Always looking for something different to build, Dad decided to redesign an old engine. Together, we set some goals that we wanted to achieve from this project. First, we wanted it to be throttle-governed and able to run slow so the moving parts could easily be seen. Second, we wanted to have lots of moving parts to watch. Lastly, we wanted to work the engine so that you could see how the governor works, and hear the engine coast and work under a load, and then coast again. We looked around the barn for an engine to start with and decided on a 1-1/2 HP IHC Model M engine that was missing a lot of parts to use as a beginning for the project.
The first thing we needed was a carburetor that had an idle adjustment and a load adjustment. Dad disappeared upstairs to the attic above the shop and after a while came back down with a couple of updraft carburetors. In order to use one of them, the cylinder head had to be rotated 180 degrees so the intake was on the bottom and the exhaust was on top. To do this, the exhaust linkage had to be modified and the head machined to fit the carburetor.
Next, while I was figuring out how to hook up the original governor, Dad disappeared up the attic stairs and came back with an old vertical flyball governor he acquired from somewhere a long time ago. The idea of the flyball governor spinning around was too good to pass up. We had to use it. By mounting it on the front of the engine near the carburetor, the linkage to the throttle would work better and it gave us a good reason to make a sideshaft to turn it. We always wanted a sideshaft engine.
Looking at the front of the engine with the head upside down, the flyball governor in front and the exhaust coming out the top of the head, it was getting difficult to tell what model engine we started with. However from the back there was no mistaking the enclosed crankcase and the hand hole cover. It still looked like an IHC Model M. Once more Dad returned to the attic and eventually came back with an automatic oiler and a fuel tank. We mounted them above the crankcase and hooked up the oiler to lubricate the camshaft. That's one less grease cup to fill.
Next, we started to work on the ignition system. We wanted battery ignition for a reliable spark at slow speeds and some way to adjust the timing while the engine was running. Once again I turned around and Dad was gone up the stairs. This time he returned with a Ford Model A distributor. We ran it with a small chain drive off the camshaft gear and had a lever to adjust the timing from slightly before top dead center to almost 90 degrees after TDC. Now we were almost ready to see if our engine was going to run. We just needed a spark. I asked Dad if he had a buzz coil upstairs. He smiled and retreated up the stairs and brought back a very odd-looking coil. It was round, with the high tension coming out the top like a newer coil but the primary connections were on the bottom. "It's a World War II Army surplus igniter from a flamethrower," he said. Well that should give us a good hot spark I told him.
I connected the wires and cranked it over. The engine almost started itself; it ran great. We set the governor speed at 200 RPMs and with the carburetor adjusted the throttle lever brought the engine down to a nice smooth idle at just under 100 RPMs.
Now we started to think about what we could belt the engine up to that would put a variable load on it so you could see how the governor works.
After looking at pump jacks, fans and a few other things we had around the barns we realized we were going to have to build something from scratch. Dad had an idea for a version of a Prony brake. A few more trips to the attic and he had the bench covered with items that included a belt pulley attachment for a Ford 8N tractor, a front axle, hub and brake assemble from a front-wheel drive car, a small gear-reduction box from who knows what and also pulleys, wheels and levers that just seemed to grow into a never ending supply. The Prony brake that Dad made would automatically apply the load by tightening the brake caliper and then releasing it.
With the brake belted up to our one-of-a-kind "HESSE" engine, you watch the flyball governor open the throttle and hear the engine bark under a load and then quiet down until the next time the brake is applied. Thanks to Dad's amazing attic we have a display that is interesting to watch and makes it easy for people to see how a throttle-governed engine works.
Contact engine enthusiast Kevin Hesse at: 6028 E.?Joy Road, Ann Arbor, MI 48105; firstname.lastname@example.org