Crank modifications for increased power Part 2
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- Опубліковано 22 лис 2022
- In this episode of PowerTec 10, episode 23, part 2, DV tackles the science behind doing an optimal balance job on the crank. He puts forth how best to balance a crank and reduce windage and moment of inertia while getting the crank to as near optimal as possible in this department.
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Hi David , I have been involved in motor industry for 54 years (71 now) and I have been a keen follower of your enterprising way of modifying engines since buying your books and reading your articles in the english CCC magazine back in the 1970ts, my main involvement has been porting old english cylinderheads for classic racing with very good results due to your input over 50+ years , now just do a bit of porting work to have something to do. Just wanted to express my huge appreciation of a master technician passing on his immeasurable knowledge to the uninitiated on a free to view basis, you deserve a million subscribers , and it might inspire newbies to take up a die grinder, a mask ( cast iron dust will make you cough rust for days😅😅.) And full face mask and start practicing your sermons,
What! It only did a couple of races and 200 dyno pulls! I would like to see any modern factory motors accomplish that. Another great lesson. Sounds easy when you describe how it is done. That is one of your most interesting qualities. The ability to teach complicated engineering to anyone that cares to listen.
Thank you David.
Terry, the test engine did not do any races. It was the companies latest spec engine and was used exclusively for dyno testing. 200 puls on a Superflow dyno is nothing for a roundy-round motor. When Terry Walters and I did the BBC up grade for GM it had to go 50 hours wide open at peak power rpm without breaking or loseing more than 5% output.
Thank you, David. I've always been attracted to those things that others may have either forgotten or simply been too lazy to try, This fit the bill on each. I really enjoyed this lesson. Super job of explaining it.
If you drive the TVR Cerbera with a flatplane crank, you will really understand what a light crank does to the car. It spins up so fast! Feels like a motorcycle engine. I think its the same with lightened flywheels.
Wish I this information 20 years ago . I built a lot of power but I could have built even more.
I am very much convinced even before viewing your advisory exploration. That hollowed crankpins are a great asset to acceleration. I got a cobber on the lathe facing my flywheel. A skim off and enjoying the cast steel hogging says, do you want to take any weight off? So we went ahead and took material off the periphery, then the back side until I was beginning to question the remaining integrity. But he confidently reassured as the mass began to resemble a billet flex plate. It still idled fine with the 5 kg lighter FW and the bottom end torque was massive. Most notably the lighter rotating mass would rev up so quick in comparison it was like adding a roller cam with some high performance profile. A lot more fun to drive. If I can the next build will get bored big end pins. As you know playing around with your own engine is a bit double edged. Especially while "just having a crack at it!"
Glad I found your new channel... I will do my best to catch up and watch each video. I love math and love your teaching methods. I am a novice, but I am hungry to learn. Thank you for sharing your knowledge and thank you to everyone who is experienced for their patience while I learn. I am looking forward to the 318 Mopar engine build series! My stock little 318 has been running for well over 40 years.... it's slow, but still making 1,000 mile one way trips. Best wishes to you for great health!
Thank you for your many yrs of learned by proving grounds and working with all the ones like you....
Any information you give is nothing but a huge gift...
Thank You
Dropping knowledge as usual
The guy is awesome...so many people would much rather be greedy and let it be lost when they leave this life
Excellent video! The reduced weight will also be easier on driveline components.
i appreciate your time ...thanks for everything you are sharing with us.
Excellent episode. Thanks DV
Fabulous DV!!! 🏁
Happy Thanksgiving 🙏🏻
Rotating mass is why I hate balance shaft engines. To me, it's like saying "Let's build something flawed from the beginning. Next, let's put a stupid burden on it."
I removed the balance shaft in our 3800 and threw it in the bin. Regularly spin it to 8000rpm @1000hp.
@@3800TURBO It's great that people delete balance shafts. However, it's rare anybody has anything other than a stock engine.
I dread to think how much was wasted because my mom had a 3.7 Jeep Grand Cherokee and drove it 165,000 miles.
@Skyline Fever check out a few of my channel videos. Can see some 3800s on dyno and at the track. No standard stuff in my life 😆
Approximately 625 miles, or 3,300,000 feet may have been wasted.
David, thanks again. This is great information.
Awesome episode! Really excellent info!
Thank you for this valuable information.
Always interesting stuff. CHEERS from AUSTRALIA.
Another SUPER job! Great mind and eye opener for me. Many thanks, Greg.
Thank you for putting these videos out. I really learn a lot from them.
Thanks for sharing this for many years I have been a bit confused on how a crank could be lightened and balanced.
I want to know how do you miss the oil passages drilled cross-wise to the rod bearings ??
Thanks David
Thanks!
great info.
Super intelligent guy 👍
Hi David I was wondering how this procedure works on Chevy S10 4.3 engine Crankshafts. Oh I decided to try out your channel. Thanks again for the info.
Thanks😊
I'm a 69 yr old retired tool & die maker, and machinist, that has been reduced to hot rodding Honda clones, like the Predator 212. I put one on a sced 80 aluminum MT bike frame, added the toughest parts I could buy or build, including a Harley LED headlight and taillight, and made a very capable motorized bike. I was very interested in what you said about putting a hole in the crank journal, and how it actually increased the strength of the crank. On a 1 1/2" journal, would a 5/8 hole be too big?
great
I own a 1993 Dodge Daytona ESWith a Mitsubishi 3.0l 12V SOHC engine. I'm doing porting on everything and I have opened up the throtelbody to almost 2" I'm leaving everything else stock although I'm having it balanced too. Just for fun.
Removing weight from the crank might free a fair bit of power but I'd be more interested in climbing the RPM range faster and possibly higher redline. I just watched this and the previous video, I'm really learning a lot here.
Hey there. Lightening and or balancing doesnt nessercierly make any HP. . Lightening and balancing helps it run smoother and rev quicker. Friction removal is the key to hp
The engine will also decelerate faster. I am curious about the torque pulse harmonics with the lower reaction mass of the lighter crank assembly. Also, what about the torsional changes?
Torsional stiffness is most effected by changes to what's known as the 'critical cross-section' (CCS) thickness (this is the thickness from rod journal radii tangency to main journal tangency) and the width of the distance across the crank web as viewed down the central axis. Anything changed outside those areas has a very low effect of torsional stiffness. Which is why you don't typically see a lot of reduction in these areas; not to mention, there's not much weight reduction to be gained!
I've got a forged Mazdaspeed 4 cyl 2.3L crank that had some damage on the balance shaft gear. Gonna do a balance shaft delete anyway. Wondered if I could machine off that damaged balance gear to lighten the crankshaft with no ill effects on horsepower or balance. Would consider rebalancing the rotating assembly and using mallory weights if needed.
Hey David good video but I have a question on doing the grinding to the crankshaft did you balance it yourself after the grinding? and how did you do that. or did you send it to a shop to have it balanced with the rods and pistons ? thanks.
Did anyone else get excited when they found that DV was on UA-cam? Does anyone know how many grams out of balance before it is felt?
He has 6.66 subs.... Recommend
201 views and only sixty nine approvals😒.
That comment didn't age well. He's already at 6.67k subs.
@@michaelblacktree his other channel had 27,000+. Which is probably the reason why he posted that.
People are stupid whoever posted that comment David Vizard is a Genius at building engines you all should listen.
@@michaelblacktree wow he went from 6660 to 6670 subs I guess the work is done. Here is the legend that literally wrote the book on horsepower and now is willing to give it all away for free but sure the jerk offs that put parts together with no understanding why have 50k. This dude should have 100× the subs as now.
Dear Mr. Vizard, Thank you so much for sharing your vast knowledge and experience through this platform. A question regarding crankshaft counterweight reduction in mass. With less mass is the engine transient (throttle) response improved, but with less rotating mass is there any reduction in output torque? Thank you
Mass would only effect instantaneous torque not produced torque.
Would like to hear your ideas on gm 4.3
v6 build tips
love your videos so far, but not gonna lie bud, the left ear audio is killing me lol
So if you buy a balanced assembly should you send it out to be modified?
What fillets do you have to do? Just the end?
Hi David,did you ever race at wallerfield in trinidad
Awesome stuff thanks so much. Any experience with large displacement air cooled aircraft engines? I'm assuming that you do all your mods for reducing windage and oil flinging first before any balancing takes place. Also what do you think about polishing the entire crankshaft? This is common in super high revving motorcycle engines, which I think is for both windage and surface stress relieving. Great information, even a knuckle head like me can understand it! :)
Is it a V tail or a conventional tail?
A friend of mine and I were vying for the job of hopping up the Red Bull's aero race planes but sadly never got the job!
Unfortunately I have very little experience on aircraft engines other that doing hi-performance cams for them.
@@DavidVizard Its a V-Tail, the only kind to have ;) I've owned it for over 30 years, she's a beautiful old gal. The balance is very critical and dynamic, there are RPM ranges that induce stress into the prop assembly that can cause cracks and catastrophic failure. My engine has a 1 minute WFO limit for that reason.
I have been seeing more and more talk about carbon fiber connecting rods and wonder how that will effect the balance
They're quite a bit lighter overall, so you'd have smaller counterweights.
Re: drilled out big end journals. Why not center drilled? Thx in advance! I know I’m late to the dance…
👍
Hi David, How do you manage the big end oil feed holes when adding a hole to the crank pin if the OEM feed holes come through the center? (Datsun A12)
I have a suggestion for video content regarding port area/size and bowl area/size and what one can do to band aid a head with too big ports/bowls for the engine ci and intended rev range.
Not sure if this is something that interests others. But since Im stuck with such heads for my engine its very interesting 🙂
Show up with them at a swap meet. Some guy will quickly buy your overp-ported heads, and you will have a fist full of cash for your next pair.
@@davidbaldwin1591 thats a good suggestion 👍
Unfortunately Im working on a 60 deg V6 so there are no other heads to use.
