I'm looking at a boat with ford/lehman diesel engines. I had a diesel mechanic look at it, run it, test it, etc. He said that the engines are fine. He also measured blow by and found both engines to be well within spec. Another mechanic said the blow by was high, just by feel at the dip stick, resulting in unburnt lube oil getting past the rings into the combustion chamber and out the exhaust without being burnt - no blue smoke. In fact no diesel smoke. The whole topic came up because it was thought that there were a few drops of oil coming out the exhaust - this may or may not be true - if it is it's usually an oil cooler leak.

Anyway my question - can lube oil can pass the rings and go out the exhaust without being burnt. This engine ran like a top and started instantly. It was without question running on all 6 cylinders.

One thing I noticed about most of these boat diesels - no glow plugs. This particular engine has a cold start valve that you pull prior to starting - it allows more fuel in the combustion chamber. I wish I could put a couple of 3.0L turbo diesels in the boat.
Thanks
Dave

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1986 300SDL