Advantages of an Oversized Piston?

[abgyak]

Hi Guys,

 

I'm planning on doing a general overhaul to my L26 engine for my 260z 2+2 and was searching for some pistons. I've gone through the forum & saw lots of people are discussing about having an oversized piston. My question is what exactly is the advantage of having an oversized piston to that of a standard stock one. I would be considering to have a set of those oversized pistons if advantages are on its side....

 

Thanks

[hoov100]

Unless you're building a track car, or want some absurd large HP number in a street car, just stick with stock, unless you have to bore the cylinders.

[blue72]

Generally larger diameter pistons were fitted to domestic engines during a rebuild because the bores would be worn out of round come rebuild time. On the Z cars it is not uncommon for 200k mile engines to have factory crosshatching visible in the cylinder bores.

The only reason I have larger pistons in my F54 block is because the engine had some serious pitting in the #1 cylinder. For the small gain in displacement it's usually not worth the investment.

[Cheesecakepiebar]

Generally, for a street engine if the bore taper is less than 0.005" (i.e. the diameter at the top is within 0.005" of the diameter of the bottom), you are fine running the stock diameter pistons.

 

EDIT: some repeated information removed since Blue72 beat me to it

Edited May 9, 2010 by Cheesecakepiebar