burning oil?

[treed2@u.washington.edu (T. Reed)]

Okay, so last weekend I checked my oil level and was mortified that it was
as low as it was (about 2mm below the cross hatch pattern on the
dipstick). I filled it up and then I checked it again this weekend and it
has dropped again (not as much, since I haven't driven it as much, duh).
I'm not leaking oil, so it appears that I'm burning it (i did notice that
I'm making a little more smoke lately). Slowly- my suspicion is about a
1/2 cup every 100 miles.

This is bad and makes me unhappy because my 1.8 16v never burned any oil -
in 3000 miles the dipstick would read the same as it did when I filled it
up. The 2.0 bottom end I put in looked beautiful and while I never checked
the compression myself (where can you buy a compression tester that will
work with a 16v's deep spark plug wells?) the P.O. told me it was good
(190 x 4 or 210 x 4), can't remember). The cylinder walls looked
excellent, and I was too cheap to buy rings and rebuild the whole thing.

My gut feeling is that its not rings, because why would they go bad so
quickly? Also my engine has just as much power as it did the day I put it
in, so I'm feeling like this isn't a compression problem.

So what else leads to burning oil - bad valve seals or valve guides or
sth, right? Thats a real possibility since I did some clean-up porting on
the head when it was off and although I used compressed air to blow the
metal chips out very carefully, some of them could have gotten jammed in
there and wore the things to the point where they leak..

That was my theory until today when it occurred to me that when I did the
engine swap they gave me a 71 C (super low temp) thermostat instead of the
standard thermo I asked for. I've been driving the car with it out of
laziness (don't want to bother draining the coolant just to change it) but
the side effect is that the car never warms up. It always stays very very
cold, in fact my heat barely works at full blast after 1/2 hour of
driving. The only time the car warms up is if its been taken for a hard
drive and then I stop and idle it for 20 minutes. Then it will come up to
what I consider "normal" operating temperature - the water temp needle at
the LED on the gauge.

Anyway.. it occured to me today that if the car is never warming up, maybe
the rings/pistons aren't expanding and sealing properly.. thereby allowing
oil past (and/or wearing out the rings prematurely - wouldn't that be
stupid!)

What do you guys think? I bought a water pump (squeak squeak squeak) and
standard temp thermo from Mark @ Adriondack last night and it should be
here in about a week so we'll find out if it stops consuming so much oil
after that, I guess. But in the mean time.. should I be reading up on
valve seals and what kind of a job that is or do you think my theory has
any validity?

-Toby