This is the third part in a three part series on Peter Rooke’s restoration of a 1 HP IHC Mogul engine. You can read part 1 in Mystic IHC Mogul and part 2 in Mystic IHC Mogul Engine — Part 2.
Fuel Pump
The IHC Mogul’s fuel pump was seized and looked a little worse for wear. When I stripped down the fuel pump I found that the check balls were stuck, the plunger was bent and badly worn around the packing, and an ordinary flat washer was the only thing holding the gland packing in place.
I thoroughly cleaned the pump and lapped the seats for the check balls using grinding paste and a steel ball that I super glued to a length of brass tube. The bore of the pump looked a bit rough so I reamed it out to 0.0625 inches over size. I made a new plunger to fit the bore, replacing the 0.3125-inch original, which had worn down to less than 0.30 inches around the packing.
Making the new pump plunger on the IHC Mogul was a simple turning task; I used brass rod, with a 0.125-inch cross hole drilled 0.15 inches from the top for the split pin to hold the spring end cap.
The washer that had been used to hold the packing around the pump plunger was only doing half a job: It was keeping the packing in place but it was not compressing it around the plunger.
To make a new packing ring I turned some brass rod to 0.75-inch diameter to fit the recess in the pump body and then drilled the rod through so the new piston was a good sliding fit. I cut a recess 0.625 inches in diameter and 0.125 inches deep in the top of the packing ring for a seat for the spring, and then I cut a 30-degree taper in the bottom side. This taper compresses the packing around the piston when the ring is under tension from the spring. I cut some new 0.125-inch diameter graphite packing to fit, although mop string and soap work equally well. I fit new check balls, and after painting I reassembled the pump.
The old fuel line connecting the pump inlet with the fuel tank had been made from a section of copper tube, and a modern brass elbow fitting had been used as the connection with the pump. This elbow had sharp shoulders, not in keeping with the style of the originals.
I replaced the copper pipe with some 0.125-inch diameter brass that I first annealed by heating until just red hot, then allowed to cool slowly. This makes it easier to bend, and I used the bending wheels to copy the bend in the original. I used brass that was approximately an inch longer at each end as an allowance for final fitting to ensure there would be plenty of length for the connection joints and the pipe would not be under any tension when the fuel tank was re-fitted.
I reshaped the brass elbow with a file to round the sharp corners and make it look more like an original fitting.
The fuel pipe from the pump to the mixer and the return pipe to the filler inlet were also missing so I shaped more brass pipe to fit. I completed the pipe by purchasing new brass nuts for the connectors.
The thread on the end of the return flow connector to the fuel filler was badly worn and not a good fit even with new nuts. Not having a replacement fitting, I cut off the section with the worn threads and threaded a new piece of brass, then center-drilled it before brazing it to the old part.
Igniter
Despite being covered in dirt, the igniter appeared to work. I brushed off all the dirt, then removed the nut holding the fixed electrode in place and pushed the electrode in to free it. I saved the mica washers and tube, even though a lot of the washers were broken or dirty and would be discarded.
To release the moving electrode I removed the split pin and then slid the springs, trip finger and washer off the shaft before I pushed the moving electrode through to the inside. The shaft appeared a good fit in the igniter body, but I cleaned the shaft with fine emery cloth and the hole with a 0.3125-inch reamer. Even after this cleaning the shaft appeared fairly tight so no repair work was needed.
After cleaning the light rust from the springs I deemed them good enough to use again, so I primed and painted the metal parts before assembly.
Assembly followed the reverse sequence, fitting the moving electrode then the fixed electrode, replacing the mica washers and aligning the fixed contact with the moving contact. Once assembled, I connected the igniter to the low-tension coil and battery, and then flick-tested for a minute to ensure it continued to spark well.
Electrolysis
To make the new metalwork look more original I conducted some experiments to see how best to quickly create rust, rather than have the look of newly painted metal parts.
I have mentioned electrolysis in previous articles as a method to remove rust from metal parts. In theory, to generate rust it is simply a case of reversing the polarity of the electrolysis setup, connecting the positive power supply (anode) to the item and the negative (cathode) to the metal plate.
As before, I made the electrolyte by dissolving some washing soda in water, the ratio normally being around 5 percent soda (50 grams) to water (1 liter), and used an old battery charger as the power supply.
