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The History of Waukesha vhp engines

A Robust History Dating Back to the early 1920s

1906: The Waukesha Motor Company was Founded

Established in Waukesha, Wisconsin, the Waukesha Motor Co. was instrumental in introducing multi-cylinder internal combustion engines to replace the large and cumbersome steam engines.

1935: Waukesha Introduces the Hesselman Oil Engine

Also known as the 6LRH, this engine was a low compression, fuel injected, spark ignited, multi-fuel engine that could run on just about any kind of fuel.

1973: The VHP Series Upgrades

VHP engine models F2895D and L5790D are upgraded to F2896D and L5792D.

2019: Cooper Supports
Waukesha VHP Engines

Cooper enters the Waukesha after sale support business and provides parts,
service, and repairs for VHP 7042 and 7044 engines.


The history of Waukesha VHP series of engines begins in the oil fields of East Texas in the early 1920’s. Waukesha Motor Company, est. 1906, was instrumental in introducing multi-cylinder internal combustion engines to replace the large and cumbersome steam engines. Waukesha engines were in demand in the newly discovered East Texas oil fields.

In 1924 Waukesha introduced three of its largest engines up to that time. One was the popular Model GU. It was a 4 cylinder engine with a bore and stroke of 5.375 x 6.25, and a CID of 567.3. The other two engines were the Model WS and WL, also 4 cylinder engines, with bores and strokes and CID’s of 5.75 x 8.00, 831 and 6.25 x 8.00, 981.8 respectfully. In 1926, another of the “W” series of four cylinder engines was introduced, it was the Model WK and had a 6.75 inch bore and a 8.00 inch stroke displacing 1145.1 cubic inches.

But the oil fields needed still more power, as oils wells had to be drilled deeper and deeper to find the “black gold”. By 1929 Waukesha introduced two 6-cylinder engines with 8.5 inch stroke! They were the 6 cylinder Models, 60S, 60K with 7.00 and 7.75 inch bores respectfully and CID’s of 1962.7 and 2405.5. By 1930 the first Waukesha engine with a bore and stroke of 8.5 x 8.5 inches was introduced and became the standard of the oil fields, paving the way for the future VHP series of engines. The model was the 6 cylinder 6LRO with a displacement of 2894.0 cubic inches.

In 1931, Waukesha introduced, what would be its largest 4 cylinder engine, the Model WOK with a bore and stroke of 7.50 x 8.00 and a 1413.7 CID.

In 1935, an 8.5 x 8.5, 6 cylinder Hesselman oil engine known as the 6LRH was introduced. The Hesselman was a low compression, fuel injected, spark ignited, multi-fuel engine that could run on just about any kind of fuel! The Hesselman engine’s success was tied directly to unavailability of quality fuel around the world.

In 1949, Waukesha introduced the model 6LRZ, which had a bore and stoke of 9.375 x 8.5 displacing 3520.5 cubic inches. In that same year the Model 6LRD went into production. It was a 6 cylinder 8.5 x 8.5, 2894.5 CID, Diesel engine. This was the first Diesel for this size engine and it replaced the Hesselman version that had become obsolete because WWII hastened the availability of quality fuel around the world. The Diesel engine used the famous Ricardo pre-combustion chamber that provided smooth power and complete burning of the fuel.

Then in 1954, Waukesha introduced it’s first V12 engine, a 8.5 x 8.5 bore and stroke engine with a 5788 CID which was designated as the VLRO because it was essentially the “V” version of the 6LRO and had double the horsepower! This engine was the direct ancestor of the future VHP series of engine that would become the new standard for the industry. (It is interesting to note that at the time, new engine models were being designated by their part number series. The part number series assigned to the new V12 engine was the 200,000 series and thus the model would have been known as Model 200. But the sales department over ruled tradition and the new model was marketed as the VLRO, the V-12 version of the popular six cylinder 6LRO engine.)

In 1955, the VLRD, the Diesel version of the VLRO was in production. In 1963, Waukesha went to a new model designation scheme and:

In 1967 the L5788 series of 12 cylinder engines were extensively redesigned with open chamber diesel technology, 4 valve heads, angle split serrated rods, new manifolding, and strengthened lower end of the crankcase just to name a few of the many improvements. The F2894 and F3520 6-cylinder engines were then completely redesigned using many of the design features of the redesigned Vl2 engine. These redesigned 6 and 12 cylinders where then designated as the VHP family of engines. By tradition, the letters “V H P” stood for Very High Power. But the actual meaning of the letter “V”, which was also used in other Waukesha engine families, was not that utilitarian. It was no more than the first letter of the word “viscount”, a popular marketing word during the 1960’s that the advertising manager at the time took a liking to. (Again it is interesting to note that VHP family of engines was originally planned to be designated as the VC family and a newly introduced family of high speed engines was to be designated VHP. But the vice president of marketing decided to switch the designations of the two family of engines. And like they say “…The rest is history.”

The Waukesha VHP family consisted of the following models, which replaced the earlier large bore engines:

  • F2895 replaced the F2894.
  • F2895D replaced the F2894D.
  • F3521 replaced the F3520.
  • L5790 replaced the L5788.
  • L5790D replaced the L5788D.
  • L7042 replaced the L7040.

In 1969, the 16 cylinder P9390 is introduced. It has a bore and stoke of 9.375 x 8.5 and a CID of 9388. In 1972-73 the VHP series of VHP Diesels were upgraded again and the models redesigned as follows. F2895D became F2896D and the L5790D became L5792D.

In 1977, the 6 and 12 cylinder 9.125 bore by 8.50 stroke VHP Diesels were introduced. The 6-cylinder engine had a CID of 3335.2 and the 12-cylinder, 6670.5. They were designated as the F3335D and L6670D. In 1982, the 16 cylinder, 9.125 bore by 8.5 stoke, 8894.0 CID, VHP Diesel went into production and designated as the P8894D.

Beginning in the mid-1980’s a series of VHP engines were released to meet the demand for low emission gas engines. The “lean burn”, low emission, VHP engines were: designated as the 2895GL, 3521GL, 5108GL, 5790GL, 7042GL and 9390GL.

Waukesha discontinued building Diesel engines in order to concentrate on it’s gaseous fueled engines, which had become the major share of the business.  In 1998, the 6 and 12 cylinder 9.375 bore VHP GSI became the series “4” engines, with new, improved cylinder heads and went into production as the Models 3524GSI and 7044GSI. The Waukesha 6LR, VLR and then the VHP series of engines have been the standard in the oil fields and gas compressor stations around the world for 84 years.

In the 1980’s Energy Dynamics Inc. (EnDyn) of Alice, Texas, began providing parts, service, and repairs for the Waukesha VHP engine line. In 2020, EnDyn was acquired by Cooper Machinery Services (Cooper), a major player in the gas compression industry. Today, Cooper provides VHP engine users a complete suite of after-sale services including parts supply, overhauls, repairs, field service, and swing engine exchanges.       

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