The Ford Barn

oldmotorsguy · 12-09-2014, 09:05 AM

I am in the process of restoring a 1917 Touring, and have added a starter to a non-starter equipped block. Accordingly, there is no generator mount and as such the magneto has to work well.

I changed the starter ring gear on a used 1926 tranny, and the coil ring and magneto were intact. It is unknown whether the magneto on this used tranny worked. I had to epoxy coat a few ragged areas of insulation on several of the coils, but all in all the coil ring looked good, and was intact throughout.

I mounted the coil ring onto the 1917 block with no shims. I then bought that fancy schmancy magneto gap gauge ($200) and made sure no high or low spots were present, and mounted the tranny and checked the clearances between the magnet clamps and the coils: on top, the clearance was .044, and on the bottom the clearance was .035, to account for the weight of the tranny that would be cantilevered over a foot or so beyond the end bearing. I divided the sum of those two numbers by 2, and got .0395, which is just inside the specified max clearance in the Blue Book of .040.

When I start the engine (which fires up nicely with a new 6V battery, first time ever for this crank engine), it runs very smoothly on battery. When I measure the AC voltage coming out of the magneto post, I get a reading of only 2 volts AC, obviously not enough to power the plugs. And of course, when I switch the ignition from BAT to MAG, the engine dies.

How do I re-charge this magneto? Do magnets get too old to recharge? Is the gap clearance of .0395 too much? The minimum specified is .025, and I would have to remove the tranny again, and shim it accordingly, which entails lots of labor (not a deal killer, but something I would love to avoid). I need it at 7 volts AC or so at an idle, and a minimum of 18 volts AC when revved up to operating speed. More if I can get it.

I need to diagnose my magneto's needs somehow, but am currently at a loss. My knee jerk thought was to just yank the tranny back off, and eyeball everything one more time, but the labor involved has me a bit hesitant.

Thoughts, guys?

Mike · 12-09-2014, 09:57 AM

I would install a coil fired distributor on the car !! Snyders carries the complete unit, I have installed 3 so far. This unit does away with the mag and coil boxes!!!

mike

tmodelman · 12-09-2014, 09:57 AM

Should be a candidate for 'in-car' magnet recharge since you have some output and not a 'dead' magneto. A dead results ususally from a short in the field coil ring.

So here is some old instructions on doing a recharge with the motor in the car.

The meter and lamp setup is a good way to check output when you are running on battery, the lamp acts as the normal load of the 4 coils.

Kelly mt · 12-09-2014, 10:26 AM

I did the in car mag charge. I went from 4.5 volts at high rpm to 29 volts. Worked great!

jboggess · 12-09-2014, 11:33 AM

This might sound silly but when my magneto wasn't working, turned out that my oil level was way to high, Id usually fill it up to come out of the top petcock, but now I just fill it up until it comes out of the lower one. Works perfect now.

dumb person · 12-09-2014, 01:30 PM

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Top clearance may be too wide, try the recharge first and no, in theory the magnets do not get too old to charge.

oldmotorsguy · 12-09-2014, 08:52 PM

Mike: I have purchased three Model T's with those conversions on them (so far), and have removed all of them and restored the coil box and timer. Call me a purist. I still have one of those distributor systems in my shop, you wanna buy it? I sell it to you cheap...

oldmotorsguy · 12-09-2014, 08:55 PM

jboggess: I have always used the top oil petcock to fill up the oil level, and have never had any magneto issues. Just for grins, I will open the lower petcock and let the oil drain to that level, start the engine and see what kind of voltage I get out of the magneto at that oil level.

If that works, I will be completely gobsmacked, as they say in the UK.

oldmotorsguy · 12-09-2014, 08:57 PM

TModelman: good stuff. Quite a few batteries involved in this process, is there a short cut of some sort?

