Crankshaft failure frequency

[Schulmann]

I have a question for those who race hard their Vipers.

What is the frequency of a Crankshaft failure on a stock GEN II engin ?
(Main Bearing Cap, journal etc).

When rebuilding an engine, people often use better connecting rods, pistons etc.

What parts should be used to strengthen the crankshaft ?

Is there any doc available ?

 

[1TONY1]

About all you can do other than getting a billet crank($$$) is to have billet main caps installed. That's good for quite a bit of power.

I think the failures are rare. I know of two that broke the snout with very large centrifugal blowers. I think Dyno Daddy caught some bearing issues before it damaged parts....he may have had stock mains/crank with lots o' power.

 

[DynoDaddy]

Pro-Gram Billit main caps is all that you need. The flimsy cast POS stock main caps are worthless above ~800rwhp or so. I was experiencing serious main cap walk @ 1000+rwhp.

I have also put in ARP main bolts, but have heard that the quickest 1/4 mile viper has stock main cap bolts installed.

I have heard of one guy breaking a crank snout with a huge centrifugal blower, but it sounded like in an effort to thwart belt slippage the belt tension was beyond tight, and is probably what caused this problem.

As far as the stock crank goes, it is an amazingly sturdy unit. Even the offset ground cranks are surviving 1300+rwhp duty.

Eagle makes a great set of rods with L19 bolts that are rated at 1500hp. These can be bought from Summit for $795 last time I checked.

 

[Schulmann]

So guys basically a weak 650rwhp Viper will live long on its stock crankshaft.

 

[99 R/T 10]

yes

 

[Joseph Dell]

Count me in for breaking the snout off the crank.

Big blower did it. Stock snout is pretty small. All that upward tension from a big belt caused the strain.

You can have a stock crank nitride treated instead of going billet... But billet is the way to go.

Stock genII rods are good for 1000rwhp... But the mains walk (ala dynodaddy) so you may as well upgrade while you have it apart.

I know of 1 other SC that busted a snout.

Oh, I had a 2nd crank get eaten up when my oil pump gear failed...

That puts me on my 3rd crank!

JD

 

[1TONY1]

That puts me on my 3rd crank!

JD

Your wife says you are "cranky"

 

[Joseph Dell]

*eyeroll*

I'm sure there is a "head" joke in there too...

 

[DynoDaddy]

If you are not making 850rwhp via turbo or 750rwhp supercharged you should be fine.

Making 1000rwhp on the stock rods sounds pretty scary to me. They look about as fragile as the main caps..

 

[Joseph Dell]

Dynodaddy is spot on. I ran 965rwhp supercharged on stock rods for a long time. no issues although one of the rods bent ever-so-slightly from hydralock (too much water from water injection). I replaced it with a STOCK rod and was fine until i upgraded the entire motor and the rods were replaced at that time.

Scary is as scary does...

JD