Best I can find is that my 2001 LS1 motor has a factory 3.898 bore. Most aftermarket pistons I've found are 3.905 but there some variances.
For anyone that has aftermarket piston installed, did you get the cylinder bored out or what? Seems like such a waste to only bore .007

 

Yeah I had that problem I put Forged JE pistons in my 04 vette and had to bore it for the 3.905 pistons but it was bored .011 because it needed .004 piston to wall clearance. (Supercharged)

 

Well the sleeves are too thin to bore out any more than that. The reason people do a 3.905 is to clean up the bores and get a fresh hone for ring seal. 98 blocks can only go to 3.903 and 99+ can go 3.905. If you want a larger bore there are lots of options such as a resleeve for a ls1 or ls2 block, lq4 or lq9 (same iron block), ls2 (alluminum version of lqx block), c5r, and soon to come l92 and ls7.

 

OK then. If I had some 3.905 pistons and I plan to turbocharge it, is there some guidance as to how much clearance there should be between the cylinder wall and piston?
Also, anyone know the going rate for a bore job? I would call but since it's sunday and the shops are closed I might as well ask

 

All you need to tell the vendor your purchasing is what crank stroke, rod length, bore diameter, head gasket and head cc to determine what size dish you need for your desired static compression ratio. The manufactuer will make the piston the right size for the application. You may be able to get away with an off the shelf piston for your application which makes the price lower. Machine work cost varies alot depending on what they need to do to the block. My guy charged 336 for iron block bore. May be alot cheaper on the alluminum blocks.

 

You did what?! Did you measure the pistons? I am 99% sure that when you order pistons from JE, they give you pistons with that clearance. You did not get 3.905" pistons, you got pistons for a 3.905" bore. For example, Diamond does the same thing, so my pistons for a 4.060" bore all came out to 4.056". You gave yourself .008" clearance.

 

The pistons will come with a spec card. On there it will say how much piston-wall clearance they want and will tell you where to measure on the piston to make sure you have correct pistons.
Also, .007" is not enough to bore out. Your gonna have to hone it out .007" to a 3.905" bore. Hope that helps
Kent

 

The pistons were MADE to FIT a 3.905 cylinder bore. The pistons themselves are not a 3.905 bore......

KCS is right.

 

i bought a 2002 block and went with mahle's 3.908 pistons.

 

As long as the cylinders were HONED to 3.908", you should be fine, but if you added .004" like RvetteJ did...well...you ever heard of Darton?