Oil on a valve - How can I diagnose?

[Turf1600]

I've got some oil on one of the valves on an m10. Is there an easy way to tell if it's the rings or the valve seals?

Here's a bad photo:




For this car:

[jlevie]

A compression and leak down test.

[Turf1600]

A compression and leak down test.

I can't run a compression tset due to the motor being out of the car. Also, I don't want to buy a leakdown - and I can't find a damn place to rent one. Maybe I should ask if someone on here has one?

[jlevie]

You can run a compression test with the engine out of the car. You have to mount the starter to the engine and attach a push button switch to the starter solenoid, but otherwise it is the same as doing the test with the engine in the car.

[Turf1600]

You can run a compression test with the engine out of the car. You have to mount the starter to the engine and attach a push button switch to the starter solenoid, but otherwise it is the same as doing the test with the engine in the car.

I'm not sure of the effectiveness - the car is 6v and the starter is SLOW

[jlevie]

The book compression values for that engine take into account the 6v electrical system and the starter. If the engine cranks over slower than others of the same era, you might need to rebuild the starter.

[Turf1600]

Since I suspect it's the valve guide seal rather than the pistons I'm going to go ahead and put the motor in the car and run it. At least this way I can do a compression test AND a leakdown.

I forgot to mention the motor has 19k miles on it - but it was rebuilt 16 years ago.
I'm going to go ahead and prepare to get the head rebuilt.