A little while ago I picked up a used 5.3l from a salvage yard. When it was dropped off, there was a signs of coolant puddled on two of the cylinders and a build up of crud on 4 more. Today in the process of disassembling the engine to replace pulley and cam, I started scrapping the junk off the exposed cylinder walls. Most of the exposed cyllinder walls cleaned up with nothing more than a knife but these two required attacking them with both a knife and then emory paper. When I was finished, I found that there was pitting in both of these cylinders. It appears that the coolant had etched pitting into the walls at the point where the pistons has been stopped. So the question is: Assuming that the pitting is above the second set of rings on the pistons, can I reasonably ignore this or am I going to have to totally rebuild the bottom half of the engine ? I would say the first set of rings but when the piston is at the top of the cyinder, I am not sure that the pitting will be above the upper rings. To gain a perspective, if you think of a V8 bank having 4 piston positions with flush with the top of the block as postion 1 and lowest point of travel as being postion 4, both of these piostons were in position 2. One side is worse than the other.

I have seen some engines get away with it, but unless you don't mind pulling and rebuilding a second time I would advise against it. The upper ring could catch a pit and snap, or break the upper ring land off the piston and grenade. The block could be rebored now, but not with a big hole from a rod through it.

It's gotta be pretty bad to have the potential to snag a ring after you clean it up with fine sand paper. If it's in good shape otherwise assuming you're going to inspect rod and main bearings, I'd smooth the affected areas out, put the old gaskets on long enough to compression test it and see where it stands.

It's not like a sbc is hard to gets parts for. This would be the time to change the pistons for better ones if you are ever thinking of turning a lot of rpm, or using boost, or No2.

This happens to my 3800 nearly every time I have changed headgaskets... Its fine.

This afternoon I was back at it with a hone but after working the hone for a while I was still left with this

http://www.flickr.com/photos/jmd1950/8462826633/

given the scoring at the second ring mark, I made the decision to rebuild the block, so my mechanic and I started tearing down the block to get it ready to be sent out for machining.

When we pulled the bottom off, we found this

http://www.flickr.com/photos/jmd1950/8462824537/
http://www.flickr.com/photos/jmd1950/8462825649/

I think i made the right decision.

Note -- based on the actual cyl wear, and the reman sticker on the heads, this engine had only been in service for about 20k miles but when it was pulled from the vehicle at the salvage yard, this did not drain or clean anything. The vehicle must have gone over on it side as there was an oil water sludge remnants in the oil pan and the coolant damage you on the cylinder walls and pistons. No oil in oil pan as it was craked and drained. After that -- definitely not stored in a proper environment

That was what I was I was afraid you might find, aren't you glad you didn't get it installed before you found it? At this point it is very saveable, had it been run like that you may have wound up with a boat anchor. Good thing is you caught it now.

yes -- there are times when you have to trust your gut feeling even when the mechanic thinks it should be okay. When he saw the bottom half it was - 'yep you made the right call'
So it is off to the machine shop this week. Time for an over bore and new diamond pistons and chrome moly rings. The rods are fine (coated or anodized0 and the crank did turn freely so there is no bearing damge but I will replace the camshaft and crankshaft bearings. The crank just has surface scaling so it is completely salvagable. While it is there, I am having them do a full rotating balance. that should allow the red line to be up around 6500 +. I should have the heads back from being polished and ported by the end of this week. So another few weeks delay and more $$ but at least there will be no questions about reliability. The G6 6-speed I picked up on E-bay earlier turned out to be brand spanking new - still has the storage oil in it. I have been taking pictures as I go and once we get to a reasonable point, I will start a build thread. This is going to be close a frame up rebuild into a Fiero Luxury Edition