BryanGT

Ill try to make it quick. Ive got a 98 K1500 I plan on using as a hunting truck. The engine ran well, but ran hot and cracked the heads. This is my first build, and I've checked my bore clearances. The manual I was referencing shows service limit of .0007 -.0027. After checking my bores against my stock pistons, I've found that most bores are about .003, but that two of them show .0045 and .0055. Checking the bottom of the bores, where the cylinder has not run, comes up as .002, and even showed some factory crosshatching. I did hone them a little just to break the glaze, but even before, 7 out of the 8 had no ridges.

It was suggested that I not worry about this so much, but that I check my ring end gap. I know that you typically want .004/in cylinder bore, so my target is .016. On the larger bores, checking against std rings, I am reading .022/.024. On the smaller, I am reading .020.

Just how important are these couple thou differences? Where should I go with this? The cylinders LOOKED good to go, so I had the cam and block tanked, crank polished, and honed myself. Couple hundred in it already.

sean Buick 76

For your application I would not hesitate to just leave the bores alone and ensure the ring gaps are within spec. Many people try to convince people over the internet that ONLY a high dollar fully machined rebuild can be reliable but the fact is that if you know how to properly measure, and assemble these engines you can often save a ton of money.

Do not get me wrong, if money is no object then sure have it bored out but then you have to buy new pistons etc and the ball of wax grows HUGE.

One trick if you are dealing with slightly worn cylinder walls is to order 10 thou larger ring set and then file fitting them yourself to each bore to ensure they are in spec.

But from the sounds of it you should be okay with standard rings.

Richardx2

I agree the cylinders that have a that are slightly oversize alone and just honing a good cross hatch pattern to break the glaze would be the smart choice and the preferred method of assembly as long as you have the end gap on the rings within specs, buying the .010 rings and filing them will work.

If you leave them as they are you stand a chance of having low compression in the cylinder and on the compression stroke allowing some of the compressed gases to blowby the ring which will pressurize your crankcase and reduce power.