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100mm Lightweight crankshaft in 4g63 stroker

Practical Engine Building

Discussion and questions related to the course Practical Engine Building


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Hi. The goal is to get about 1000 hp at flywheel. At the moment i'm using stock MMC 100 mm used crankshaft from 4g64 and it is easily handling 800 hp. Would that be a good idea to install light weight crankshaft along with aluminium rods that i already purchased or i should stick with the stock beefy one? I understand that the less mas we have to rotate the better it is for the engine but still concern about the integrity at moderate power level since 100 mm aftermarket crankshafts are prone to cracking ( this is why i sold brand new Eagle crankshaft)... Anyone has any experience with those?

I've run the stock OE 100 mm crank to the 1000 whp mark and 9500 rpm and it held up just as well as the 88 mm stroke cranks. Reducing mass would be helpful but not something that I'd say is essential. I found that both stock and billet cranks would show cracking on the fillet radius after a season of drag racing. I got to the point where replacing a stock crank once a season was more cost effective than replacing an expensive billet crank.

Super. Thank you very much, Andre...

I was trying to dig out some more info on crankshafts cracking issue and came across Corvette forum where guys shared their experience with using ATI or Fluidampr harmonic balancers saying it helped with cracking issue. Andre, can you please tell if you were using any of those in your experience when 4g63 crankshafts were cracking? I have been using Fluidampr on my setup an wander if it is a real difference maker or it does not really matter and crankshaft cracking will still be an issue...