H4 Magneto timing

Farmall Super A, AV, 100, 130, & 140 1939 - 1973

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H4 Magneto timing

Postby wbw1mi » Thu Feb 23, 2017 11:08 am

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.

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Rick Spivey
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Re: H4 Magneto timing

Postby Rick Spivey » Thu Feb 23, 2017 4:44 pm

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.
Rick Spivey
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Jim Becker
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Re: H4 Magneto timing

Postby Jim Becker » Thu Feb 23, 2017 9:41 pm

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

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