8N Ford Distributor - Points and Condenser Replacement.
By Kimberly on Apr 28, 2009 | In Everyday Thoughts | 49 feedbacks »
Sunday I had intended to take the time to replace the points and condenser in the distributor of the 1949 8N Ford tractor I use to plough the veggie gardens and finish replanting the hostas that I had not manage to finish on Saturday. However, Sister #4 rang and wanted to know if I could come down and help her. She had gotten a new grass mower and I could have her old one if I helped her set up the new one. She also needed a bit of help putting down soaker hoses in her Iris bed and a few other odds and ends. She also had an Angel's Trumpet she had rooted during the winter and I could pick it up as well. After the work, we planned on having a nice dinner of grilled tuna steaks with suitable sides and a nice white wine.
Sister #4 use to just get me to do things; however, lately she has decided that she wants to learn more about maintenance so she can be more self sufficient. Last year I showed her how to check and change the oil in her mower, and how to remove the blade and replace it with a new one. She is learning more about how to do her own work on such things and not have to depend on a garage and worrying about if they are actually doing the things you pay them to do. I was very pleased to help her and even though the mower she was giving me was used, it was still in very nice condition. It had a 6 hp engine, self-propelled mechanism, a grass bagger, large rear wheels and starts with the first pull of the rope. After we finished doing the chores, she help me to load it in the boot; I had to unload it this morning by myself. However, I was not foolish enough to try and lift it out of the boot. I got the shelf units out of some wooden shelving and made a ramp. I simply let the mower roll down the ramps onto the ground.
One of the chores I did today was to replace the points and condenser in the distributor that did not get done on Sunday. It really isn't that hard of a job. This particular 8N Ford tractor has a front mount distributor with the coil mounted on top. Some of the 8N Ford tractors have a side mount distributor.

You can see the coil mounted on top of the distributor. The coil you see in the photograph does not work. This tractor has the original six volt positive ground system. The coil failed and Dad wired in a six volt tubular coil that he mounted to the side of the engine. My Dad was a smart man and he knew how to arrive at a solution to a problem. A new top mount coil for an 8N is around $30.00 and I would not be surprised if Dad did not already have a six volt coil on hand. I would like to replace the coil, but spending $30.00 is a bit more than my finances can allow when the tractor runs fine with the replacement that Dad added.
The distributor is held to the front of the engine block with two right-hand threaded bolts. The bolts are removed using a 1/2 inch box-in spanner; there are no metric size bolts, this tractor was built in the US in 1948 ('49 model). Before removing the distributor, unclip the spring that holds the distributor coil in place and remove the spark plug wires. If you find that a wire slips off of the terminal, don't worry, you can replace the terminal easily with a set of pliers. In fact, in order to thread the spark plug wires through the cable guide, you have to have the boots off of the end of the wires and add the terminals afterwards. Be sure to notice the order the spark plug wires are connected, if necessary mark them with electrician's wire numbers. After removing the bolts, I position the coil out of the way and remove the distributor.

In the photograph above you can see the condenser mounted to the top of the distributor. There is a screw that holds the condenser to the distributor casing which grounds the body of the condenser. Just to the right of the condenser you can see the screw that connects the output of the condenser to the points. The head of this screw is concave and a spring on the coil fits into the head of this screw; this is an electrical connection as well. I am not going to go into the principles of how the high tension spark is generated from a low voltage source at this time. If I get enough feedback requesting this information, I may write a blog post on it later.

In the photograph above you can see the shaft that drives the distributor. This shaft drives the mechanical spark advance system as well as a cam that open and closes the points and the rotor that distributes the spark to each plug as needed. If you will examine the shaft, you will see it is offset. There is no way to get this distributor mounted so the timing is off, it will only mount back to the engine block in one direction.

In the photograph above you can see the points set to the right. There are two set screws that hold the points set in place as well as an adjuster screw used to adjust the points gap. There is a spring (the long curved shiny metal thing) that loads the points so they close when the points move off of the cam lobe. At the top you can see a screw that mounts the spring and the connector strip of the side of the points connected to the output of the condenser. All of the screws mentioned, except for the adjuster screw, have to be removed to replace the points. The tricky part in installing the new points is replacing the screw at the top that holds the spring and connector strip in place. Of help in replacing this screw would be an extra pair of hands; since I did not have any extra hands, I had to made do the best I could.


