My brother just bought a 1990 4runner with the 22re motor. The previous owner was very proud of the fact that it had 300,000 kms on it and it didn't burn any oil. So... my brother never checked it until his oil pressure started to go down. He then had to add about 2.5 litres to fill it up. Then we figured out it had a valve cover leak so we fixed that and it still used some oil but nothing bad. Now all of a sudden it has started to use a full litre of oil every 300 kms.

On start up it doesn't smoke at all but the exhaust has a wierd smell to it. If you bring it to redline and rev it for a bit you see a trace of black smoke but not blue at all. I checked the plugs today and they had a trace of white on them, not very much at all. I also did a compression test with the motor warm and I got.
cyl.1-150
cyl.3-160
cyl.2-160
cyl.4-155
Thats normal right?

What could be the problem of it using this much oil?
BTW there is no oil leaking onto the ground where the vehicle sits but I haven't jacked it up yet to check if its leaking. I have to put in my new alternator in my truck tomorrow so I can use the garage.

Have you checked the coolant for oil contamination?

Yup, checked the coolant today. It's still right to the top and perfectly green, even in the overflow reservoir. I also checked for leaks and found none.

Would it be the head gasket?
valve seals?
actual valves???

The exhaust has a wierd smell but its definately not a sweet smell. As I said before the plugs have a slight white residue on them and the exhaust has a hint of black when its revving up to redline. It hasn't puffed blue once.

There are only so many places oil can go to. If it's not in the coolant & not showing up on the outside of the engine, then it's getting burned. I had a van that would burn a quart every 100 miles yet only occasionally emitted blue smoke.

Could be the head gasket or valve seals (bad valves will not cause oil burning, but if the seals are bad you're looking at a valve job anyway)
Rings would be another possibility, but your compression numbers would put that low on my list.

Sounds like valve seals. If its not leaking, then its getting burned. If it were anything but valve seals your compression should be affected.

-Scerb