The Technical History of the Fairbanks-Morse Z

Wayne Grenning offers a technical history of the Fairbanks-Morse Z series gas engine.

| July/August 1981

This is written to help Fairbanks-Morse collectors. Original manuals, catalogs, documents and reprinted sales literature were used. For this article only 1, 3 and 6 HP engines will be discussed.

The Fairbanks-Morse Company was founded in the late 1880s with headquarters in Chicago, Illinois. Fairbanks-Morse manufactured many kinds of engines including the 'Eclipse Pumper,' 'Jack of all Trades' and many industrial engines. In September of 1916 the 'Z' series was introduced. In the following paragraphs and figures the development of this style will be outlined. Development of the 'Z' engines will be described chronologically through the years 1916 to 1944.

In September of 1916 (Number 200,000) Fairbanks introduced a new engine line, the 'Z' series. The 1, 3 and 6 HP engines were 'headless,' with valves and igniters on the governor side. 'Headless' describes a type of casting in which the cylinder and head were cast with the crank-case body as one unit. Rotary, Sumter magnetos were used on these early 'Z' engines and were driven by the crankshaft gear. 'Headless' construction for all models was short lived because of the difficulty of overhauling and 'take down' of the engine. 'Headless' engines were characterized by a governor located on the upper left side of the cam gear.

An 'improved' model of the 'Z' series was complete in January 1917, (Number 260,000) just four months after the first 'Z' series. New 3 and 6 HP engines were made with removable heads. Location of the magneto and governor remained the same as the first version. On this model as well as all future models, the gas tank was located within the base. An exception to this practice, were those engines with a partial base. The carburetor and exhaust outlets were changed to the head. The carburetor was on the side, while the exhaust was on the bottom of the head. At first this type 'Z' engine used a water injector to cool it while operating. Later, it was taken off because of too many poor starting engines and fouled igniters.

(Poor starting was caused by water leaking by way of the needle valve into the carburetor from the hopper.) A fuel starting reservoir and pump were incorporated in the carburetor of the 3 and 6 HP engines. In this series, engines had an igniter and magneto installed as two separate units. A change later became necessary because of the difficulty in timing the magneto with the igniter. The 1 HP engine remained a 'headless' hit and miss, while the 3 and 6 HP were throttling governors in design.

June 1917
Next, a change was made in June of 1917. (Number 295,000). The difference between the January and June versions can be seen in figures 1 and 2. On the 3 and 6 HP engines the magneto and igniter were mounted on a cast iron unit. Magnetos used remained Sumters. Instead of having the magneto driven by the crankshaft gear, the design was changed to an oscillating magneto with a trip and springs. (When the magneto was tripped a lever on the end of the armature hit a movable contact arm and separated the contact points.) This method was useful because it was 'self timing.' (See figures 1 and2.) The 1 HP engine still remained a 'hit and miss.'

Highpockets003 (Smokstak)
9/22/2009 12:36:16 PM

Mr. Grenning, I have a 1.5 (1920) and 2hp (1926) F-M engines. Your history is very helpful regarding how these engines were originally configured. The article however didn't include any pictures or figures, as mentioned within. Could you email those or re-post them? Thanks, Mark


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