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WHY WOULD U REDUCE CRANK COUNTER WEIGHTS #1160335 01/18/12 08:19 PM 01/18/12 08:19 PM
Joined: Apr 2005 Posts: 1,505 TN S SCATPACK 1 OP pro stock
SCATPACK 1 OP pro stock S Joined: Apr 2005 Posts: 1,505 TN	Have read a couple of post relating to reducing the outside diameter of a cranks counter weights. Why would u want to or need to do this Old Geezer Racing

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: SCATPACK 1] #1160336 01/18/12 08:26 PM 01/18/12 08:26 PM
Joined: Dec 2006 Posts: 3,395 Pa Hot 340 master
Hot 340 master Joined: Dec 2006 Posts: 3,395 Pa	to reduce rotational weight, and for short rod/low deck combos with long strokes for piston skirt clearance

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: SCATPACK 1] #1160337 01/18/12 08:35 PM 01/18/12 08:35 PM
Joined: Aug 2003 Posts: 43,176 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,176 Bend,OR USA	It is usually done on Mopar BB or Hemi cranks being cut down to use in low deck blocks You cut the counterweights down to clear the main webs as well as cutting down the main sizes. Another reason to do this is to reduce rotational weight in the crank when your switching to ultra lightweight racing parts, rods, pistons and writs pins Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: SCATPACK 1] #1160338 01/18/12 09:02 PM 01/18/12 09:02 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	I do it to MOST of my cranks for 3 reasons... 1 to get the counter weight close for balancing... 2, move the weight in closer to the center line so it can accelerate quicker and 3, move it farther away from the oil

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: MR_P_BODY] #1160339 01/18/12 09:16 PM 01/18/12 09:16 PM
Joined: Apr 2005 Posts: 1,505 TN S SCATPACK 1 OP pro stock
SCATPACK 1 OP pro stock S Joined: Apr 2005 Posts: 1,505 TN	Ok. Makes good sense to me. Old Geezer Racing

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: MR_P_BODY] #1160340 01/18/12 09:47 PM 01/18/12 09:47 PM
Joined: Feb 2007 Posts: 970 Backwater, PA B bwdst6 Bob George Racing #1 Fan
bwdst6 Bob George Racing #1 Fan B Joined: Feb 2007 Posts: 970 Backwater, PA	Quote: I do it to MOST of my cranks for 3 reasons... 1 to get the counter weight close for balancing... 2, move the weight in closer to the center line so it can accelerate quicker and 3, move it farther away from the oil Number 1 and 2 contradict each other. This post is available in double vision where drunk.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160341 01/18/12 09:59 PM 01/18/12 09:59 PM
Joined: Jan 2010 Posts: 588 Franklin, TN 23T Hemmee mopar
23T Hemmee mopar Joined: Jan 2010 Posts: 588 Franklin, TN	Not if you're balancing to a light rod/piston assembly. Ronny 6.789 @ 198.63 .956 Brand New 60'* 4.17@ 169 1/8th mile John 14:6 https://www.youtube.com/watch?v=TUku_hjYRh8

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160342 01/18/12 10:00 PM 01/18/12 10:00 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: I do it to MOST of my cranks for 3 reasons... 1 to get the counter weight close for balancing... 2, move the weight in closer to the center line so it can accelerate quicker and 3, move it farther away from the oil Number 1 and 2 contradict each other. Not really.... if you run light parts you dont need all that weight out far from center line

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: 23T Hemmee] #1160343 01/18/12 10:07 PM 01/18/12 10:07 PM
Joined: Feb 2007 Posts: 970 Backwater, PA B bwdst6 Bob George Racing #1 Fan
bwdst6 Bob George Racing #1 Fan B Joined: Feb 2007 Posts: 970 Backwater, PA	Quote: Not if you're balancing to a light rod/piston assembly. the absolute value to counterbalance is irrelevant. Whatever the number you determine to balance will result in the same rotational inertia regardless of diameter. If you want the weight on a smaller diameter you will add more of it! This post is available in double vision where drunk.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160344 01/18/12 10:26 PM 01/18/12 10:26 PM
Joined: Nov 2004 Posts: 4,330 Lynchburg, VA Leon441 master
Leon441 master Joined: Nov 2004 Posts: 4,330 Lynchburg, VA	If you find your crank is heavy for your parts. You have a choice either cut holes on every counterweight to get in balance or simply trim the counterweights until you get close. Career best 8.02 @ 169 at 3050# and 10" tires small block power.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160345 01/18/12 10:27 PM 01/18/12 10:27 PM
Joined: Jan 2003 Posts: 5,894 Florida Locomotion master
Locomotion master Joined: Jan 2003 Posts: 5,894 Florida	Quote: Quote: Not if you're balancing to a light rod/piston assembly. the absolute value to counterbalance is irrelevant. Whatever the number you determine to balance will result in the same rotational inertia regardless of diameter. If you want the weight on a smaller diameter you will add more of it! Basically, it is much more efficient to cut down the overall diameter of the counterweights to eliminate the unneeded weight to balance rather than keep the overall diameter the same and drill them full of holes to reduce the weight. The smaller radius will allow for faster accelleration as well as reduced windage. I believe it will also reduce the stress/flex the crank experiences. Last edited by Locomotion; 01/18/12 10:29 PM.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Leon441] #1160346 01/18/12 10:32 PM 01/18/12 10:32 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: If you find your crank is heavy for your parts. You have a choice either cut holes on every counterweight to get in balance or simply trim the counterweights until you get close. Yep... if you need to drill... turn it down more... but alot of the guys that balance find it easier to drill

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: MR_P_BODY] #1160347 01/18/12 10:36 PM 01/18/12 10:36 PM
Joined: Jan 2003 Posts: 31,035 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,035 Oregon	You have to do a little bit of math to figure out how much material to remove in order to balance the crank when turning. I usually try to get the crank within 50 grams on the lathe and then let the balance guy finish the job on the balance machine.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Locomotion] #1160348 01/18/12 11:15 PM 01/18/12 11:15 PM
Joined: Feb 2007 Posts: 970 Backwater, PA B bwdst6 Bob George Racing #1 Fan
bwdst6 Bob George Racing #1 Fan B Joined: Feb 2007 Posts: 970 Backwater, PA	Quote: Basically, it is much more efficient to cut down the overall diameter of the counterweights to eliminate the unneeded weight to balance rather than keep the overall diameter the same and drill them full of holes to reduce the weight. The smaller radius will allow for faster accelleration as well as reduced windage. I believe it will also reduce the stress/flex the crank experiences. this is true only if you need to lose weight! Also, the smaller diameter does reduce Windage but does not effect acceleration. Rotational inertia effects acceleration which like I said remains constant per your desired weight to counterbalance. Ditto with flex/stess. This post is available in double vision where drunk.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160349 01/19/12 12:15 AM 01/19/12 12:15 AM
Joined: Jan 2003 Posts: 5,894 Florida Locomotion master
Locomotion master Joined: Jan 2003 Posts: 5,894 Florida	Quote: Quote: Basically, it is much more efficient to cut down the overall diameter of the counterweights to eliminate the unneeded weight to balance rather than keep the overall diameter the same and drill them full of holes to reduce the weight. The smaller radius will allow for faster accelleration as well as reduced windage. I believe it will also reduce the stress/flex the crank experiences. this is true only if you need to lose weight! Also, the smaller diameter does reduce Windage but does not effect acceleration. Rotational inertia effects acceleration which like I said remains constant per your desired weight to counterbalance. Ditto with flex/stess. Let me present my theory/question in a simpler form; You're saying that a 10 lb 5" diameter wheel is not easier to accellerate than a 10 lb 10" wheel??? (Representing short cut counterweight vs tall drilled counterweight to achieve the same balance.) Despite the similar weight, wouldn't the larger wheel with weight further out be a little more difficult to accellerate? After all, the larger diameter has further to travel than the smaller diameter. I said "similar" because less weight would be required to balance as the counterweight is moved further out. But the extended travel radius would have to be a hinderance. Am I getting in over my head and/or would this require some complicated mathamatical formulas to prove or disprove? Last edited by Locomotion; 01/19/12 12:17 AM.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Locomotion] #1160350 01/19/12 12:27 AM 01/19/12 12:27 AM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	if you have two crankshafts with identical weights, but crank # 1 has a circumference of 8" and crank # 2 has a circumference of 6", crank # 2 will need less force to accelerate because the mass is closer to the center of mass. simple way to prove it to yourself. tie a 1 lb weight on a string 3 feet long, make up another one with a string 1 foot long. twirl them both and see which one is easier. keep in mind that a crankshaft in a practical application still needs to overcome the forces working against it outside of the engine such as more rotating mass, vehicle weight, etc. in some cases a heavier rotating assembly can be more beneficial to overall performance. i.e. heavy vehicle with a high reving, low torque small CID engine. Last edited by Performance Only; 01/19/12 12:33 AM. machine shop owner and engine builder

