 5x because it's irritating the crap out of you. Then close the window. I can't say for sure, but I can gather that is how most of the dislikes get there.
I watch many videos before I decide there are different ways to to the but can get a person teaching that give you wrong way to do things I will watch this and expand my knowledge before I go hog wild. 90% is safe any more is dangerous...true...,good job nice teaching g
I'll bowl hog the piss out of my head because I know what works in the real world. But Im not gonna be stupid and go so far its unrealistic I just feel im waisting my time on this video with no proof that I can see as to why he states we shouldn't do this or that. The point of the matter is a flow bench is the wrong tool if your using only that to teach others because nothing the flow bench shows you is present in the real world and allot of what effects flow on a bench may not affect flow on a running engine take for instance pulse flow how can you determine how and what rpm this will change or what rpm will be effected with what your doing as far as im concerned when you tell me the air NATURALLY will flow around a valve as in thats what it wants to do then your a joke. Becuase in the real world the intake port flows into the chamber with the valve completely in the way the air will take the least path of resistance so it inevitably will go around the valve. If you take metal away air will fill that spot this can be bad but it can be good . But as far as im concerned I find massive flow (in the real world) cutting off the third angle on the intake port gaining 4-6mm without a bigger valve. Then rounding the edge on the back cut "on the intake valve"
The exhaust is another story instead of an average "angle cut" ill do a radius and polish the last angle into the port he says this will effect reversion I find this vary minimal and could car less about reversion because this is something a good cam can take care of and in most circumstances isn't even a big issue if you help reversion if you are gaining more with flowing the proper direction. In my opinion i think we got a couple people on here that are a little stuck in there ways and like to point the finger at who is doing it wrong for 30 years and bashing others that have studied and learned a bit about flow dynamics. Its a toss up.. I say just do what you want but don't tell people they are wrong if you don't have a way to prove it because its all words and no proof
I have one hater who dislikes every one of my videos within 5 mins of posting lol. Haters gotta hate!
@@bigboatben That's hilarious 😂. People are out there so sour their face hurts. Definitely not the brain trust. Still haven't figured out that shyting on someone else only makes you feel worse over time lol. A grade school lesson.
It's basically dealing fluid pressure head, the angles and flow cross-section area determines the fluid velocities and pressure heads. On a more critical examples are the design of wind tunnels and nozzles.
Great video. Back in mid 90s I was in my 20s I bought a set of "performance GM iron heads" from Aerohead, they were the best of the worst 993 76cc heads with screw in studs .525 springs and 3 angle valve job. I payed for optional 2.02/1.60 s/s undercut stem valves (aeromaxx?) And a $100 "bowl port special" when I delved into porting about 10 years ago I did all the staple mild porting procedures with full exhaust polish, I left the bowls alone I figured where I heard Areohead was a division of INDY Cylinder head they knew more about a bowl port than me. You must remember seeing adds for Aerohead in the lower tier car magazines back in the day. I think the base price was $250 +/- not terrible with the options back in 93ish. And my 355 with a Howard's
.480/.480- 232° @.050, 108lsa, (max torque 112031-08 best SBC cam I've ever used and I've tried a pile most underwhelming was crane 450 lift Saturday night special) Torker 1 intake (with 2" spacer) and flat tops it actually runs surprisingly lively for mild smallblock in a pickup. That cam is magical tho, I recommend it to practically everyone with a warmed over 350 and wants a nice broad power band and nice roudy idle with no power brake issues and stock converter will work fine, a 2500 stall was bit un necessary.
Very good points...I might add that an easy mistake is to hog into the short side radius with a porting tool (Specially on
the intake port) which will cause major turbulence across the valve. New Guys, Read Smokey's book for the basics.
A good Hi Pro book for porting tips is Phil Irvings Tuning for speed. Bikes but I got a BSA up to 12-1 comp and over 100mph
I like to show folks pouring water out of a bottle, and that spinning it, can make it flow faster than the glug...then dump out a glass, and see that it runs to 1 side.
That the air has to spin to be as efficient as possible.
For beginners, just clean the flash and make the surface finish uniform for your application, dont change the geometry , and youll do just fine.
