Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

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Ole90633
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Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

Postby Ole90633 » Fri Jan 14, 2022 8:25 am

1949 Farmall CUB, J4 Magneto, #97508

I tried but couldn’t re-find to quote here, MiCarl’s October 21, 2020 9:17PM post, with his method of timing the mag to the engine.
The ‘Book’ has you tipping the magneto out at the top, following the basic “… coil cover against the block with distributor aligned with #1 plug and one complete revolution to the next top dead center.” to trip the impulse coupling.
MiCarl suggests, the same basic actions but, “3) slowly turn the magneto clockwise as viewed from the operator seat until you hear the coupler snap. Tighten the magneto.”
I just refreshed the magneto (new points, condenser, flush impulse coupling, grease pivot post and contact heel, new gaskets).
I like MiCarl’s method however, there is ‘The Book’ method too.
Help me with my ‘coin flip’…

Don

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ricky racer
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Re: Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

Postby ricky racer » Fri Jan 14, 2022 9:44 am

MiCarl's way is the way I static time my tractors with mags. On my Cub with its distributor I use a timing light.
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Re: Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

Postby Stanton » Fri Jan 14, 2022 10:04 am

I've always used Hengy's description. Cecil did a shorter, condensed version of the same method. Either will put your mag / engine in time.
http://farmallcub.com/phpBB2/viewtopic.php?f=140&t=44397
http://farmallcub.com/phpBB2/viewtopic.php?f=140&t=44401

I'm not seeing the difference or discrepancy you're talking about. If I'm not mistaken, the Book appears to direct the same procedure as MiCarl, Hengy, and Cecil, just saying it in different ways. All have the top of the mag tight against the engine until that last rotation of the crank, then rotating the top of the mag outward until it trips the impulse coupling.

Here's page 32 from the 1947 Owner's Manual giving the same procedure for installing / timing a magneto:
http://farmallcub.com/rudi_cub/www.cleancomputes.com/Cub/Cub%20Owner's%20Manuals/McCormick-Deering%20Farmall%20Cub%20Owner's%20Manual%205-23-47/Page-32.jpg
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Ole90633
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Re: Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

Postby Ole90633 » Fri Jan 14, 2022 10:25 am

Thanks ‘Ricky’ and ‘Stanton” :hattip:
Back out to the garage to do it !

Don

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Re: Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

Postby MiCarl » Sun Jan 16, 2022 8:09 am

I think the post you're looking for is HERE.

The difference between my description and the book is the book is forcing you to time the engine with the #1 cylinder in the firing position by pointing the distributor rotor at the #1 position on the cap. That requires you to remove the cap and eyeball the rotor position. I also don't believe the book description will consistently work if you happen to start the procedure with the rotor pointing at the #1 position, especially if the mag is sitting an advanced position.

What needs to happen is the engine needs to be in firing position with the impulse coupler cocked but not tripped. By following my method you get the timing retarded by rotating the mag top fully toward the engine and then turning the engine to firing position (timing mark aligned) which will cock the impulse coupler without tripping it. Then you rotate the magneto until the impulse coupler trips and it's in proper time.

My method will work with the engine ready to fire either #1 or #4.
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Re: Magneto Timing: the ‘Book’ or ‘MiCarl’s’ way ?

Postby k hutchins » Sun Jan 16, 2022 4:12 pm

If you really think about it they are saying the same thing. If you pull the top away from the block, per the book, you're actually rotating the mag clockwise.
Tha's the only way l've timed my mag for 40+ yrs.
Why is there never enough time to do the job right, but always enough time to do it over. :?:


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