All Ford-Ferguson 9N, 2N, and Early Ford 8N
NEW! For an evaluation and test of a new electronic distributor and ignition wires by AIP Electronics, click here.
The front mount distributor on the 9N, 2N and early 8N tractors was a victim of bad publicity. I believe most of the bad publicity was caused by folks who were afraid to remove the distributor and attempted to service it in-place. Yikes! That is not impossible, but much more difficult. Remove two bolts, and it comes right off. You can even undo the clamps and leave the cap and coil attached to the tractor. There is no need to disconnect the coil wire or plug wires. I usually go ahead and take everything to the bench. The entire assembly is more difficult to get out past the fan and belts. Once you have the distributor in your hand, it can be taken to the workbench to replace/set points, check timing, and all the other things in there that cause problems.
Yes, it is possible to remove the distributor assembly with coil and cap already attached. That is generally the way I install the distributor. For removal, I usually undo the clamps and wires to remove each piece. That's just what I do and seems easiest to me.
Remove Wire to Coil. Pry bail forward and remove Coil. Pull spark plug wires out of cap, release clips, and remove Distributor Cap. Note position of rotor. Snap a photo or draw a picture. This will help reinstall the distributor, as long as the engine doesn't get cranked while the distributor is off. Two small bolts hold the distributor on. Grab a 1/2" box end wrench, sit a front tire and remove the bolt on that side. Move to the other tire, remove the other bolt and fish the distributor out from the fan and belt. Don't worry too much if you forget to record the position of the rotor, or someone cranks the engine with the distributor off. It's not that hard to find the correct position later.
Turn the distributor around and look at the back side. You will see the offset tang that engages the camshaft. The offset is obvious when you look directly at the back-side of the distributor. If this is an original casting, it will have an arrow cast into the back face showing distributor shaft rotation. If no arrow, it's a replacement aftermarket casting. That's ok, the replacement distributors seem to be decent quality. One of my spares is aftermarket. I just drew my own arrow with a sharpie. Shaft rotation is clockwise, when looking at the back-side.
Take the distributor, cap, and coil where you can get comfortable and have good light.
Mostly it's the front bushing, the little one, right behind the rotor, that holds the end of the distributor shaft. Rotate the distributor shaft until the points are open, then watch the points while trying to move the distributor shaft side to side. If you can see the point gap change, the bushing is worn and needs to be replaced. No problem. That just means we get to have a little more fun with the distributor. Remove the rotor. Pay attention to how the condenser wire connects to the points. Disconnect the condensor wire and remove the points.
If the condenser and wire look good I leave them alone for now.
If the front bushing seemed tight enough and the tractor was running well, you may just want to put new points in there. If so, skip down to POINTS.
If bushings need to be replaced, or distributor is so filthy full service is needed, proceed with disassembly.
The advance mechanism is under the top plate. Remove the screw and timing plate on the side of the distributor. The entire points and top plate assembly is held in the distributor body by a large wire clip that runs most of the way around the inside of the distributor. Take a photo or remember how that wire clip is positioned. It should pry out fairly easy with a small screwdriver or grab one end with pliers to pull it out of the groove. Start at one end and work the clip out. The timing plate, distributor shaft, and everything else shoudl then pull right out IF you actually took the timing screw and timing plate off.
Pull timing plate off the distributor shaft. Clean everything thoroughly. Check all the spring tabs, weights, and rivets. Make sure the advance weight mechanism works smoothly. The weights should swing out away from the distributor shaft smoothly, and spring tabs on each weight should pull them back smoothly. The next photo shows the advance weights and distributor shaft assembly completely taken apart. There is no need to go this far unless the parts are really dirty, and won't move smoothly.
