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.