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Old 03-01-2020, 11:39 AM   #1
johnbuckley
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Default Why a fibre thrust washer on distributor?

1) I can see the reason to have a thrust wsher to stop axial movement of the distributor shaft but isn't the fibre thrust washer (A12181) sold by the usual suppliers going to wear out within the first few thousand revs? Surely a steel shim washers would be better?
ALSO. 2) What is the logic for having a plain washer under the lock washer of the cam screw? (no part number for the plain washer but it's item #33 in the Brattons/snyders exploded diagram)
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Old 03-01-2020, 12:52 PM   #2
Russ/40
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Default Re: Why a fibre thrust washer on distributor?

The fiber thrust washer on the bottom gets well lubricated, and the load on it is negligible. It is much like the fiber washers found in generators, that never seem to get any wear. The flat washer under the cam lock washer helps keep the point cam from moving when tightening the cam screw. At least that is my feelings on the matter. I have observed that the fiber washers at the bottom are always too thick. I use one like the kind found under the top plate, for the lower thrust as well because they are closer to the thickness needed. I adjust up/down thrust, if needed, by honing the top surface of the bottom collar enough to set thrust and allignment of the bottom pin. Works for me, although time consuming to get it right.

Last edited by Russ/40; 03-06-2020 at 05:29 PM.
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Old 03-01-2020, 03:56 PM   #3
johnbuckley
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Default Re: Why a fibre thrust washer on distributor?

Thanks Russ, all makes sense now you've explained it!
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Old 03-06-2020, 07:47 AM   #4
RonC
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Default Re: Why a fibre thrust washer on distributor?

Ford specified .004-.010 end play. There should be a fiber washer A-22331 under the shaft collar to keep the oil out of the top housing not a steel washer. No washer goes on the bottom. The design is to allow the engine oil to travel up the shaft.
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Old 03-06-2020, 12:37 PM   #5
Benson
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Default Re: Why a fibre thrust washer on distributor?

JOHN,


WWW.MODELASTORE.COM (berts) has both fiber and steel washers


steel are .015


fiber are .030 thick


so you could use two steel in place of the fiber one for a total of three washers.


steel here:


https://modelastore.com/electrical/d...roduct_id=4221


Fiber here:


https://modelastore.com/electrical/d...roduct_id=4222
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Old 03-06-2020, 01:52 PM   #6
johnbuckley
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Default Re: Why a fibre thrust washer on distributor?

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Thanks all, I was intrigued by why a fibre washer wouldn't wear away quickly and why there a washer was used under the cam screw . Russ's explanaton #2 sounds logical .
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Old 03-06-2020, 02:05 PM   #7
Tom Endy
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Default Re: Why a fibre thrust washer on distributor?

I am also in agreement with post #2. I believe that the .015 steel washer at the top is there as a thrust washer and helps prevent wear to the top of the casting tunnel. The fiber washer goes to the bottom. I am not sure the purpose, but most drawings show it there. When rebuilding a distributor I try to eliminate excessive thrust clearance. Sometimes I have to add a second .015 steel washer above the fiber washer at the bottom if there is excessive thrust. Other times I have had to grind material off the top of the collar at bottom to achieve proper thrust clearance with a steel washer at the top and a fiber washer at the bottom.

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