Australian-Built Stover Engines

Cooper Engineering Co. began rebadging Stover engines around 1907.


A pre-1936 Cooper brochure, evidenced by the old style bracket arm (the overhead, belt-driven shaft from the flywheel), used from 1929-1935.

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Background Information

In 1998 I obtained my first engine, an open-crank 3 HP Stover Type W. In an attempt to find some information on this engine, I wrote a short article for The Old Machinery Magazine here in Australia. As a result, I found that I had a 1920 Cooper, badged as a Stover Type W.

This led me to start researching the Cooper Engineering Co. and the engines they sold. One of the first things I was told was that Cooper never built an engine. Subsequently, this proved to be untrue and I had to sort out the facts from the myths that surrounded the company. As a result of recent research, it now looks as though Cooper began importing and rebadging Stovers about 1907 or 1908.

From the mid-1920s, the range of Stover engines were: 1-1/2 HP Type KE, 2 HP Type KA, 3 HP Type KB and KF, 4 HP Type KG, and 6 HP Type KC. Although these engines were Cooper badged, they still had the Stover serial number stamped on the plate, as did the earlier engines.

Enclosed Crankcase Engines

From 1929, Cooper started selling the new CT range of enclosed crankcase, horizontal Stover engines, and this is where the confusion started. The 1-1/2 HP Type CT-1 was called the Type TA, the 2 HP Type CT-2 the Type TB, the 3 HP Type CT-3 the Type TC and the 4 HP Type CT-4 the Type TD.

The serial numbers posed a problem because some engines had Stover numbers, but other serial numbers did not coincide. The latter only started to become clear as I gathered more information; I will deal with this subject later.

About three and a half years ago, I was contacted by William (Bill) Quirk, who at 89 years of age was still very active and had a vivid memory of his time as an employee of Cooper. He started work in Cooper's Melbourne branch at the age of 15 in 1927, and only left to join the RAAF (Royal Australian Air Force) in 1940.

Bill told me that instead of importing complete engines from the U.S., Stover supplied partially machined frame and cylinder castings to the Melbourne branch through the head office in Sydney. The connecting rods were made of malleable iron, and, along with the Wico EK trip magnetos, were made in Sydney. Cooper had companies around Melbourne manufacture various parts for the engines. The trip mechanism for the magneto was only made locally if it was in short supply.

At first, cylinder heads came from Stover. But later, they were cast locally by McMillan's of Brunswick, along with other castings. The castings were fettled and some machining was done at Cooper. Heavy machining was done by Davidson's of Latrobe Street.

The white metal bearings were cast and machined in-house and reamed with a special line reamer by Sutton's, who still makes twist drills today.

Royal's Axles of Carlton forged the crankshafts, which were machined and ground by Davidson's. C.B. Dawson, makers of pistons, rings and sleeves, supplied the cast pistons and rings. Bert Craig, who owned A. Craig Pty. Ltd., machined and ground the cylinders and pistons to size for each engine.

Stover flywheels had six holes in them, and on sheep shearing plants, these were covered with a sheet metal disc. This was done for safety reasons, because if the shearer brought the hand piece backwards, it could catch in the holes on the flywheel. Locally-made flywheels were solid, for the reason cited above. Bill is unsure who cast and machined the flywheels.

Local Ingenuity

The two small holes drilled in the hopper to allow the Cooper plate to be affixed were done with a hand drill. Bill recalls the manager was unhappy with the number of small drills that were broken; this was solved in a very ingenuous way in 1931.

First, you must appreciate that Cooper's parent company was the Chicago Flexible Shaft Co. The Sunbeam division of that company made household products such as the Mixmaster, therefore Cooper ended up as the Australian agent for Sunbeam products.

The story goes that a Mixmaster came in to Cooper with a noisy motor, which Cooper replaced. Some bright person came up with the idea of fitting a small drill chuck to the old Mixmaster motor, which was then used to drill the holes on the hopper for the Cooper plate.

And a Stewart Little Wonder engine was converted to an air compressor for use in painting engines. The painting was done by anyone with nothing to do at the time - the fitters were expected to be versatile and able to do all sorts of work. There was a large chimney still in place that had been used for a boiler, and the natural updraft of the chimney drew the paint fumes from the spray booth.

Engines were built as - and when - the supply of parts allowed. One fitter could assemble three engines per day; the finished engines were run on a test bench for two and a half to three hours to check speed and power. There was no check on fuel consumption.

So, how do you identify a Melbourne-produced engine? Bill told me that "Made in USA" was chiseled off the frame and cylinder casting. They also have the solid flywheels and the Cooper serial numbers.

As to the number of Stovers built in Australia, no company records exist, so it is hard to be exact. I estimate between 2,500 and 3,000 were made from 1929 to 1950.

The Melbourne branch moved into a larger, two story building in the center of the city in 1928. The ground floor was office space and a showroom, and upstairs was the workshop, machine shop and welding area. Engines and other machinery were lifted from ground level by a large hydraulic platform on the outside of the building.

The number of employees during the 1930s did not vary too much. There were 15 men including the shop foreman and manager, a salesman and an accountant.

