John Scott Posted July 17, 2001 Share Posted July 17, 2001 Who is using what brand crankshafts in your strokers? I have one engine builder claiming there is lots of wasted $$ on aftermarket hype for a street motor. 500+ hp 6000 or so rpm. The prices for cast steel seem pretty reasonable. Trying to put the $$ where it will do the most good. JS Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 17, 2001 Share Posted July 17, 2001 John, I agree, a cast crank should be fine for a street motor. Cast is usually more ductile anyway and tha can make it live longer, so Bill Jenkins used to say. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 17, 2001 Share Posted July 17, 2001 If you want a little bit of insurance, you can buy a Scat crank, with very reasonable prices, that are made of cast steel (stronger than cast iron, not as expensive as forged steel)--David Vizard swears by them for the budget builder. I have seen them on ebay going for cheap and brand new! If I do another motor, I'll definitely buy one. Davy Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 18, 2001 Share Posted July 18, 2001 I've gto an aftermarket crank in mine - it came with the 383 kit, Eagle Rods, etc. etc.. Had I been doing a 350 I probably wouldn't have worried much about the new crank. Doing a 383 though I preferred new over having one ground. (shrug) Quote Link to comment Share on other sites More sharing options...
Guest Night_rider_383 Posted July 18, 2001 Share Posted July 18, 2001 Here's my two cents. If you got the extra money to put into the engine then i would do it no other ?'s asked. Here's the pros and some con's on the aftermarkt forged cranks. PRO's The aftermarket 4340 forged cranks is much much stronger than stock (hold more hp, tq rpm), Most of the aftermarket ones weight less that stock forged units(ligher rotating mass for better throttle response) , Knife-edged counterweights(cuts down on power robbing windage) CON'S Price If the rest of your short block aint build with the same strenght in mind then the crank would be a wast of money. If you dont use good forged 4340 rods and good forged pistons then you still gonna have weak links that wont be able to hold up to the higher hp, tq, and rpm. So that comes back to price of rods and pistons now. If you aint gonna run the forged rods and pistons then i would say theres no reason to go forged on the crank. Cast will work pretty good As for the parts im useing in my blown 383 stroker heres the bottom end. callies 4340 forged crank with smaller 2.00'' rod journals, crower custom ordered 6'' forged 4340 h-beam rods (was gonna use manley rods but they don't have what i wanted in the 2.00'' rod journals, and i wanted to stay with the smaller journals for weight and rpm), JE forged -28cc pistons. Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted July 18, 2001 Share Posted July 18, 2001 guys, isnt there a limit on how high a stock crank can rev? everyone seems to say that they're good for about 7 Grand. This of course depends largely on the type of mains present. Does this max RPM have more to do with the type of crank used, or the type of mains? Quote Link to comment Share on other sites More sharing options...
Guest Night_rider_383 Posted July 19, 2001 Share Posted July 19, 2001 Tom... There's more to the engine's max rpm than just cranks, rods, and pistons. I really wouldnt wanna take a stock crank more than 6k but i'm pretty sure it will hold more than that but pushing the engine higher than that with stock pistons, rods, valves, springs, etc. more than likely will spell death to the engine being most of the blown up engines die from valve float, broke rod bolts and or caps, busted pistons etc. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 19, 2001 Share Posted July 19, 2001 John, I reread you post and some of the replies and I'd like to make a few more comments (just try and stop me! ) First, what Pete said about a ductile crank shaft it true. Because of the nature of the metal, they have a tendency to not transmit high frequency vibrations the same way that a forged crank does, and thus won't develop cracks the same way. This is a huge subject and I won't get into the specifics, but all is covered in David Vizard's book in the email I sent you--check your email tonight. Also, power is not made by the crank per se. Yes, if you go to a stroker crank, you will end up with more torque, but maybe at the expense of rpm & horsepower. There seems to be a tradeoff. Heads & camshaft is where you really make power! However, the whole combination of parts must work together as a whole or you'll end up with an expensive, lack-luster performance motor. What Night Rider said is also true; that if one part of your motor is built up one way, and the other part is not built up the same way, that is a waste! To summarize it all, the Scat cranks are great--just shop around. They range in price from a few hundred dollars depending on application) to just over $1000. If I remember correctly, the 9000 series is the lightened one? That is one strong, light, fast-spinning mother! Take your time and read your email tonight. Davy [ July 18, 2001: Message edited by: DavyZ ] Quote Link to comment Share on other sites More sharing options...
John Scott Posted July 21, 2001 Author Share Posted July 21, 2001 Thanks for all the replies, advice etc. Here's the plan: Scat9000 lightweight steel crank, lightweight 6" forged rods,AFR 195 heads. Isky custom grind solid lifter specs (guess around 240 @.050/ 550/ 110 center.) 10.5 SRP forged flat tops. 750 holley or similar. Lightweight 15# nodular iron flywheel. Still deciding on manifold. Builder likes to run on dyno before installation to verify/document hp!! This is going to take a while, probably need to sell the Procharger, 4.3 parts, but the planning is 1/2 the fun How do I explain this to my wife?? JS Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 22, 2001 Share Posted July 22, 2001 AWESOME MOTOR!!!! Those are specs I can live with, man!! I bet the dyno on that baby will be what, in the 500hp range???? HooBoy! You'll need bigger tires for sure! Take lotsa pics! Davy Quote Link to comment Share on other sites More sharing options...
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