Cranks

[Broadus, Don F.]

The cast crank does flex less as you state, and it is also brittle, once you
exceed the limit the cast part shatters like glass.
many stroker cranks are cast for cost savings and flex. The harmonics are
some what dampened in a cast crank were a  billet or steel crank will "ring"
at certain harmonics transferring loads to bearings and rods.
 
Just my $.02  

> -----Original Message-----
> From:	AL8001 at aol.com [SMTP:AL8001 at aol.com]
> Sent:	Friday, June 04, 1999 6:23 AM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Cranks
> 
> In a message dated 99-06-03 23:15:18 EDT, ECMnut at aol.com writes:
> 
> >A relative of mine builds Chevs & some SB Mopars
> >for NHRA Super Stock class cars, and he insists that 
> >the cast cranks flex less, resulting for more accurate
> >spark/valve/combustion events from cylinder to cylinder.
> 
> Flexing could be tested with a torque wrentch and/or a long bar.  Fasten
> the 
> crank at one end then turn the other. ( The crank may need to be placed on
> 
> roller for a accurate test. )  As for a cast crank flexing less, stiffer 
> sometimes means more brittle.   For short term use ( drag ) accurate
> timeing 
> and such may outweigh frequent crank replacements.
> 
> Isn't the material for cast steel crank closer to cast iron than a high
> alloy 
> steel?
> 
> Harold