DanielW
Well-known Member
- Location
- Haliburton, Ontario
New coils have been known to go bad, but within a week would be very rare. Very first checks would be to check if you have power to the top of the coil, and then to the Pertronix module (if equipped) - both with the key on, of course. Before giving too much thoughts/advice, it would be good to know if your 12V conversion kept a points/condenser system, or if you went to an electronic/Pertronix kit (as I suspect). If electronic, that's where I'd start looking (assuming you have power to the coil & module with the key on). How is the power to the module supplied? Is it via one (or more) ballast resistor? Lots of problems on N's with 12V conversions with the power wire to the module being wired from the wrong source or wrong side of the firewall resistor. A lot of folks try to pull the power directly from the wire feeding the coil to save adding another wire back to the firewall. If you do that, you get iffy results at best. You need it supplying full battery voltage to the module - not coming via any resistor (neither the factory N resistor on the firewall nor any other ballast resistor). That's the most common problem with electronic conversion kits on N's. Lots of other things it could be, but let us know what you have for ignition (points/condenser vs. Pertronix), what resistors you have on there (and where), and if you have power to the coil & module, and we can give more advice.
Other thing I'd look at is how the coil is placed on the dizzy. Easy to accidentally have the contact spring on the coil slightly mis-positioned so it grounds out on the dizzy body rather than only contacting the brass contact screw. Can be really finicky to get it to drop a front-mount N coil on there and have the contact spring properly in-place. And is your cap fully seated? A lot of new/aftermarket caps for those front-mounts don't have the gasket inset inside the groove on the cap when they come. If you put the cap on as it comes in the box, it won't sit fully on the body and make marginal contact with the rotor.
Other thing I'd look at is how the coil is placed on the dizzy. Easy to accidentally have the contact spring on the coil slightly mis-positioned so it grounds out on the dizzy body rather than only contacting the brass contact screw. Can be really finicky to get it to drop a front-mount N coil on there and have the contact spring properly in-place. And is your cap fully seated? A lot of new/aftermarket caps for those front-mounts don't have the gasket inset inside the groove on the cap when they come. If you put the cap on as it comes in the box, it won't sit fully on the body and make marginal contact with the rotor.
Last edited:
old
Well-known Member
- Location
- Camdenton Missouri
Simple way to trouble shoot is to use a hot wire from the nonground side of the battery to the coil. Touch the wire to the coil and watch for a spark. If you have a spark that says the points are closed or you have a short in the distributor. Turn the engine over just a little bit and see if the spark goes away. If it does the points are working if it doesn't you have a short
I was just about to start a new thread about this exact problem, that I had resolved, just as a reminder of how simple fixes can sometimes be
I converted my 8N to "upgrade" to a true 12V coil and changed over to a free electronic ignition kit I received from Amazon Vine (product tester program), and a complete rewire about a year ago. The difference to my tractor has been incredible - until 2 days ago.
I decided to try and push over an old dead and rotting tree stump on my way over to pick up my shovel scoop to do some digging. Everything was going great until the tractor suddenly just shut off! Attempted to restart and it didn't even try to fire. Pulled one plug wire to check for spark but couldn't see any at all. First thought was that the free EI kit had died. But, I had to go to my grandson's final high school baseball game so I just covered the tractor up and left it there.
Yesterday, it rained all day. We needed it bad so didn't complain. This morning I rounded up my multimeter, spark tester and JMOR's wiring diagram on my phone. First thing I checked for was 12V at the coil with the switch on. Got about 4.5V. Hmmmm Went back and checked both sides of the ignition switch - solid 12.6V. Next, checked it at the black terminal block behind the toolbox - 12.6V. But... the terminal leading to the coil was loose and moving as I moved the meter probe trying to get a good connection. The nut was loose!. After moving the coil wire terminal on the connection post a couple times, checked voltage at the coil again - 12.6V!! Tractor started right up. Brought it to the house and tightened up the nut. Good to go!
Because of all this I did notice my plug wires' insulation is cracked pretty badly from age so I will order a new set. They have been on there for years.
So, what could have been a bad coil, bad EI module, or who knows what else turned out to be a loose wire. Before you tear everything apart, do some troubleshooting...
Last edited:
DanielW
Well-known Member
- Location
- Haliburton, Ontario
There are a few options for 12V conversion kits for front-mount N's. Most will want you to keep the original Ford firewall resistor no matter what. And most will say to use no other resistor if you're using a new 12V coil, but to add a ballast resistor if you're using the original 6V coil with a 12V system.
This is all guess work - we'd really need to know what you bought when you converted to 12V. I'm guessing that you have a new 12V coil on there. In which case you probably don't want that new ballast resistor. But I'd be looking at the instructions that came with the kit to confirm for sure. What came with a 'kit'? Did it come with the coil, ignition module, and resistor all as one? Or did you buy the coil separate from the Pertronix module/resistor? Do you have a a Pertronix/electronic ignition kit (as I'm assuming), or are you still on points/condenser?
