crankshafts

[Bobs rare 6]

I am posting this for a friend. What is the general rule for .20/.20 turned stock crank in a mid to high 10 sec. stock block setup? I have always heard not to go more than .10/.10 on a high perf. setup. This is a fresh build with roller cam, billet mains, ported heads, 67 turbo, etc. Would you suggest running this crank or having a new stock crank put in? Any input appreciated, Thanks, Bob.

 

[REDS HOT AIR]

I have found no difference in them being cut or not they will break in time if its std/std or 30/30

worst part is most of the time the rod side clearence gets out of hand on one thats been cut unless they knew not to grind the sides of the rod journals


I just finished building another 9 second capable stock block/crank/ rods motor but tell him its good to mid 10's ...I wont tell anyone a stock rotating assemble is good for any faster .

and yes I know of many that are faster

 

[tbirdv6]

With all those good components, why mess w/a stock cast crank??
I have available an Brand New Eagle Steel Crank for $600
FRED
turbobuick2@yahoo.com

 

[jpratt]

I would think that a 10/10 crank would be pushing it. I am a little worried about using a 10/10 crank on my street car. I do not think that a 20/20 crank would handle that much HP. I would most surely go with a stock size crank.

 

[Razor]

Maybe put it this way, whats the history on the crank that was turned? Was it subjected to 100's of high boost 1/4 mile passes or was it from a high mileage daily driver non-boosted application.

See the difference.. as the history on the piece plays a role on its probable longetivity.

My thoughts.. as to stock cranks.. the ones out of 4.1 NA motors are the best when std/std. Ones out of 9 second GN's run at 35 PSI boost for a few seasons std/std.. ehhh.. not the best :biggrin:

I agree with the above, get a steel crank if building a race engine and the money has been thrown at it. Actually a steel crank makes more sense than a roller cam. IMHO