Exhaust port gunk

[jakev]

So, with the heat exchangers off, I noticed that there are variations of deposit in the exhaust ports. 3 of them have a brownish, dry deposit in them, and 3 of them have an oily gunk deposit. Is there anything I can infer from this, or am I just whistling in the wind?

[Nitrometano]

Maybe can be oil from a bad exhaust valve stem.

[Rot 911]

The three with the oily deposits, I agree with Nitro, probably worn exhaust valve guides.

[Nitrometano]

I change the exhaust system from a 1979 3.0 911 the last saturday. I notice that the engine on exhaust ports from cylinders #2 and #3 are wet wit oil gunk. Thats why the engine smoke white some times at the start up. Worn valve guides or bad valve seals can be the problem. You can use the car until the problem grows, because it is a bad valve guide you will need to tear down the engine. If a bad valve stem you can change it with the engine installed in the car, but is a little difficult. You will need a overhead valve spring compressor, a spark plug air hose (can be from a compression tester gauge) and an air compressor. If you will need to replace the valve guide, you can refresh the engine with some new parts like gaskets, seal, etc. Also another problem that can be the origin of the oily gunk can be the use of teflon valve seals instead the original viton valve seals. I have really bad experience with teflon valve seals, I really don't recomended it.

I dont worry about oily exhaust ports until the problem go really bad.