Anyone here know of a quiet vacuum booster motor?
however to my surprise made 11 to 14 at 2500 rpm
And the vacuum at stall is?
Once the booster is fixed, it only takes a couple of seconds to evacuate it. I mean it is a really small chamber when you think about it.
The Check valve is the key; it has to work, else the vacuum in the booster will follow the intake manifold vacuum lock-step. That would be bad. The booster has to "store" the vacuum created during high-manifold vacuum, to be used as required, including during periods of low vacuum. That's why the checkvalve is there.
The pushrod length is only right one time; when it left the factory, and IMO, it was too long right from the get-go from Chrysler. You can, over a narrow range, use the length to fine-tune the assist timing, not the amount per se, but when it starts.. If you find yourself, as is usual, diving for the windshield every time you brake, your timing is wrong for your driving style. Usually the boost is coming on too soon or rather too suddenly. Shorten the Pushrod. And vice-versa. If you find yourself pressing harder and harder in attempt to slow down,and you know the booster is charged, then lengthen the pushrod some.
There are a few caveats;
1) if the pushrod gets to be too long, the piston will cover the compensating port.If not corrected;
2)Over time your pedal will drop and mess up your boost timing, but also
3) a full pedal will not apply the brakes properly. And
4) you will eventually break the control valve, trying to put the pedal into the carburator.
so the take-away is to prove the C-port continues to work after every adjustment. One turn atta time, until you get close, then a half turn.
Happy scre, er adjusting.