If you do need to take everything apart, the shaft assembly is held together by small spring clips. Use a small pick tool to work one end of the clip out of the groove, then continue around until the clip is out. Look for scored shafts, bent or broken spring tabs, and loose bushings. Each moving part should fit snug and still move freely. Bushings can be replaced. Other parts can be purchased separately, but if too many parts need replacing, it might be better to use this one for parts and buy a replacement distributor. Most of the time all this stuff needs is a good cleaning. Brake or carb cleaner can help remove varnish deposits. Reassemble distributor shaft assembly with a very light coat of engine oil on moving parts.
There were two extra parts in that photo. One is the special screw that connects the condenser terminal to the points and provides a place for the coil springy terminal to connect. These screws get lost, worn out, or broken and are impossible to find. The new screw is an 8-32 x 3/8" thumb screw that looked like it could be a good replacement (with a little work).
A close-up of the screws.
This is a pack of the thumb screws I found that happen to be the right size to make replacements for the special screw.
The front bushing is in a small (weak) bracket that is riveted to the distributor plate. The new bushing can be used to press out the old one as it goes in. Carefully! Apply pressure only to the bushing and the immediate edge of the bracket. Do not press with the support bracket unbraced. It is easy to bend the bracket out of alignment. Do that and you will need a new distributor plate assembly. If you don't happen to own a professional set of bearing/bushing driver tools, there are other ways. Find a short bolt that fits snugly inside the bushing. Select a 12 point socket that the new bushing barely drops inside. Remove the points from the breaker plate. Turn the breaker plate upside down on the open end of that socket. Put the bolt thru the new bushing, and then into the old bushing. The bolt will be used as a bushing driver. Never bang or press directly on a new bushing or bearing. Work slowly with a hammer or press. The new bushing will slip into place as the old one goes into the socket. This may still have created a small ridge on the edges of the new bushing. Test-fit the distributor shaft in the new bushing. It should be a snug fit. If it's too tight, a round file can be used to carefully chamfer any bumps that may have formed at the edge of the bushing when driving it in.
Check the larger bushing in the distributor body. This one is usually ok. Put distributor shaft in bushing and check for an side play. If bushing is loose, replace the same way as described for the front bushing. Lubricate new bushings with a very light coating of motor oil. Just a little, we don't want motor oil getting all over the points.
Place the distributor shaft in the distributor. Put the breaker plate in with the timing screw lined up with the hole in the distributor body. The bracket for the timing screw should be visible somewhere within the slot in the distributor body where the timing plate and screw goes. Do not install the small timing plate or timing screw yet. First, install the big wire clip on top of the breaker plate. The flat side of the clip aligns with the timing screw bracket. Make sure all of the clip goes all the way into the groove. Wipe off any oil that may have been pushed out of the bushings.
Install the points loose. The points have two main pieces. There is a base plate with fixed contact, and a movable contact arm held in place with a small cotter-pin. The base plate has a center slot that fits over a bolt head, then is secured in place with a screw at each end. Leave those screws slightly loose for now. That center bolt head is an eccentric cam that is used to set the point gap. Turn that screw head, and watch the point base plate move back and forth. The main reason we left the timing screw out is so we can rotate the breaker plate far enough to get a screwdriver on both screws that attach the points spring and condenser contact. Just rotate the plate until a screwdriver will work thru the hole in the top of the distributor body. Don't install the timing plate and screw yet.
Carefully inspect the installation of the points spring, copper foils, condenser wire, and special top screw. The two screws that these items attach to must be completely insulated from the rest of the distributor metal. The arrows and red line in the photo above show where a copper foil strip connects the two terminals. Make absolutely certain that nothing in that area can touch any other metal in the distributor.
The special top screw may have been replaced with something else. The screw was not available as a replacement part when I first created this rebuild page. The special brass screw can now be found at just8ns.com. Part No. 91A12159 Years:1939-50 Screw (Condenser Primary Contact). The ones I've been making are a little different, but they work for me.
