Originally Posted by barry123400

I read your compression numbers. In theory you could have that much general oil usage and destroyed oil control rings. I just suspect your compression rings would not still be that good. Remember your first compression readings where over 400 pounds before you adjusted the valves and tightened them down too much.

Figure out a way to find out if the head gasket is comprimised in the pressure feed to the head area. Thus dumping oil into a particular cylinder. Run the engine with the injector of the cylinder closest to the oil passage removed. If it spits oil out you have your proof.

Actually I would expect the injector of that cylinder to look pretty different than any others as well. If bad enough that also is a reasonable indication of proof as well. It just does not prove where the oil is coming from as running with the injector out. This engine with those compression numbers does not sound generally worn out to me. Many other members have little more than half the compression you posted and are motoring around.

Originally Posted by RallyRebel

I'll take another look at the tailpipe tomorrow and report back. What you suggest isn't unreasonable, I'm just frustrated and tired of pulling wrenches on this car. But I also can't stand not knowing and am pretty anal about stuff, which is why I got into aviation maintenance. Question: would oil puke out of the glow plug hole just as likely as it would the injector port? If so I didn't get any oil spray when doing compression checks which I did through the glow plug holes.

The only thing I probably haven't explored is something I've seen mentioned here about oil getting into the IP through an o-ring IIRC. I'd think a side effect of that issue would be improved fuel economy, lol.