The Stovebolt Site Forums The Shop Area Engine Shop Oil Smoke

Suppose you have an engine that was just rebuilt 800 miles ago, overbore, new pistons, etc, done correct I'm told. When you first start it up, the exhaust is clear for a minute or two, then the blue smoke starts, pretty good cloud of blue.As the engine warms up the smoke disappears completely until the truck is shut down and sits long enough for the engine to cool down.The engine runs very well, has good compression, no unsual noises, normal oil pressure, no blowby.The exhaust pipes have a oily deposit on them so for sure it's oil smoke.I even saw the smoker in action for myself. All cylinders are smoking evenly, not just one or two. I'm thinking some sort of oil ring problem, like improper tension? It's a Chevy small block

Poorly run in ? .. glazed bores ?? ..

I had a friend's motor doing the same thing. After checking it, I found the machine shop didn't use the umbrella style seals on the valve stems. They used the stock Chevy ones and the valve guides weren't as tight as they should be. Since it was in a T-bucket, and easy to pull the heads, we put the umbrella seals on and tried it. It stopped the constant smoking completely. You can change the seals without pulling the heads if that happens to be your problem. This doesn't cure loose guides however.

Tony,
I saw a similar problem on my brother's freshly rebuilt **** V8. Every oil ring was installed incorrectly. Each of the center (corrigated looking) oil rings was overlapped rather than butted resulting in no pressure against the cylinder walls.
Frets