I started grinding and polishing valve seats on small bl chevs. at 14 years old. I never changed any of the flow dynamics. Only cleaned up small casting imperfections. That is all it takes to improve the flow where the valves are concerned. To finish waking up the engine, best bang for buck is tuned exhaust. DIY port matching is kind of the same concept. Just grind the very top of the port to match. Don't get crazy on removing a lot of materiel and again, clean up casting imperfections. If you need particular track race heads, go purchase them from the pros. Basically to wake up a stock engine, simply clean up the manufacture's slop. Their numbers are close enough to perfect.
There's work to do relieving the intake to combustion chamber clearance which improves flow at ALL valve positions. Some castings can shift around so every valve needs to be checked.
Perfect explanation. It becomes obvious when you flow the head from the sonic sounds that transpire over the sharp corners of the 45 degree top cut.
I’m new to the game. I tried doing some head work on some Honda’s
I must say that you make a lot of sense and I know what your talking about Bc I lost a ton of low rpm power but I am able to rev higher, 2000 rpm’s higher but the engine has to stay up in the high revvems for that power.
Again, it is just a 4 banger anyway!
I learned a lot, thanks for sharing 💪🏼🔥👍🏻🤣
Good video. I have used 90% on the intake ( with a back cut on the valve) and 85% on the exhaust for years and years (motorcycle heads) with excellent results. Bored on a Serdi for uniformity. Low lift #'s at .100 and .200 are very good (bike cams have .300 to .400 lift in general). Low lift #'s are critical as the event happens twice during the opening/closing cycle.....I am glad you made that point about them being important.
can i use 87 percent on exhaust?
Geat info! Not many talk about what not to do and newbies like me would get caught.
You say a lot here that makes sense regarding the venturi effect and make sure that you do not exceed 15 degree angles so that the air does not detach and cavitate, which is well known in the aircraft industry. with such large valves and so little mass left between them, I would be worried about cracks between the valves, and maybe a lot of sharp edges for detonation. but now I'm not an expert on this, I've been an engine mechanic for 30 years for boat engines + various hobby tuning projects on the side of this. but in terms of porting, I have limited this to minor fixing in casting errors and port matching
I love it man… I apparently ruined a set of heads 6 years ago, but man they were crap when I started. I want to clean up some 5.3 heads but I know better than to do more than clean em up a little.
Very informative, about to rebuild a magnum and need all the info I can find. Thanks!
good tips eric.alot will kill the throats and dont get how much just a good valve job is even worth.
Never have the words been uttered by a craftsman with such pride "This Thing is Gunna Suck!" (7:52) and the customer is happy.
This video is exactly why I watch!! It’s all in the details!! Nice job sir
Great video. Love your comment about people saying "I've been doing like this for 30 years". I've been responding to them by saying they've been doing it wrong for 30 years for awhile. Great minds think alike I suppose 😂
I've always used 85 percent fwiw. I've found that Japanese bike heads are 85 percent as well. I used a new way style cutter as a boring tool. Worked in a pinch
What do you think about setting the bowl hog at 90 percent of the valve and cutting anything smaller than that.
It’s all Bernoulli’s Principle and fluid dynamics! Newton has a few laws as well. Good stuff Eric
Thank u so much for all good things u teach us bro.u r great
That’s for sharing all the head porting wizardry!
Does increasing the throat on a stock head to a safe, maybe 85-87% help top end power or bottom? I'm thinking it would only help top end, because you said at low lift, if it's too big it hurts. I think of rpm and lift being the same things at times but that's a mistake. But the only time you're using all your flow at high lift is at wot, probably on the top end of your power curve? Am I correct or confused?
Thanks for sharing your knowledge. That aluminum head looks maxed out since there appears to be no room between the intake and exhaust valve to go with a larger intake valve. Am I correct? Some people don't think to do any research before they start hogging out their heads. Even if you were get one of the intake and exhaust ports correct is that novice person going to be able to repeat the same dimensions with seven more intake and exhaust ports? They don't think about that factor.
If I've invested several thousand dollars in a set of heads, you can bet that I'm going to take them to a reputable head shop for porting. If head work was as easy as some folks think, it's obvious that you wouldn't be in business. Personally, I can do a lot of engine work in my small garage, but I'm just not set up to do anything to those heads but some flash and rough casting clean up, plus I'd have a real problem living with a dumbass, (myself) if I screwed them up. Thanks again for the video.
The seat angles help the air/fuel charge to stay closer to the seat and curl around it due to molecular cohesion, rather than it coming away from the sides of the throat and seat and slamming into the valve which causes bad turbulence and a high pressure area. It is for the same reason that the short side radius is very critical for flow.