Cooper in the Mid- 1930s

In 1932, a drop in the value of the Australian pound in relation to the U.S. dollar made it unprofitable to sell machinery imported from the Chicago factory. It was then decided to establish an Australian plant to manufacture the then-existing products that had previously been made in the Chicago plant.

The new plant in the Sydney suburb of Waterloo came into operation in April 1933. It is interesting that the production of Stover engines was never moved to the main factory in Sydney.

Between 1933 and 1935, the number of employees in the Sydney factory more than doubled. This was at the time of a worldwide depression, and the Cooper Engineering Co. was one of the few Australian companies that continued to expand its workforce.

Thanks to American Stover enthusiast Curt Andree, who has access to the Stover sales ledgers, I have learned that from 1934 to 1936, Cooper imported 2 HP Type TBs in batches of 100, plus a few 3 HP Type TCs.

This must have been because Cooper was not able to produce enough locally made Stovers to satisfy sales. Also in 1934, the first Cooper-badged, Australian-built, Southern Cross vertical gas/ kerosene engines were sold.

Serial Numbers

Here's what I know about the different serial numbers found on these engines:

Serial numbers such as no. TB 220440 - This serial number is one of the Stover-built engines that came to Australia in 1934; a friend in England now owns this engine.

Serial nos. TB 2646, TB 18224 and TA 14249 - With serial nos. 14249 and 18224, I put a 2 in front of each number, and according to C.H. Wendel's Notebook, 214249 is a 1931 model, and 218224 is a 1933. I had Curt Andree check these numbers in the Stover records, and the following information was found. Note they are listed as TA and TB, not CT-1 and CT-2, as I would have expected, as they were sold in the U.S.:

TA 214249 (1-1/2 HP) was sold to Stover Windsted Co., Indianapolis, Ind., on Feb. 19, 1931.

TB 218224 (2 HP) was sold to F.E. Myers Bros. Co., Ashland, Ohio, on Oct. 4, 1933.

With serial no. 2646, if you put a 20 in front, it becomes 202646 (1929). Is this one of the first Melbourne-assembled engines? What I think happened was, a second frame and cylinder casting were sent to Melbourne with the first one or two numbers missing. In this instance, 2646 is stamped on the raised area above the cylinder head, as well as on the Cooper plate.

Serial nos. TB 3701 to 373844 - Some of these engines have casting dates on their frame and cylinder. These dates are from late 1936 to early 1938. TB 3701 looks to have been produced in early 1937, hence 37 was used at the beginning of the serial number. I think engines with serial numbers beginning with 37 were produced in the years 1937 to 1942.

Cooper post-1943 serial numbers - The serial numbers were changed again in 1943, and this type of serial number was also used on the little air-cooled Type JM, RV and PT engines. So serial no. TB 461574 is broken down into three parts: 1) TB is the engine type, 2) 46 is the year of manufacture (1946), and 3) this is engine number 1574 of that year.

The engine numbers started at 0001 at the beginning of each year. I own serial no. PT 550001 - engine no. 1 of 1955.

From 1942, Cooper started building the Johnson Iron Horse engine and Chore Horse generator sets at their new Mascot factory in Sydney. Serial no. 373844 is a 1942 Type JM (Johnson X400 series engine). The first of these engines used the 37 series numbers. A generator set has now come to light with serial no. RVE 442106 (1944), another interesting story.

The 2 HP Type TB was still advertised in the 1950 McPherson catalog, driving one of their Ajax pumps. I have recently acquired a picture of a Cooper shearing plant seen at an auction; the engine is the 2 HP Type TB.

The plate is hard to read, but the serial number looks to be TB 50277, so this could be one of the last Stovers built, eight years after the plant closed. I am trying to get confirmation that this serial number is correct.

After the war, Bill Quirk worked for Bert Craig, whose company machined the bores and pistons for Cooper. He states the last one he remembers doing was in 1948, six years after Stover closed.

Stover CT Series Engines

There is one last twist to this story that American readers may be able to answer for me. Bill said that some 6 HP enclosed-crankcase engines (imported) were sold, confirming that in 1931 these were the 6 HP Type KC. C.H. Wendel says in American Gas Engines Since 1872, the K series engines "were also available as special hay press models," with a cover over the crank and connecting rod.

Bill was adamant that later engines were 6 HP versions of the CT engines, saying he installed several in the late 1930s. Wendel makes no mention of CT series engines larger than the 4 HP CT-4. In the 1937 Power Farming Technical Annual, Cooper is shown as selling 1-1/2, 2, 3, 4 and 6 HP horizontal engines.

Further, a friend obtained some Repair Price List and Instruction Books for open crank Type K engines. One that was updated in 1932 shows other Stover products on the back page. There is a picture of a Type CT engine with the following caption: "Stover Engines, Completely Enclosed, Automatically Lubricated, 1-1/2 to 15 HP."

This is the only reference I have found to engines in this series bigger than a 4 HP. The TD (CT-4) is very rare, so do any of the larger engines still exist? I would be interested in hearing from anyone who owns or knows of one of these larger engines.

My thanks to Bill Quirk and Curt Andree for their help with this article.

Contact engine enthusiast Ron Wiley at: P.O. Box 1011, Victor Harbor, South Australia 5211; Information