I measured one intake valve to guide clearance using a dial indicator and got 0.005 which I believe is okay. The seal I removed prior to measuring is very loose on the valve stem so I think I may have identified the main problem. I will check all the rest for stem to guide clearance and inspect the removed valve stem seals but given the visual appearance of the valves through the ports I anticiapte they will all be similar.
Too bad I pulled the engine and the pistons out rather than just replacing the valve stem seals with the engine in place but I'm glad I did check everything out rather than assuming everything was put together correctly.
I suspect that the stem seals dried out between build and initial operation and basically stuck to the valve stems such that they wore quickly. The ID of the seal that should be riding on the valve stem has a white plastic apperance leading me to believe the rubber material that was intended to be between the plastic and the valve stem is totally gone away. As a result the engine has been operating with essentially no seals and I shouldn't be surprised it was consuing oil as a result.
