My 63 220SEb M127.984 134 hp engine burnt a valve in a strange way (see picture). Instead of the seating area of the valve, there is a pinhole in the tulip area. Did this model come with sodium filled valves? What could have caused a pinhole like that? It was discovered when I made a compression check and the result in the #5 was 60psi! I squirted oil in the cylinder and another check brought the compression back to normal giving me the impression that I had a broken or stuck compression ring when in fact the oil was temporarily filling the pinhole! Removing the head was a relief upon discovering the valve as opposed to a possible broken ring and scored cylinder and possible engine replacement. Appreciate any comments for cause.
|pinhole in #5 exhaust valve.jpg||45.2 KB|