converting from magneto to distributor

I have a 49 Farmall M and want to convert from magneto to distributor and wanted to see who has done it and what all is involved

if you are not having problems with the mag I would not change it---[my reason why not]distrutor75 to 100--points-condencer-rotor-cap-plug wires--50-75.00--coil-30-75.00-12volt alternator if 6 volt system now--30-60.00--12volt battery --50 --100--- key switch with acc to pulse alt and not drain the bat with switch off-25--50.00--new alt belt[29 inch to keep alt under hood completely][ 1/2 inch wide][ 300-400 in parts and a lot of work under the dash-elec ignition--about 150.00 --mags are not to hard to find50--100or less---my.02 good luck--roger

All you need to do is change the on-off sw to get batt voltage to the dist. Just unbolt the mag and instal the dist. set timing and go. What is the reason as a mag is a lot lees trouble just old wives tales. Even if you want to go to 12v you dont need to change. If you are going 12v there is a lot of things to change but you can still use the mag.

Funny thing is, I converted mine back to a mag simply because I like the old school look, and I'm loving it. Has yet to fail me. It runs and starts just as good now as it did when it had a distributor. You do what you want, it's your tractor, but if it was me, I'd leave it. I don't think you quite realize what you have there. Sure the mag has gotten a lot of bad press in the past, but like Gene said, it all old wives tales. Combined with a 4 position light switch, and cut-out regulator, and a 6 volt positive ground system, it's good, good, good!

That BTW is a freshly rebuilt mag by Kenneth Weaver out of Shiloh, Ohio, and in my opinion, he does em better than new. That boy do know his mags. Tractor started right up first try.

Welcome to the forum.



Best regards
Patrick
'49M

like Gene posted, pretty simple if you want to change.
I, too, like my mag tractors.
soon as the engine starts to rotate, they are running.
couple of my workers have pretty much no wiring at all.
mag, 12v battery hooked to the manual push/pull rod starter.
That's it. Without the ignition draw, and with instant starts, I just need to remember to put a battery tender on it once a year or so.....
If your mag's fairly expensive coil has expired, just wire in an external round coil for battery ignition. works fine.

And if you own your tractor long enough, there will be a hand crank start situation eventually. Then you will be glad the mag is still on it.

A battery ignition unit will give you a smoother running engine at your lower engine speeds and especially low idle. On a magneto, as soon as the engine starts the timing is full advance which is normally 35 degrees on the H4 magneto. Now, problem with battery ign units is you need to know which one you need. Most came from factory with a 40 degree advance when they still used the std bore and cast iron pistons. A flat head increased bore gasoline head , aluminum piston should have a 30 degree advance, if fire crater it should be 22 degree advance. So, you can see. Depends on what head and pistons you have for best fit. Most used ones are worn out and advance way too much at low speeds. Most rebuilt ones are 40 degree advance. When I talk advance, that means it should be fully retarded at low idle and gradually advance as you speed the engine up so it reaches full advance at rated engine speed. Mags are ok but IH didn't change to battery ignition just to add more parts to the system.

I think pete 23 nailed it.

I like my mags--they do have some advantages for starting in my opinion and they are very reliable BUT he is right, IH switched to distributor ignition for a reason.

Well, call me dumb if you wish, and despite of all the technical information that's out there (of which I don't understand), I'm still not convinced.

Best regards
Patrick
'49M

Not calling anybody dumb. Just stating what has evolved over the years. Lots of magnetos on lots of tractors with no problem to owner. Just because something gives you better control of combustion doesn't mean something else does not work. When dealing with hundreds of tractors over 50 plus years a person kind of goes what works best most of the time.

With all due respect, I understand what you're saying Pete. My M ran just fine when it had it's distributor ignition as it does now with it's magneto. What hackles me is people avoiding magnetos like the plague simply because of the bad press they have received over the years. There's people over at the Red Power forum that are adamant over their dislike for magnetos. Seems like more so than here. What really attracts me to the magneto ignition is it's simplicity. At one time I had a '67 XLCH Harley Sportster with a F-B magneto and no battery. The wiring on that bike was so simple, even a dumb A. like me at the time was able to figure it out. The points were set with a piece of cellophane from a pack of cigarettes. But to each his own I guess.

Best regards
Patrick
'49M

Guess I might as well throw some fuel onto the fire; I believe what you guys say about the mags. I don"t have one, but on my "H" I was able to get the points / timing / etc. tuned up so well, with 12-volts, she starts after 1/2 a crank. Starts immediately. I can see how a mag / crank could do that too.

For what it is worth, I would never change a mag equipped tractor to a distributor nor would I switch a distributor tractor to a mag. I am a purist and like originality. Some folks don't like mags by experience. They may have had trouble with one at one point in time and therefore all were deemed bad from that day forward when the root of the problem is that the individual did not understand how they work. To open another can of worms, the same can be said for the generator vs alternator debate. Absolutely, the alternator is an improvement over the generator, but a generator system in good condition with good wiring, and proper sized battery cables will require very little maintenance and prove to be reliable as well. It often gets down to the a good understanding of how electrical systems operate.

To answer the original poster's original question, it is very simple to switch from a mag to a distributor system. Gene Bender basically covered it. A different on/off switch and unbolt the mag--bolt on the distributor.

I guess I should have stated that I am building a pulling tractor, that's the only reason I bought it everything has been stripped off the tractor that is not needed. it already has 12 negative ground system. I have heard that the mags aren't good for pulling...... I am new to this so im taking all advice I can get from either view........I also already ordered the pertronix ignitor kit for a distributor before I even realized I didn't have one....someone correct me if im wrong but I read somewhere that magnetos were only used on "base model" tractors, with no lights no key switch start... thanks for all the replies!

brad

For a puller I am going to assume you have made alterations to the original engine. That may or may not include increasing bore, stroke, compression ratio etc. This pretty much brings you to the point that battery ignition is your only choice to obtain the correct spark advance curve. Can't do much about a curve with a magneto. Once running it has fixed advance and that is it. Also, I used to have a whole box full of magneto's in the test room that were replaced with battery ign units. I rummaged through those for years picking the best left over parts to repair magnetos that were still in use. The parts became so expensive and unavailable it was not practical to buy new parts for repairs. Impulse couplings were the worse. We found alternate places to buy less expensive coils than IH but most other parts had to come through regular IH parts. There is actually considerably more to wear out in a H4 magneto than in the IH distributor. I will add also again. A magneto and battery ignition both use and have to have a distributor when used on a typical multi cylinder as used on farm tractors. Just kind of a thing with me when so many refer to a battery ign unit as a distributor. Far as original, magnetos and battery ign were options for several models for several years so either could be original. Generators work great. It is the more recent regulation systems that are the major problem. IH stayed too long with the 6 volt system and gave us tremendous problems in the later tractors like the 400 and 450 gasoline tractors. Five foot long battery cables, live hydraulics, independent pto drag, higher compression, just plain trouble right off the rail car brand spanking new.

Mags were used from factory on all A,B,H,M and W series also DIESELS until late 40s.

thanks pete 23 great reply.
no alterations have been made to the engine yet but will. I am probably going to buy a used distributor, is there anything I should be aware of that could be worn out in it as far as the drive gear or anything? or should I just buy a new one to be on the safe side? thanks again

Don't you wish the everything in the picture could be bought for 1962 prices.

I would be happy to pay list price