Farmall H timing

Farmall H, HV & Super H, 300 & 350, 1939-1958
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pokitisme
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Farmall H timing

Postby pokitisme » Mon May 08, 2023 10:28 pm

Okay so I'm having a hell of a time with this. Got another Farmall h. It was running it was running perfectly then I had to take the belt off. After I got the belt off and got the other one installed it ran for a little bit and then freaking stopped. I think the timing is off on it I've read all the manuals I have watched as many videos as I could. I've read as much information as I could on forums. It is a Magneto drive. So three marks on the crankshaft there's two that are close together a few millimeters apart and there's one off by itself the one off by itself is for lubrication the two that are together is the timing. As far as I understand I need to rotate those two until they line up with the pointer. And if I go a little bit beyond that the Magneto should click. And then I would just rotate it back to the number one spot again. I'm thinking I possibly have a Magneto issue with weak spark I'm curious. About how to time it and how to check for weak spark. Also I don't know anything about the Pistons lol. So when somebody says top dead center in the Piston should be open or whatever that is on the top lol. I'm completely lost
Last edited by Barnyard on Tue May 09, 2023 7:49 am, edited 1 time in total.
Reason: Remove foul language
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Eugene
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Re: Farmall H timing

Postby Eugene » Tue May 09, 2023 1:58 pm

Check the spark quality. Should be either hot blue or white hot. No so, internal magneto problem.
pokitisme wrote:Also I don't know anything about the Pistons lol. So when somebody says top dead center in the Piston should be open or whatever that is on the top lol. I'm completely lost
Yup. More book time.
I have an excuse. CRS.

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Rick Spivey
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Re: Farmall H timing

Postby Rick Spivey » Tue May 09, 2023 3:37 pm

Top Dead Center refers to the position of the crankshaft when the piston is at the very top of its travel, and ready to begin back down the cylinder. This is when the spark would fire if your timing was set to "0" degrees. However, because the burning of the gasoline/air mixture takes a wee bit of time, engines run better (smoother, more power) if the spark is advanced a bit so the burn is reaching maximum potential at Top Dead Center. Also, on a 4 stroke engine, each piston will reach a TDC position twice in a full cycle; once at the end of compression stroke when the spark fires, and again at the top of the exhaust stroke when expelling the burnt mixture. So it is important to know WHICH cylinder is at TDC when setting the spark timing. The convention is to always use cylinder 1 for that purpose.
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Re: Farmall H timing

Postby farmallcubkid » Wed May 10, 2023 12:18 pm

I had a problem were I screwed up the magnetos internal timing.

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Re: Farmall H timing

Postby Eugene » Wed May 10, 2023 6:28 pm

pokitisme wrote:It was running it was running perfectly then I had to take the belt off. After I got the belt off and got the other one installed it ran for a little bit and then freaking stopped.
If you didn't mess with the magneto when you replaced the belt. Then you didn't change the magneto's timing.

if you didn't mess with the magneto then it's either the magneto's points and condenser, or it's coil.

If you have a yellow spark, condenser.
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pokitisme
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Re: Farmall H timing

Postby pokitisme » Fri May 12, 2023 12:37 am

Well I did a little bit of testing the spark plug wires going to number two and three off of the distributor cap are not putting out any spark. One and four I can hold the wires and feel the spark but don't see spark on the plug. I've been thinking of switching over to a distributor instead of using the magneto. And yeah I did change the position of the magneto. But every time I try to get the rotor to line up with TDC on the crankshaft it's always pointing at the wrong plug location on the distributor.
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Re: Farmall H timing

Postby Rick Spivey » Fri May 12, 2023 7:17 am

pokitisme wrote:And yeah I did change the position of the magneto. But every time I try to get the rotor to line up with TDC on the crankshaft it's always pointing at the wrong plug location on the distributor.


Not quite sure what has been done, or what this statement means. Because a magneto has an impulse coupling, the rotor will "pause" just before it arrives at a tower position, and then the impulse will "snap" it over such that it quickly passes by the tower position. This allows the magneto to create a strong spark even though you are only hand cranking the tractor, so turning the engine at very slow speed. It also "retards" the spark timing so that the engine does not spark and try to turn backward, or "kick back". When that happens people get broken thumbs and wrists from the kickback.

So you won't be able to get the rotor to line up exactly when trying to time the engine. The best you can do is make sure that the #1 tower (assuming you are using cylinder 1 TDC) is coming up next as you place the magneto drive lugs into the governor drive gear. Then you have to static time it exactly like a cub.

Now, IF you actually removed and replaced the rotor to try and line it up correctly, then you very likely messed up the timing of the rotor to its drive pinion (the "internal" timing of the magneto referred to above). If that is the case, be aware that an H4 magneto has two alignment marks on the rotor; one is for cw rotation of the magneto, the other is for ccw rotation. The H4 was used on some "starter" engines for larger diesel motors in large equipment, and they rotate opposite of most tractor applications. If you changed the internal alignment (timing) of the rotor to pinion, that must be corrected before you can proceed.
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Re: Farmall H timing

Postby Eugene » Fri May 12, 2023 10:02 am

Suggest obtaining a service manual for the H. The manual should have photos and a description for setting the H's rotor and timing the H with a magneto.

If the magneto's coil if faulty, but otherwise functional you can remove/disconnect the coil and install an external ignition coil.
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pokitisme
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Re: Farmall H timing

Postby pokitisme » Sat May 13, 2023 12:18 am

Eugene wrote:Suggest obtaining a service manual for the H.

If the magneto's coil if faulty, but otherwise functional you can remove/disconnect the coil and install an external ignition coil.






Yeah I have various service manuals but they're not as accurate or detailed as I would like them to be. As to installing a secondary ignition coil my cousin actually did that on one of the other Farmall h that I have. In my desperation to make it go vroom vroom again I did remove the entire Magneto. But I never adjusted anything on it I just pulled it off and then put it back on since then I have rotated slightly towards the engine and slightly away attempting to make things go vroom lol.. you guys have given me some good ideas here and some tips. Thanks very much
Favorite quotes by me. If you want to you can but if you don't you wont... most possibly yes but maybe no.... and as always buy guns keep America free


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