Distributor shaft end play

psimet

psimet

Senior Member
Long story but I got into a situation where I cracked my distributor casting. I ordered a replacement (not going to say where as I haven't even tried to call them and won't if I find a quick solution) but it came with the shaft and corresponding parts assembled.

The roll pin they used on the lower shaft "collar" isn't pressed all the way in and the shaft is already binding slightly in a couple of spots when rotating. If I put the pin in all the way the shaft locks up. I pulled it and took the thrust washer they have on the bottom off and of course now there's a lot of clearance in the shaft. The washer in there is roughly 0.015"

I have a lathe, have been a machinist in my misspent youth. I was looking for quick solutions as I was wanting to get the distributor in the car this weekend. Was thinking I would put the collar in the lathe and take a couple thou off the end but was looking for what my target should be for overall shaft end play. 1-3 thou? (0.001-0.003)? or like 0.005?

Thoughts?
 
I can't talk to the proper clearance. But here are my thoughts on the issue: May be binding on the lower bushing, if it was not pressed all the way in. You could just hit the bottom of the distributer on a belt sander and see if you can take off just enough to not get the binding. I don't have a lathe so would use my belt sander on either the collar or the end of the distributor to get the clearance.

Even if you fix it an don't send it back I would let the supplier know.
 
jwmckenzie said:
I can't talk to the proper clearance. But here are my thoughts on the issue: May be binding on the lower bushing, if it was not pressed all the way in. You could just hit the bottom of the distributer on a belt sander and see if you can take off just enough to not get the binding. I don't have a lathe so would use my belt sander on either the collar or the end of the distributor to get the clearance.

Even if you fix it an don't send it back I would let the supplier know.
Click to expand...
Another thought - I've seen some distributors assembled with a thin washer at the top of the shaft, between the bottom of the flange and the distributor housing. The distributors did not originally come with that washer, so you may be able to remove that washer (if it's there) and get a bit of end play. All you are after is barely clearance fit - 1 to 3 thou is good. I don't think this is a horribly critical value, all you are trying to do is make sure you don't bounce the cam and throw off the points. If you can't get the end play you need by removing the top washer (if present) then you can either take a few thou off the top of the collar as you suggested, or (as suggested by jwmckenzie) sand the bottom of the distributor a bit (assuming that both the upper and lower bushings were pushed all the way in).

You do need the thrust washer at the bottom between the collar and the distributor housing. Bert's sells thin metal (0.015") and thick fiber (0.030") thrust washers for that purpose. Sort of a bummer that you need to do that on a brand new distributor, though.

JayJay
 
This is how I do it.
Many shafts are too low, causing the rotor to be too low from the contacts in the cap and the rubbing block will be at the top of the cam.
Many times I need to put a fiber washer and a thin metal washer at the top to raise the shaft up to make the rotor centered with the contacts in the cap and the rubbing block on the contacts centered on the cam.
After I get the correct height of the shaft, I machine the bottom coller in a lathe just enough to let the shaft turn easy without binding. Sometimes you will need a fiber washer on the bottom and sometimes you do not need a fiber washer on the bottom.
 
I also have found that most of the time the shaft will bind if the metal and fiber washer is used as shown in some diagrams. I do as 1930 coupe above does in that I put the coupling in the lathe chuck and trim it off until it fits on the distributor shaft with the pin installed without any binding.
 
I ended up taking a tiny bit off each end with some emory paper assembling until I got reduced binding and started to develop a tiny bit of end play.

Put a tiny bit of oil on the bushings and checked the whole assembly up in my lathe and ran it at low speed for 30-50 seconds and everything seemed to wear in a bit and it was able to spin without binding at all. Should be good.
 
Make sure you oil it BEFORE you run it in the car. I have seen a few that didn't get oil and be toast in a short time.
 
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