More significantly: If (as I suspect) you have an electronic ignition (Pertonix) module: Where is the power coming from that's feeding the electronic ignition module? It needs to be coming from the up-stream side of the firewall resistor or directly from the ignition switch. The power feeding the module can't be coming via any resistor; neither the new one you have on there, nor the original firewall resistor. You absolutely need full battery voltage to the Pertronix module for it to work reliably/consistently.
This is all guess work - we'd really need to know what you bought when you converted to 12V. I'm guessing that you have a new 12V coil on there. In which case you probably don't want that new ballast resistor. But I'd be looking at the instructions that came with the kit to confirm for sure. What came with a 'kit'? Did it come with the coil, ignition module, and resistor all as one? Or did you buy the coil separate from the Pertronix module/resistor? Do you have a a Pertronix/electronic ignition kit (as I'm assuming), or are you still on points/condenser?
More significantly: If (as I suspect) you have an electronic ignition (Pertonix) module: Where is the power coming from that's feeding the electronic ignition module? It needs to be coming from the up-stream side of the firewall resistor or directly from the ignition switch. The power feeding the module can't be coming via any resistor; neither the new one you have on there, nor the original firewall resistor. You absolutely need full battery voltage to the Pertronix module for it to work reliably/consistently.
DanielW
Well-known Member
- Location
- Haliburton, Ontario
Interesting. Looks like that 12V coil require both the factory Ford resistor and external ballast resistor. Sounds like a lot of resistance for a 12V coil, but I have seen other 12V kits that require that setup. You could try bypassing the new resistor temporarily to see what happens with more coil voltage - you're not going to do any harm running it for a short time like that (indeed, many folks ran their old 6V coils with 12V and no ballast resistor for years. Not recommended, but folks have done it).
But it also looks like that kit doesn't have an ignition kit. So perhaps you're still running the points/condesner system? That's certainly not a bad thing: I never understood why folks get so keen to convert their old tractors to Pertronix. Nothing strictly wrong with them and I've also used them for other applications. But for an old, slow-revving tractor I don't see the advantage. it's not as though an old N is needs crisp, precise dwell at 7000 RPM. At least with an old points/condenser system any parts are only a couple of dollars each, and they're dead easy to diagnose and change (well, not quite 'dead' easy on a front-mount N compared to every other dizzy, but certainly not too hard either).
What condition are the points/condenser in? With the new coil and 12V system presumably putting out a hotter spark than the old 6V system, a condenser that may have been marginal before may be donezo now. Might be worth a quick points touch-up and new condenser. Easy enough to put points in while you're in there, but it's harder and harder to find points for an N that are bent correctly - most sets you get these days need some tweaking to allow the gap to be set correctly. If the old points aren't too burned/pitted, I'd give them a light touch with a points file and see how that does before replacing.
Are you for sure on a points/condenser system, or have you at some other point (or a previous owner) converted to electronic ignition? If it's been converted, where are they pulling the power from that feeds the Pertronix module? If they ran it like some folks do off the wire leading to the top of the coil, that could be your problem. They really should be ran directly from the ignition switch, but some folks have run them from the coil without issue. But now that you have that ballast resistor in there in addition to the factory firewall resistor, it'd likely be far too much voltage drop for an ignition module to work reliably if it's wired from the coil wire.
But it also looks like that kit doesn't have an ignition kit. So perhaps you're still running the points/condesner system? That's certainly not a bad thing: I never understood why folks get so keen to convert their old tractors to Pertronix. Nothing strictly wrong with them and I've also used them for other applications. But for an old, slow-revving tractor I don't see the advantage. it's not as though an old N is needs crisp, precise dwell at 7000 RPM. At least with an old points/condenser system any parts are only a couple of dollars each, and they're dead easy to diagnose and change (well, not quite 'dead' easy on a front-mount N compared to every other dizzy, but certainly not too hard either).
What condition are the points/condenser in? With the new coil and 12V system presumably putting out a hotter spark than the old 6V system, a condenser that may have been marginal before may be donezo now. Might be worth a quick points touch-up and new condenser. Easy enough to put points in while you're in there, but it's harder and harder to find points for an N that are bent correctly - most sets you get these days need some tweaking to allow the gap to be set correctly. If the old points aren't too burned/pitted, I'd give them a light touch with a points file and see how that does before replacing.
Are you for sure on a points/condenser system, or have you at some other point (or a previous owner) converted to electronic ignition? If it's been converted, where are they pulling the power from that feeds the Pertronix module? If they ran it like some folks do off the wire leading to the top of the coil, that could be your problem. They really should be ran directly from the ignition switch, but some folks have run them from the coil without issue. But now that you have that ballast resistor in there in addition to the factory firewall resistor, it'd likely be far too much voltage drop for an ignition module to work reliably if it's wired from the coil wire.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.
Copyright © 1997-2025 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy