Caterpillar 1693 T TA Engines

About The Engine

The 1693 was one of Caterpillar’s first attempts at an OTR truck engine,

this one being a modified version of the D343 bulldozer engine.

This is one of the engines most closely associated with the “Clatterpillar” nickname thanks to its use of precombustion chambers giving it a unique, rattly sound. The precombustion chambers also meant that the engine could not be fitted with a traditional engine brake (jake brake), so instead CAT used a hydraulic retarder which they called the “brakesaver”.

CAT sold this engine until 1976, though I heard from a few people that you could still find for a few years after that.

The 425HP configuration was very popular as it was the most capable truck engine on the road at the time.

About The Mod

You will find five horsepower options for this engine in all vanilla trucks and many modded onestoo.

The first four are based on official specs (As best as I could find), and the fifth is an

estimation of what you could tune the engine to based on stories I read from former owners.

1. 325HP 1000lb-ft

2. 375HP 1145lb-ft

3. 380HP 1275lb-ft

4. 425HP 1275lb-ft

5. 500HP 1575lb-ft (Tuned)

(Yes, the 380 and 425 made the same peak torque, however the 380 falls off considerably faster as RPM climbs.)

This mod also includes a Spicer 18 speed compound transmission.

This is made up of a 6-speed PSO140-6A main box and a 4-speed AMO1750-4D auxiliary

transmission with Low, Under, Direct, and Overdrive gears.

Driving Habits

You have peak torque at around 1400rpm in all of the configurations, and peak HP around 2000rpm.

As a result, you’ll get the most out of the engine around 1750-1800rpm. Shift point at 1900.

Supported Trucks & Changelog

Please see the Steam Workshop page for full details.