How do you figure that ? You could sell swamp land in Florida.
Wouldbe interesting to try cutting angles in the short radius. Very difficult task.
Since I am way ignorant if I pay attention I can avoid mistakes on my 2-valve BMW motorcycle. Thanks for this.
If you have the earlier 'boxer' motors there is an awful lot that can be done.
Most difficult but dramatic is angling carbs outwards so you no longer have air doing 110+ degrees to get into cylinder
I don't know if you ever saw the twin plug modification that gave around 11bhp due to high dome pistons being used in race motors? (probably around 1979~80)
I was taught entire point of porting is to move most air possible with least restrictions. Now I’m a water well driller pump installer by trade and have a ton of experience understanding how water flows and restricts so it only makes sense to me how air moves and small restrictions with water make tons of splashing etc so a tiny turn making a restriction will definitely cause tons of air turbulence.
Interesting.
I read somewhere about fluid dynamics and water can be a good substitute for air/fuel mix but is around 1,600 times denser (and not about 1000 times as is mostly quoted) so you can use a much slower flow but high volume.
I had a friend who sold his flow-bench (he stopped professional porting)
He had a 55 gallon drum on top of shed to see where and how fluid discharged through valve. (he 'invented' measuring devices to use it as well)
He said it was real handy if a customer wanted to 'see' where his money had gone plus it extrapolated very well with Superflow' bench results
This was a long time before any 'wet flow' flow benches came into being (early 1970's through to mid 90's)
He also told me, the biggest issue was waiting for the water drum to fill up though
And though, sonetimes an crappy port and an good intake length make an excellent combo.
Least restrictions, yes. But the limitation is keeping fuel droplets in suspension. There's always some that drops out/finds the floor, and as mentioned, enough people have done enough work to show that 15 degree changes is a very good guideline - a pure radius does worse. Things get weird in the 4 valve world regarding throats - numbers in the 85 to 87% suggest there is a minimum step change [throat vs valve diameter] needed to flash fuel back into suspension during early intake opening event.
Thank you for the great video .
I want to port my Chevrolet Camel Hump heads and I have a question. Can more porting be done, basically at the beginning and at the ending of the throat and maybe taking a half of a millimeter off the throat ? ( and of course, not touching the valve seat ).I am a beginner at this but I know , when I get it figured out , I'll do it right .
I honestly believe while the flow would hurt, it's still a good tool in some cases. If you remove those angles, the mixture has to go straight, the valve is in its straight path. And a big thing in combustion is when the fuel hits that hot valve, it vaporizes and you get a better burn, so if more fuel HAS to hit the valve... it's good for trucks and street/drag cars
You are Amazing and HILARIOUS 😆 I just died when u told your joke because I'm married and going through a divorce.. I know there's a level of truth to that. I have 3 Mustangs and 3 Chevy trucks. Mine would def do it😉😆🙏😇💪😎👍
well the felpro 1266 did not work i have deeper issues.. Great Vid. I have a fresh 355 with Dart heads that were from a circle track car. Heads were milled and i can see light on #8 intake through my victor Jr intake. My machine shop said to use washers on all 4 corners that equal gasket I'd. Then mold BB` model clay on all runners top and bottom. Slice in half and measure depth. Going to try tomorrow. Also china wall close but not hitting yet. Anything else i can try? Thanks. John
What seat and guide machine and tooling are you using?
What is the effect of reversion pulses when the valve closes? Would deep bowels act as accumulators and have pressurized air for the next opening cycle?
Great info, thanks for sharing. Makes me want to spend more time porting!
What if I think the following when I try this for the first time: I first make the valve seat cuts and the undercuts, and make sure the undercuts are not touched. Can that be a starting point, and not do too much damage?
I have really enjoyed your channel Eric. Do you have a video on what us cheapskates 'should' do? Should we leave the dimensions intact but smooth out original castings? I am asking for us that are running oddball heads that don't fit the domestic realm but want to make improvements while our heads are off the engine. Again, love & respect your insight.
I thought that was what it was all about was smoothing out the castings
The air hits the valve as it enters the valve forces the air to turn around the angle.it rolls in?
I been watching your videos trying to learn how to port heads, but then it darn on me. What if you running turbo engines like I do, is the porting method the same for forced induction heads and on 4-valve heads? Cheers from Sweden :-)
Hi! In what can be problem if valves not flat with their place?
Eric have you ever tested a valve with multiple back cuts ?
