Worn Distributor rotor

[BUBBAS IGNITION]

Another tip learned over the years:

Use same brand name rotor and cap ......
Mixed brands often hit......

 

[scooder]

Bubba,
What was the issue with your friends burnt back coil lead? Why dit burn so?
Martin.

 

[BUBBAS IGNITION]

Bubba,
What was the issue with your friends burnt back coil lead? Why dit burn so?
Martin.

Loose or defective connection. Starts with a small gap increasing as heat etc makes gap larger. Larger gap higher voltage until the gap is so large it wont jump any more......

 

[Walt Dupont--Me.]

Walt....here's a UK spigot . Spin one up on your lathe; or your neighbour's.

The large diameter slides in to the rotor.....measure from the small end.

Got it ?

Got it Tiger. I mic the hole today in a couple of rotors, they are tapered, I'm going make a spigot with a tapper that will tap in the hole of the rotor, sounds like the best idea so far. I want to see if I can get .010 clearance. I've got to admit I've had them before with a couple **** hitting and just grind a little off the rotor, I can see now thanks to Babba that grinding is not good. Walt

 

[SofaKing]

How about this possibly stupid idea. Take a thin strip of scotch tape and stick it to the rotor. Reassemble and turn it by hand...if it doesn't hit, add another strip until it does hit. Measure the stack of tape.

I decided to try the clay and tape ideas for measuring rotor gap and learned three things:

1. Clay works but there is no method of accurately measuring it suited to my attention span.

2. I used 3m painters tape for no particular reason and got light drag on one terminal with 3 layers, approximately .011 gap. I added a fourth layer and got light drag on all terminals, approximately .014" gap.

3. My brand new rotor will rotate .10" inch around the distributor shaft rendering it unusable. The measurements above are from the 40 year old cap and rotor that came with my truck.

 

[Tom Walker]

Like Walt, I'd like to know how to reasonably check the clearance between rotor tip and cap on a 1941 type distributor. I just put them together and they work, but I've never known what the "Standard" should be.
Thanks Bubba for posting that the gap should be less than the plugs.
Good to know
Jim

Jim, is there a brass tip on the rotor? If there is would a small blob of soft solder on the end work? You could file it back to a few thou thickness and try it in the dizzy.