Mag over distributor

AL Moyer · Oct 24, 2017

Can anyone give reasons why so many mags where changed over to distributors ? I know that with the mag there does'nt need the battery to run,
as on my 48 Luscombe 8A airplane, no electric or starter, hand propped, had a 41 H & my 53 Super H have the distributor, but recently looked
at another 53 Super H that still had the mag, which is preferred by some of you & why ? Are the mags harder to find parts or rebuild ? Thanks
for any & all responses. AL

john *.?-!.* cub owner · Oct 24, 2017

Back in the 50s through the 70s when a lot of mags were still around, you could buy the coils at local auto parts stores or at a dealer. The ones from the auto parts stores cost the equivalent of 1 1/2 to 2 days wages if you had an hourly job, and would last 3 or 4 years. Ones from a dealer typically lasted 5 or 6 years, but cost the equivalent of 4 or 5 days wages. A battery ignition coil normally lasted 10+ years and cost about 2 hours wages equivalent. A lot of mags were converted to battery ignition by adding an external coil for that reason, and then as used distributors started becoming available from tractors being parted out or junked the mags were frequently replaced with distributors. Not only was the coil chepaer, but you did not have to worry about the impulse failing and making a tractor hard to start, but the distributor also advanced spark gradually making the advance proportional to the rpm, rather than TDC or fully advanced (no in between) as a mag did, but a distributor also usually advanced farther than a mag giving more power at the higher rpms.

D Slater · Oct 24, 2017

Distributors had timing advance curves that gave smoother and better running from idle to full RPM. Easy to change for different engine uses. Probably cheaper to make than a magneto didn't hurt the distributors becoming the most common ignition around 1949 to 1950 on IH tractors.

john *.?-!.* cub owner · Oct 24, 2017

In about 1964 or 65 when I was around 15 I walked the 1/2 mile from the corn field I was working in back to the house and took the coil off an old car we had that the transmission was bad in, and walked back to the cornfield with the coil and a couple wires. I then disconnected the mag coil and wired up the battery ignition coil from the car and finished cultivating the corn with our old Farmall H. We rewired the switch and used it that way for a year or two till Dad found a used distributor to replace the mag with.

D Slater · Oct 24, 2017

Think this is from 61 or 62. Don't know how the cost stacks up from back then to today. But the price to change one over to a distributor sounds cheap now.

fixerupper · Oct 24, 2017

A distributor is more simple and easier to service.

tractorguy2 · Oct 25, 2017

In my opinion. Mags are less trouble than a distributor. A lot of mags got replaced because the owner didn't understand how they work. 90% of the time when a mag doesn't work all it needs is points. People think they h have to send it in for rebuild.

rustyfarmall · Oct 25, 2017

(quoted from post at 18:34:05 10/24/17) Distributors had timing advance curves that gave smoother and better running from idle to full RPM. Easy to change for different engine uses. Probably cheaper to make than a magneto didn't hurt the distributors becoming the most common ignition around 1949 to 1950 on IH tractors.

Yes. Better performance=more horsepower.

Mag over distributor

AL Moyer

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john .?-!. cub owner

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D Slater

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john .?-!. cub owner

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D Slater

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fixerupper

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tractorguy2

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rustyfarmall

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