Set the point gap to exactly 0.015". The manuals often state a range of 0.014" to 0.016" but I have found that my tractors work best when I take the time to set the gap dead on 0.015". With the screws at either end of the points slightly loose, turn the eccentric screw in the middle to set the correct gap. Tighten the screws at each end. Check the gap again to make sure the points didn't move. They usually do. If they moved open or closed, loosen the screws and adjust the points slightly more or less than perfect, so when the screws are tight the adjustment will be perfect. This process nearly always takes a few whacks. If either points screw is stripped, the fix is to replace with a slightly larger diameter screw. The replacement will be a very short length #8-32 screw. That length should not any longer than necessary to engage the threads in the top plate. Longer screws will interfere with the rotating advance weights below the top plate. Screws that are too long can be cut off and used. If your top plate already has the larger diameter screws, it may be time for a new top plate assembly.
If the tractor was running ok and all you did is replace the points, the timing is probably ok right where it is, but it only takes a minute or two to check. Less than that if you are fortunate enough to have a jig such as the one made by The Old Hokie, Dan Allen. Browse the N Board at ntractorclub.com and get one when he offers a batch for sale. Once set, the timing should not change. However, low quality replacement parts make it more and more important to check everything. Some people have run into parts that simply do not fit right. If your new points are not made and gapped EXACTLY the same as the ones you are replacing, your timing could change. There are cases where people had to enlarge holes or drill new ones to get a set of points to fit! Try to buy the highest quality replacement parts available. Return or throw away parts that do not fit right. The time inferior parts will cost often just ain't worth trying to use them. It is not a good thing when we find ourselves modifying original parts to make inferior replacement parts work. Sometimes there are no other options. While you have the distributor on the bench, its easy to check and set timing.
The point gap must be set first before setting timing, so go back to the previous paragraph and do that if you skipped it.
This photo shows how to measure the 1/4" timing adjustment on the front distributor to set it at zero degrees TDC. Place a straightedge on the wide side of the tang on the distributor shaft as shown in the photo. Rotate the distributor shaft in the normal direction until the straight edge is 1/4" away from the outside edge of the distributor mounting hole. The distributor points should just be starting to open. If not, turn the timing plate until the points are just beginning to open. It is best to turn the distributor shaft in the correct direction to the 1/4" measurement. This will remove any slop in the advance parts. The 1/4" setting will set your initial, fully-retarded timing at top dead center. That is correct for these engines.
Is it just me or does this timing adjustment look like something the engineers came up with after the distributor was designed and hundreds were in production? It seems obvious that if timing had been considered prior to production, a timing mark of some sort would have been cast into the distributor body. Really? We are supposed to turn it so the wide side of this thingy is turned to point 1/4" away from the edge of this hole"? This looks like a big OOPS that generated a mountain of memos before someone came up with a solution that allowed production to continue.
This is a timing jig made by Dan Allen (The Old Hokie). The arrows showing distributor shaft normal rotation help prevent confusion when flipping the distributor from front to back. Again, with the wide side of the distributor tang pointing 1/4" past the bolt hole, turn the breaker plate until the rubbing block for the points just maked contact.
This is why we left the timing screw out when the breaker plate was installed. IF you can get still see the threaded hole in the timing screw bracket, GREAT. Install the small timing plate and tighten the screw. I'm not that lucky. Most of the made in China replacement points available today are not exactly the same as the original points. In many cases there will not be enough length to the timing slot to get the timing set correctly. There are two solutions. Buy a different set of points and start over - or - Disassemble the distributor, remove the timing plate, distributor shaft, and carefully file the timing slot longer in the direction it needs to go. I've done this a few times with a rat tail file in about 30 seconds. File a little more than necessary to allow some extra adjustment. The cast housing material is soft and files away easily, so don't get carried away.
This is one of the things that happens when points are not made exactly to specifications. Filing the slot to set the timing will move the special screw off to the side. This makes it more likely there will be problems getting good contact between the coiled springy terminal on the bottom of the coil and this screw. The solution is a combination of carefully bending the bracket for the top screw and/or carefully bending the coiled terminal so it is offset to the new brass screw location. Don't get turned around flipping the coil over and bend anything the wrong way. Bend the coiled terminal by prying between the individual coils so the solder joint does not come loose.