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Locomotion] #1160351 01/19/12 12:47 AM 01/19/12 12:47 AM
Joined: Feb 2007 Posts: 970 Backwater, PA B bwdst6 Bob George Racing #1 Fan
bwdst6 Bob George Racing #1 Fan B Joined: Feb 2007 Posts: 970 Backwater, PA	Quote: Let me present my theory/question in a simpler form; You're saying that a 10 lb 5" diameter wheel is not easier to accellerate than a 10 lb 10" wheel??? No, obviously not. First of all that assumes a homogeneous disk with one material. Real cranks have mallery (spelling?) possibly, undercut counterweights sometimes and somtimes holes on the OD. When one goes to balance a crank the weight of the pistons, rods, underbalance/overbalance gives you a bob weight. That tells you a rotation mass you need to counter balance. That's set!!! To counterbalance it you either need to put less mass on a large diameter or more mass on a small diameter. But it will be the same rotational mass. And will be the same to accelerate! F=ma. In a rotational system. If F remains constant and m (rotational mass) remains constant then a remains constant. This post is available in double vision where drunk.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160352 01/19/12 01:16 AM 01/19/12 01:16 AM
Joined: Nov 2009 Posts: 2,177 ill D dennismopar73 top fuel
dennismopar73 top fuel D Joined: Nov 2009 Posts: 2,177 ill	I think every one is right ! Lite weight is always good, can be less bearing fatigue, mains can see longer use, increase in rpm range. Thus more harmonics the block has to endure, Loss of 'initial hit' over come by increase in tq rate of stahl, thus increasing thrust bearing issues? OO the domino effect, Ain't it great!! I will do it to clear the block,other wise I don't worry about it.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160353 01/19/12 01:24 AM 01/19/12 01:24 AM
Joined: Jan 2003 Posts: 5,894 Florida Locomotion master
Locomotion master Joined: Jan 2003 Posts: 5,894 Florida	I understand the "set" amount of rotational mass required to balance a rotating assembly. We're just saying that the distribution of that mass away from the centerline will affect how quickly the rotating assembly can be accelerated. I'm tired, gotta work early tomorrow & all this thinking is giving me a headache! G'nite.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Performance Only] #1160354 01/19/12 01:25 AM 01/19/12 01:25 AM
Joined: Dec 2008 Posts: 415 Peru cbarracuda mopar
cbarracuda mopar Joined: Dec 2008 Posts: 415 Peru	Quote: if you have two crankshafts with identical weights, but crank # 1 has a circumference of 8" and crank # 2 has a circumference of 6", crank # 2 will need less force to accelerate because the mass is closer to the center of mass. Nunber 2 will meed more weigts because tre mass is closer

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Locomotion] #1160355 01/19/12 01:37 AM 01/19/12 01:37 AM
Joined: Feb 2007 Posts: 970 Backwater, PA B bwdst6 Bob George Racing #1 Fan
bwdst6 Bob George Racing #1 Fan B Joined: Feb 2007 Posts: 970 Backwater, PA	Quote: We're just saying that the distribution of that mass away from the centerline will affect how quickly the rotating assembly can be accelerated. Yeah, I know. And That's incorrect. If the moment of inertia is the same than rotational acceleration is the same. This is just high school physics. If you want to keep the mass closer to the centerline you'll need to add more of it to keep balance. This post is available in double vision where drunk.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160356 01/19/12 01:57 AM 01/19/12 01:57 AM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	Quote: Quote: We're just saying that the distribution of that mass away from the centerline will affect how quickly the rotating assembly can be accelerated. Yeah, I know. And That's incorrect. If the moment of inertia is the same than rotational acceleration is the same. This is just high school physics. If you want to keep the mass closer to the centerline you'll need to add more of it to keep balance. you would really need to understand how engines are balanced to understand why it's not as simple as you think. here's a little more info compliments of the internet. Moment of inertia is the term used to measure or quantify the amount of mass located at an object's extremities. For example if all the mass of an object was located in a small compact size (like a lead ball) its moment of inertia would be small compared to the same amount of mass shaped into a dumbell. Because a dumbell has most of its mass located farther from its center. But there is a "qualification" here. Moment of inertia is calculated relative to a hypothetical spin axis. Once you choose the spin axis then you calculate the moment of inertia by multiplying the mass times its distance to the spin axis squared; I = MR^2 So in the example between the sphere and the dumbell the moment of inertia of the dumbell would be significantly larger relative to a spin axis perpendicular to the dumbell length. If you instead choose your spin axis to lie thru the dumbell parallel to its length then its moment of inertia,relative to this axis, would be much smaller because the mass would be located closer to that axis. And ,in fact, it might even be smaller then the moment of inertia of a sphere about an axis thru its center. A way to store kinetic energy is with a spinning object. In calculating how much energy would be stored in a spinning object the energy is proportional to the moment of inertia. So all other things being equal you would choose a spin axis and object shape that gave you the largest moment of inertia for maximum stored energy. Last edited by Performance Only; 01/19/12 02:04 AM. machine shop owner and engine builder

