Series 1C1-1C157, 1931 - 1932.

The DIESEL SIXTY was the very first Caterpillar diesel tractor and used the new D9900 diesel engine.

During the production the designation was changed from DIESEL SIXTY to DIESEL SIXTY FIVE.


Photograph courtesy Galynn Ferris

Production began in 1931 and continued until 1932 with only 157 tractors being built. It was replaced in 1933 with the DIESEL SEVENTY tractor.

Both 1C1 and 1C2 have survived into preservation. It is believed that 1C1 and 1C2 were made in California (and painted grey) and the remainder in Peoria ( and painted Hiway yellow).

The tractor used the gas 60 chassis design but strengthened in key areas as well as a larger radiator. No sheet metal covered the engine.

The diesel engine was started using a small two cylinder gas engine called a “pony engine” or “donkey engine” as because of the diesel’s higher compression ratio, it could not be barred over to start it like the gas SIXTY.

Serial number 1C12 set a record by ploughing 6880 acres in a run of 46 days, an average of 149 acres per day!

Apparantly 100 conversion kits were offered by Caterpillar to convert gas 60s to diesel, the first using the 5 1/4 inch bore D7700 engine and later the 5 3/4 inch bore D8800 engine.

Converted tractors are distinguished by having had an extra 12 inches or so added to the chassis length (as well as not having a 1C serial number prefix), like the Best 60 in the picture below.



1931 - 1933
D9900 Diesel engine 4 cylinders 6 1/8 inch x 9 1/4inch bore / stroke.
70.25 D.H.P.
Weight 24,400 lbs.

Below is a list of machines made by year and serial number.

1931 1 14
1932 15 157

It is not known when the change from DIESEL SIXTY to DIESEL SIXTY FIVE took place.

The color was changed from Gray to Hi-Way yellow in December 1931.

The members here at ACMOC have a wealth of knowledge on Caterpillar machines and machinery.

Join today and you'll find digitized original manuals, historical photos, helpful members, and a wealth of information whether you already have a Caterpillar machine or are thinking of getting one, like the rest of us here at ACMOC, and trust us, you do need one.

The ACMOC Members Library contains Operation and Maintenance Instructions books, Parts Catalogs and Serviceman’s Reference Manuals, as well as links to YouTube videos showing detailed restoration of many popular tractors and some less popular ones!

Created by John Gaunt

Go to top