Here's another part I couldn't buy, so I made a few. When the timing slot has to be filed, the original timing plate can become too short to completely cover the slot. It turns out 16ga exhaust pipe is the correct thickness. Cut a couple of pieces from the end of an old exhaust pipe just over 1/2" wide. Cut to lengths just over 1" long. Drill hole for the timing screw offset to match the original and ofset to allow more plate to cover the slot. Match curve to an original part or side of distributor body. Grind to final size by bolting a stack together with an original in the middle as a guide. Leave one side longer to cover the slot if necessary. Stamp timing marks in slightly wider side, aligned with the bolt hole. Three marks was the best I could do with the stamping set I have. It should be possible to do 7 equally spaced holes like the original. This is good enough for me. The timing marks don't really serve any purpose if you time the distributor as shown in the manual. The marks might help jog my memory when these turn up in my parts bin several years from now.
Before installing the distributor on the engine, use a test light or ohmmeter to check that the points are opening and closing electrically. Place one test lead on the hollow screw where the condenser wire connects. Place the other test lead on the distributor housing. Turn the distributor shaft and make sure you can see the points open and close. Check wire connections and copper flex strip for shorts. Drag a point file between the points until any varnish is scraped off, and they are working.
TIP: A point file isn't really a file. A proper point file is really a burnisher. They are usually about 3 inches long, very flexible, with a square tip to help get it started between the points. A burnisher cleans and polishes the contact surfaces using normal spring pressure as it is drawn thru the points.
Recently, a no-start condition with my side-distributor 8N was eventually diagnosed to a build-up of something on the points. They showed closed with a test light, but actually had some electrical resistance when closed. There was just enough resistance the coil would not fire. This was not fixed until an actual fine tooth file was run thru the points to scrape them clean. Once they were showing zero resistance closed, the burnisher was used to remove file marks and polish the points. Problem solved, it started right up. Don't ask how many times the points were checked and how many other things were cleaned or replaced before this problem was found.
As mentioned previously, I have found it easier to reinstall the entire distributor fully assembled. It's a little more difficult to get it past the belt and fan blades, but I find that easier than assembling the cap and coil after the distributor is on the engine. When installing the distributor, the slot in the end of the camshaft (front of motor) is offset. The tang on the distributor will only mate easily to the slot on the camshaft one way. If you have it lined up correctly, the distributor will fit flush to the motor and the two bolts will go in easy. If the tang isn't aligned and in the slot, the distributor will not fit flush to the front of the engine. If you put the bolts in and force it, the casting on the distributor will break. It is not real hard to get things lined up right, but it is easier if you remember about which way the rotor/tang was pointed when you took it off.
These engines can be very sensitive to timing and need to be very close to dead-on Top Dead Center for it to start easily and run right. If the point gap is set perfectly and the timing is adjusted exactly as shown in the manual, they should start and run well. Miss just a little bit on either adjustment and you can "fix" it by making a slight adjustment to timing without removing the distributor. Loosten the timing lock screw, shift the timing about half a mark, tighten the bolt and see if that helped. This simple trial and error approach, making small adjustments one at a time and then testing the results, is often the best way to find that perfect final adjustment. No two engines are exactly the same, and factory settings can be tweaked slightly. The key is to keep track of each change so you can undo the change if there was no improvement or things got worse. Fortunately, my 2N is perfectly happy with the distributor set up on the bench.
AIP Electronics contacted me and offered to send one of their replacement electronic front distributors and Dragon Fire high energy ignition wires for evaluation. There is no shortage of projects for my average weekend, but it would be really great to know there are some good replacement parts available. Plus, there aren't many things easier to swap than the front distributor. For people who struggle with getting everything inside a distributor the way it needs to be, this distributor could be a bolt-on miracle.
