By Kendra Cook Curator/Manager - Boyertown Museum of Historic Vehicles

Reading’s Middleby Automobile—Air Cooled and on Display at the Boyertown Museum of Historic Vehicles!It’s a question we often hear from visitors at the Boyertown Museum of Historic Vehicles: “Why aren’t the hoods open on the cars?  We  want to see the engines!”  Well, this weekend, March 10 & 11, during regular hours from 9:30 am - 4 pm, the hoods WILL be open on the cars and trucks in the gallery.  Because so many of the vehicles we have on display are so rare, you may find that some of the engines in them are also a bit…unique. Take, for instance, the 1909 Middleby.

Joseph Middleby bought the Duryea Power Company of Reading, PA after it went bankrupt.  He built a radically different auto than what Charles Duryea manufactured.  Middleby autos featured an air-cooled engine, thought to be the height of technology in 1909.  Air cooled engines were advertised as having fewer things to be concerned about than water-cooled engines.  There were no radiators or hoses to worry about, nor did they need antifreeze in the winter.  This 1909 high-tech engine boasts an exhaust valve on the bottom of the engine (in addition to the exhaust valve on top like a normal water-cooled engine).  So why the extra exhaust valve?

Reading’s Middleby Automobile—Air Cooled and on Display at the Boyertown Museum of Historic Vehicles!In March of 1909, H.H. Franklin, creator of the well-known air-cooled Franklin automobile out of New York state wrote the following in Automobile Dealer & Repairer magazine, “efficiency of air cooling increased…with the use of simple auxiliary exhaust at the base of the cylinder. [It] will get rid immediately upon completion of the power stroke of 71% of the burned gasses, leaving only 29% to pass up through the cylinder and out through the regular exhaust.”  Essentially, this means the cylinder runs less hot, as most of the hot air is pulled away from the cylinder almost immediately.  Other ways the engine stays cool?  The fins on each cylinder give it more surface area for the air to move over and cool.  Plus, there are large fans in both the front and back of the engine compartment so that air moves all the way through—this is further helped along by the belly pan mounted underneath, in effect creating a wind tunnel to pull the air all the way through the engine.

But let’s get back to that auxiliary exhaust valve.  Both the top exhaust valve and the auxiliary have exhaust pipes that go the full length of the car (dual exhaust!) but only the auxiliary pipe has a cutoff valve before the muffler.  The cutoff valve is opened and closed by the driver using a foot-operated pedal.  Why would the driver ever want to close the valve, risking overheating the engine?  Because there is one instance where the driver would want the engine to heat up quickly—when starting the car.  So the auxiliary exhaust is shut off when first starting the car, but this is only temporary.  You’d very quickly want that valve open so as to prevent overheating!

Come visit us on March 10 & 11 during regular hours to see the Middleby engine and the many other interesting mechanics that make the Boyertown Museum’s collection so very unique!

The Boyertown Museum is located at 85 South Walnut Street in Boyertown, PA.  Visit us online at or ‘like’ us on Facebook!  Hoods Up Weekend is included with regular admission: $8 adults, $7 seniors and AAA members, and ages 15 & under are FREE.