Another one jumping on this thread...advice welcome.
My track car is on 88k and had a top end rebuild (new valves and cams etc as it went bang) by Rentech at 67k. When I removed the stock inlet some time ago there was a small amount of oil in the inlet plenum (not from the breather as I vent to atmos)..I'd say less than a teaspoon. I cleaned the inlet in the dishwasher and refitted, then when I swapped over to the new custom inlet, there was the same oil amount present.
When I removed the lower inlet, each of the ports on the head had a golden sheen to them (no oil visible but obviously oil had been in there). I cleaned all this and fitted the new inlet.
100 miles have passed since then and when I removed the custom inlet last night the golden sheen is there on the ports again and once again a small trace of oil in each runner at the port end and less than a teaspoon of oil in the inlet chamber.
The car doesn't seem to burn any large amount of oil, also I don't notice any oil under load or otherwise out the back....any thoughts?
I'm going to buy a compression tester from Halfrauds at the weekend to see what's going on as others have suggested (might then go for a leakdown).