Re: [DML] Vacuum Advance Problem

[mike.griese@xxxx]

Most vacuum advance mechanisms merely rotate a plate 
in the distributor housing around the rotor shaft. 
In the old days, this plate held the breaker points.
As the plate moved, the points changed position relative
to a cam attached to the rotor shaft, causing the points
to break earlier or later. Breakerless distributors move
a hall-effect sensor instead of the points, changing the 
postion of the sensor relative to the rotor itself. 
It is possible that the pivot on which you distributor's
advance mechanism moves is damaged, causing the plate to 
twist instead of rotate. This would cause the rotor 
to hit the hall effect sensor, making the noise and vibrations
you are experiencing.

--
Mike

> Just to give a bit of background, I have just completed replacing the engine on 
> my one of my Deloreans due to severe engine damage caused by the previous owner. 
> I picked up a used engine with 22K miles on it, and installed this in the car, 
> and an having an issue with the vacuum advance.
> 
> The car starts right up, and runs well when it is cold. When cold it runs 
> normal, idle is normal, and there is no unsual sounds. As soon as the car warms 
> up and the vacuum advance kicks in on the distrubutor to advance the timing, I 
> can hear a clicking sound coming from the distributor. It sounds like metal on 
> metal, and the timing is not being advanced as it should.