I was messing around at work. Took a 460 stock valve and put a 15°, 30°, 45° and 50°.
Then reversed my cuts from 50, 40, 30, 20 and that blended into the 15.
With .070 width. Just curious what you or anyone who's actually flowed something like this (surely its been done a million times) ill get the flow bench at work going and see. Vs a few other used valves with different angles
Who makes the best bang for our buck bare import 195 cc SBC aluminum heads ?
Great video , very informative.
This will be one to watch 100x over
great information, much appreciated!
Excellent explanation
Ty
is it better to blend in angals?
Glad you clarified that it applies to the intake only. I did a set of turbo Buick heads that are 92% intake and 91% exhaust. Flow numbers are excellent and the exhaust side is the highest I've seen on a 8445 Buick head. 91% on a 1.5 valve forced a very narrow 45 which is not ideal but everything is a compromise. Your doing a great job.
How does a higher exhaust flow % help when there is 20+ lbs of back-pressure?
@@mr.know_it_all Always remember... a huge amount of the gasses are expelled the instant the exhaust valve lifts at all. Right before the exhaust valve even opens there can be between 50 and 100 psi, and this is more than plenty to spool the turbo. If work on the exhaust port leads to more flow, then the cam doesnt need to start lifting the exhaust valve as soon, and more of this excess pressure can be used to continue pushing down on the piston, making more power that way. The turbo is always supposed to be the exhaust restriction and nothing else, and is easiest to change, via a different exhaust housing. If the exhaust port flows better, then all of a sudden perhaps the turbo exhaust housing doesnt need to be so small for best spooling. This is how a higher exhaust flow % can help the boosted engine.
I seriously doubt it matters on the intake having those angle because the flow is in the opposite direction which those angles ate of little help. This is why the tesla valve works so well at restricting flow in one direction and not the other. I believe the opposite of what this guy is stating in his video. I say prove it (on the intake side)
@@Engine_biulds, When compared to those with experience, your position is the minority. The burden of proof falls to you. Also, remember there is a great big restriction in the way for most of the intake cycle (valve). In fact even for a fairly hot street engine, the valve is never out of the way. Pretty sure David Vizard has some #s in some of his books if you want someone else to do the testing for you.
@@Engine_biulds The boundary layer of the air flow coming out of the intake port will widen as it exits. Remember the boundary layer barely moves any air. The harder the turn the air must make the less of degrees the boundary layer moves. This creates a false wall that the velocity must overcome. the reason you see long slow sweeping "trunk" areas on very fast vehicles is the accommodate this principle, allowing the boundary layer to transition to the chamber surface as fast as possible.
On point Eric, way too many heads are butchered by people that don't have a flow bench and if they do they dwell on full lift flow only ignoring the mid to low lift numbers which you know is in a way almost more important than total lift because the valve passes through those lower lifts twice!
You gotta go wit the flow . Amen brother.__
What about where you cut into the head bolt hole on port's, don't that hurt it?
How much would it help if I just smooth the rough casting in the throat area and not cut much. I have a pair of #13 Pontiac cylinder heads. I noticed on the Pontiac heads the exhaust bowl has the outlet port offset. Is that to create a swirling action? I would like to learn as much as I can about #13 Pontiac heads thanks
Polishing up casting errrors and scratches is way less material removed than porting and is therefore “safer” if you can have the discipline to not do more
Thanks for the great video. The reasoning for throat ratio not being critical for exhaust make sense but it begs the question: would the poor flow characteristics of the throat being cut too wide be lessened with an increase in pressure of the intake charge (i.e. forced induction)? Thanks for the informative videos!
The point is with forced induction you no longer need skill. Just boost and more boost. If you blow fuel straight through it doesn't matter as you can brag the dyno results.
Normally aspirated is like a musician in perfect tune across the spectrum. 250bhp per litre was achieved in the 1960s. Many turbo engines can't get close now. Except F1... £1000000 engine, 250 miles
Now that's a bargain.
i always like to make the bowl a little egg shaped near the short side. then you dont need such a big throat. Eric you are doing a great job on the videos!
Whenever I do porting, I typically just try to remove all the rough edges. I’m not looking for 800hp on anything I build. So a gasket match and a de-burring is all you need. Unless it’s a Chevy inline 6, then you have a little work to do.
The crux of the 250 is that the head bolts run straight through the middle of the intake ports. You don’t even need to port a 250 to boost power. Just cut out the head bolt pillars and add a short bolt instead. Use the “lump port kit” for even more power. It’s how you can turn 200hp into 250hp with no other modifications.
