I've only owned one car with vacuum wipers, my 62 Comet, and they worked great. Fun to watch them slow down when the vacuum secondaries kicked in on the carb then speed away when I lifted. My friend today showed me an old vacuum powered windshield fan he had found. Got me thinking though. How do vacuum accessories not cause massive lean conditions? It's like a huge vacuum leak in your intake manifold.
That's a good question. I am going to make a guess because I really don't know and guessing is fun.
Did the old vacuum accessories feed to the carb or the manifold? If they go to the carb, they could go past an enrichment circuit.
Modern vent controls are vacuum, but they are so intermittent that even older systems probably don't care and anything new enough to have a MAP sensor will deal with it. My grandpa's (and then uncle's and then dad's) MG TD had vacuum wipers, but by the time I was aware of them the seals were so long gone that they only worked on manual.
It has resistance to the flow of vacuum to provide work.
Either one is a motor, the vacuum supplies a pressure differential and a valve of some sort opens briefly once the pressure equalizes. The next vacuum pulse once again provides a pressure differential.
So it's not a complete open hole, which would be a massive leak.
they connect to the manifold and they don't cause a massive lean condition unless they're getting pretty worn out.
The "vacuum wipers going away" thing is caused by a couple things. Either someone has taken the vacuum reservoir out of the system and/or the double-acting mechanical fuel pump has been swapped out for a single acting pump because it was cheaper.
Double acting pumps have a vacuum pump on one end and a fuel pump on the other. Plumbing goes from the manifold to the vacuum pump, then to the reservoir or accesories. The vacuum pump is there to ensure that you still have wipers when you open the throttle all the way.
FWIW, my wife's 1970 Continental has all the power accesories operated by vacuum except the windows. Power vents, door locks, etc are all vacuum. There's MILES of hose in that car.
I always got a chuckle out of the diesel Benz's with all the vacuum stuffs.
In reply to 46HRL :
My 300SD had all the vacuum locks and stuff. Now it has vacuum brakes and shutoff, nothing more.
Miles of vacuum hoses you say?
My friends mom had one of these in the late 90s... asked me to look at it. Popped the hood, and said "sorry can't help."
buzzboy said:I've only owned one car with vacuum wipers, my 62 Comet, and they worked great. Fun to watch them slow down when the vacuum secondaries kicked in on the carb then speed away when I lifted. My friend today showed me an old vacuum powered windshield fan he had found. Got me thinking though. How do vacuum accessories not cause massive lean conditions? It's like a huge vacuum leak in your intake manifold.
The engines probably ran rich all the time for best drivability.
In the 1940s, Chevrolet had a vacuum-operated shift assist on the 3-speed column shift transmission. That was real funky.
In reply to Saron81 :
That image makes me uncomfortable, even as someone that used to troubleshoot and test installed avionics.
It's like a wiring diagram, only E36 M3tier.
In reply to Saron81 :
Quitter...
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