The built slant six I bought has had the crank radiused champfered and (paperwork says) TUFFTRIDED, it is forged also.
Its a 225, and i'm wondering if anyone has had an experiance with carburizing on their crankshaft.
I read the trade name TUFFTRIDE is not done in the U.S. but mine has been carburized and I take it as a max performance option.
Will the carburized crank hold up if I enter the aftermarket rod realm of performance, say over 390 cfm carb capabilities.
I assume the stock glass peined rods are about good for what a 390 HOLLEY can give a 225.
Plans are some drag racing but a street car too.

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Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.

What that treatment does is provide a hard wear surface on the journals. It doesn't do anything for the crank's fatigue strength. The bearing area on a forged crank /6 engine is such that the loading in psi is relatively low. There are 300hp cast crank (narrower bearings) slant six engines and they don't trash the bearing journals either. You aren't even going to come close to needing a hard crank. All you might get for that treatment is not having to regrind the crank on the next rebuild. Maybe.

Shot peened, not glass beaded, rods are fine for most streetable builds and many race builds.

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Joshua

I've got stock 198 rods in a motor with a 600 Holley double pumper, and it has held up to being shifted at 6700 RPM and also multiple passes with 150 horse nitrous shots.

Crank is a steel reground from Car Quest.

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Official Cookie and Mater Tormentor.

did you have all this balanced?

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slant six's RULE!
http://www.usajon.com

for what it worth'

TUFFTRIDE is a form of nitriding and is not carbonizing. The Tufftriding effect is to increase the surface (case) hardness of the structure. One by product of the increase in surface hardness is that the fatigue strength of the total part is also increased.
At one time Tufftriding was a common practice used in the manufacturing of crankshafts designed for HD applications. Today much cleaner grades of steel are available and Tuffriding is not a common production design practice for crankshaft processes.

Is it needed in slant six applications? Being an inline six there are already some good balance characteristicks in the motor,, so fatigue from bending is not likely an issue. Would one tuffride to have a 'best in class high HP slant',, certainly. Those moments of bending are not necessarily going to break the crank,, at least not immediately,,,they can allow a piston to touch a valve, or at best,, the additional movement will allow an energy use that is not going to the drive shaft.

regards
DT

Nope.

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Official Cookie and Mater Tormentor.

The build was done in 1983 and listed in my paperwork, I'll check it when I pull the pan (soon) and also look for shot or otherwise blasted rods, thanks.

P.S. Got ALL my ARP hardware first thing!

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Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.

Bought "New" stock forged rods on ebay for my previous motor ran 9.6's in the 1/8th street car on motor, basic head work, 10:1 compression, big cam, some good bits and made a couple bottles worth of street pulls with a 100 shot never hurt anything in that motor.

Kev

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