Exhaust valve color analysis?

did u use oem, or other valve seals? i had a lot of my new seals leak after a new build. i had put in the cheap seals, that came with the gasket kit. i had to replace them all with new, oem seals. all is well now.
after u put some more miles on it, i would do a leak down , and compresion test before u tear it apart. it would be nice to know if u had an oil ring issue .
i dont know if a bad oil ring would show up in thses tests but if there was anything odd about the tests, u could look into it during the tear down.

I'm not sure what seals were used - I had a shop do the headwork for me. Good idea to test things out before the teardown. It always helps to know what you're looking for. It sure runs great and doesn't show any signs of a problem except for the different appearance when the exhaust is off.

By the way - any theories on why the inside of all 4 exhaust down tubes look the same? They are all carbon flat black looking, not shiny like the valve and exh port.

because they are all coated with a layer of unburned hydocarbons?bj

OK, so other then discussions on bad seal concepts, has anything been found out/confirmed on what this goo is?

Oh crap, 79MKII is a smuggler... Black Tar Heroin....:blink:

I didn't see where what the exhaust system was. But if the port area is slightly smaller than the header tube, and with the sudden larger diameter causing a loss of velocity with the lower pressure area having the heavies left from rich/ oily combustion sticking there. Plus the cool down as the gases pass over the sudden change in thermal properties of going from the head to a tube.