The photographs above show the replacement kit and the contents of the kit. My local tractor supply shop had the replacement kit in stock, but I found the same kit on eBay at a $5.00 savings. In the bottom photograph from left to right, the points set, the rotor, and the condenser; at the bottom you can see a small washer, a split pin, and a gap gauge for setting the points. Once you remove the old parts, the new parts go back exactly the same except in reverse order.

In the photograph above you can see the new points and condenser and rotor installed. I photograph the distributor with the rotor installed; however, there is a thin phenolic disc that goes in place behind the rotor. I left it off so my readers could see the points as well. Before mounting the distributor to the engine block, install the distributor cap. It is easier with the distributor off of the engine, and with the cap installed, it helps to keep dirt out of the distributor. After you have mounted the distributor to the block and tighten the bolts snugly (CAUTION! Do not over tighten the bolts, you can easily snap the bolt heads off making a nasty repair job. I use a spanner and tighten by hand guessing at no more than 20-25 foot pounds of torque) mount the coil on top and reinstall the spark plug wires.
With the distributor back in place, it was time to test things. I open the fuel valve and then climbed into the drivers seat. After making sure the transmission was out of gear, I push in the clutch, turned the switch, pulled out the choke and hit the starter. The old girl started with just one turn over of the engine. She was running fairly smoothly and I was rather pleased with her. I still need to remove the plugs and clean and check the gaps. I would also like to get some new battery cables as the ones on her are not in the best of shape. I do need to do some other maintenance on the old girl, but I just don't have the finances to do much. Considering the age of the old girl, it is amazing at the parts that are available. I was browsing in the tractor supply shop and found that I can get a new wiring harness for the old girl. The wiring harness is original and wires do deteriorate with age. One thing that I really want to do is to have the headlamps back in place. I think the old ones could not be used, or Dad would have replaced them. I am not even sure where they are located since we moved since Dad did the repaint. As you can see in the first photograph, I need to do some repaint as well.
I switched the engine off, closed the fuel valve, and gave the old girl a pat for being so faithful. There is a certain joy in having the old girl around; it is a connection with Dad for one thing and she does help with the veggie garden work. After I put the tools away, I turned my attention to finishing up the replant of my hostas.







