LT1inaMGB

I was talking with the CEO of Scat yesterday and he said that the small diameter of the stock sbc crank nose makes them susceptible to breakage when turning a blower drive or dry sump pump. The added torque generated with a 7" pulley will eventually twist the nose off the crank. Has anyone here experienced a problem with that happening?

Scat makes a crank with a bbc diameter nose on it to relieve the stress on the crank nose.

Jim

383tpimachine

For this reason I went with a dragonslayer callies crank.

LT1inaMGB

Does it have a larger diameter snout? If so, what did you do for a timing set and balancer?

383tpimachine

No. Still stock diameter but much harder material.

There are BBC snout sbc cranks out there as well as the timing set to go with it.

FWIW the vortec series blowers are not as hard on the snout as procharger or PD blowers due to the higher (lower numerically) gear ratio within.

LT1inaMGB

That's good to hear. I haven't heard of a snout failure using a Vortech.

383tpimachine

Another way I look at it is:
LS3 uses a a cast crank. I know people spinning them to 7-7500 and making 800-1000rwhp on a blower setup. That is a completely stock crank.

If that can survive so can any belt driven setup on a forged setup.

Cog or gear driven blowers are a different animal altogether.

Anything can break but with proper tuning and not sitting on the limiter it should not be an issue.

LT1inaMGB

Scat's main issue was the small diameter of the sbc snout, not sure what diameter the LSx snout is.

dizwiz24

absolutely no problem here.

13 psi boost at 6500 rpm, stock bottom end 93 lt1

8 rib dedicated drive belt and ati super damper 6+8

383tpimachine

1.245 vs 1.4821

so 0.24 larger.

Again on a linear setup I would not be worried. The PD sc are the ones that put huge strain on the snout.

dizwiz24

interesting! thanks for sharing

i could see an issue with a cheapo 'eAgle' cast crank, for example.

prob the oe cast crank is made with better materials/ metallurgical techniques.

though everything has its limits at some point

dizwiz24

I feel that crank snouts being broken by superchargers ARENT a problem on the cast lt1 OEM cranks

but are an issue on the cast / some of the forged lt1 sbc replacement cranks

drive it

I was using a no name forged crank with no problems. The new one is the "mid-range" Callies forged with 2 keyways machined in it and I'm not worried about it either.