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Author Topic:   crank?
racer s
Member
posted September 12, 2004 08:27 PM
whats better for racing a cast or forged crank??????


joetaylor
Member
posted September 12, 2004 08:31 PM
4340 can't get much better than that unless you get a dragon slayer

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if every thing is under control your not fast enough


2nd2none
Member
posted September 13, 2004 03:37 AM
a dragon slayer is 4340


racer s
Member
posted September 13, 2004 07:41 PM
gotta use stock so whats best a stock cast or a stock forged


Ego Racing
Member
posted September 13, 2004 08:05 PM
IF you have to run stock what kind of RPM are you looking at? Can you run a stock replacement? If so we have had good luck with the cast steel Scat crank you can get for about $170. If you are going to keep the PRM at or below 6500 and the track is not real rough the cast should be ok if the machine work is done right, you need a large radi on the mains and rod bearings. If this dose not fit use a steel and have it gone over at the machine shop. IF you can I would run the Scat or Eagle I have yet to bust one when keeping everything else in the realm of reality and not trying to twist one into a cork screw, Broke the trans and it went to about 8400rpm before it shut off.


racer s
Member
posted September 13, 2004 08:21 PM
Thanks ego that is the type of answer I was looking for.I think we can run the scat but I have a cast but I haven't ruled out buying a scat.Can you tell me if a 3970010 block is large journal block?


2nd2none
Member
posted September 13, 2004 09:30 PM
if you use a stock cast crank, or any cast crank in that matter, use the lightest rods and pistons you can find. That will help the crank live longer, also better to have it magnafluxed about every 30 races or so.


Ego Racing
Member
posted September 14, 2004 11:24 AM
Large


Raz_900
Member
posted September 17, 2004 08:58 PM
I'll second the above. A cast (or cast steel replacement) will be fine up 6500 or so with 6" rods and LW pistons. I prefer Eagle crank & rods and Keith Black pistons. Total for crank, rods and LW pistons (KB260) is $500-$600. It's not top shelf stuff, but when used realistically will last for a long time. I have 2 setups with 3 years on them and another that's gone all this year with no problems.

Don't skimp on the machine work though. At the least have the block main bores checked for size & straightness, assembly balanced, block bored with a torque plate and square decked. Decking the block .012"-.015" should net a .005"-.008" in the hole piston height.

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