We discussed wires a bit. For the original ignition with points, the best wires have always been solid core non-resistor wire. The solid core has zero resistance and is a very durable type of wire. Durability is very important for a tractor. There are usually no sensitive electronics or radios on these tractors, so the best choice is still the solid core type wire.
However, if the distributor has been upgraded with an electronic module rather than points, solid-core, non-suppression wire can cause problems or even damage the electronic module. Electronic ignition and radios in cars made suppression type wire necessary. The most common type has a core that looks like dark grey or black fibers rather than copper or stainless steel wire. That carbon core is not very durable and breaks down in use, especially when exposed to the elements on a tractor. The resistor wire reduces spark energy to the plugs and only gets worse with age. Some of the newer high-quality spark plug wire is made with a very fine spiral-wound conductor core. Some of these can suppress EMI/RFI that causes problems for sensitive electronics and still deliver high energy to spark plugs.
The Dragon Fire ignition wires provided by AIP electronics are advertised as "high energy" but the specifications also mention a fairly high 1800 ohms per foot resistance. I put my ohmmeter on these wires and got almost exactly 1800 ohms per foot, but any low voltage resistance measured with a normal DC ohmmeter is not properly measuring how well high voltage spark energy will pass thru the wire. The best way I have to test that is to stick them on my tractor and see what happens. OK, confession time. The packaging and products all say "Dragon Fire". They should get 5 stars just for the name!
This is new for me. Prepare to be bored by some amateur video clips.
Everything from AIP Electronics came well packaged and looks very high quality. The fully-assembled distributor, coil, and cap looks great. There is an extra wire run out of the distributor body for the electronic module. Not sure why it has a ring terminal. What will work best for me is a male/female butt splice that can be pulled apart when the coil or entire distributor needs to come off for service. The wire length and ring terminal seem to imply that this wire should be connected to the terminal on top of the coil, but I know it won't work that way. This electronic distributor requires a separate wire from the junction block that is switched by the ignition key, but does not go thru the ignition resistor. The coil will still be connected to the wire from the ignition resistor.
The cast housing and machine work is very nicely done. As a true test of what many people expect to do, I should just stick this distributor on my tractor and see what happens. Sorry, I've never done that and can't force myself to do it now. Taking a few minutes to see what this looks like inside might head-off a problem before it happens. It's better to tinker now than troubleshoot gremlins later.
It only takes a few seconds to pop the clamps and see what we have. The gaskets are impressive. There is an O-ring in a slot on the distributor cap and the coil has what appears to be a silicone gasket. There is even a dust cover under the rotor. Nicely Done! I'm glad I looked!
Oops, there is one minor assembly issue. There is a wire laying against the support bracket for the front bushing. This isn't an immediate problem, the distributor would work fine until vibration eventually caused that wire to become grounded. How long that would take is unknown, but adding a second zip tie only takes a few seconds to prevent a future problem.
This is the new distributor next to an original distributor. Note the two holes drilled into the bushing area on the original. Those holes are so engine oil splash can easily get to the distributor shaft and bushing. Most aftermarket distributors don't have these holes. The distributors seem to work ok without those oil passages. That may simply be due to much better modern oil technology. Engineers may have decided the additional oil was unnecessary and could cause other problems if it got into the distributor. The original distributors also have a recess machined around the flange that goes into the engine. This helps the gasket stay in place while the distributor is being positioned on the engine. That brings up a point, the new distributor did not come with a new gasket to go between the distributor and engine. Most people probably won't have one of those hanging on the wall with other tractor parts and gaskets.
Another thing that should be checked is to make sure the coiled springy terminal under the coil is making good contact with the brass screw. Even though this distributor doesn't have points, it still relies on that connection. With the cap off, set the coil on the distributor, look in there and make sure that connection is good. The point of the spring should make contact with maybe a millimeter or so to compress the spring. If the spring needs to be extended, pinch between the individual coils with a pair of side cutters. Do not yank on it and destroy the solder connection!