Kelly mt · 12-10-2014, 01:37 AM

Just use three 12 volt batteries in series. 36 volts does it. PK

redmodelt · 12-10-2014, 12:36 PM

When setting up the gap, leave the the drums and triple gears off to save weight. The gap should be more like .035. If you had the magnets off are you sure they went back on NN SS NN etc?
I hope with all that work you used new screws. The old ones become brittle and can snap off very easily. I would have left the windings bare rather then add any kind of coating. The coating can come off and plug your oil line. I would have suggested spending the $200 on a rebuild coil ring, which may be part of the problem if it's shorted out.

jboggess · 12-10-2014, 01:02 PM

Quote:

Originally Posted by oldmotorsguy

jboggess: I have always used the top oil petcock to fill up the oil level, and have never had any magneto issues. Just for grins, I will open the lower petcock and let the oil drain to that level, start the engine and see what kind of voltage I get out of the magneto at that oil level.

If that works, I will be completely gobsmacked, as they say in the UK.

Well that's cool, I was just saying what i've been threw. Every Model T has a different personality.

oldmotorsguy · 12-10-2014, 02:05 PM

Red: I did indeed use new screws, but did not disassemble the transmission when setting the gap. I carefully removed the magnets when replacing the ring gear and put them back the way they were. Of course, who knows if they were NN SS when I got it. Wouldn't zapping it with 50 amps change it to the correct polarity in any event? But its possible that the magnets are not correctly installed. How are they supposed to be installed, and how can I tell if they are or not? With a compass? I will probably want to know this if I have to yank the transmission back off and start over.

I've used this epoxy quite a few times before on the coils, and it has yet to come off from my observations. You would think the unravelling of the existing tattered insulation areas if left alone would be more of an oil line clogging threat than sealing them with epoxy.

Coil ring: since I get a 2 volt reading currently at idle, the coil ring is not shorted out. If it were shorted out anywhere, I would get 0.0 volt reading (dead mag), or am I wrong about that?

redmodelt · 12-10-2014, 08:39 PM

Are you checking the mag output with an analog meter across a load? If it's putting out 2 VAC then it has hope!

Like any magnets like poles repulse NN, SS etc, opposite attract NS NS etc.
Guess 50 amps DC will ether smoke em or make em sing! Make sure you zap a couple of times not hold, then 1/4 turn and repeat all the way around. I have done the in car recharge a few times.

Farmallcub49 · 12-10-2014, 09:24 PM

Do you have the MTFCA manuals on the transmission? This gives you all the info you need and they arent' expensive, I sell them for $11.00. You can't zap the magnets to the proper polarity, if you recharge them incorrectly the magnet is junk.

I am not a fan of the in car recharge, many people are, but it is hard on the cast iron frame of the field coil, generally it cracks them when all that voltage snaps them towards the magnets. Wally S. claims more and more of the frames he takes in as cores are scrapped out, because they don't pass a magnafluxing test.

The best way to recharge the magnets is to remove them from the flywheel and recharge them individually, this way they can be checked for cracks as well. This also give you a chance to weigh each magnet and put the same weight magnet opposite each other. But, you need several sets of magnets to do this. If you want to I always have several sets recharged on the shelf 'seasoning' that are for sale.

A rebuilt field coil is not cheap, but it is cheaper to do it once and not have to tear everything apart again.

Royce P · 12-11-2014, 07:54 AM

I bet you are glad you didn't run out and spend $325 on a distributor!

Quote:

Originally Posted by Kelly mt

I did the in car mag charge. I went from 4.5 volts at high rpm to 29 volts. Worked great!

Royce P · 12-11-2014, 07:59 AM

It could be shorted at one of many places around the coil ring. Unless it was shorted to ground at the magneto post connection it would likely produce SOME voltage despite being shorted.

Try the in car recharge, either it will work or not.

I always recommend doing a recharge before assembling the engine so you don't have this issue after it is all together. You can do a magnet recharge with the coil ring laying on top of the fully assembled magnets / flywheel before assembling the transmission to the engine. It's too late now but maybe someone will read this and not do the same thing that you have done.

