16 replies to this topic

[gazza82]

The distributor will hold the top steady.

[tiger99]

Yes, indeed it will, which is how it is intended to work. Otherwise you would have a rigidly located shaft engaging tightly with a rigidly located drive gear, and any error in concentricity would result in bad things happening, starting with rapid wear. I thought that should be explained lest anyone thought that it was just sloppy manufacture, which it isn't. However, in some cases there is sufficient sideways play that the distributor drive dog will engage 180 degrees out, which you can't see as you install the distributor, and probably can't feel either, and then you have a very wobbly shaft, forced out of position, which will be noisy, and self-destructive. It will also, after not too long, damage the lower bearing, which is plain cast iron in the block. A good machine shop could fix that by boring concentric with the distributor mounting bore and fitting a bush, but it would be an engine out job. Very careful observation as you fit things together will avoid the problem. Obviously you would install the dizzy with the cap off so you can prevent the innards rotating too far from the estimated position for correct engagement, and you wiggle the rotor arm slightly till the dog engages..

 

The other thing that happens is that the distributor bearings themselves start to fail, which is detectable by sideways movement of the rotor arm. There should be rotational movement against the springs of the centrifugal advance mechanism, but negligible sideways movement, as it affects the points gap and the timing. Failure can be surprisingly rapid, and possibly accompanied by brass/bronze powder in the distributor. When one of my Lucas distributors failed in that manner, I had to adjust the points about 6 times to get the car home from Heathrow, a distance of about 20 miles, it was wearing so fast in the final stage. It was running ok when I left home. That was actually on a Hillman Avenger, but fundamentally the same Lucas distributor.

 

If you don't have a Lucas, but a Ducellier that still works, I for one will be amazed, as they were dreadful and had a very short and troublesome life. 99% of the time the Lucas was ok. I had nearly 200k miles out of one. If a Lucas is faulty, don't get ripped off, send it off to the Distributor Doctor for proper reconditioning.