Updated – Every once in a while during the pursuit of the history of the motor vehicle, something unusual crosses our radar screen. This large water-cooled V-Twin engine with several unique features certainly fits into that department.
Little is known about the power plant, other than the photos originate from the NAHC, Detroit Public Library archives. The images by Spooner & Wells, Inc., photographers at 1931 Broadway, New York City were likely taken in the area. The engine appears to be circa 1908-1915. The lead photo shows the timing side of the engine and the lower images the output end.
One of the features of note behind the open cam and magneto drive, is a pair of very unusual intake runners with expansion chambers located between the carburetor and the intake manifolds. The fuel and air mixers feeding this induction system are of the auxiliary air valve type and the spring-loaded valves are next to the camshaft gear.
- Drive side view of the engine, water pump driven by the camshaft, and the backside of the magneto.
Update I – The ignition system is also of interest. The simple magneto without a distributor appears to be driven at two times engine speed. The mag also has a double ignition point housing on the backside much like Bosch used on some of their units, which can be adjusted to vary the ignition timing. Many V-Twin magnetos and battery ignition systems fire the spark plug near the end of the compression stroke and also a wasted spark at the end of the exhaust stroke.
The holes seen on the sides of the cylinder heads are interesting. Both could have been used to get the core sand out of the casting and then later filled w/core plugs. There is also the possibility that the pair of holes on the drive side might have been used for the exhaust ports? Another scenario is the exhaust may have passed through passages to the sides of the heads.
The engine is also quite interesting due to its advanced design features that include: lightweight o.h.v rocker arms and overall general construction, pushrod guide bushings on the side of the intake manifolds to help prevent flexing, and the long studs in tension holding the heads and cylinder barrels to the crankshaft. Possible uses where for aircraft, automobile, cyclecar (like the GN seen below) or a large motorcycle engine like that in the North London Garage Special.
Update II – The patent for this engine appears to have been found, learn more at: Mystery V-Twin Engine Solved – 1909 Gibson Patent Discovered. Please let us know if you can add more to this story.
The images were located by vintage casting expert Lee Storr, who engineered and oversaw the Frank Lockhart Miller racing car intercooler replicas covered earlier here in a three-part series.
- A gentleman holding the engine shows its light weight construction and also serves as a size reference.
- An English GN 200-Mile Race cyclecar with a similar-sized engine that is a 4-valve per cylinder o.h.c. unit, which passed through our workshop a few years back.