This model Holt 75 Caterpillar engine was made by Reinhold Kruger, of Germany, in 2001. The engine is 12”-long, 7”-wide, 10”-high, and weighs 15 lbs. The Holt 75 Caterpillar casting kit was first introduced by Cole’s Power Models of Ventura, CA around 1940, but after WWII it lay dormant. Coles re-activated it in 1970 after a new set of patterns was made to comply with the modern foundry practices. It is a 4-cylinder, 4-cycle, water cooled inline engine that was, at full-size, most successfully used in tanks of WWI. The speed of the engine is controlled by a centrifugal fly-ball governor that was commonly used for governing the speed of steam engines. The model engine has a bore of 1 inch and a stroke of 1-1/4″. The crankcase holds the lubricating oil that is distributed by the crankshaft as it spins, but external rocker arms must be manually lubricated before operating the engine. it is water cooled and burns gasoline using a spark ignition. Watch a YouTube video of a different model Holt Caterpillar engine being run by George Britnell.