Chevy Vega
You might be wondering why this Ford guy would write a blog about a GM car like the Chevy Vega. The memories all came to the surface this week when a fellow Ford retiree mentioned that the air conditioning system was acting up on his 2015 F250 pick-up. As someone who started out as an engineer at Frigidaire in Dayton working on a/c systems for General Motors, I volunteered to help him diagnose the problem - from a distance that is, in light of the Covid-19 protocols.
Here’s what the a/c system looks like. When the air coming out of the registers is warm, a number of possible issues could be at cause. By checking temperatures and pressures around the system, the problem can be generally isolated. In this case, we diagnosed the problem to be a plugged orifice tube which provides a critical function within the system. If it’s plugged, the refrigerant cannot flow to the evaporator to cool the air flowing over it. The F250 was taken to the local Ford dealer who confirmed the diagnosis, removed the debris from the plugged orifice tube, reinstalled it and recharged the system with refrigerant. It’s now working perfectly.
That orifice tube looked very familiar as I had worked with the Frigidaire engineer who patented the orifice tube over 50 years ago in 1968. His name is Dick Widdowson who had served under General George S. Patton during WWII and developed over 30 patents while employed by GM.
As a coop student in my sophomore year of college at General Motors Institute, my work assignment at Frigidaire was in the test labs. Each of us coop students were assigned to an engineer who took us under his wings, so to speak. Mr. Widdowson was in charge of the a/c system for the upcoming 1970 Chevrolet Vega, GM’s first foray into small cars. The a/c systems in most small cars at the time were not factory installed, instead provided by the aftermarket. |
| Thermostatic Expansion Valve |
So the challenge for the Vega factory-installed a/c system was to be lighter, smaller and less costly than the aftermarket units. I was fortunate enough to be part of the development team lead by Mr. Widdowson. And the orifice tube was a key enabler to meet the goal in that the aftermarket systems had complex thermostatic expansion valves with many moving parts and costly components while the orifice tube was simple, light and had no moving parts. I can vividly recall how Mr. Widdowson created plexiglass housings for many of the a/c system components in order to visually see what was going on inside with the refrigerant as it circulated around the system during our various test runs in the lab.
The Vega was to be assembled in Lordstown, Ohio with the cars shipped across the country in railcars that held the units vertically rather than on all four wheels.
So it became important to make sure the a/c system would still function properly after being shipped in such a position. Lo and behold, we discovered a serious lubrication issue in that compressor oil that normally circulates in the refrigerant would migrate to the accumulator and upon start-up would starve the compressor of much needed oil. The fix was a small bleed hole in a u-shaped tube at the bottom of the accumulator to allow the oil to drain.
A smaller, lighter weight a/c compressor was also being designed for the Vega by another group within the department, where I was fortunately assigned to during my next work period. Then eventually as the products went into production, as an upper classman at GMI, I became a key member of the launch team, providing invaluable experience that paid off handsomely throughout my entire career. I like to think Dick Widdowson was mentored by George Patton, so no doubt many of the traits Dick taught me came indirectly from the General.
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