WC56 12V generator pulley size?

[BCA]

I have 2 GDJ-4808 12 volt generators with different pullies: 3.75" OD and 5" OD. The ORD9 G502 says the pulley is AL- SP270 but I can't find a casting number or spec. in any book. Does anyone know the correct OD for the 12V generator pulley as used on WC56 Command (as well as all the 1/2-ton radio trucks with 12v systems)?

[Gaston C Barmore]

The pulley OD on my WC-56 measures 4 3/4 inches.

[W. Winget]

The one on my '42 WC56 and the spare I picked up a long while back are both 5" across the face, edge to edge. This is the generator which is almost as large as the more modern M series types. Cast iron fan mounted behind the pulley flange, oil cup on the end.

By the way, idling them will not charge the battery...need to not sit waiting for a parade for an hour at idle, as it will pull the battery down.
V/R W. Winget

[BCA]

Thanks for the comments. I think the 5” was original. I’ll stick with the 3.75” pulley however since it will spin the generator a bit faster at idle. Still checking various parts books to see if there is a specified OD for the SP 270 pulley. …. Brian

[BCA]

Doing a bit of light reading: TM9-1808A Power Plant, Clutch and Electrical Systems for 3/4 and 1-1/2-ton Dodges, 3 Sept. 1943. There is a reference on p. 197 to the 6V generator pulley being 4” diameter the 12V generator pulley as being 5” diameter. No reference to pulley part numbers. So I’ll accept 5” as being the correct pulley diameter on the 12V GDJ-4808 generator in my WC57 Command Car.