Any oil present cannot flow up through the base of the valve stem seal on one of our diesel engines. So any seal there would be without purpose in general. The internal blowby pressure would have to be higher than both the exhaust stream and turbo pressures.


Perhaps that is why the design of the injection pump shutoff was designed to shut down if that kind of pressure was built up in the crankcase. Anyways it would be expected for a metal set to be a very tight fit. There is no way they can easily expand to hold on tight otherwise. Like the all rubber ones do.

Your choice to change them out or not. At the same time they might have been just an alternative seal for your engine. Great pictures as well.


These seals might have troubled me on a gas engines intake valves. Especially if they were not a really tight fit.