DAT Joyner Engine

This Joyner double acting tandem is comparatively small.

DAT Joyner Engine

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Box 4, 8250 200 Ave., Bristol, Wisconsin 53104

With this engine, DAT means Double Acting Tandem. The engine collectors that go to Cool spring and take the side trip to Heath Station see the six big Snow DATs. Each are 400 HP with 20" bores, 36" strokes and weigh about 40 tons. These are among the smallest of the DAT's that were made.

What is unique about the Joyner is that it is comparatively small. It has a 6" bore, 8" stroke and 32" flywheels and weighs about 3,200 pounds so it can be trailered to shows.

Now for those who do not know about these engines, the Tandem is that there are two cylinders, one in front of the other. The Double Acting means that it fires in front and in the back of each piston. The connecting rod from the crankshaft goes to a crosshead. A round piston rod from the crosshead goes through a seal at the back of the rear cylinder to the rear piston to the seal in the front of that cylinder to the seal in the rear of the front cylinder to front piston and out the front seal of the front cylinder. This piston rod is hollow so water can be pumped through it to cool the rod and the seals. This water enters at the crosshead. The engine has four combustion chambers with four spark plugs, a four cylinder engine on one piston rod. The usable HP is very low on this engine because there is so much friction to overcome with a crosshead, four seals, eight lobe side shaft, water pump, mechanical lubricator and magneto. Also the 2 Vs' piston rod takes up part of the 6" bore.

The engine was built by Lanson Joyner of Washington, Louisiana, about 1919-20 as a one-of-a-kind prototype to prove his patent on cooling DATs. This patent was granted September 27, 1921. He previously had another patent on a DAT in 1918 when he lived in St. Cloud, Minnesota. I believe that by the time he got his patent, the market for DATs being small, it did not pay for him to get into it. My engine has no plate as to name, serial number or HP. I only have the patent to go by.

I met engine man Don Blousey of Baraboo at a show in 1994. He saw my patent drawing of the Joyner and said he would like a copy to make a model of it. 1 sent him the copies. He came down to see the engine in early 1995 and said he would like to take it up to his shop and restore it.

I got this engine in 1992 from Oklahoma. At the time it was mentioned something about no rings were on the front piston. On dismantling the engine, there were no rings on either piston. Someone took it apart and removed the rings and put it all back together. Don found the piston rods needed replacing as they had pipe wrench marks on them. He got some DOM (Drawn Over Mandrel) stock and made the two new rods, one being 44" long, the other 30". Also he made new seals and other miscellaneous parts. The new rings came from Sykes in New York.

Don did the machining work and 90% of the restoration, with me procuring parts and working on the engine when I drove the 2xh hours to Baraboo. It was first run a couple days before being shown at the Badger Steam and Gas Engine Show in August. We ran it for short periods while trying to solve problems in cooling and carburetion. It drew a crowd even when it wasn't running. Its second show was at the club I belong to, the South East Wisconsin Antique Power and Collectable Society, at Union Grove, Wisconsin, in September. It ran better, but the weak point is the carburetor. Have since tried LP but have work to do on that. Starting this engine by rolling the flywheels is hard to do because you come up on compression every half turn. I want to make a starting engine for it.

It was fun showing this engine last summer, as very few people in the Midwest ever saw a DAT. I hope you enjoyed reading about this unusual engine. I expect to take it to many shows in 1996.