Distributor shaft screw size

D

Don/WI

Senior Member
What is the diameter and pitch for the distributor shaft screw? It does not seem to be anything standard. Thanks for any response. Don/WI
 
Are you talking about the cam screw? The one that goes in the top to lock the cam in place? I believe it is an odd size. The one that goes in block to lock the body down is 3/8-24.
 
don,


Something I learned the hard way ... pay attention to length of screw that Bob C posted!



If the screw is too long it will bottom out and cam will never get tight.


Originally Ford used a thin lock washer AND a thin flat washer.


If either one is missing, the screw will "bottom out" when using original Ford screw.


SOME of the recent Repro screws come with a THICK lockwasher (twice the thickness of Ford lockwasher and no thin flat washer.
 
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25/64” NF, good luck finding a tap for that at the box store! I had trouble pulling my distributor. I initially thought about fabricating a puller but the size of that thread gave me pause. I finally just kept tapping thin wedges alternately under each side while offering generous applications of penetrating oil.
 
Thanks guys, it was the distributor cam screw info that I was looking for. I should have been more explicit in my description. Don/WI
 
That odd size screw is likely an old American Standard #20 extra fine thread. The American Standard system has been obsolete since 1949. The #20 major diameter is 0.321

Joe B
 
I discovered that my distributor cam screw was missing a washer. This might explain the problem I was having keeping the car in time. I installed a new cam and a thin washer that was on a spare distributor I had knocking around the shop. Is a lockwasher on top of the thin washer a good idea? Some suppliers carry them, and some don't.
 
.. and whilst we're on it why DID Ford originally put on a thin washer as well as a lock washer... does the washer serve any purpose? ( if it's to stop the screw bottoming out it surely it would have been cheaper $$ and quicker $$ to have a marginally shorter screw)
 
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why DID Ford originally put on a thin washer as well as a lock washer
Click to expand...

I would suspect that the thin flat washer is to protect the shaft from getting chewed up by the lockwasher.
 
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