Is there anything that can be done to a crankshaft so that it can handle more power? What does coating a crankshaft with titanium nitride do for the crank, I saw this on a posting and was wondering what that does.

 

Nitriding helps with surface hardness. This is important - not to reduce damage should the bearing touch the cranks surface - but because major cracks start on the surface and work inward. If the surface is super hard and resists cracking, you have a better, stronger crank.
I'm thinking of sending a Lunati 4.25" crank to have it cryo treated. It's not extremely expensive and the physics of it make about as much sense as heat treating. I may actually do the same with my new rear end gears and the posi case.

 

I have the Scat 9000 series crank and I'm planning on adding a blower so I want it to be able to handle some power, it already does, but I want to be safe and feel confident with the crank. How much do you think the this process would cost? So I can this also be done to the rods, and can you get this done at a machine shop, or do you have to send it somewhere?

 

Anybody running the scat 9000 crank, if so how much HP are you pushing through it

 

I think if I was doing a blower there is no way I'd be using a 9000 series crank. It's a good piece...but not that good. You also need to worry about the nose of it depending on how much boost you plan on running.

Decent steel cranks are reasonable and already treated properly. Sell the cast one while it and your motor are still in one piece.


JIM

 

I'm going to go with the Weiand 177 blower, nothing too big. You think that crank will hold?

 

No way. The nose breaking on those is their weakness. What happened to the turbo idea?

 

I have a 9000 crank on my small block but am only pushing in the low 300's which is clearly not what you plan. I (last year) helped a friend build a 600+ (natuarally aspirated) hp 496 using the big block version of the 9000 cast steel crank and he's not had any issue so far.

Its a good piece, about the only thing I wouldnt expose it to is large shots of laughing gas

 

I'm not up on the stregth of small block cranks but; Nitriding increases the hardness (helps with wear) and develops a small amount of compressive resdial stress (CRS) that can help with fatigue. Shot peening the fillet radii develops very high CRS and will give you the best defense for crack intiation. Most high end cranks are made from 4340 steel and heat treated. Cryo treatments can help but it is CRITICAL that the crank is retempered at the same temperature it was originally tempered at. Cryo treatments transfer retained austenite to untempered matinsite which is very brittle.

With that all said, any treatment after the crank has been finish ground is not a good idea as the part can distort a small amount. Just .001 distorition in total indicator runnout can cause fatigue issuse in a high RPM enigne.

 

I'm thinking that's for the camaro, and the blower for the Vette.

 

I never knew that the nose was a weak part of the crank, I wish I would've joined this forum before buying the assembly.

 

Hell guys are breaking exteranlly balanced cranks and using a cast crank for your build maybe a mistake. If this is a SBC we use the BBC snout on these builds.

We don't use any cast cranks in our builds as we have heard and seen to many break.

A GM cast crank is better then the Scat or Eagle JMO.

 

If the crank need to be turned a good chamfer on the oil holes is a plus and a good radius is very important for strenth as most shops don't dress their wheels for a good radius.

 

If I was going to beat on an engine, it had better have a forged crank!

 

Hi

Are you referring to the nose of the blower ?

Or what is a nose on a crank ?

Rgds. Günther

 

I was talking about the snout the damper mounts to on the crank. I think Blockman had posted previously on this being an issue with the scat 9000 small block cranks.
Here is a google search on Scat 9000 broken snout. A lot of these out there. Now, bolt a blower drive on the front of it and wind it to 6000 RPM.
http://www.google.com/search?hl=en&s...&aq=f&oq=&aqi=

 

Hi

Thanks.

Rgds. Günther

 

Crankshaft strength is determined by the material in the crank and the way it is processed. Cast cranks are weaker than forged cranks because of the grain formation in the metal due to the hot-forging process [and because forged cranks will almost always be made of better grade metal than cast items]. Surface hardening and coatings like titanium nitride are good for wear resistance, but do not add strength to the part.

Cryo-hardening is more of a 'parlor trick' than anything else. While it is a valid method for increasing hardness (by a small amount), it also has the potential for inducing additional surface stresses into the part which can lead to premature failure in some cases. I have witnessed chunks of gear tooth surface that simply popped off the gear while sitting on a shelf because the part had been cryo-nardened; and there were no defects [at the surface] of the part after treatment. It's safest not to use this process unless you have lots of experience with specific parts.

With a blower and the added horsepower and shock stresses imparted through the powertrain (during 'dead' starts under power), you should really get a forged crank for your engine. You need to increase part strength, not wear resistance.