Just found this picture on the 'Days gone by' picture thread. Looks like a 2 cylinder engine mounted cross-wise to power a GMC blower. I don't see any fuel-delivery system (carbs or injectors) and the intake of the blower (facing forward) seems to have a screen over it. I also see a belt dive of some sort on the left side that looks like it could be turning an injection pump. Anybody know anything about this set-up?
That auxiliary engine looks like a "Coldwell engine" . They were used to power some of the first self propelled lawn mowers. The ignition is magneto and fires like a Harley ie. both cylinders at the same time but not on the same cycle, is water cooled and develops 5-6 hp. Very interesting setup but I doubt it would work very well since the boost would not be regulated with the main engine speed.
I wouldn't think 5-6 HP could possibly be enough to develop the required boost. The idea I see is to eliminate the parasitic loss of actually driving the blower and netting the entire gain of the boost instead of only a percentage.
In WWII there were experiments with bombers where an engine in the fuselage drove a big blower that fed the other four engines. Probably where these guys got the idea. I wouldn't think 6 hp gain would be worth the extra weight and complexity on the digger, though.
The Jalopy Journal