49 comments - Show
bent it down the flat piece starts for awhile gets hot and
quiets, should that flat piece be bent enought to stay
in contact with the distributor.
bent it down the flat piece starts for awhile gets hot and
quiets, should that flat piece be bent enought to stay
in contact with the distributor.
The flat piece on the coil is the output connection to the distributor cap and then to the rotor. That certainly does need to make a good contact or you could get arching between the output of the coil and the distributor cap. You would probably see this arching as a discolouration and possibly burnt at the distributor cap button that this flat piece contacts (see the distributor cap photo in my blog)
The little spring thing and the flat piece should be making good contact and you should feel that the coil has to be pushed down when you place the retaining clip onto the coil. You can feel this resistance, if the coil just fits down flat on its own, something isn't right here. I hope I am making myself clear. These coils are expensive, so be careful with the spring thing and flat piece so you don't break them off.
You stated that the tractor starts and runs until it gets hot, then quits. I am guessing there is no spark output when it is hot. When it cools off, you can start the tractor again and the process repeats. Is this correct? This would indicate that something is breaking down when it is hot. It is possible that the new coil is bad, I had someone who had to replace a new coil. Have you replaced the points and condenser? It is possible that the condenser is breaking down when it gets hot. My tractor would run fine when it was cold, but as it got hot, would run rough and want to quit. I replaced the points and condenser and the problem disappeared. If you have not replaced the condenser, I would suggest that and see if it helps.
By the way, there is a set screw on the outside body of the distributor. This screw adjusts the timing of the distributor. If the timing is correct, do not move this screw. Be sure to note the position of the set screw (there are little markings) in case you move this screw. If you are looking at the front of the distributor with the flat part (coil location) at the top, this screw will be located to the right on the outside. I suggest not moving this screw if possible so you don't get the timing changed.
If you have a spark output when the engine is hot, then we have to investigate other things.
Hope I have been of some help.
-Kimberly
Bob
Thanks,
Kim.
My old 8N almost torched itself yesterday when the original wiring caught on fire. Lots of smoke, etc., but no serious damage except for the fried wiring. The good news, the event helped make up my mind to convert to a 12V alternator/wiring system, which are fairly reasonable (new) on eBay and comes with a new wiring harness. If your 8N has original wiring you may want to consider replacing it, odds are against it lasting much longer; eBay also has new 6v wiring harnesses.
http://shop.ebay.com/i.html?_nkw=ford+8n+12v+alternator+kit&_sacat=0&_trksid=p3286.m270.l1313&_odkw=ford+8n+wiring+harness&_osacat=0
We have good tractor support in our area but just about everything I’ve ever needed for the 8N was available on eBay.
Plan to put new points in at the same time and your tutorial is a good refresher. If you have not converted to a 12v setup it works very well – no need to change the starter, the 6V starters just spin faster, which make for much faster starts.
Relative to your comments about living in a city environment, could not agree more, been there, done that. We do not have even one permanent traffic light in our county – in Southside Virginia, but are an easy drive to four different cities.
Happy New Year, Bob
http://www.ntractorclub.com/howtos/6to12v.htm
wildweaselbob
Editor's Note: I did not see where the above website illustrated how to replace the standard coil on a six volt; perhaps I simply overlooked it. The above website deals mainly with converting from a six volt system to a 12 volt system. The site does show some good wiring diagrams, so that is why I allowed the comment. Personally, I have not had any problems with my six volt system, and I prefer to have my tractor as original as possible. With a proper system in good order, a six volt system will start an 8N Ford tractor without any problems. Furthermore, I have recently brought a new six volt battery for my tractor and had no problem locating one at the many auto parts shops; in fact, each shop I visited had one as I was shopping for the best price. I see no real reason to go through the expense of converting from six volt to 12 volt, but that is a choice for the owner of the tractor to decide on her own.
When I touch the contactor of the coil on the body of the distributor, it has spark there, but none at the plugs. I thought it might be a wiring issue. An owner from long ago had wired a toggle switch in instead of the standard ignition switch. It also had another toggle switch next to it that turned the ammeter off and on, but the ammeter never worked, although it had to be in the "on" position for the engine to run. I removed both of these switches and installed a regular ignition, but for troubleshooting purposes, have removed it and I have been temporarily connecting the wires when trying to start it and disconnecting after so as to not "burn up" the points. I'm baffled and frustrated. Wiring diagrams for this conversion are confusing, showing from anywhere from one to three resistors, diodes, etc. This application has only one resistor mounted next to the ammeter inside the firewall.
Should I replace the ammeter? If so, can anyone offer some advice to ensure that I'll wire the new ammeter correctly? I love this old tractor, but right now its not doing any work I bought it to do. Please help-anyone!
I had a toggle switch on my tractor once as the key switch is just an on/off switch on these models so that should not have been a problem; I have left the key switch accidentally turned on at times. I don't understand about the switch for the ammeter. Ammeters usually has a shunt resistor since the ammeter can only handle a very little bit of the total current. The shunt resistor may have went bad, and that would have burned out the ammeter. I would check the shunt resistor and maybe replace it and the ammeter. The switch on the ammeter may have something to do with the conversion. As I said, I know nothing about these 12 volt conversions.
