ok so my car has been smoking at startup lately (bad valve stem seals). but the past coulple weeks, its smoking while its running. it is burning oil, and not just running rich. if its smoking while running, is there a chance it could be the valve stem seals just getting worse, or is it probably the piston rings?

im doing a compression test saturday, but i was told it may not even tell me if the rings are the problem. i was told that there are 3 rings per cylinder (2 for compression and 1 for oil). is this correct? he said if the compression rings were fine and the oil ring was bad that a compression test could still pass for being good.

i need some second opinions guys. thanx,
Ryan

 

True there are 3 rings. Indeed the oil ring could be a problem. But I've not seen one in 28 years. Ring problems are rare at best. While a compression test is ok, the better test to do is a leakdown test. By testing and removing every other item as a possibility, you kind of fall into a ring issue by the virtue of "nothing else left".

Chances are you have an increasing valve issue or head gasket or intake problem. I'll put my money on your intake gasket(s) leaking.

Unfortunately neither compression or a leakdown test can find that.

You could check all the plugs to find which cylinder(s) is/are the problem and use a borescope through the injector hole to see if the intake valve is wet. If the valve is wet but not the rest of the port, chances are good the problem is at the valve. If the port walls are also wet, chances are it's the intake gasket.

 

Also what you can do is if you get a low compression reading you can squirt a little oil in the cylinder and if your compression comes back up then you have bad rings.