J4 Restoration by Ed Jeter
Part II Rebuilding Ollie J-4
Saturday 14 March '98
By the time I had descended the hilly
terrain of Little Rock and transversed twenty miles or so of the Grand Prairie and pulled
into Robert's shop north of Lonoke the cold drizzling rain had stopped and Robert had
already mounted the J-4 in a red plastic drum half-filled with water.
We mixed a half-gallon of fuel-oil mixture and put it in the fuel tank connected to the engine. Then we removed the cowl by loosening the clips on each side and very optimistically pulled the plug wires to keep it from springing to life during the lubrication stage. If you remember it had been at least 30 years since it was last fired up.
We each pulled it a few times to pull some fuel-oil into the engine and to get water pumping through the water jackets. It felt pretty good- not frozen up yet seemed to have pretty good compression. We next removed the plugs with a 13/16" box wrench and examined them. They didn't look too bad either, but we cleaned them with a wire brush anyway and retorqued them back into the head and connected the spark leads. Look at the picture taken from fore side of the engine and you'll notice that one of the spark-plug leads has a copper band around it. That is the lead that goes to the top plug. The other one, of course, connects to the bottom plug. The next pull could potentially start the engine, but we expected at most a pop or two and maybe a puff of smoke. Robert went first, and second, and third, and fourth, and fifth. Nothing! I did the same. Still nothing. Not a hint of burning fuel-oil.
Now, it was time to analyze.
I always check the ignition first as it is not dependent upon carburetion, whereas
carburetion is somewhat dependent upon ignition. We removed both plugs again so that
it would turn over easier and faster and I grounded each plug in turn to the chassis as
Robert yanked on the starting lanyard. No spark at any time. Just to make sure, I held
each plug. Still nothing. Don't try this technique on anything but an old points and coil
system. The new high-energy systems will hurt you badly.
Robert; "What now?"
Me: "The spark-leads come out from under the flywheel, so the ignition system must be under there."
The flywheel had to come off. Two screws fore and two screws aft were removed. The starter top assembly came off and was set aside. The rope pulley was held on by four screws as shown in one of the pictures and was easily removed. The brass starting rachet serves two purposes. One was to serve as a starting rachet and the other was to hold the flywheel on. The rachet had kind of a stylized spiral nebula shape. It was shaped the wrong way to be loosened with a rod and hammer.
At one time I'm sure every Oliver tool kit contained a special wrench to remove it, but we definitely didn't have the tool nor any chance of getting one soon. Tell-tale marks indicated it had been removed previously with a pipe wrench. We did have one of those. Robert clamped a 10" pipe wrench on it and tapped the wrench lightly with a ball peen hammer and it loosened. The rest of the way it screwed off with finger pressure. We put the brass rachet and its washer into a baggie and into our parts bucket. The flywheel was next. We found out later the flywheel was fitted over a tapered section of the driveshaft and a woodruff key was used to prevent it from running free. Ideally you would enlist the aide of a wheel puller or gear puller to separate flywheel from shaft. We didn't have one conveniently located so Robert tried to remove it by tapping lightly around the bottom edges. That had no effect. They seemed to be welded together.
Method Two. Robert placed a brass bar on top of the driveshaft and had me put upward pressure on the flywheel with a steel bar. He then tapped the brass bar sharply and the flywheel popped free. He said this only works if you have endplay in the shaft. You could probably replace the brass bar with a brass hammer head if you have one. The flywheel then lifted off and we set it aside.
Underneath the flywheel we found a circular cast aluminum plate with a diameter of 6 inches. (See photos of top and bottom) On the plate were mounted a pair of coils, two laminated 2-pole stators, a pair of condensors, and two contact point sets. One reason for lack of fire was obvious. The potting of the coils was badly disentegrated and an ohm check showed the secondaries to be open circuits. That's about what you would expect since the secondaries are many, many turns of extremely fine wire and not hard to break without the support of the potting. The coils are easily removed once you get to them by simply unsnapping clips at each end of each coil. We removed the Ignition Plate (held on with 4 screws located near the ends of the condensors) and looked at the bottom side. It read "Scintilla Magnetos - a Division of Bendix-Aviation ". Also there were the Part Number and the Serial Number.
Our next step must be to get coils or rewind the ones we have. Robert suggested the Small Engine Shop about a mile from where we were. The search was on. Next time we'll report on efforts to get fire.
Ed Jeter, Little Rock, AR