How Many Different shutdown valves are there?
I like your idea Mike of having filters on vacuum lines, clear ones at that, would isolate many problems vacuum wise much quicker. Patsy I don't have an elaborate vacuum system on my car as others might. For the ignition vacuum circuit it takes vacuum off a three way "Y" off from the tee from the power brake booster line, goes to the ignition vacuum switch them out to the shut off solenoid on the pump. I don't have any vacuum lines going down to the tranny, all linkage driven. No vacuum valve at all located on the valve cover. I would say the constant vacuum on the injection pump shut-off diaphragm after shut down sucks just enough oil through a crack or pin hole in the rubber to pull oil to the switch, causing droplets to form on a daily basis. The stopping action of the engine is almost immediate once I turn off the key, maybe a second will go by. There is no other source of oil in the system except through the vacuum pump itself, and that was fixed last week with a huge difference in oil consumption and WA LA no oil in the air filter housing, at all.
My main question is how do you know if a new valve will fit your pump? Looking through the manual for the engine, is shows several MW style pumps, and would assume that the shut down valve is different on each of them, is this correct? How can I isolate which vacuum valve I need using the numbers located on the pump. Also, which numbers do I use? There are numbers on a plate at the side front of the pump as well as the rear side of the pump. Which plate is the tell all?