Here's the rub; Just disassembled a 6.0LS engine that came in to me as a core. I was told by the shop that removed it that it was burning excessive oil. As I'm going through it I can see that there is oil in all of the exhaust ports on the engine, and if I rub my fingers in the ports, I am getting actual oil. I pulled the heads and all cylinders show signs of oil getting into them. I then started checking the back of the intake valves-very little oil on the back side of any of the 8 intake valves.. With the heads off, I then vacuum tested the cylinder ports on both heads and all 16 ports pass a vacuum test. So that rules out valve guide seals. I then began pulling the bottom end apart. No spun bearings on any of the mains. No spun bearings on any of the rods. The rings were not stuck in the ring lands. The cylinder walls still show good cross-hatching and no serious scratches, or blown cylinder walls. Nothing at this point to tell me why the engine was consuming so much oil. Then, I decided I would pull the rings from a piston and put them in the bore to measure the ring gap. That's when I found the problem.. The ring land between the bottom of the 2nd compression ring, and the top of the oil control ring pack is broken! I then inspected multiple pistons and find the same situation on all that I checked. I can post pics if you guys want to see them. Any idea what would cause those ring lands to break? My first thought was detonation. Would there not be evidence on top of the pistons of detonation? What other areas, or signs, can I look for proof of detonation? These pistons look fairly normal with carbon build up on them, and a little oily as a result of the oil getting in.. Anything else I should be checking to figure out why it broke so many ring lands? The only other thing I can think of would be they over-heated the engine to a point where the cylinders got so hot they began squeezing the pistons and that then broke the ring lands. Just a guess. I'd appreciate hearing anyone elses thoughts.

 

Have you measured the ring gaps? It's possible the engine was being used for something other than NA.

 

Almost sounds like the 2nd rings end gap wasn't set properly, if at all. That or the pistons have a material defect in that area, for whatever reason.....

 

One of Richard Holdener's SBE test engines "Hey guys! What happens when we set an engine up with LESS ring gap than stock? Watch and find out!"

 

This engine is already .030"! I was cleaning the crown of a piston today and can see .030" stamped on top of the Speed Pro pistons. They HAD the black coating on the skirts, but all of it is gone. I'm not sure what they were doing with the engine before, but I'm going to turn the block in to my machine shop and have them blue print it, then I will build it. I don't think it will have to be bored again as the cylinders are all falling within .002" of 4.030" using my dial bore gauge. Whatever happened to it in the past hopefully will not repeat itself in the future. It had 243 heads on it as well... It came to me with the cam and lifters already removed. Someone was messing with it for sure.

If somebody needs a set of 243 heads, I'm selling them cheap as I have no need for them.

 

Are you saying the motor wore itself into an oversize?? Just kidding. Do you think someone maybe forgot to gap the 2nd rings? Could be someone also didn't run a good air filter. You just never know. I'll tell you a Jim dandy story about my Blackwing air filter. First time I ever cleaned and reoiled it, I held it up in the air while standing outside in the sun. To my shock, I saw sunlight coming thru where there shouldn't be any!!!! Upon further investigation, the front of the filter, the nose where the filtering media is bonded to the black plastic, a small area wasn't totally sealed!!! This wasn't detectable by looking at the outside of it. It all looked as it should. Only when held up to the sun, at just the right angle, while looking at the inside of the filter, could you see it. I used hi-temp black RTV to finish what the factory didn't. But who knows how much crap got in there in 30,000 miles of driving, some thru the Mojave desert on old 66! DOHHH!!!

 

I would think a bad air filter would have worn the cylinder walls significantly and in fact, these walls still show very apparent cross-hatching. I would also think the rings would be worn out causing low compression, but it is only the ring land under the 2nd ring that is broken. It's weird. I'm just gonna machine it, build it, and run it.