Quote:

Originally Posted by oldmotorsguy

Red: I did indeed use new screws, but did not disassemble the transmission when setting the gap. I carefully removed the magnets when replacing the ring gear and put them back the way they were. Of course, who knows if they were NN SS when I got it. Wouldn't zapping it with 50 amps change it to the correct polarity in any event? But its possible that the magnets are not correctly installed. How are they supposed to be installed, and how can I tell if they are or not? With a compass? I will probably want to know this if I have to yank the transmission back off and start over.

I've used this epoxy quite a few times before on the coils, and it has yet to come off from my observations. You would think the unravelling of the existing tattered insulation areas if left alone would be more of an oil line clogging threat than sealing them with epoxy.

Coil ring: since I get a 2 volt reading currently at idle, the coil ring is not shorted out. If it were shorted out anywhere, I would get 0.0 volt reading (dead mag), or am I wrong about that?

oldmotorsguy · 12-11-2014, 08:50 AM

Red: I am measuring the voltage with an analog device that is perhaps 60 or 70 years old that I borrowed from a retired Motorola electrical engineer. He knows electricity like nobody else, but is not up to speed on Ford magnetos, but he said this unit would not lie to me.

In any event, I am jerking the tranny off the block today, going to shim to as close to .025 as I can get, and ensure my coil ring is rock solid. Additionally, I am going to make sure my magnets are all up to snuff and polarized correctly, although I am not exactly sure how that is going to go. But in the end, this is the absolute last time I am going to tear this apart, I am certain about that.

oldmotorsguy · 12-11-2014, 08:54 AM

Farmall: I may take you up on your offer, depending on how things look when I tear out the transmission (again). I will have the magnets and field coil on my bench today, and will see what I have.

How much for a field coil ring, out the door, guaranteed up to snuff? I have perhaps four used rings laying around, none of them are perfect, and how would I check them out?

oldmotorsguy · 12-11-2014, 08:59 AM

Royce: do you mind walking me through recharging the magneto on my bench before I put it back together? I intend on ensuring that all the parts involved are good before I proceed, and would love to know that I am good to go before putting the unit back together and then crossing my fingers at the initial run up.

FYI: I do the run up on an engine stand, not in the car. Too much pain and effort yanking the engine back out of the car if things go wrong.

12-09-2014, 09:05 AM	#1
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Magneto doesn't work, what's the deal? I am in the process of restoring a 1917 Touring, and have added a starter to a non-starter equipped block. Accordingly, there is no generator mount and as such the magneto has to work well. I changed the starter ring gear on a used 1926 tranny, and the coil ring and magneto were intact. It is unknown whether the magneto on this used tranny worked. I had to epoxy coat a few ragged areas of insulation on several of the coils, but all in all the coil ring looked good, and was intact throughout. I mounted the coil ring onto the 1917 block with no shims. I then bought that fancy schmancy magneto gap gauge ($200) and made sure no high or low spots were present, and mounted the tranny and checked the clearances between the magnet clamps and the coils: on top, the clearance was .044, and on the bottom the clearance was .035, to account for the weight of the tranny that would be cantilevered over a foot or so beyond the end bearing. I divided the sum of those two numbers by 2, and got .0395, which is just inside the specified max clearance in the Blue Book of .040. When I start the engine (which fires up nicely with a new 6V battery, first time ever for this crank engine), it runs very smoothly on battery. When I measure the AC voltage coming out of the magneto post, I get a reading of only 2 volts AC, obviously not enough to power the plugs. And of course, when I switch the ignition from BAT to MAG, the engine dies. How do I re-charge this magneto? Do magnets get too old to recharge? Is the gap clearance of .0395 too much? The minimum specified is .025, and I would have to remove the tranny again, and shim it accordingly, which entails lots of labor (not a deal killer, but something I would love to avoid). I need it at 7 volts AC or so at an idle, and a minimum of 18 volts AC when revved up to operating speed. More if I can get it. I need to diagnose my magneto's needs somehow, but am currently at a loss. My knee jerk thought was to just yank the tranny back off, and eyeball everything one more time, but the labor involved has me a bit hesitant. Thoughts, guys?

