oil in the exhaust port of head?

[rtviper]

Took off the headers to check for trueness and discovered 1 of the exhaust ports was wet 360 degrees inside with oil. Looked at the valve with a mrror and it is dry on the stem and the valve head. The port inside the header is dry also. Would this indicate a leak from the valve cover into the port ? The motor does not smoke at partial or full throttle but if left at idle for a will give a puff of smoke when you rev it up. No smoke when you start the car either. Thanks

 

[Blown&Injected]

Sounds like a bad guide.

There is no way, short of some failure, for the oil in the valve cover to get into the exhaust port.

 

[rtviper]

If it was a guide wouldnt there be oil on the stem and the valve? The head around the outside of the port had oil on it and the surface that mates to the header was black. Could it not run into the port between the header flange and head? I had just got the car back from about 10 pulls on a dyno plus the plug looked oil free like the other 5. The strange part was the oil was 360 degrees around inside the port and wet but again none at all on the stem Thanks

 

[Blown&Injected]

OK, I reread the OP and I think I get what you're saying. You suspect that oil is leaking past the valve cover, onto the head, flowing onto and around the exhaust port where the manifold bolts to the head. The black sounds like exhaust leak. If it gets out, then oil could get in.

If it were leaking bad, I would believe it would show in the header tube too. How wet is it inside the exhaust port in the head? If it is just around the edge with no or little depth inside the head, then it would support the leak from above theory.

I have to ask, why did you pull the header to check? It must have been leaking. Could be just that simple. Were the bolts tight? How straight was/is the manifold flange?

Yes, there would be some oil on the valve if the guide were leaking. I ignored the part about mirror and valve appearance because it seems like it would be hard to detect some oil on the valve stem via mirror inspection.

 

[rtviper]

Blown thanks The port was wet all around and in about an inch but at the valve guide it was dry. I removed the header to have an external wastegate installed. I checked the header and the center port was hitting the head before the 2 end ports were so its possible the end port wasnt sealing very well. Good point about the black on the port edge being exhaust leaking past the header cause the 2 end ports had that and the center port was nice and grey