Glad that info was useful! It’s a very cheap upgrade that yields impressive results and does not take away from overall reliability.
Best advice I have read here.
Also match the head to the cylinder. Place head on block with no crank in it. You'll be surprised what you see. Improvement can be made here.
I'm a Ford engine builder. 40 years. Don't like chevy engines. I have my reasons. But the 250 is a great engine. I have one in my boat. Good on gas mileage and power.
Makes sense... the angles help the air make the turn into the chamber.
When he took out to much metal of the valve it's amazing that he didn't grind thru into the next one
I work in a machine shop mainly doing street stuff not much for performance. Often I'm cutting three angle seats on stock heads with replacement seat inserts, I'll set the cutter up on the valve as normal. Most of the time I'll end up with next to next to no bottom angle. I always aim to have the seat in the middle of the valve face usually an 060 or 080 width for street use. Does this mean stock heads will flow like crap until you fit a bigger valve and you're able to increase the venturi effect? What's your take? I'd be interested to know what you think.
On a wedge head how do you keep all the valves in a straight line ? If I take a straight edge and place them across the valve stems no shop ever gets them straight.
Is there room for a bigger valve ??
So what You're saying is instead of Directing the Air down into the Combustion Chamber, the Air goes Straight over top of the Valve hits the back of the port and then goes through the Valve?
I really like the 2 "booster ports" that aluminum head has now! Talk about thinking outside of the box. They look super trick and will become craze of the future no doubt.
You got a thumbs up with the Pillow Joke.
You got a Sub with the Macca's Story. 👍
Can you do a video on a ford "C" head as far as fixing the valve guide problem from overheating and porting correctlly. Oh and it will have a twin screw added
Short side radius is the most important part of good flow...
Do you less small choke percentage if you are limited to lower lift cams?
Does a radius undercut help over multi angles?
If anything in that case I usually try make the throat larger as long as I don’t compromise the angles of the valve job too much. Radius valve job should only be used on exhaust because you need that angle on the intake to help with atomization.
on the exhaust they weld up the botttom of the port build up a tonsel looking likr floor of thhe port aka e port head and they have a flat bottom of port caled a d port head they also have port stuffer plates to put on exhaust port
Thanks for the tutorial. I hear a lot of the lingo, but haven’t had it explained in detail.
I always enjoy seeing the holes into the head bolt. I have to try this myself.
93% throat on a 2.3 valve becomes 91% when using av 2.35 valve so it should work ok I guess.
Simple rule is don't mess if you don't understand.
Port velocity as important as flow and bigger ports reduces velocity.
indeed
I think Ford has finally realized that
@@oscarhedden9524 Explain?
Port velocity is only relative to the engine it sits on. A 454 at 7500 RPM can use a much much bigger port than a 454 pulling a trailer up a hill.
@@superkillr The inlet ports on a European Ford 2 litre Pinto engine are huge for a road engine. Wouldn't know about American built engines.
Eric activates the translation to avoid losing details of the video,Thank you
Thank you Eric
In my realm of 4 link suspension I tell my customers real data and numbers is what you go by. Never so and so said this, or dude runs that and bla bla. No facts, no data, no using of components or services. Good video man.
Pay it forward , and your right... we hardly hear about the good things out there. 👍
I used to think the throat is more of a restriction than anything in some heads, then it occurred to me that it might be there for Venturi effect and to help direct airflow toward the seat, then I realized I shouldn’t attempt my own port work. 😄
The air favours one side of the valve, as far as I understand it. You do most of the work there.
If I had just dropped $2,000 on a set of cylinder heads I wouldn't have the cajones to take a grinder to them!
So Its Better To don't Spend too much On the throat ?
Very informative. Thanks again for a great video!
If you hunt around, here on UA-cam, you'll find some pieces on how to build yourself a flowbench on a budget. I built one around forty years ago, inspired by an article in Car Craft magazine. It proved a real aid to my engine building, along with articles on cylinder head modification written by the genius David Vizard.
What would u say the percentile is on the exaust
If the intake flows poorly with too much throat, but the exhaust is helped, would adding a supercharger be a benefit to the enlarged intake heads?
+1
My question is. on a boosted application would this still apply? or is it all just valve angle / throat related.
It still applies. If it’s bad na it’s going to still not going to be as good with boost.
good video, it is more important to know what not to do than what to do.
