DAT Joyner Engine

By Staff
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Joyner double acting tandem gas engine: 6" bore, 8" stroke, 32" flywheels.
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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.

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