I recently did a complete engine overhaul on my 97 lt1(first time). Being the noobie mechanic that I am, I thought that breaking the piston rings in with full synthetic oil was ok. I noticed I was burning oil, which is normal on a break in I hear, but I was also told that I screwed up by breaking it in with synthetic. After hearing that I immediatley put in conventional at 600 miles. I then ran it for about 100 more miles, and drained again, trying to get out as much of the synthetic out as possible. I am now at 2200 miles, and am still burning a little oil, but significantly less. Is there anything I can do to get those piston rings to seat properly, or is the damage already done? Thanks

 

I've always understood that using synthetic for break-in can cause the piston rings to glaze over the cylinder walls. At that point, the damage is already done.

 

Yeah that is kind of what I figured. I guess these are the things you learn, and I learned the hard way. Ive been told its no harm to the engine, I will always just burn oil until I tear into the motor again.

 

LT1 Vettes come from the factory with Mobile1, right? Letting it idle when you first get it started causes more problems than anything. The cylinders burnish and even if it uses no oil the top rings are likely to never seal up, making it a weak sister. Poor top ring seal=low power. If you think it's the synthetic, try putting cheap non-detergent oil in it for 1000 miles, do all the freeway drivng you can. or, take a road trip.

Good luck, Ed

 

Did you have it bored? did you hone it, flex hone it? How did you space the gaps in the rings? What about your valve seals, did you take your valves out?

 

Yes I had it bored 30 over and honed, new pistons and rings. I did not do the pistons rings myslef, mechanic friend of mine did(very reputable). He followed instructions that came with them, so the gap I am not sure. Valve seals were good, like i said, a complete enginge overhaul pretty much. Does this change anything? Here the last 4 days or so, i havent used any oil, so I am crossing my fingers that I swapped the oil out in time, now have 1700 miles on conventional oil so wish me luck. Thanks for the responses guys.