That's my motto for everything in life
Hi mate from Australia! What is your opinion on valve guides that protrude into the port past the guide boss that is cast into the head . I have a set of edelbrock performer rpm heads for a big block chev and believe that they should be removed as I think they reduce air flow.
Your opinion is very important. Thanks.
That is great question. No doubt they hurt flow but you have to leave them in there. If not the guides and valve job wear out fast. I know from experience.
Just put together a small black Chevy 355 with iron eagle dart heads that were ported really horribly and they put apoxy to cover up that mistake. I have to reput the heads on noticed oil and number 8 cylinder a lot.. Took the manifold back off found number 8 cylinder runner have a small hole in the casting. Where would it be sucking oil from somewhere in the middle of the casting?
By the pushrod is where most break through.
@@WeingartnerRacing Was not the intake it was the head cracked on the headbolt. down deep before threads.runner sucked oil out into #8 cylinder. Heads are junk. ugg. i now have 1200 paper weights.
Hi. Did you ever do that valvetrain weight video you mentioned here?
Yes about a week later.
Does this apply to turbocharged engines at boost, or will the turbo flow enough air into it to negate the difference? Or will the difference still exist at higher pressure than atmosphere?
Of course it will matter with spool up at low boost.
Turbo is positive pressure, different set of principles, but from my experience not as sensitive
@EricWeingartner Where can I purchase the cutter your using? Same with the the 5 angle blade? Any videos of you using it? Doing port work on a la1 with a lx9 head and intake swap. 12:1 comp w/turbo here I come lol
They are custom cutters I had made by Serdi.
'Anyone' can buy SERDI cutters, they are not cheap though.
Last time I priced them, (around 2009) the cutter blades were about $90.00 (US) and the most basic SERDI set up cost $160,0 although you could go for fully automatic (industrial head production) for around $3~500,000
Hello from Greece.
I have one question regarding the area below the valve guide.
Its better to leave that line parallel with the flow?
Or it doesn't matter to grid it away and make an overall cylindrical port?
You do NOT want the port to be shaped like a perfect cylinder…. It needs the center of the port to have an ‘hourglass’ shape by creating a bottleneck half way up , that’s why he mentions 91% ratio of the valve seat ( large hole at top of port ) when compared to narrowest point of the throat.
@@Pwnulolumad thank you for the answer
But i was mean the area exactly below the valve guide.in this video there is guide line in the cast of cylinder head.
Some others grid it away.
Awesome bro! Subbed
There is 2 things a flow bench are worthless for. One is a rotary engine. Complete an utter waist of time with trying to flow test the ports on a rotary. Those engines are all about volume and timing not the amount of flow. One can also argue this with 2 stroke. And the second is boost application. Especially on small displacement high rpm engines. Granted there is more usable information with the flow bench on a boost head then an iron of a rotary but one can argue your theory about bowl size and choke points when you put pressure behind that valve above atmospheric at any given lift point. Object is volume at that point not creating a Venturi to speed up air flow. I come from rotary. Both na and boost. One thing I have learned with them is it does not take psi to make power but a massive charger at a lower boost level will make power and at a safer level. Example take a 13b with a gt35 . That engine will and has made north of 600bhp but at above 28 psi on pump gas and will stop producing tq at about 5500 rpm . Now take that same engine bolt a gt4202 to it now to make north of the 600 bhp you only need 18psi an tq production does not fall off and exceeds what the 35r did at all rpm points and is just as responsive . Same can be said to a point on a 2.3lt turbo 4 cylinder engine head port. Not the turbo size but volume of air flow being forced into the cylinder. I recently did one with taking the port bowl to full square to the seat. Much like you explained in this vid and said was wrecked. The results with the same turbo was about 500 rpm sooner spool gained about 50 to 70 tq depending on rpm point and gained about 25 whp and the power curve pulled 2000 rpm further out as this particular engine was always a lower rpm power peak from the get go now seems corrected. Explain that
With the exhaust. Can you flow it like an intake port then reverse the flow and get a foward to reverse flow ratio? If you could the higher the ratio but the more exhaust overall flow you would think would be better.
Yes. Sometimes I do that. The flowbench can really misguide you on exhaust flow.
Thanks for the tip. Why do you leave a peak on both sides of the guides. Please explain. This is all new to me. Also what about the holes in the chambers, and could you epoxy the throat back or weld it. Ronnie.