I recently bought a 1940 Chilton manual for my car (and others from the pre-war vintage). I learned that when the vacuum booster diaphragm has failed the vacuum booster pulls oil from the engine and sucks it into the intake. This causes excessive oil consumption and smoke from the exhaust. I thought, before this, that my car needed to have the rings replaced. Turns out that the diaphragm was shot in my vacuum booster!
I rebuilt a spare fuel pump/vacuum booster I had and mounted it on the motor. Smoking problem solved. That would have been a costly repair had I not discovered it. I haven't found this info anywhere else. I thought it would be a good thing to share here. The place where I have learned so much valuable information.
Joe,
Very good info! Thanks for sharing. Am sure it shall be of help to others.
This unit is basically a dual fuel pump? Fuel pump one side and vacuum pump on the other operated by one lever or pushrod that goes into the crank case?
I have seen fuel pumps partially fail and pump fuel into the crank case. Makes sense that a part failed vacuum pump could suck in oil.
That is helpful.
Same thing happens on 1964 Caddies and newer (up to maybe early 1980') when the turbo hydromatic transmission vacuum modulator fails and trans fluid gets sucked into intake manifold. Only difference is the car shifts poorly and you have a good clue what problem is.
Thank you!