Generator pulley ID
 

I've been advertising what I thought to be an 81A- style generator pulley - has fan mounting screw holes - 4 3/8" OD. However, one gentleman asked about the inside diameter and when I told him it was 0.585 inches he said it must be for a '36 because the '38/'39 pulley had a larger ID. The Green Book shows the 68- part was replaced by the 81A- one. This is true for both pulley and generator. So, my question is: Did the original 68- generator have a different shaft diameter than the 81A- version? There is no part number on this part. Kube - is this in your area of expertise?

Re: Generator pulley ID
 

The picture is to dark for me to see but it looks like it is keyed. This would make it for an early to mid 30's model or truck with a fan. It also is a large diameter as show by the fan mounting screw lugs. and your measurements Larger trucks used the larger pulley's so they wouldn't over charge the batteries. The later generators used a larger screw on pulley. G.M.

Re: Generator pulley ID
 

Yes, it's keyed.

Re: Generator pulley ID
 

I saw the pictures posted in your for sale ad here and felt that it looked identical to the pulleys on my stock '35 generators. I have '38 - '39 std fan mount pulleys and the cooling fins and ID are different than your pulley, plus they have the 81A-xxxx part number. I believe whoever told you it's not '38-'39 is correct.

Re: Generator pulley ID
 

What years had fans on the generators?

Re: Generator pulley ID
 

Not my area but I would hazard an opinion... I think this is '33 - '34. The cooling fins do not look correct for '35 - '36. Mike Driskell would know that.
The '39 pulley had an inside diameter of around .660" if I recall correctly. It is definitely not 39.

Re: Generator pulley ID
 

Through 1939 Ford mounted the fan on the generator. However, in '39, only the "standard" models had this particular set-up.

Re: Generator pulley ID
 

Thanks everyone!! I'm getting a better picture! Not at all what I thought it was!! Looks like '33 through '36? Maybe '37?

Re: Generator pulley ID
 

Here's a good site page that identifies the pieces to the assemblies they belong to...

http://www.fordgarage.com/pages/generatorchart.htm

Lonnie

Re: Generator pulley ID
 

DD931...you must have put in some time with Uncle Sam on that US Navy Destroyer :)

The pulley in your picture, post #1, is part number 40-10130-B, used on Ford passenger cars from '34 to '36.

The pulley you thought you had is part number 81A-10130, used on '39 std. passenger cars for sure and possibly '38 as well.

Attached are front and back pictures of both pulleys. 40-10130-B on left, and 81A-10130 on right. I have a collection of these fan mount generator pulleys. Probably at least one sample of most that Ford used on the early V-8's. I believe you can see the difference in ID and cooling fin configuration that I mentioned in an earlier post. Both of these pulleys have 4.375" OD.

Re: Generator pulley ID
 

Definitely not '33. '34 to '36 passenger car. Check with Michael Driskell or maybe his Dad, Danny Driskell, the EFV-8C/A 1935 Ford Advisor.

Re: Generator pulley ID
 

John - Yes - USS Forrest Sherman (DD931) Engineering Officer '66 - '69. And Thanks for the great info!! Norm

Re: Generator pulley ID
 

Binx - Just what I needed!! Thanks!!

Re: Generator pulley ID
 

What is the difference between a 78-10130 and a 81A-10130 Generator Pulley? Thanks

Re: Generator pulley ID
 

Charles - Look at the link in Post #9. It shows pictures with dimensions and part numbers. Even though they look a lot alike, my guess is that the shaft diameters are different.

Re: Generator pulley ID
 

Norm,
The 78-10130 Generator pulley shaft diameter is the same as the 81A-10130, and both pulleys are 4.375 OD". Maybe John can help. Thanks, Charles

Re: Generator pulley ID
 

One of them threads on and the other is keyed on.
I believe the 78-10130 threads on.
Bill

Re: Generator pulley ID
 

Charles, I have samples of both of those pulleys. The only two areas that I can see that are different are the cooling fins are a bit higher and longer on the 78-10130, and the shaft mounting ID is positioned a little deeper in the front and higher in the back on 78-10130. This may be because the configuration of the armature shafts were different where these fans mounted and/or possibly the mounting hardware was different for each pulley on the armature shaft. Hopefully the attached pictures will better show what I am trying to describe. The 78 pulley is on the left and the 81 is on the right in all of these pictures.

Re: Generator pulley ID
 

The difference between 78- and 81A- is very subtle. Both were used in 38-39 (maybe as early as 37). As already mentioned, the shaft diameter is the same (the "large" late model shaft diameter) with the same means of retention (Woodruff key, etc.). The difference is they mate with different front plates. The 81A mates with a 79-10139 front plate (for the small diameter, three-brush generator case). The 78 pulley mates with the the 78-10139 front plate (for the large diameter, two-brush case). You have to look very carefully at the Ford drawings of these pulleys to see the actual dimensional differences. During 37-39, there were several different fan-mount generator assemblies used - some oddball assemblies were low production versions used on a trial basis.

Re: Generator pulley ID
 

That does not appear to be fact based on the samples I have. Both have smooth, keyed bores of the same diameter.