Old Engine Restoration Tips

Useful engine restoration tips for beginning engine restorers

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We recently traded for a McCormick-Deering model M 1-1/2 HP engine from our partner Eddie Hall of Milton, Indiana, for use on our flour mill. This engine was basically complete and not stuck but had sat out for many years and would need a good engine restoration. Eddie had not done anything to this engine other than locate a couple of broken gear replacements. We are not going to bore you with a tale of cleaning, priming, painting and so on, but we do want to share a few things which we learned and which may help others, particularly beginning engine restorers.

One of the best tools we used was a large can of Liquid Wrench. This works far better than WD-40, which is basically a lubricant, for loosening rusted parts. An early task was the removal of the flywheel on the magneto side. The key was stuck and so we applied Liquid Wrench liberally around the flywheel hub for about a week. Some stout blows with a long iron bar and a 5 pound hammer eased the key right out. But the flywheel was stuck to the crankshaft. More Liquid Wrench was applied over a period of a week. We tried a hammer and oak block with no success. A hydraulic jack, chain and wood blocks did not move the wheel. Finally a log chain was hitched between the far flywheel and the skid. We seized the stuck flywheel and rocked it back and forth vigorously, letting the chain stop the shaft from which it could easily be worked off.

The ignitor cam was rusted solidly together. We removed the key and soaked the assembly in Liquid Wrench for a few days. Two hours' work one evening with a propane torch, more Liquid Wrench and a hammer and punch permitted separating the cam and sleeve. The fuel pump was a mess. More soaking and some heat permitted withdrawal of the pump plunger and packing gland. But over the years water had corroded the interior so both check balls were stuck.

We reamed the inside of the bore by using increasingly larger twist drills turned by hand to remove corrosion. Some heat and a few sharp knocks removed the check balls. After cleanup we determined the ball seats were leaking. The pump is a single casting of white metal with no removeable seats. We polished the seats with a piece of 1/4" fiberglass rod in a drill press with valve grinding compound as abrasive. Thorough washing in kerosene was required to remove the valve compound. The pump was reassembled and new packing of 3/16" graphite coated cord was used. About a 3" length seemed about right.

The cam and magneto gears were broken and needed replacement. Three teeth on the crankshaft had been deformed by pieces of broken gearing and would not mesh properly with the new gear. We spent 2 evenings carefully filing and reforming these three teeth until they would mesh properly. A piece of the old camshaft gear was very handy for checking proper tooth shape and mesh.

This engine was designed for starting on gasoline and then changeover to kerosene when hot. We intended to operate on gasoline and have not replaced the starting side needle valve and parts yet. We learned that the original idea was to let the fuel pump fill the kerosene side of the mixer while the engine was running on gasoline. A 5/16" fuel pump rod with a short stroke feeding a 3/8" fuel line takes a while to bring gas up to the mixer. A piece of 1/2" dowel rod about 2 feet long reaches easily behind the flywheel and permits pumping up gas to the mixer with a few short hard strokes.

The only return of electricity from the igniter to the magneto is through the frame. The igniter has a gasket under it and so the metal contact is through the igniter mounting studs and mounting nuts. The metal surfaces under the nuts and the igniter surface of the nuts themselves must be clean in order to have a good ground connection. It was necessary to remove all paint and rust and have a good smooth surface for good operation.

The instruction and parts manuals are always very useful in restoring an old engine. But be careful of the starting instructions. Remember the manuals were written for use with a new engine. Over the years needle valve shapes and sizes have changed and thus the recommended to turn open will result in a flooded engine. We found our engine operates well at to turn open with little difference between starting and running settings. An additional tip regarding the IHC M engines. When reinstalling the igniter after cleaning or inspection, be sure to lift the trip rod above the igniter position. Otherwise one has to remove the igniter again to get the trip rod back to its proper place.

Our magneto appears to be in good working order. However, the engine starts more easily on a battery and coil, but runs much better when switched to the magneto after starting. Thus we have arranged a double throw switch for changeover. Since our engine is installed permanently near the flour mill which it powers, we wired our coil to a 6 volt battery which is part of our Delco light plant system.

We hope these few pointers will be helpful to other engine restorers. We want to thank Eddie Hall of Milton, Indiana for his help on several problem areas and continued interest in what we are doing.

Contact James D. Jones at 200 S. Spruce St., Centerville, IN 47330