This is a Hicks Marine engine mounted on the chassis of a 1915 White Fire Truck. I saw this engine at the Quartzsite 2002 "Main Event" in Nevada, USA when I was stationed in California. It is a fascinating engine.

Hicks Marine Engine
The engine was manufactured somewhere around 1927 to 1932. It is three cylinder, four cycle with overhead valves. The engine has a 6" bore and a 7" stroke. It is a 9.7 litre (594 cubic inch) displacement. It peaks at 27 H.P. at 500 rpm. It uses a low tension magneto and ignitors for ignition. It is water cooled. To vary the speed, the position of the intack rocker arm positions is altered with a handle.

The subject of this engine came up recently when Lauren Williams This email address is being protected from spambots. You need JavaScript enabled to view it. mailed me with:

Ahoy Paul!

I think that if you look really closely at the Hicks engine in your
Quartzite site that you'll see that it's a three cylinder engine (even
more exotic). Notice the three branches on the intake manifold (a four
cylinder Hicks has two carburetors, each serving two cylinders). I can
also count six push rods, two per cylinder. Along with the overhead
valves, another of the very modern aspects of the Hicks was that they
had roller tappet cam followers (starting in 1910!)

For a little more on Hicks Engines, have a look at the website
I replied,
Many engines had roller tappet cam followers (known today as roller rockers) - take a look at the Fairbanks Morse range of large engines for example (eg. the type R and RE engines).
and received back some more good info...
The rollers in the Hicks are a little different than those that we call "roller rockers" in a High Performance Chevy etc.. The rollers in the Hicks are at the bottom of the pushrod, against the cam lobes not riding on the top of the valve stem. I bet there are roller cam followers on modern engines too. I know that some single overhead cam engines have used them.

Hicks engines had no patent on good ideas. I've worked with Washington and Atlas Diesels that showed as much sophistication, but those were later engines.

The engineers that put many of the successful early gas engines together had plenty of smarts and experience in steam. I figure that folks that could figure out and understand the "Joy", "Marshall", "Corless" and "Cammed, Adjustable Cutoff Poppet" valve gears for steam engines had the details of what they could do with the metallurgy of their time and swift ideas about mechanical linkages down cold.

I find the Hicks engines a joy because they show that my father and I weren't the first smart guys. There were a few before us and there'll be some after us. It takes off some of the pressure that say's that we have to solve all the worlds problems ourselves.

How's that for a little social philosophy and self engrandizement (sp?) mixed in with esoteric engine info. Harumph!