Saving An Historic Otto
By Ivor Hughes

Hidden for over 40 Years, a Rare Otto is on Regular View at Rough and Tumble in Kinzers, Pennsylvania

This story starts on the outskirts of Boston in the 1950s. Major construction of the infamous Route 128 (now I-95) was underway, and in its path stood the historic laboratory and workshop of Francis Blake, an inventor and physicist who, among other things, patented the carbon microphone used by Bell Telephone Co. The workshop, dating from the 1870s, had been closed up in the early 1900s when Blake passed away. It had remained untouched all that time, as if waiting for him to return and fire up the Otto gas engine that sat in the corner, once again setting the belts in motion and the line shafts rumbling.

With bulldozers drawing ever closer it was time for action. A New York engine collector, with plans to restore the Otto, gathered up the engine and all the contents of the workshop, removing them to a storage building in New York state. Remarkably, before anything was disturbed, the workshop was photographed just as it had appeared in Blake's time.

The Otto Engine

As the Otto was studied further, some of its mysteries started to unravel. It was deduced that Blake converted his workshop to electrical power when electricity became available some time at the turn of the century. Traditional Yankee that he was, Blake had made the transition with minimum investment by belting an electric motor up to the Otto's flywheel. He removed the gears driving the side shaft, disconnected the connecting rod and pushed the piston up into the cylinder (this was fortuitous, as we will see later). This allowed him to use the Otto's crankshaft - which was already belted up to the line shafts - as a jackshaft, and by correct selection of pulley size he effected the necessary speed reduction between the electric motor and the line shafts. The electric motor, incidentally, was found in the rubble along with the Otto.

The Ontario Science Center staff had indicated that the gears on their engine were very noisy, and inspection showed one of the spur gears on Blake's engine has been modified using a then-accepted method of quieting meshing gears. This consisted of fabricating a gear in the form of a sandwich, made up of discs of rawhide fixed between two outer steel discs. The gear teeth were then cut across the sandwiched gear. There was not much left of the rawhide on Blake's engine, which had evidently been a delicacy for the local rodents. Blake also modified the timing cams on the sideshaft. Their radial location and profile were suspect, but in the early stages of the restoration not enough was understood about the engine to make any changes.