Re: School me on center counter weighted cranks
[Re: Dragula]
#2621450
02/14/19 10:24 PM
02/14/19 10:24 PM
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Joined: Jan 2003
Posts: 9,996 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Frostbitefalls MN (Rocky&Bullw...
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Ford stock 2011/19 5.0 cw cranks are sold as thier performance crank. Never had a failure! I run one from Crower in my 528. No cap walk anymore. They take the extra loads off 2& #4 bearings caus e d by non cw cranks, and put it on #3 where it belongs. Would reduce flexing of the crank also, adding to crank life.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: School me on center counter weighted cranks
[Re: Dragula]
#2621482
02/15/19 12:19 AM
02/15/19 12:19 AM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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The theory is sound, but the practical aspect? IIRC CCW cranks were used in 392 fuel engines back when, no improvement (Gene Adams). Perhaps this crank is inherently stiffer than current big blocks due to shorter OAL?
Boffin Emeritus
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Re: School me on center counter weighted cranks
[Re: dthemi]
#2621526
02/15/19 02:25 AM
02/15/19 02:25 AM
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gregsdart
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The practical reasons for a ccw crank are better stock block life, and ultimate life of the crank. Also helping reduce or eliminate cap walk in my Megablock. Most racers won't really need one. But the advantages are there or Ford wouldn't use them in all 11 to 19 year 5.0 Mustang motors. Also as i said earlier , they sell that stock crank as thier performance part, zero failures. Some of those race turbo motors i assume are putting out some serious hp!
Last edited by gregsdart; 02/15/19 02:27 AM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: School me on center counter weighted cranks
[Re: 340Cuda]
#2621687
02/15/19 02:48 PM
02/15/19 02:48 PM
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Joined: Aug 2003
Posts: 43,163 Bend,OR USA
Cab_Burge
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I Win
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Bend,OR USA
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I'm putting another pump gas 400 stock 4.250 stroke block stroker motor that has a Windberg crank with billet steel Crower rods I bought used from a member back east several years back, it doesn't have the center counter weights I do have two fully counterweighted older top fuel or blown alcohol cranks, one is a Bryant that was 4.25 stroke with Mopar rod size(now offset ground down to BB Chevy size with 4.375 stroke) and the other is a older KB 4.500 stroke that was cracked in four places that I had fix with Mopar rod size, it couldn't be offset stroked though I'm planning on using both of those cranks in after market blocks to help prevent cap walk and see if I can exceed 1000 HP + N/A
Last edited by Cab_Burge; 02/15/19 02:48 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: School me on center counter weighted cranks
[Re: Dragula]
#2621842
02/15/19 09:06 PM
02/15/19 09:06 PM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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Strictly speaking, for greatest control of out-of-balance forces, the counterweights should be moved inboard touching the cheek radius, and made as thin as possible to concentrate inertia as close directly opposite (180°, at the smallest diagonal) to the pins as possible, with the OD increased as needed to get the correct mass back. Any late weight adjustments (holes, Mallory) should be limited to the shallowest correction to the inner face of the CW only. Not practical. This is true (and nearly impossible) even for the "inherently perfectly balanced" L6 engines as well.
Note that the Winbergs shown are directionally biased for rotation...
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Re: School me on center counter weighted cranks
[Re: polyspheric]
#2622089
02/16/19 12:50 PM
02/16/19 12:50 PM
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Joined: Nov 2011
Posts: 287 PA
Harry's Taxi 2
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Strictly speaking, for greatest control of out-of-balance forces, the counterweights should be moved inboard touching the cheek radius, and made as thin as possible to concentrate inertia as close directly opposite (180°, at the smallest diagonal) to the pins as possible, with the OD increased as needed to get the correct mass back. Any late weight adjustments (holes, Mallory) should be limited to the shallowest correction to the inner face of the CW only. Not practical. This is true (and nearly impossible) even for the "inherently perfectly balanced" L6 engines as well.
Note that the Winbergs shown are directionally biased for rotation... So, is a center counterweighted crank an improvement or not?
'86 Maple Grove KOS Mopar low qualifier......true street legal with no power adders.
NOS-used when losing since 1940.
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Re: School me on center counter weighted cranks
[Re: Dragula]
#2622271
02/16/19 07:38 PM
02/16/19 07:38 PM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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Yes, but it's: 1. expensive 2. not magic - your power level and specific engine design may make it a conversation piece
You would also be faster if you center-drilled every fastener, like they did with Moto-X in the 1970s. 10 hours of labor to save 1 lb.
Expanding on my prior post: given a clean sheet of paper, a "V" engine can, and has been built with separate crank-pins at the same position (G.M.C. 301 etc. V6), which would allow a counterweight between them. But if you don't need it, it's just one more thing for the engineers to argue with the accountants...
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Re: School me on center counter weighted cranks
[Re: Dragula]
#2622359
02/16/19 11:17 PM
02/16/19 11:17 PM
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Posts: 5,485 SoCal
Brian Hafliger
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Higher rpm engines seem to like CCW cranks. The weight becomes rotating inertia...not a bad thing.
Brian Hafliger
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Re: School me on center counter weighted cranks
[Re: Dragula]
#2622367
02/16/19 11:28 PM
02/16/19 11:28 PM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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Ideally, every mass would be opposed by a counterweight placed exactly opposite: 180° away. This is not possible since the pistons occupy that space. Any compensating mass NOT correctly placed (alongside, diagonal, etc.) has the effect of forming a bending plane with its axis a line through both centers of mass - a diagonal angled away from the crank's axis of rotation. The greater the misalignment, higher RPM, and greater mass the stronger the bending force. Bad.
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Re: School me on center counter weighted cranks
[Re: polyspheric]
#2622477
02/17/19 10:10 AM
02/17/19 10:10 AM
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Harry's Taxi 2
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Ideally, every mass would be opposed by a counterweight placed exactly opposite: 180° away. This is not possible since the pistons occupy that space. Any compensating mass NOT correctly placed (alongside, diagonal, etc.) has the effect of forming a bending plane with its axis a line through both centers of mass - a diagonal angled away from the crank's axis of rotation. The greater the misalignment, higher RPM, and greater mass the stronger the bending force. Bad. So, does that mean CCW cranks do or don't reduce cap walk?
'86 Maple Grove KOS Mopar low qualifier......true street legal with no power adders.
NOS-used when losing since 1940.
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