Need help with piston size .20over

[Keefs240sx]

Looking to build my s13 sr20 block. I have been told stock bore is 86.5mm therefore I want to bore it .20 over to help clean up cylinders so what size pistons do I need to get?

[MAPERFORMANCE]

Stock bore is 86mm, .20 over is 86.5mm.

[Newtypex]

Don't waste your time on this site finding out faulty information. Take your block to a good machine shop. They will measure you cylinders and tell you what you need. If theres no scouring of the walls to begin with then you shouldn't be wasting money on pistons.

[Keefs240sx]

Ok thanks for the quick response

[Keefs240sx]

Engine spun a bearing is the reason for wanting to bore

[Newtypex]

Check all the engine for damage and what not if everything is fine don't waste money replace the bearing and put it back together. Machine should measure and determine the appropriate bearing and/or if it needs to be machine. Don't make yourself have to fix it twice.

[waxball88]

Spinning a bearing doesn't mean you need a bore. If you blew a piston or something cyl related you'd be more likely to need a bore. Like it has been said take it to a machine shop. You need to worry about having your crank shaved and an oversize bearing along with a new rod

[Keefs240sx]

Already got a new crank with sized bearings so I figured while it's out might as well get a good bottom to build off of

[Newtypex]

Waste of money. If everything is stock and in good shape it already is a good bottom end. Make sure you get all of the bearing material out of your turbo or you'll need a new one of those too

[Keefs240sx]

Got a new turbo as well I have had an s14 car gave to me an a motor an tranny for 300 so got money to spare

[waxball88]

Waste of money. If everything is stock and in good shape it already is a good bottom end. Make sure you get all of the bearing material out of your turbo or you'll need a new one of those too
The likelihood of bearing material being fine enough to get into the turbo and cause damage i feel is minimal. Changing the oil, of course, but if the engine is part its not going to have any material left in it if its properly cleaned.

[Newtypex]

I've seen a few turbos go from bearing material. Mostly hks turbos cause they have small restrictors.

[waxball88]

I've seen a few turbos go from bearing material. Mostly hks turbos cause they have small restrictors.
A smaller restrictor would make it even harder for material to get in.....That makes no sense.

[Newtypex]

A smaller restrictor gets clogged easier with material preventing oil flow into the turbo. I've seen two hks turbos go this way.

[mikeroy420]

The reason for the smaller restrictor opening is to maitain proper flow, pressure and velocity to the turbo.