Check timing. Ok, I tried. Attach a handy timing jig and even though there are no points, it is possible to use a small nail or scrap steel to see where the magnet is in relation to the module. This appears to be retarded a bunch, but since I'm not sure exactly when the magnet causes the spark to fire, I'm going to assume the timing was properly set by the factory.
Did you notice the highlighted cylinder numbers on the cap? Little things like that can head-off mistakes. It's way too easy to get turned around and hook things up backwards. I did cut the ring terminal off the module wire and replaced with male/female terminals for the new wire to the terminal block. Running that new wire took longer than anything else. I wanted the wire in the harness with the other wires. It took a while to pull the covers off the harness and tuck the new wire inside. Disconnect the battery when making wiring connections to avoid shorting something out with a wrench.
The new spark plug wires seem to be good quality. They have a center spiral conductor that is wound around a core, then covered with insulation. I normally recommend changing spark plug wires one at a time, so the timing doesn't get mixed up. If you are still sticking all the wires in the original conduit tube, they have to be pulled thru the tube before putting the distributor boots and terminals on. There is no way to accomplish that one at a time, so mark the wires and make sure they go in the right distributor holes.
This set of wires would also work fine for the side distributor engine. There are two extra terminals, two boots and a plenty of extra wire that can be used to make a coil wire. The solid core wires that came off were checked to see if they were the right length or if a change would work better. Cut new wires to length, plus about an inch that will be stripped for terminals. Slide the boots on and attach the terminals.
The #12 wire hole on a wire stripper worked really well to strip everything but the center spiral conductor. It was a bit tricky to get that fat spark plug wire properly centered in the stripper. When crimping the terminals, make sure the gripper points on the terminal have been buried in the insulation. Do this right and the terminals will stay on when they are pulled from the distributor later. Make sure distributor wires and plug wires are not going to get rubbed by the fan belt. Check firing order again.
Yes, the distributor was swapped, a new ignition wire was added, and new plug wires were installed right where the tractor was sitting. It was a nice day with no threat of rain for a change. The distributor went back on the engine easy (once I got the tang properly aligned). If you are struggling to get a distributor to fit flush, rotate the distributor shaft 180 degrees and try again. It will go on extremely easy if aligned properly.
If you listen carefully you can hear a little lean burn pop, pop-pop sound soon after the engine was fired up with the new distributor. That went away when I throttled up to run the cutter. It is possible the new ignition system is helping the fuel/air to burn more efficiently/completely and causing a slighty lean condition.
The test drive was about 10 minutes with the cutter on trails I cut frequently. The tractor ran at least as good as before. Can't say there was much difference, but that is expected since the tractor was running fine before we started. When I ran the idle back down, the lean burn popping was gone and it didn't seem to be running lean. The engine seemed to idle down smoother than before the swap. It might be good to readjust the carb and see if it now wants a slightly richer mixture. That might hint that the engine is making a little more power. Even if true, I'm not going to get all excited, nothing will change the fact that this is a 25 horsepower tractor. We won't be doing any smoky burnouts.
In my opinion, the electronic distributor by AIP Electronics is very well made and should work well right out of the box. This distributor may solve problems for people who struggle to set points and all the other things that can go wrong inside the front distributor. If you do decide to go with an electronic distributor or conversion module, please make sure you are using high quality EMI/RFI suppressor type spark plug wires. The DragonFire wires provided by AIP deliver good spark to the plugs.
FOLLOW-UP: After one month the cutter has been run for about an hour just about every week. In addition, the tractor was started and driven around a few times, just for fun. I am convinced the tractor needed a slightly richer mixture with the electronic distributor. Fuel consumption and power seem normal for this tractor. If you have a front-mount distributor/coil assembly that you simply cannot get to work right, the AIP Electronic distributor and Dragon Fire plug wire set should solve the problem.
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