They are too big from the factory. 🤷♂️
@@magnusdanielsson2749 why not just weld or fill them to get what you want?
Beating the competition by 100ft is about 4 car lengths...
. . . . If you're racing a stretch limo . . . .
@@peterdarr383 most cars are 20ft long in the US. Give or take.
That means the first 20 feet in that 100ft win is your own car. Then there are 4 car lengths between your back bumper and his front bumper.
How would this video apply to a flat plane I4 stock cast crankshaft? Specifically a dodge neon srt4 crankshaft used in drag racing. Im very curious, because in my best opinion, that crank seems quite heavy for a 4cyl crank.
When I look into cross drilled rod journals what I find is claims that at high rpm they will centrifuge out the oil in a way the starves the rod bearings of oil and leads to failure. Can you comment on that?
I think That that is What Tartro explains on the HD motorcycle engines , as for the reason for restrictors on the crank .
if not fitted then starving other parts of the engine .
Would this work on a 300 straight 6 Ford crank. I can't find a forged crank. Not interested in 7k for a custom crankshaft. I haven't heard of failures in the cast crankshaft but want to turbocharge the engine. They got over 500hp and almost 600lb/ft @13 psi boost. But they had the forged crankshaft. I have heard rumors that it can handle upper 20's. I'm happy with the 13 psi power levels. Lol. Does your 128 program work on an inline 6? Thanx DV
Turbo engines need less overlap or they blow the charge right out the exhaust.
Not mentioned in this video - when you grind on the crank you will create "stress risers" which are locations where cracks start from. All grinding needs to be followed with "polishing" and then "shot-peining" to restore surface tension. Mallory Metal plugs can be pressed into the counter-weights to allow further weight reduction.
You should run all your ideas by your machinist who will have to balance the assembly when you're done lightening everything.
“Stock bottom end…”
What about oiling of the big end? My crank pushes oil through and if i make a hole in the big end there how will the lubrication going to work?
On the Merlin Rolls Royce plugged the ends of the drilled bigends with aluminium caps. The drilling just formed part of the oil passage.
Does a lighter crank/ rotating assembly have a affect on engine braking? I think it would. Something to consider per application.
i believe compression ratio and friction (piston rings and valve gear) compensate for it. any drag from a high pressure/high volume wet sump oil pump likely doesn't matter due to any deflection in the oil pump shaft running it.
@@albertgaspar627 compare a gearbox versus auto set up. The gearbox car offers far superior engine braking. It has less drag than a transmission, i put it down to the flywheel weight. Installing a lighter flywheel reduces engine braking. In a drag set up going light as you can may be preferred, what about track use? Will a lightweight rotating assembly hurt engine braking. Its probably a silly question ? Consider the cost of going lightweight rotating assembly, then you throw on a heavy flywheel. What difference will it make. Thanks for the reply, and happy new year.
@@GG-rj4oj An automatic transmission provides worse engine braking because there's a hydraulic connection--the torque converter--between crankshaft/flywheel and the transmission/driveshaft, while the manual gearbox has a more solid connection.
think of the average torque converter as two desk fans facing each other on a table. Turn on one, and eventually it sends enough air into the blades of the second fan to get it turning and then up to a matching speed (it also explains why OEM torque converters are typically larger in diameter than a 9inch racing TQ--more surface area creates a reaction sooner, ie, at low engine RPM). shut off the first fan, and consider how long the second fan takes to react--depends on mass of the blades etc.
as for driveability, a lighter than OEM flywheel means launching from a dead stop (out of the pits etc) will require more throttle or slippage from the pedal. It also means changing gears in the corners will cause the RPMS of the engine to fall faster due to less inertia. If you're running a turbo, you may not just fall out of the torque curve but lose boost if RPMs drop enough.
great question--the only silly question is the one someone doesn't ask worrying what people think :) Happy new year to you as well!
www.zndmotor.com/blog/pros-and-cons-of-lightweight-flywheel#:~:text=The%20pros%20of%20lightweight%20flywheel%20are%20the%20same,But%20the%20con%20of%20lightweight%20flywheel%20is%20drivability.
Old crank grinders call that " big end ", the " throw ", or " throws " .
Big end is British
What years is all his information from?
All of them.
I'll tell you what I have learned in many years of building engines
There are foolish ways to spend your budget and not so foolish ways.
Decide on a budged, then research what kind of power you can get out of an engine for said budget.
2000 hp on a 500 Dollard budget isn't going to cut it.
It coasts more money to make more power. Don't expect high hp numbers on a small cubic inch engine won't happen easily.
Turbo charging is a great option for high hp numbers on a low budget. Id suggest a budget of 2k to 4k for a 1000 hp build. As I don't believe in using cast parts in a high hp engine. Forged rules. Hyperutechtic pistons are weak junk. Cast pistons chip easily. If you have to use all stock internal parts budget wise go with an ls engines. It's the biggest bang for the buck.
Sadly he is competing with 7 billion other interests on planet Earth. Only a tiny fraction of the population is interested in this kind of science. Sex money and entertainment dominated 99% of hunans interests.