This worked well for the first parts, two short lengths of steel held back-to-back between two cathodes in the bucket. In this case a stronger solution of 10 percent soda was used. However, when it came to the larger part I found that the battery charger kept overheating, and this was due to a too-large current draw. After some experimenting, I diluted the electrolyte solution with water to 5 percent, and immersed only a bit of the large part in the electrolyte, keeping it as far away as possible from a single cathode. Another solution would have been to find a larger receptacle so the item and cathode would have been farther apart, or possibly the whole of the item could have been immersed if a resistor was used to reduce the amps drawn. This resistor could be a rheostat or even a light bulb, with experimentation needed to get the right balance.
In the smaller bucket the rust creation only seemed to occur in direct line of sight of the cathode. When I placed smaller parts in the same bucket, the rust appeared to be created all over, perhaps because the electrical forces were able to circulate more freely. Once the rust starts to build up on the item the current draw falls even farther.
Painting
I had to repaint the restored engine, as an earlier restoration had resulted in it being stripped to bare metal then repainted an indifferent green.
Looking at the paint on the sled, the original color appeared to be what has been described as “pond scum green.”
There has been some debate on the colors used on these Mogul engines, and from inquiries on Smokstakabout the original engine paint colors, it would appear that there were frequent variations. In some cases this might have been driven by what was available at the right price rather than the use of accurate paint-matching to get an exact copy of a master shade. Furthermore, some Moguls appear to have two colors, with a light green on the flywheels and sled and the main body a dark green. For this restoration the light “pond scum green” would be used throughout.
I found a new source for fuel-resistant enamel paint, produced by a firm less than 50 miles away. A visit one day saw me coming away with numerous cans of paint — the primary colors, white and several shades of green — providing enough stock to paint several engines over the next few years.
To get the right shade for this engine, I mixed a color in a small mixing pot to be a little cleaner and lighter than the green on the sled. I painted some of this on a piece of test material and allowed it to dry. I found this initial color by adding some green to yellow and a small drop of brown. It was necessary to make a few adjustments to the test sample to get the required color. Once happy with the eventual color, I made up a pint can of the correct color.
I had painted the various components of the engine with an anti-rust primer when I cleaned the engine, and would now paint the topcoat before assembling the engine. I brushed rather than sprayed the topcoat on and I made no attempt to smooth out the casting and other marks. After the first topcoat, I gave the paint a light sanding with 400 grit paper to remove any brush marks and other minor imperfections, and then I added two more coats. After the second coat, I gave the paint another sanding, this time with 600 grit paper, and then took extreme care with the final coat to leave no brush marks, brush hairs or drips. I then allowed the paint to harden for a week before I used rubbing compound to tidy any small blemishes.
Once the painting was finished I applied the two decals to each side of the hopper. I made reference marks on the hopper using a white glass pencil to ensure the decals would be applied square. These were water decals, so I soaked them in warm water for 30 seconds before sliding them into position and pressing out any bubbles with a thin card. I then dried the decals with a paper towel before washing with clean water to remove any traces of adhesive and dried again. I left them untouched and uncovered for at least 24 hours.
Assembly
Once the paint was finished and allowed to harden, I reassembled the engine.
I fitted the gear wheel to the muffler side flywheel. The holes for the mounting bolts are offset, which ensures that the magneto gear meshing mark is in the correct place. As I assembled items, I cleaned the threads of any bolts and the mating surfaces of paint. I hadn’t painted any of the mounting nuts and bolts prior to assembly; this would take place when assembled. I then fitted the governor assembly on the other flywheel after lightly oiling the shaft.
I set the fuel tank in the base of the engine, and after installing the pump feed pipe I put the fuel inlet pipe into place, ensuring that the elbow for the filler pipe was correctly aligned so that pipe would not foul the governor rod.
I fitted the hopper/cylinder with the two large nuts and evenly tightened them to ensure the hopper was correctly aligned. I fitted the piston and con rod from the front of the engine, using the piston ring compressor after oiling the bore, piston and rings. I retained the old piston rings as they still had plenty of thickness and spring in them.
