H4 Magneto timing

[wbw1mi]

1940 Farmall A; when timing the H4 mag to tdc; is the same method used as if you were timing the mag on a Cub? Currently I have the pinion with one tooth cut low and flat, not angular. The cut tooth is meshed directly between the R and L markings on the distributor spindle gear. At tdc, the rotor tab is pointing at the secondary leadout.
Thank you. I appreciate your time.

[Rick Spivey]

It needs to point to either the R or the L, but not between. One tooth off will not crank, based on an H I worked on last weekend. The H was supposed to be set to the R, I suspect the A is the same. If I'm wrong, hopefully someone will catch it and correct it. The R and the L were for opposite rotation; I believe most of the "standard" Farmalls will use the R. I don't know what engines used the L.

[Jim Becker]

Yes, what Rick said. Left rotation was only used on 9-series and gas start Diesels.