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160357 01/19/12 02:47 AM 01/19/12 02:47 AM
Joined: Feb 2003 Posts: 1,238 Nevada D dezduster pro stock
dezduster pro stock D Joined: Feb 2003 Posts: 1,238 Nevada	An easy way for a high school class to prove this would be to remove a broom stick from your broom. Drill a hole in the center of the end, install a lag screw into hole cut the head off the screw. Now chuck a cordless drill motor up. Now pull the trigger as fast as you can and feel how little rotational resistance and how quickly it reaches top RPM. Very little resistance felt and up to speed quickly.. REMOVE CUT OFF LAG SCREW!! Now drill a 3/8 hole in the middle of its length, install 3/8 bolt into the hole, tighten the nut and bolt so the handle will not spin on the bolt. Be sure to use a bolt long enough for the same drill motor to chuck up to. Pull the trigger feel the rotational force act apon your wrist how long did it take to reach top speed? Much more force and much longer. Smaller counter weight good. Larger bad even if its same weight. Class dismissed.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Performance Only] #1160358 01/19/12 02:47 AM 01/19/12 02:47 AM
Joined: Jan 2003 Posts: 75,008 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 75,008 U.S.S.A.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: JohnRR] #1160359 01/19/12 02:58 AM 01/19/12 02:58 AM
Joined: Oct 2007 Posts: 4,206 New York polyspheric master
polyspheric master Joined: Oct 2007 Posts: 4,206 New York	Of course - if XYZ Crankshafts wanted the crank lighter, they would have done it themselves. Remember, these are the people who carefully contour their throw arms and counterweights exactly the same on the leading and trailing edges (examine some photos), because engines sometimes run backwards... I'll learn eventually that some requests for comment actually mean "please tell me that the decision I've already made is right".

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: polyspheric] #1160360 01/19/12 04:25 AM 01/19/12 04:25 AM
Joined: Aug 2003 Posts: 43,176 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,176 Bend,OR USA	Me thinks we have a person on here discussing theory versus real world experiences Not all "theorys" are accurate, especially when it comes to racing Do you know how much a NASCAR Cup crankshaft weighs? Have you ever seen a state of the art racing crank that is pendulum cut and made to be as lightweight as possible? And had the counterbalances moved off center to extend crankshaft life at 9000 RPM+ Lots of modifying parts after the all theorys are outrun (thrown out to go faster) I like the idea that we never outrun progress, if we keep our minds open to learning and experimenting Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: bwdst6] #1160361 01/19/12 06:13 AM 01/19/12 06:13 AM
Joined: Jul 2009 Posts: 413 Norway (old world) Oyvind Mopar mopar
Oyvind Mopar mopar Joined: Jul 2009 Posts: 413 Norway (old world)	Quote: Quote: We're just saying that the distribution of that mass away from the centerline will affect how quickly the rotating assembly can be accelerated. Yeah, I know. And That's incorrect. If the moment of inertia is the same than rotational acceleration is the same. This is just high school physics. If you want to keep the mass closer to the centerline you'll need to add more of it to keep balance. Yes, I would do it your way, and it is also proven (refer to Cab Burge below) in the racing crankshaft where they put the weight in the periferi (mallory metal on pendulum throws), even undercut the throws to take away dead weight. Turning down the throws on another engine is going in the opposite direction, It is all about balancing forces most efficiently, and get the total weight as low as possible. Another way to do it is like Frod and GeM do, to save an ounce of cheap material (to gain profit) by putting the mass externally to the damper and flexplate. Increases stress (if you can really say these engines are stressed!) but saves on total weight. Most efficient way to reduce the crankthrow for total weight saving would be to cut the sides from them, and keep the mass opposite of the crankpin where it generates most of the counterforces for balancing the rod/piston assy. My

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: Oyvind Mopar] #1160362 01/19/12 07:57 AM 01/19/12 07:57 AM
Joined: Jan 2003 Posts: 3,575 The Netherlands BigBlockMopar master
BigBlockMopar master Joined: Jan 2003 Posts: 3,575 The Netherlands	Quote: If you want to keep the mass closer to the centerline you'll need to add more of it to keep balance. Technically/Mathematicly, that line is correct. But not in real life. Because, going from stock to a performance engine, balancing a (stock or new) crank never means 'adding' weight somewhere. If you need to do that, you've screwed up earlier and now need to fix your mistake. Race parts are pretty much always lighter than factory parts. BigBlockMopar.com