12-09-2014, 09:57 AM	#2
Mike Senior Member Join Date: May 2010 Location: ASTON, PA. Posts: 725	Re: Magneto doesn't work, what's the deal? I would install a coil fired distributor on the car !! Snyders carries the complete unit, I have installed 3 so far. This unit does away with the mag and coil boxes!!! mike

12-09-2014, 10:26 AM	#4
Kelly mt Member Join Date: Jun 2011 Location: Noxon, MT Posts: 83	Re: Magneto doesn't work, what's the deal? I did the in car mag charge. I went from 4.5 volts at high rpm to 29 volts. Worked great!

12-09-2014, 11:33 AM	#5
jboggess Senior Member Join Date: Feb 2011 Posts: 112	Re: Magneto doesn't work, what's the deal? This might sound silly but when my magneto wasn't working, turned out that my oil level was way to high, Id usually fill it up to come out of the top petcock, but now I just fill it up until it comes out of the lower one. Works perfect now.

12-09-2014, 01:30 PM	#6
dumb person Senior Member Join Date: Apr 2011 Location: South pacific island Posts: 1,724	Re: Magneto doesn't work, what's the deal? Sponsored Links (Register now to hide all advertisements) Top clearance may be too wide, try the recharge first and no, in theory the magnets do not get too old to charge. __________________ <Link> This is how we roll<Link> "I'm Convinced that no one really reads posts anymore; they just fabricate what they think the post says then ramble on about red herrings."--Bob Outcasts rules of old cars #1 Fun is imperative, mainstream is overrated #2 If they think it is impossible, prove them wrong #3 If the science says it impossible you are not being creative enough. #4 No shame in recreating something you never had #5 If it were not for the law & physics you would be unstoppable

12-09-2014, 08:52 PM	#7
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? Mike: I have purchased three Model T's with those conversions on them (so far), and have removed all of them and restored the coil box and timer. Call me a purist. I still have one of those distributor systems in my shop, you wanna buy it? I sell it to you cheap...

12-09-2014, 08:55 PM	#8
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? jboggess: I have always used the top oil petcock to fill up the oil level, and have never had any magneto issues. Just for grins, I will open the lower petcock and let the oil drain to that level, start the engine and see what kind of voltage I get out of the magneto at that oil level. If that works, I will be completely gobsmacked, as they say in the UK.

12-09-2014, 08:57 PM	#9
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? TModelman: good stuff. Quite a few batteries involved in this process, is there a short cut of some sort?

12-10-2014, 01:37 AM	#10
Kelly mt Member Join Date: Jun 2011 Location: Noxon, MT Posts: 83	Re: Magneto doesn't work, what's the deal? Just use three 12 volt batteries in series. 36 volts does it. PK

12-10-2014, 12:36 PM	#11
redmodelt Senior Member Join Date: May 2010 Location: Portland OR Posts: 6,340	Re: Magneto doesn't work, what's the deal? When setting up the gap, leave the the drums and triple gears off to save weight. The gap should be more like .035. If you had the magnets off are you sure they went back on NN SS NN etc? I hope with all that work you used new screws. The old ones become brittle and can snap off very easily. I would have left the windings bare rather then add any kind of coating. The coating can come off and plug your oil line. I would have suggested spending the $200 on a rebuild coil ring, which may be part of the problem if it's shorted out.

