blue thunder

And what first hand facts do you base that advice on?

BT

Infomaniac

That was not a "personal" attack on Blue Thunder.

The GM crank is a decent piece. A cast steel Scat crank would be a step down. A decent 4340 forged crank is only $600.00

I ran a GM crank for 3 seasons in my blown injected alcohol engnie with no problems.

I would not even consider doing that with a Scat cast steel crank.

I have built an engine or two in my time.

blue thunder

I don't take any of this personal Infomaniac, so don't you either. So can you quantifiy how many Scat noduluar steel cast cranks you have witness break at under 600hp? I'll am guessing it is something less than one? In fact I would open that up to anyone with experience with these cranks. WOuld like to know of any marine engine, less than 500hp, iin which the cast nodular steel cranks that have failed due to lack of structural integrity??

BTW, most forced induction alcohol engines exceed 600hp. I have had a GM forged steel crank break at under 400hp. They are notorious for cracking at the journal radius, or lack thereof.

BT

Infomaniac

Well I will have to admit I have no first hand experience with cast steel cranks. i guess you got me there. But on the other hand, I will have to say I am well qualified to express an opinion. I would not even consider using one in my own engine or a customer's engine. Much less recommend someone else purchase one.

And I guess your GM crank broke due to structural integrity? No out of balance, detonation, poor machine work, over rev, jump out of the water stresses etc.

OK back to the topic and every one else that has had first hand experience with Scat cast steel cranks.

blue thunder

I use them with great success. I see no need for the forged piece at 500hp5000rpm or less. Would I rather run forged? Yes.. That is if money was no object. It is for me and I suspect for a lot of other folks out there. So until some facts surface that indicate cast nodular steel is not a good choice in these relatively low hp/low rpm applications, I will continue to recommend them to people like me operating on a slim budget. For the rich folks who can afford the "best" of everything, let tribal knowledge lead the way.

BT

Infomaniac

Agreed.

MESABALANCING

Lethal
I've been repairing cranks for 20 years and I can tell you for 100% sure that the nitride gm uses goes deeper than many people think and read about the most important thing to keep in mind is to have the crank inspected for cracks before you start any work and the radius issue Bob RMBUILDER wrote about needs to be correct this is the reason I grind and repair cranks for 300 different machine shops in Florida good crankshaft shops are few and far between if you can't get it done that way call me and I'll take care of it for you Laz Mesa 1-305-884-5368

dyno

I run a GM cast crank turned 10/10 at 500 hp and 5200 rpm all the time never had a problem yet.