er82
Proven Member
- 243
- 28
- Apr 18, 2014
-
Sacramento,
California
Does anyone know if aftermarket pistons are exact diameter? For example advertised 85mm then piston would measure the same and not less. I think oem measures a bit less than 85mm.
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They aren't always 100% exact. It's better to get the cylinders bored/honed to match each piston, number them, and keep them in that order.
However, that being said, I did have my block bored .5mm over BEFORE I had my new 85.5mm oversized CP pistons delivered, and mine is still running strong after nothing but all out beating all summer long since 2007ish. I have several hundred timeslips, and a shelf full of autocross trophies which show that it can work.
Generally the clearance is built into the piston. So a piston for a 85mm (3.346") bore that specifies a .003" clearance will measure 3.343" I'm assuming your looking at wiseco's I'd suggest calling them to make sure, there customer support is pretty decent.
What pistons are you planning on using? Also keep in mind that the cylinder won't be worn perfectly round. It will be egg shaped. That's less than optimal. If it were me I'd be prepared to .02, and have the shop hone one cylinder to like 3.348", which would put you about perfect clearance for a set of standard bore wisecos, for a performance engine.
Bastard, your math is a tad off.
If the block is honed .02 (3.366) then he will be ready for some .020/.50mm pistons
If you meant honed .002 (3.348) about any STD piston will have about .005 PTW
@er82 Just what are your goals for the engine? the car? What is your budget?
With this info, we can help and suggest a set up
Make sure they have the updated .200 wall piston pin. Other than that your good to go man!