

| Subject: | Checking vacuum diaphragm was Re: Looking for a 83-85 distributor |
| From: | David Beierl |
| Date: | Tue, 7 Oct 2014 13:23:42 -0400 |
At 11:31 AM 10/6/2014, Ryan Perry wrote: >Excuse the unknowing question and possible thread jack but how do you check >the vacuum advance? I have an 84 with a terrible time taking off...I have >to rev and get throttle up for it to go or it just sits there hesitating. >wondering if this might be my issue as well? The 1.9l distributor has centrifugal advance and vacuum diaphragm mechanisms for both advance and retard. I'm sure Bentley has specs for degrees of change vs amount of vacuum, but to check that they work, pop the top off the distributor. Pull the vacuum lines off the advance mechanisms and using a spare piece of tubing suck on each one and watch for movement of the rotor. It should rotate as you suck, come to a hard stop at some point, and smoothly return to a stable neutral point as you gradually allow air back into the tubing. One should cause clockwise and the other anticlockwise rotation. The centrifugal advance is operated by a pair of spring-loaded weights inside the distributor body. I don't think you can directly check them with the distributor in place (but they're affected only by rpm). While you have the top off put a few drops of oil into the felt in the top of the distributor shaft, under the rotor. Yours, David
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