Topic: 46 Ford Distributor Bushing Dimension


51woodie    -- 03-12-2018 @ 9:24 AM
  I am in the process of rebuilding the distributor for my 46 Super Deluxe and need some information on bushing sizes and recommended shaft to bushing clearances. The shaft assy. has P/Ns 11A-12181 and 11A-12185 stamped on the cross plate. The following measurements were taken with a digital vernier caliper.
Shaft drive end: 0.860 points end 0.370
Existing bushings: 0.866 points end 0.378
Clearance: 0.006 0.008

I purchased a drive end bushing from DC, and the I.D. measures 0.869 (not installed) which would only increase the clearance to 0.009.
The Van Pelt web cat. shows the I.D. for their bushings to be: drive end 0.865, which would still leave 0.005 clearance, and the points end at 0.377 and result in 0.007 clearance. During my days as an Industrial Mechanic, the rule of thumb was 0.001" per 1" of shaft diameter. I know on smaller shafts that would not apply, but I don't think that a 0.006 to 0.008 clearance would provide for very stable points operation. Does any one have the correct dimensions for these parts? What are acceptable clearances?

Also when I looked (from the numbers side) at the curved slots in the cross plate, where the flyweight pins sit in, someone put a small spot weld (= about 0.015" in the end of one of the slots. The weld stops the weights from fully retracting. Any ideas why this would have been done, other to change the amount of advance?


ken ct.    -- 03-12-2018 @ 12:27 PM
  I have all the NOS bushings in stock. Usually they must be reamed out for good fit after installation. They usually close up some when installing. ken ct. 1-203-260-9780 cell.


supereal    -- 03-12-2018 @ 2:22 PM
  We fit them with our Sunnen piston pin machine. If you have a good machine shop in your area, they can do it. The fit is important to get and maintain stable distributor performance. The condition of the distributor shaft is also vital. We see a good many that are worn to the place that getting a proper fit in the bushing is affected.


ken ct.    -- 03-12-2018 @ 2:54 PM
  Ive been doing them by hand reamer for 20 yrs never had any trouble with them. Theres more than 1 way to skin a cat. LOL ken ct.


40 Coupe    -- 03-13-2018 @ 8:28 AM
  Ford published Spec. for the distributor including the bushings. I am away from my Service Bulletins maybe someone else can post these.


deluxe40    -- 03-13-2018 @ 11:36 AM
  I have Dealers' Specification Service Bulletin, Subject No. 12000, April 18, 1948. In table 12132-LOWER OR REAR BUSHING, on the line for part number 18-12132 it shows the Max. Inside Diameter to be 0.863 with a wear limit of .8655. In table 12175-SHAFT, on the line for part number 21A-12175 it shows the MINIMUM FRONT DIAMETER to be 0.3742 with a wear limit of 0.373 and the Minimum Rear Diameter to be 0.8625 with a wear limit of 0.861. The box for End Play is blank. The 21A-12127 distributor is for the '42 to '44 engine. The '45 to '48 engine has distributor number 59A-12127. I copied the 21A numbers because they were closest to your measurements and there is no entry for 59A-12127.


ken ct.    -- 03-13-2018 @ 11:48 AM
  I don't think ive ever had an installed bushing that was too loose,most if not all have to be reamed out.This does not apply to the front bush. with the flange those are always on the sloppy side on the helmet jobs. OMO. ken ct.


51woodie    -- 03-14-2018 @ 9:42 AM
  deluxe40, thank you for the info. Any idea what engine/year the 11A-12185 shaft is from? It is odd that Henry would not spec the shafts diameters to be an even size, such as 0.860" vs the spec in your book of .08625".

ken ct I'll contact you for the bushings.


deluxe40    -- 03-14-2018 @ 12:17 PM
  11A is the prefix Ford used for the '41. The '41 distributor looks like the '40 (helmet type) but the internals are slightly different (advance curve is supposed to be superior). The '42 (21A) is like the '46-'48 except that the cap, rotor and bail are different. The Green Book shows many variations.


51woodie    -- 03-15-2018 @ 7:29 AM
  So the 11A is from a '41 and showed up in a '46 bail type dist. Is the advance curve going to be an issue? Would that be why someone put a spot weld on the cross plate to restrict the weight travel (see original post). I wonder if Johnny cash owned this car at one time?


deluxe40    -- 03-15-2018 @ 11:03 AM
  I can't explain how an 11A-12175 shaft could wind up in a 21A or a 59A distributor. In the Green Book (Ford Chassis Parts and Accessories Catalogue - cars '28 - '48 & trucks '28 - '47) the table on page 518 shows that the 11A-12175 shaft fits only the 11A-12127 distributor. (I know it will also fit the earlier 68A distributors like the '37 to '40.) These "helmut" type distributors have a bushing at the front (#12120) as well as the back. The table shows that the 21A-12175 shaft assembly fits both the 21A-12127 distributor ('42) and the 59A-12127 distributor ('46-'48). These distributors only have the bushing at the back, the rotor goes on the front. Are you certain you have a '46 (59A) distributor? Is it possible that your car has a '41 engine? You can't use a '41 (11A) distributor on a later engine without an adaptor. Also, I can't find a part #12181. However, part #11A-12187 was the number assigned to the original shaft, cam and weights assembly for '41. Perhaps you should invest in the Green Book. The distributor section is 19 pages long and it has great diagrams.


ken ct.    -- 03-15-2018 @ 12:18 PM
  Pardon me but 42-48 dist shafts will not fit in a helmet dist. Also there are 2 bushings in crab type dist. Lrg. one on the drive end and a small one on a bridge on the point plate. ken ct


deluxe40    -- 03-15-2018 @ 7:27 PM
  Ken, The '42 (21A) shaft doesn't fit the helmet distributors, but the '41 (11A) shaft does fit - the '41 has a helmet type distributor. I didn't see the second bushing in the diagram of the 21A (pg. 506) but it is shown on as part #12120 in the exploded view of the "distributor breaker" on pg. 515. Thanks, I learned something.


TomO    -- 03-16-2018 @ 8:31 AM
  The OP said that the 11A stamp was on the cam and weights assembly (11A-12176). These parts will fit the 21A and 59A distributor. The shaft, P/N 11A 12175 will not fit the 21A or 59A distributor. The 21A-12175 shaft is only used for the 21A and 59A pancake distributors.

Tom


ken ct.    -- 03-16-2018 @ 8:41 AM
  I know that Tom O. thanks . ken ct.


51woodie    -- 03-16-2018 @ 1:56 PM
  Thank you for all the posts fellows. Is the "green book" you refer to the green 1939-1948 Service Manual, Passenger Cars and Trucks (which I have) or is there another "green book"? If there is, what is its full name and where can I get one.


MG    -- 03-16-2018 @ 2:46 PM
  This is the "green book" aka 'Green Bible' > https://www.ebay.com/itm/Green-Bible-Ford-Parts-Book-1932-1933-1934-1935-1936-1937-1938-Chassis-Catalog/361864327877?epid=2119688480&hash=item5440cb72c5:g:XY4AAMXQskFRHBru&vxp=mtr


ken ct.    -- 03-16-2018 @ 2:47 PM
  NO you have the right book. ken ct. I go by feel not dimentions and go slow with the reamer (adjustable ones)


51woodie    -- 03-17-2018 @ 7:27 AM
  MG Thank you for the link to Ebay. The book I have is green but different purpose. The one you show is also available from Rock Auto, also at a price of $53.99. I ordered one from RA along with some other parts. Ebay is good place to find stuff, but not my first choice.


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