Generator Pulley Sizes.

[Phil Gillespie]

1939 Standard Coupe fitted with 2 brush generator. Fan bolted to pulley. Single vee belt type.
Started it up and a rattling noise from generator. Pulled it off for inspection.
In the process of stripping it managed to break a piece off the vee belt area!!
I found another repaired pulley and so fitted that one.
The one I damaged was 3.58" OD Part No on pulley 74.10130.
The one I fitted was 4.38" OD only No on this was S4?.


According to Green Bible the correct pulley for 39 is a 4.38" pulley so it appears the pulley of smaller diameter was not correct? This would give some extra genertor rpms. Now the correct size one is on so its always hard to be sure over the years whats really correct. This generator would be rated at 28 amps?


Would the smaller diameter pulley be from a 3 brush earlier generator?
Seems these pulleys especially with the bolt on fan are a little hard to come by.


Phil NZ

[FlatheadTed]

Phil Others will know more about pully sizes offerd ,but I have looked at the possibility of maching the early 3 brush pully to fit the later 2 brush shaft when I was doing alternater conversions and it couldn't easily done ,Ted

[supereal]

If you hear any vibration from the fan, carefully check it for crack between the blades and the hub. Any found will eventually cause a blade to break, usually damaging or destroying the radiator. Same is true for any blades which are bent, loose, or otherwise distorted. Pulleys on old Fords require a belt pitch that matches the groove. Over tightening the wrong belt to reduce slippage will cause damage to the bearings and bushings of the generator and water pumps.

[Phil Gillespie]

Originally Posted by FlatheadTed

Phil Others will know more about pully sizes offerd ,but I have looked at the possibility of maching the early 3 brush pully to fit the later 2 brush shaft when I was doing alternater conversions and it couldn't easily done ,Ted

Yes I see the earlier ones have a smaller boss for the smaller diameter shaft and can see how it would be difficult to machine for the larger shaft dia of the 2 brush generator.
just wondered about the one I damaged the 3.58" daimeter one part No 74.10130 what one it initially belonged to. Most listec Green Bible page 477.
Phil NZ

[Phil Gillespie]

Originally Posted by supereal

If you hear any vibration from the fan, carefully check it for crack between the blades and the hub. Any found will eventually cause a blade to break, usually damaging or destroying the radiator. Same is true for any blades which are bent, loose, or otherwise distorted. Pulleys on old Fords require a belt pitch that matches the groove. Over tightening the wrong belt to reduce slippage will cause damage to the bearings and bushings of the generator and water pumps.

What had happened in my case was the back side of the pulley where the cooling fins are located was catching on the front side of the genertor end cover, hence the noise. Just eased it a little in this area on the fins to ensure a clearance in this area. Fan blades, its a 4 blade fan are solid without defects.
Phil NZ

[FlatheadTed]

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In my book 74-10130 ,3.53 - 1938 use with 82A

[John R]

Phil,
The 74-10130 pulley is for 1938-39 60 hp engines with 2-brush generators. A rare animal for sure.

[Phil Gillespie]

Originally Posted by John R

Phil,
The 74-10130 pulley is for 1938-39 60 hp engines with 2-brush generators. A rare animal for sure.

John appreciate your clarification. That was the one I damaged and was on the 85 hp flathead. Now the larger diameter one is fitted and now correct.
Took it for a run today and all quiet. Still able to use existing belt with the slightly larger one.Nice to know and always appreciate assistance.


Phil NZ