Quest for the Perfect Engine


| November/December 1998



4 HP Mogul sideshaft engine

This 4 HP Mogul sideshaft engine is owned by Jeff Wahl, 9709 Ripple Run Court, Fairfax Station, Virginia 22039.

9709 Ripple Run Ct. Fairfax Station, Virginia 22039

The quest for the perfect engine for the Wahl Family Gas Engine Collection has finally ended. We always used to say, 'A Mogul sideshaft engine, now wouldn't that be a nice engine to have?' The sound of a Mogul quietly purring away was always music to our ears. Well, my dad and I finally decided to hunt down a Mogul for our collection, and we purchased a 4 HP Mogul sideshaft in November of 1995.

We bought the Mogul from a friend who shares in our engine enthusiasm, but only likes to play with the bigger toys. We had visited him many times, and the picture of a neglected 4 HP Mogul sitting in his machine shed was one of the reasons we decided to purchase the Mogul and one of the reasons why he was willing to sell it. The engine was in original condition and on original skids. It looked to be in good shape, but as with most unrestored engines, it turned out to be a much bigger project than we had expected.

Although my dad and I bought the engine, we left the restoration up to my grandpa, Harvey Wahl, for many reasons. One, the engine was located in Iowa and we live in Virginia, whereas my grandpa lives in Minnesota, just one hour away from where the engine was located. Two, the Wahl Family Gas Engine Collection is displayed, as it has been for the past 31 years, in Minnesota at the Butterfield Steam & Gas Engine Show. And three, my grandpa always does an excellent job of restoring gas engines, if an engine has all the pieces, my grandpa can make it run to perfection.

After the terms were agreed upon, Grandpa picked up the engine on November 19, 1995. Because the frigid winter was just around the corner in Minnesota and my grandpa wanted to be able to work on it, the engine was stored in our friend Mylan Larson's heated garage. The first job was to disassemble it, check for wear, and clean the engine. Every part on the Mogul was removed except for the six bolts that connect the water hopper to the base. This was done very carefully due to the complexity of the engine and its parts. The sideshaft mechanism was carefully diagrammed and parts were carefully marked so that they would be put back together properly. Little did my Grandpa know that the sideshaft mechanism would come back to haunt him.

Parts were then cleaned, some sandblasted, and some were remanufactured because they were badly worn. New piston rings were ordered from Starbolt, and the cylinder was honed in preparation for reassembly. Harold Larson, an excellent machinist from nearly Hadley, Minnesota, was given the challenge of machining a number of much needed new parts. He machined a new wrist pin and brass bushings for the piston since the originals were badly worn. Also, he machined a new plunger assembly and other parts for the fuel pump, as the originals were pitted and rusted. The valve guides were worn, and both the exhaust and intake valve heads were completely rusted off. My grandpa found new valves from a 1941 Model A John Deere tractor with a stem diameter of 1/2 inch. The original stems were 7/16 inch, so the valve guides had to be bored to allow for the larger valve stem. The stems were then cut to the proper length and threaded to match the original valves. The exhaust valve seat was completely gone and it appeared to have been repaired once before. Mylan was able to clean away the remains of the old seat and weld in a new seat. The valve seats were then resurfaced to ensure a proper fit with the new valves.