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: SCATPACK 1] #1160363 01/19/12 10:23 AM 01/19/12 10:23 AM
Joined: Nov 2004 Posts: 3,544 Syracuse,NY CompWedgeEngines master
CompWedgeEngines master Joined: Nov 2004 Posts: 3,544 Syracuse,NY	I'm just curious for the sake of being curious here...lol...I know some engineers, I know some very well " entrenched" shops who do some pretty technical builds shall we say,I know some NASCAR guys, I know some everyday guys who build a lot, I know some manufacters that BUILD and engineer these cranks, and I have my own 27 years experience and so forth and my current engine shop. My simple question is here, how many of the guys responding own, operate, or HAVE operated a crank balancer? Not just watched one run, not watched their crank get balanced, but actually DID it? We have 27 something responses, lets see how it shakes out. How many guys have built over 100 engines, over say 35 engines, and how many maybe 5 or less engines? My opinion is there is a TREMENDOUS mix of theory and reality here. What SHOULD work, what COULD work, and what DOES work.My point being, both sides have valid points, but I think in REALITY, in an engine, under load, accelerating down a track, things arent always as assumed. I know some things ( that I am not going to get into a debate on...lol) thaty absolutely DO work, in a stock eliminator car, that most of you would say is wrong.It goes against much of the theory, but in a practical mans thinking, makes sense.It revolves around the 4 speed components, and involves some of what is being discussed here. No finger pointing, just some things that popped up in my mind while reading this. I have my own curiosity is all.....carry on Hey, its cold and wintertime, I'm just thinking. RIP Monte Smith Your work is a reflection of yourself, autograph it with quality. WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: CompWedgeEngines] #1160364 01/19/12 11:03 AM 01/19/12 11:03 AM
Joined: Jan 2003 Posts: 2,129 Vermont T TrWaters top fuel
TrWaters top fuel T Joined: Jan 2003 Posts: 2,129 Vermont	I am in the 5 or less category. To answer the OP question, I would say the least technical answers would be 1: for clearance issues, and 2: to aid in the balancing procedure. After that I would guess to modify the effects on acceleration. But then again, I am not an engine builder, nor do I claim to be.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: CompWedgeEngines] #1160365 01/19/12 11:06 AM 01/19/12 11:06 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	I have actually balanced 4 cranks(my own stuff) on a balancer(using the shops balancer)before that they (shop) did the balancing and I've built a FEW engines

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: MR_P_BODY] #1160366 01/19/12 11:46 AM 01/19/12 11:46 AM
Joined: Jul 2009 Posts: 413 Norway (old world) Oyvind Mopar mopar
Oyvind Mopar mopar Joined: Jul 2009 Posts: 413 Norway (old world)	I am a mechanical engineer MSc, and own my enginebuilding shop. I have a crankshaft balancer, and do most type of jobs. I would fit in the 35+ engines category since the last 3 years in business (plus a number of engines for myself and friends since 1973), spread on different brands but mostly Mopars. I have also worked myself up in the practical machining and engine building, and enjoy Moparts and all the good comments here from us oldtimers. And, I do not think there is a mismatch between theory and practice, it is a matter of using the right comparisons.

Re: WHY WOULD U REDUCE CRANK COUNTER WEIGHTS [Re: BigBlockMopar] #1160367 01/19/12 12:26 PM 01/19/12 12:26 PM
Joined: Feb 2007 Posts: 970 Backwater, PA B bwdst6 Bob George Racing #1 Fan
bwdst6 Bob George Racing #1 Fan B Joined: Feb 2007 Posts: 970 Backwater, PA	Quote: Technically/Mathematicly, that line is correct. But not in real life. Because, going from stock to a performance engine, balancing a (stock or new) crank never means 'adding' weight somewhere. If you need to do that, you've screwed up earlier and now need to fix your mistake. Race parts are pretty much always lighter than factory parts. That's because the pistons and rods are usually lighter than stock, so you need less to counterbalance. Look, if keeping the mass close to centerline is the ideal you would see high end cranks with 3" crank throughs loaded with Mallory. Or better yet 2" or less loaded up with depleted uranium or some crazy dense material. But what you DO see is undercut throughs with thicker sections on their outside diameter. This post is available in double vision where drunk.

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