Lotus Elan

What is acceptable distributor wear?

PostPost by: Elanman99 » Sat May 13, 2006 7:33 pm

Using a dial gauge I measured the free play in the distributor spindle and the total lateral movement is about 10 thou. Most of this is play between the distributor main spindle and the bore through the cam. The main spindle and bushes having less then 2 thou clearance.

I have an Aldon Ignitor fitted, this is probably more tolerant of worn bearings but the downside is that the shaft does not have the 'sidetways preload' of the contact breaker so possibly flops around a bit more.

I presume that excessive free play will make the ignition timing erratic, or at least add some random scatter to the ignition pulses, the question is, how much wear is acceptable before it affects the engine performance?

Ian Phillips
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PostPost by: rgh0 » Sat May 20, 2006 6:15 am

The original Lucas distributor I have has about 0.006 inch lateral play at top of the points cam. I ran this distributor with points on the road and track for a lot of years without problems with this amount of movement. The engine however was smoother at high revs with this distributor after I switched it to an optical lumenition system which is insensitive to shaft wobble.

In comparision my spare Bosch points distributor that I now use has 0.0008 inch lateral play at the same location.

I would think 10 thou lateral movement would be excessive and probably not great if using points, how it will work with the modern magnetic trigger systems I dont know.

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