Info needed: M38A1 vent tube

[rob love]

The fording valves are to defeat the PCV system. The size of those tubes is all that is required.

By closing the two valves, you shut off the ventilation system thereby causing some level of crankcase pressure due to the normal blowby (and about 15,00 miles into the life of the engine, the abnormal blowby) of the pistons. This pressure, which may only be a few pounds, helps seal the engine from the ingress of water. Of course, it can also cause seals to blow should it be applied for too long a period of time when there is no need for it.

Personally, if you are not leaking oil, I would live with the problem. One possibility is that the rings have not yet set in on a freshly honed engine...it can be a few hundred miles up to a thousand miles before they fully seat, depending on the tolerances followed.

Another possibility is that the rings may not have their gaps spaced around the piston. I have opened up engines before where the OCD mechanic lined up all the spaces, which is a very rooky mistake.