I've been trying to figure out why my rebuilt 22R with about 2,000 miles on it has been using a quart of oil every 200 miles for years now. I've posted about this before. Leak down test has about 5% on each cylinder. Compression is good. There's no smoke visible at any time. But now I'm seeing black dots in the snow, every few inches, at walking speed. From tail pipe. My 94 doesn't do that. If there was a head gasket leaking oil into the exhaust manifold it seems like there would be a drop in compression. Any suggestions would be appreciated.

 

If it's not leaking externally, it's most likely burning it. Were the valve guides replaced and new seals installed when rebuilt? If the rings don't properly seat you can have high oil consumption. You can still have good compression and bad oil control. The PCV system can pull excessive oil vapor if baffles and such aren't in place. I can't explain why you don't see any evidence of smoke in the exhaust.

I guess I'd see if there was soot on your spark plugs. All of them, Certain ones only? Does the intake have oil in any or all of the runners? You might want to invest in a borescope so you can better look at things. You'd have to pull the exhaust manifold to see if any ports are more sooted up than others. If the intake has no evidence of oil and all plugs are sooted up or oily, I'd suspect rings never seated.

If the intake is very oily find the source. Are all vacuum lines hooked up properly? PCV working properly?

You can get black soot drops from the exhaust just from a rich fuel mixture as well. Any chance that someone is pranking you? I'd doubt it after two years, just had to ask. No oily film on the bottom of the truck?

Tough one, good luck with it and please follow up.

Scott in AZ.

 

Thanks, good suggestions. Don't want to redo the rings yet. Or rehone. Don't think the fuel is rich, as I've done pretty extensive adjusting on the new carb and it runs good. Vacuum lines are good, PCV is good, vacuum is good. I'll check both manifolds, for sure. Plugs looked normal. The baffles inside the valve cover are all in place. Head is new, from LCE, came complete with valves. There is no oil on the bottom of the truck. But I have just notice a thin coat of oil on the two vacuum lines between the distributor and the intake side, which the fan has thrown to the sides, just a little. The oil filler cap has no O ring so thats on the list. Should be able to say more in a couple of weeks.
Since I replaced the carb when I did the rebuild and it needed so much fiddling with, I didn't get it on the road for a good break-in as soon as I was hoping. If I ever break another engine in Ill do it with a reliable carb or FI setup. I did run it up and down my road a bit with some load on, before I hit the highway so its hard to say