I have torn down the motor after 220k on it. all is well with the internals. I had to overhaul a noisy transmission, so I thought it was time to freshen up a great motor. I am rebuilding it based on 03 zo6 ls6 specs. cam ,valves,springs and possibly pistons. Porting the heads and reusing the crank and rods as there is nothing wrong with them. my question is , I have read here and other ls1 sites that if I even hone the cylinders I need to get oversized pistons as the standard size will not work. is this true. I am not boring the block , just a finish hone to seat the new rings. The specs say .00040" for any material removal max. Do I even need to hone the block for new rings. I read on another site that gm, when replacing rings, does not recommend honing. The problem is the 98's cant be bored and the next size up piston is .010". I would have to special order a custom forged piston and that is costly. the original pistons look to be in good shape, no skirt scuffing at all. they measure out to 3.8965 I may reuse them ,as long as I can put new rings in. this motor never burned one drop of oil and it is only going to be my daily driver. Any advice or experience on this would be great.I have included pics of pistons and bore, before cleaning. thanks in advance

 

My pistons were setup on 3.903, I had to have the block honed to size, these blocks do not get bored out. I believe if you just try to finish hone the sleeve, you will still be removing matierial, causing the need for bigger pistons, I would think that after 220k miles the sleeves would have noticable wear and to clean them up would cause a need for a hone, requiring new pistons. If you just run a dingleball hone thru the cylinders and clean them up,, use a good set of mics and get an exact measurement and compare it with the GM manual specs.

 

I mic'ed all the bores before any hone and what I keep coming up with is 3.897. The spec is 3.897 -3.898. is it possible that the rings do not wear the bore. I inserted a top ring and made measurements. the gap spec is .00149" and the gap is .0024".This is telling me that the rings wore because the bore does not have a lip top or bottom anywhere in the bore . typically you have trouble pushing out the pistons because the rings catch on the ridge in the bore from the wear. If this is true ,then can I slap new pistons and rings in it with or without a hone. thanks for the help in advance

 

I had 120k on my LS1 before rebuilding it. My cylinder's were honed and I was able to use the stock pistons, just got new rings. 220k is another story though