12-10-2014, 02:05 PM	#13
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? Red: I did indeed use new screws, but did not disassemble the transmission when setting the gap. I carefully removed the magnets when replacing the ring gear and put them back the way they were. Of course, who knows if they were NN SS when I got it. Wouldn't zapping it with 50 amps change it to the correct polarity in any event? But its possible that the magnets are not correctly installed. How are they supposed to be installed, and how can I tell if they are or not? With a compass? I will probably want to know this if I have to yank the transmission back off and start over. I've used this epoxy quite a few times before on the coils, and it has yet to come off from my observations. You would think the unravelling of the existing tattered insulation areas if left alone would be more of an oil line clogging threat than sealing them with epoxy. Coil ring: since I get a 2 volt reading currently at idle, the coil ring is not shorted out. If it were shorted out anywhere, I would get 0.0 volt reading (dead mag), or am I wrong about that?

12-10-2014, 08:39 PM	#14
redmodelt Senior Member Join Date: May 2010 Location: Portland OR Posts: 6,340	Re: Magneto doesn't work, what's the deal? Are you checking the mag output with an analog meter across a load? If it's putting out 2 VAC then it has hope! Like any magnets like poles repulse NN, SS etc, opposite attract NS NS etc. Guess 50 amps DC will ether smoke em or make em sing! Make sure you zap a couple of times not hold, then 1/4 turn and repeat all the way around. I have done the in car recharge a few times.

12-10-2014, 09:24 PM	#15
Farmallcub49 Senior Member Join Date: Jan 2011 Location: St Joseph,MN Posts: 278	Re: Magneto doesn't work, what's the deal? Do you have the MTFCA manuals on the transmission? This gives you all the info you need and they arent' expensive, I sell them for $11.00. You can't zap the magnets to the proper polarity, if you recharge them incorrectly the magnet is junk. I am not a fan of the in car recharge, many people are, but it is hard on the cast iron frame of the field coil, generally it cracks them when all that voltage snaps them towards the magnets. Wally S. claims more and more of the frames he takes in as cores are scrapped out, because they don't pass a magnafluxing test. The best way to recharge the magnets is to remove them from the flywheel and recharge them individually, this way they can be checked for cracks as well. This also give you a chance to weigh each magnet and put the same weight magnet opposite each other. But, you need several sets of magnets to do this. If you want to I always have several sets recharged on the shelf 'seasoning' that are for sale. A rebuilt field coil is not cheap, but it is cheaper to do it once and not have to tear everything apart again. __________________ 'OSO HANDY RESTORATIONS Specializing in Model T Fords 320-293-1953

12-11-2014, 08:50 AM	#18
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? Red: I am measuring the voltage with an analog device that is perhaps 60 or 70 years old that I borrowed from a retired Motorola electrical engineer. He knows electricity like nobody else, but is not up to speed on Ford magnetos, but he said this unit would not lie to me. In any event, I am jerking the tranny off the block today, going to shim to as close to .025 as I can get, and ensure my coil ring is rock solid. Additionally, I am going to make sure my magnets are all up to snuff and polarized correctly, although I am not exactly sure how that is going to go. But in the end, this is the absolute last time I am going to tear this apart, I am certain about that.

12-11-2014, 08:54 AM	#19
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? Farmall: I may take you up on your offer, depending on how things look when I tear out the transmission (again). I will have the magnets and field coil on my bench today, and will see what I have. How much for a field coil ring, out the door, guaranteed up to snuff? I have perhaps four used rings laying around, none of them are perfect, and how would I check them out?

12-11-2014, 08:59 AM	#20
oldmotorsguy Senior Member Join Date: Jun 2010 Location: Crossville, Tennessee Posts: 157	Re: Magneto doesn't work, what's the deal? Royce: do you mind walking me through recharging the magneto on my bench before I put it back together? I intend on ensuring that all the parts involved are good before I proceed, and would love to know that I am good to go before putting the unit back together and then crossing my fingers at the initial run up. FYI: I do the run up on an engine stand, not in the car. Too much pain and effort yanking the engine back out of the car if things go wrong.