I fitted the inside gear for the eccentric after marking the two faint punch marks for the meshing point with white paint. I assembled the plate for the eccentric/pushrods, but I did not bolt it in position. I lightly oiled the crankshaft journals before sliding the crankshaft into position. I carefully aligned the timing marks before I bolted its side plate in place. Then I bolted the con rod to the crankshaft, taking care that the shims made earlier were correctly fitted; the nuts were made doubly secure by tying wire through the holes in the bolt.
It was necessary to make a new key for the eccentric. It was then a bit of a fiddly job to fit the fuel pump lever under the eccentric and position the fuel pump so everything was ready to bolt in place. I found that by fitting a long, temporary stud in place of the rear bolt on the pump mounting plate it was possible to push against the pump plunger spring to fit the second bolt. After tightening the second bolt, I could remove the stud and fit the correct bolt. Once assembled, I poured some fuel into the tank and activated the pump to ensure that it worked, draining the fuel from the tank after the test.
Then I fitted the igniter along with a new gasket so I could fit the trip rod. To do this it was necessary to temporarily fit the governor side flywheel so the timing marks could be seen, so I could adjust the pushrod to get the igniter tripping at the correct position.
I then assembled the cylinder head with the valves plus springs and the rocker arm. It was then fitted with a new gasket. I also made new gaskets for the mixer, which I bolted in place, and then fit the needles and completed the fuel pipe connections.
The original tube for the oil feed to the cylinder was bent, so I threaded a new piece of tube 1/4-inch NPT at both ends. As this was only a slight bend I heated this in the brazing hearth without packing the core with sand and bent it to shape.
I fitted the gear wheel to the magneto and then put the magneto, along with its new guard, in position, only finger-tightening the bolts until the timing had been set.
I purchased new key stock to replace the original, damaged flywheel keys. Before starting to fit them, I double-checked the keyways in the flywheels and the crankshaft to ensure they were free from paint and any burrs. I trimmed the new keys to length and then filed them to fit by draw filing. I applied engineers blue to the key so that the high spots where it rubbed off in fitting could be filed. When test-fitting the keys, I only lightly tapped them in so they could be easily removed.
I bolted the governor rod to the governor yoke after fitting the flywheel.
Finally, I fit the rear cover plate and bearing securing bolts, and filled the greasers and oilers.
I then craned the engine onto the sled and bolted it in place, ready for its trial run.
Setting the timing
I used the timing marks on the governor flywheel to set the timing, lining them up with a mark on the crankcase, which is near the hopper securing bolt. I set the timing of the igniter first, adjusting the length of the rod so that the igniter was about to trip when the “ignite” mark lined up. I then meshed the magneto gear with the gear on the flywheel so that the second mark on the shaft lined up with the mark on the bearing wall. The second mark is counted by moving in the direction that the shaft is turning. When set, I tightened the magneto bolts.
The exhaust valve should close when the flywheel mark lines up with the reference point. If the gears are meshed correctly using the marks, this should be automatic. When the exhaust valve is closed there should be a 0.031-inch clearance between the end of the rod and the ball end, the two nuts on the rod being moved to affect this adjustment.
Running
After ensuring the drain tap was shut, I poured water into the hopper. I tightened the grease cups and then filled the oilers. I set the governor side oiler to 10 drops per minute and the cylinder oiler to five. I then gave all moving parts a squirt of oil from the can. After pouring some gasoline into the fuel tank, I primed the fuel pump until fuel appeared in the mixer cup and the needle opened by half a turn. While the handbook recommends that a squirt of fuel should be injected into the air intake, this did not prove necessary.
As I started the engine on gasoline it was not necessary to use the priming reservoir and top needle. Eventually I found the correct position for the bottom mixer needle, a quarter of a turn, and the engine fired into life. Although running a little fast, I ignored this for the time being as there was little point in adjusting the governor until everything was bedded in. I allowed the engine to run for half an hour, and then I checked the tightness of all nuts. Using the tachometer, I adjusted the engine speed by altering the tension of the governor springs until it ticked over at 450 RPM, a little slower than the rated 600 RPM. Another engine successfully brought to life again.
Contact Peter Rooke at Hardigate House, Hardigate Rd., Cropwell Butler, Nottingham, NG12 3AH, England • peter@enginepeter.co.uk • Peter Rooke’s Engine Pages
