Stage II Piston Question

[DDot690]

I have a Stage II 4.1 Off center engine I had set up and balanced ect.. a couple years ago. I bought all the parts but but never assembled, I was going to use stage II heads but now I'm thinking of using the Aluminum Champion heads I have on the car.

My question is Do I have to get new pistons to work with the champion heads. I believe the pistons look similar to the regular turbo buick. I took a some pics of the pistons if that helps. The pistons are Ross Racing 4.20 size with I want to say 8.5cr.

 

[mygn276]

Your valve clearance that are machined into your pistons designed for stage 2 heads are different. Chamber size would be different too with stock style heads so the only thing i can think of is recuting the pistons and re-balancing the weight.$$$$

 

[DDot690]

Don't know what the chamber size difference is, Will have to check that. I believe they cut the valve reliefs because of the cam lift was high, I am not going to run a high lift cam now so the valve reliefs shouldn't be a problem. Thanks

 

[gnxtc2]

The valve arrangement is different from a Stage head vs TA/Champion (stock style) head. You're going to need a different cam also. Along with the other parts.

Billy T.
gnxtc2@aol.com

 

[BlownV6]

You will need to check the piston to valve clearance. Chances are that they will work as is. But a couple of them may require a little clearancing right at the valve notch. I cant imagine that this could possibly require a rebalance
as you will not be removing enough material to weigh much of anything.
These are balanced OUT OF BALANCE anyway and the percentage of balance will vary depending on the engine builder. just my 2 cents!! Mike