??? About Crank and HP
 

Hello,
I have a 6 bolt engine and am thinking of installing 9.0 to1 pistons. What is the stock crank and rods good for? Also were would I get a good rebuild kit from? I do need to have the crank turned as well and does anyone know of a good machine shop in the southern metro?

My last ? is what is the pros and cons of eliminating the balance shafts?

Re: ??? About Crank and HP
 

The stock crank is good for 1000+ HP, the stock 6-bolt rods are good for something in the 525-600whp range. Most aftermarket off the shelf pistons are not designed to work with the stock rods. Your best bet would be to pick up a set of Eagle rods, if you want to run over 500whp consistantly.

Pros of the balance shaft elimination are a very small HP gain and not having to worry about the balance shaft breaking from high RPMs or wear and taking out the timing belt with it. Cons are higher oil pressure, if you do the stub shaft. This is mainly only a problem for oil filter housing fed turbos. There are ways to fix the oil pressure problem, even with the stub shaft.

Re: ??? About Crank and HP
 

Do you need the crank turned down, or polished? If it needs to be turned, I would look into getting a different one. The 6 bolt cranks are nitride coated and an actual turn will take that off. A polish is fine though.

Re: ??? About Crank and HP
 

ecoli thanks for the info! I will have to check into a set of rods then as well. Also could you educate me a little more about fixing the oil presure problem with the balance shafts out? Also What is a stub shaft. Sorry total newb when it comes to these engines.

I need a polish, the crank looks a little rough is all.

Re: ??? About Crank and HP
 

The stock rods are only good for 500+ whp if your tune is perfect. The slightest bit of detonation at those levels will aerate your block in a hurry.

Re: ??? About Crank and HP
 

It depends how on much the crank is turned, right? Somewhere on the net are the specs on how thick the nitride thickness of the 6 bolt cranks is and if I remember correctly, there is enough that a light turn will still be OK.

Re: ??? About Crank and HP
 

Any turn is going to kill the nitride coating. .006" will be the max thickness of the coating. Bearings are .010" under usually. You can have it re-nitrided, but it is usually cheaper to buy a used crank and get it polished.

Small grooves in the crank don't really have a detrimental effect, as long as there aren't many and it is polished flat.

Re: ??? About Crank and HP
 

It's about $350 to have a crank turned and re-nitrided at Crankshaft Supply. Never again, you can almost buy a new crank for that, and not have to worry about it.

Small scratchs on the journals are just oil channels. :D