well im not looking to go big power,i just need a set of pistons to replace the stock set with and without spending big bucks , wossner has the right price range but dose not offer a piston set with a 12.5 to 1 comp ratio though a tech told me i could go with a thicker base gasket .020 to bring the compression down, to your knowledge would this be correct?
The stock head gasket is alot more than .020" thick.
I have a new one for a Gen2 at home, but cannot remember their thickness.
Personally I would shop around for a stock set of pistons, and oem are available.
And stick with an oem head gasket.
If you're replacing pistons that means that they are worn, and I would go to the first size bore up from stock, which also means having your cylinders replated, as they have a nykosil type plating.
But, before you get too far ahead; have you measured the bores or the pistons?
Are they in spec?
Do the bores still have a good cross-hatched pattern?
Techincally you can have the bores machine honed(not bored) and put in a new set of rings on the old pistons and bores, assuming they are in spec.
And, Always check the ring end-gap, and grind the ring opening larger if needed(Always Only with a ring grinder, and Always only one end of the ring).
And, have you measured the main and rod bearing clearances?
Will the crank need turned?
Will you Need oversized bearings, or will stock size still fit.
Even with high miles, a good running Busa engine rebuild, in most cases can get by with stock piston and rings and stock bearings, have the valves lapped, and maybe a new set of springs.
A timing chain, tensioner, and gaskets.
The cams may or may not show much wear, and are easily replaced if needed.
Also
On Any Gen1 that you are rebuilding.
Having the transmission undercut is a great idea, as 2nd gear is known to fail randomly in them, and requires the cases split to remove it, so now would be the time.
