Home | About GEM | Classifieds | Books and Products | Links | Subscribe
	Web Exclusive A Galloway Comes Home Playing Safe Start Your Own Engine Club Other Links Advertising Info Past Features Complete Archive SmokStak Forums Customer Care Also Visit Farm Collector Show Directory Farm Collector Steam Traction	Compressor Engine Missouri Collector Breathes New Life into Au-To Air Compressor By Robert Best   Looking at the finished product, it's easy to see why some old iron collectors mistake Robert Best's converted Au-To compressor for an original, vintage stationary engine. I wonder how many collectors have ever seen – much less owned – an Au-To flywheel air compressor? Better yet, how many collectors have seen an Au-To air compressor converted to an engine? After seeing a few engines made from air compressors some 15 years ago, I decided to make my own. I attended numerous auctions looking for a compressor that would make a good engine, and for $5 I picked up an Au-To compressor. The old compressor sat around my shop for a while, and then I moved it to my storage building, where I forgot about it until 2002. Getting Started Picking the project back up, and not sure exactly how to proceed, I worked on my engine by trial and error. Using some drawings of other engines as a guide, I finally adapted a concept I thought would work. I wanted the finished engine to have dual flywheels, but the compressor was only fitted with a 14-inch flywheel on one side and a ring gear of equal size on the other, which, I assume, was geared to an engine that supplied power to the compressor. For the second flywheel, I used one from a Cushman Binder engine. It's a little larger, but at some point I'll turn it down on a lathe to the same size as the original. The Cushman flywheel had a tapered center hole, so I reamed it straight and installed a steel bushing to size it to the Au-To's 1-1/8-inch crankshaft. I sourced a 2-to-1 distributor gear set from a Volkswagen, which I decided would work well to drive the vertical flyball governor and camshaft I planned on fabricating. Robert's converted compressor features a vertical flyball governor. Note the linkage for exhaust lockout on over-run, plus the integrated spark-saver. Very nice work.   Not surprisingly, the Volkswagen distributor gear set also had to be sized to fit. Fixing the larger drive gear was no problem, as all I had to do was machine a bushing to reduce its inside diameter to 1-1/8-inch. I knew I'd have to machine the smaller driven gear, but it was so hard I had to anneal it before it could be machined. I did this by heating it cherry red and slowly cooling it in a bucket of sand. Then I turned it on a ..drives the vertical flyball governor and camshaft. Robert also cut out material from the base of the cylinder to expose the crankshaft.
Looking very much like a factory-built engine, Robert's converted Au-To compressor engine is an attractive and certainly unique engine.

I then fabricated the exhaust rocker arm and cam, and with some trial and error to get the right lift on the valve, it worked out fine. I also fabricated brackets to support the cam gear and shaft. The trick here was to attach the top bracket on the head before finally drilling it for permanent location so I could adjust the alignment of the shaft. It wouldn't take too much misalignment to wipe out the gears.

Ignition is by buzz coil with an adjustable wipe system mounted on the cam. The wipe is adjustable to regulate timing. I also added a spark saver since the engine coasts so long between ignition cycles. I made the flyballs for my governor from 1-1/4-inch brass. I was anxious to fire it up, so before I made the fuel tank I shot some fuel into the carburetor. The engine fired, but the flyball shafts were so long the engine wouldn't fire again so I shortened the shaft lengths. I ended up changing the length of the flyball shafts three times before I found the correct speed. Springs can be added to the bottom of the flyballs to increase engine speed, but to keep the engine running slow, I've left the springs off. Now fully functional, this engine runs between 100 rpm and 150 rpm, and after it hits it coasts 12 to 15 revolutions before firing again.

I also added a zerk fitting to the connecting rod so I can grease the crankshaft through the opening in the base, and I added grease cup fittings to the two main bearings. I put a drip oiler on the cylinder wall to lubricate the piston.

I believe the air compressor was originally painted blue, so that's what I painted it, along with white pinstriping. Since the engine was my own design I decided to likewise make a truck of my own design – oak trimmed in blue. I've shown this engine at a number of shows, and it is quite an attention getter. Blue is an unusual color for an engine, and when they look at the engine most people can't figure out what company made it.

I finished the engine in the spring of 2002 and first unveiled it at the North Kansas City, Mo., Mo-Kan show in June 2002. So far, not too many people have seen my Au-To compressor engine, but with each and every engine show I attend, that's changing.

Robert Best is a member of the Mo-Kan Antique Power Association of Kansas City, Mo. Contact him at 3521 N.W. 60th Terrace, Kansas City, MO 64157; e-mail: RODUEBASE@aol.com