-Kimberly.
The best way would be to pulse the coil and see if it will generate a good spark. I would use a spark plug so I could see what kind of spark I get across the plug gap. Just don't let the output get you. If you are talking about an original 8N top mount coil, these coils are known for going bad. A replacement can be had for around $30.00. Please realise that condensers can be bad out of the box, I have seen my Dad replace new condensers just installed because they were bad. Wish Dad was here as he was a wizard on engines of any type. Dad replaced the top mount coil on my 8N with a six volt (my tractor is still a six volt system) tubular coil mounted on the side of the engine block.
Hope this helps a bit,
-Kimberly
I checked the voltage at the top of the coil and have 6.5 volts. Is the resistor in the circuit supposed to reduce the voltage input to the coil? Could I have burned out a second one?
I removed the old induction ammeter and and connected the wire back to the resistor. I'm trying to find a series one that is 2 in. diameter to fit the hole in the dash.
Anybody have an idea of what to check next?
Thanks
Have replaced the coil, points and condenser, still did not take care of the problem.
Will a Ignitor take care of the problem and will it work on this tractor?
I don't know anything about a 631 or the ignitor so I can not give any help there.
-Kimberly
NO FIRE FROM COIL OR DISTRUBTOR I CHECKED COIL FROM POSSITIVE SIDE TO BATTERY HOT FROM NEG SIDE TO BATTERY NO NOTHING WIRE INSIDE DISTRUBTO WERE OFF WHEN I GOT IT BUT NOT SURE ABOUT GROUND WIRE AND OTHER 3 WIRES ARE IN CORRECT PLACE
My tractor would start fine when cold, but not start when hot.
Replacing the condenser and points seem to have done the trick. Thanks for your excellent instructions.
Bob
When you rebuilt the carburettor, did you make sure to use compress air and blow out through as many of the ports and holes as possible? It is best to let these old carburettors set in a cleaning solution over night, but I have just used the spray carb cleaner. and blow through the holes. You also have to make sure the venturer goes back in correctly. One side is slightly larger than the other.
You did not mention if you put a new condenser in when you changed the points. You can check for the quality of spark by taking a plug out and put it on the head and rotate the engine over. If you have a good hot consistent spark then don't bother with the electrical system. Basically with these engine it is spark or fuel.
This year I came close to buying a new carb for my tractor. Found one that a guy had for around $100.00 which is a good buy. However, I took my carb off a second time, and gave it a good cleaning blowing compressed air through all the little holes and it started and ran. So I almost brought a carb I did not need. I would take the carb back off and reclean. Make sure the venturer did not get put in upside down. Also, check the strainer that is at the carb inlet (if yours is still in place) and make sure it is clean. Also check the strainer up at the tank inside of the settlement bowl.
If good hot spark, then it is a fuel problem.
Good Luck,
-Kimberly.
I inherited an 8 N with 12 volt alternator, in line resistor to a front mount 6 volt square coil distributor just like shown. It ran great till I changed starter and bendix. Now It turns over easily and starts and runs smooth for about three seconds. The ammeter shows big charge after crank as normal but noticed the point motor dies (just as if turned off ignition) when drops down to 20 amps. Everytime it dies as amps drop after start, right at 20 amps. I can hit the starter button and keep it running as if the jump in amps or the 12 volts gets fire to the coil but when amps drop to 20 it dies. What could it be? Today it won't hit at all . I did the hitting starter button trick a lot thinking at first I just needed to fine tune the carburator as this all started when I pulled and cleaned carburator. I am afraid I fried the coil or condensor or points or the alternator by hitting starter to trying to keep her running. Any advice? I am way out in the country. I am not restoring and really just want to keep her running and get some work done. Any advice? I can start replacing everything but wonder what my original problem was. All advice welcome.
do you have any ideas,,?
thanks
george
Thanks for these great pictures and instructive verse. My 8N now runs again. I have never done anything to it but change trans/hyd. fluid and oil in the last 8 years. So I guess it was time for her to have a tune-up. She is happy once again. Excellent!
And what you displayed is a big help=
Even tho I. like your Dad am pretty mechanically inclined That info will be a great help.
- For years I rebuilt VW engines.
The offset shanks on the distributor drive look much like the VW.
let me tell/ask you a couple of things just for conversation.
About the purchase of your parts-
Did you actually buy them off the web?
what was freight?
and did freight not eat up the 5.00 savings you mentioned.
Reason is I was in the parts business and hadto go out because of the web-
Folks wanted my knowledge then with that in mind , they turned to the web to save 50 cents?
so each time I see that in writing I am in amazement-
I hope you do purchase some parts from your local folks--
If not --they'll wind up like me.
About the only place locally now to obtain Ford 8N parts is Tractor Supply and their prices are a bit high, at least for the Ford 8N stuff. We use to have a Ford dealer in my home town and they carried anything you could wish for. Now it would mean a long trip to another city and with fuel prices the way they are, it quickly becomes cheaper and easier to order from the web. When I rebuilt the hydraulic pump, I ordered the rebuilt kit from Steiner Tractor as it was the only source.
There use to be a tractor salvage yard not too far over in the next state but I have not been there in years; the last time was when Mum and I went there to get a new muffler for the old girl.
-Kimberly
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