Wogaman 4 HP

Ohio-built Sure-Go is a Sure Thing

| January 2005

This 4 HP Wogaman engine was used on a local farm and was built in approximately 1906. It has a 5-inch bore and 6-inch stroke. The flywheels measure 24-by-2-3/8-inches. It is very unique in that it is made with only one casting, and the cylinder is not a through hole, causing machining problems.

About 26 years ago the farm changed ownership, and this engine was hauled to a local scrap yard along with other old iron that had accumulated on the farm. A friend of ours purchased the engine from the scrap yard, and then sold it to us a few years later.

Condition Assessment

The engine was in very rough condition from sitting out in the weather for so many years – we did a lot of grinding and filling on the cast parts.

The steel parts were badly rusted, and the long pivot arm was badly pitted. I lightly machined all surfaces to alleviate this problem. The valves were badly pitted and unusable, so I machined new ones, along with some of the linkage. I machined new bolts because I wanted them to remain the original 1/2-12 size, instead of the 1/2-13 size that's common today. The piston and cylinder were okay, so I just honed it out, cleaned the piston and installed new rings.

Engine Operation

This is a gearless engine. There is a brass ring on the crankshaft that has a double track that crosses in one spot. One side of the ring has a cam. A follower runs in the track and is attached to a long pivot arm. The follower crosses over to the opposite track on each revolution. The cam operates the exhaust valve. When the follower is on the cam, it acts on the pivot arm, which in turn pushes the exhaust push rod. The ignition is also controlled by this part. A flat tin piece inline with the cam is used for timing, and a piece on the cam strikes it, pushing it back against the rear contact screw, completing the ignition circuit and causing a spark.

There is no fuel pump; this engine draws fuel by way of suction. The original fuel tank is located in the base. The bottom side of the mixer has a spring-loaded flap which creates suction as air is drawn in. A screw just above this flap adjusts the needle valve. This design was later changed, as it proved to be unreliable. Later models were equipped with a Lunkenheimer mixer and the fuel tank was installed above the cooling tank plumbing, directly above the cylinder.