These Brodbeck side port .60 tether car engines are presumed to have been built by John Brodbeck, of CA, in the mid-1940s. Tim Dannels’ issue of The Engine Collectors’ Journal, Volume 44-#4, Issue 256 for July 2020, has an interesting article about these little-known engines. Word of mouth by model engine collectors over the years says they were designed and built by John Brodbeck of K & B Engines in the mid-1940s. Though they appear with a cam drive/propeller flange, it is said they were actually designed for tether cars.
The unique side crankcase induction system is timed off the thickness of the crankshaft web. Apparently, this feature was effective but required high-tolerance machining to maintain the close fit between the crankshaft web and the induction port.