[RB20s13]

what else other than worn piston rings could be causing me to burn oil? i did a comp. test and got ~180 across the board, which i understand is reasonable. i lose at least a quart a week (about 300 miles). its not a leak because i've never seen a drop under the car.

any ideas?

'91 si, 180k miles

 

[Tiersin]

It could passably be bad valve seals.

 

[ZeniceguyCRX]

head gasket leaking oil out the block, valve cover gasket, oil pan... lots of stuff could make u lose it.

 

[Tiersin]

I never thought of that. Are you leaking at all, or do you know its burning?

 

[jfrolang]

Any oil on your spark plugs?

 

[ludesrv]

Valve steam seals can get worn and slowly leak oil ontop of the valves, especially when the car sits overnight. You should see blue smoke on start up if thats the case. Go and double check that you are not leaking any oil. Also, have someone chase you when you go thru all the gears all the way to red, they will tell you if your burning oil at high RPMS.

 

[RB20s13]

Valve steam seals can get worn and slowly leak oil ontop of the valves, especially when the car sits overnight. You should see blue smoke on start up if thats the case. Go and double check that you are not leaking any oil. Also, have someone chase you when you go thru all the gears all the way to red, they will tell you if your burning oil at high RPMS.

o i'm def. burning it at high rpms, the smoke is pretty bad.

yeah, there is some oil on the spark plugs

looks like i need to get my 240 all fixed up so i can pull the head off this thing...

 

[bobski]

You can have oil leaking past the piston rings and still get good compression, strangely enough. Oil leaking past the rings shows up mostly at high RPM, though the worse the leak, the lower the RPM required to see smoke.
If you have enough compression blow-by, it can force oil back up through the valve cover breather into the intake.
A stuck PCV valve could pull an excessive amount of crank case air into the intake manifold, picking up oil along with it.
As ludesrv said, bad valve stem seals would primarily give you smoke at startup, though a bad enough leak could give you constant smoke.
An oil leak from the head gasket would result in oil on the exterior of the block, or in the coolant. There's no place on the gasket where an oil passage is next to a piston, so you would end up burning coolant, not oil.

 

[ludesrv]

Valve steam seals can get worn and slowly leak oil ontop of the valves, especially when the car sits overnight. You should see blue smoke on start up if thats the case. Go and double check that you are not leaking any oil. Also, have someone chase you when you go thru all the gears all the way to red, they will tell you if your burning oil at high RPMS.

o i'm def. burning it at high rpms, the smoke is pretty bad.

yeah, there is some oil on the spark plugs

looks like i need to get my 240 all fixed up so i can pull the head off this thing...

Sounds like your piston rings are done. The compression rings may be fine, but your oil ring is definitly in need of replacing. I say it's time to swap it to a B16 .

 

[andystart]

I have a similar problem with my DOHC ZC though not so bad.

A local mechanic suggested putting Sea Foam in the crankcase, driving till the oil's black then changing the oil and repeating till the oil stays clear. Supposedly, the sea-foam will eventually eats into the carbon deposits that cause the oil rings to clog and stay contracted in their slots.

Seems like a decent theory so I'm trying it. I've driven about 500 miles since the first lot of Sea Foam went in and the oil's black already - so by his criteria, I'd need to change it.

Car's in blankets for the winter so I won't be changing the oil again till Spring.

I got my Sea Foam from Fleet and Farm - I think most auto stores carry it.

Give it a try - unless you really are looking for an excuse to put in a B16!

 

[RB20s13]

Sounds like your piston rings are done. The compression rings may be fine, but your oil ring is definitly in need of replacing. I say it's time to swap it to a B16 .

b16 would be nice, but im done w/ engine swaps for a while lol (due to lack of funds). i'll be keeping the d for the forseeable future.

 

[rex2nr]

what trim car do you have again?

 

[RB20s13]

what trim car do you have again?

'91 si

 

[rex2nr]

Damn, I have a D15 bottom end... I'd recommend rings, bearings, and gaskets. I was going to use it in my mini me but the A6 block is stronger.

If you're interested, its just taking up space, but is disassembled and has been honed.