LINK AS-TRACK 2019118 - Caterpillar

Reference: Service Magazine; April 6, 1992; "Engine Oil Recommendations Have Been Changed"Caterpillar Engine Oil Recommendation
The latest oil recommendation for Caterpillar engines is the new American Petroleum Institute (API) performance category CF-4 (except for 3600 Engines). Oils in this category were originally developed to meet emission regulations for the United States truck engine market. They are now recommended for Caterpillar engines used in other applications because of operation with higher piston temperatures. Both the regulated emissions engines and the engines used in machine, industrial, generator set, and marine applications are operating at higher temperatures. The newer designed engines with the two-piece ferrous/aluminum piston and even engines with the one piece aluminum pistons are operating at temperatures higher than in the past.
The oils meeting this API CF-4 performance must pass the following engine tests:
* Cat 1K single cylinder oil test engine (SCOTE). Evaluates piston deposits and oil consumption. (New engine test)
* Cummins NTC 400 multi-cylinder engine test. Evaluates piston deposits and oil consumption. (Same engine test as for API CE oil performance, but more stringent passing criteria)
* Mack T-6 multi-cylinder engine test. Evaluates piston deposits, oil consumption, ring wear and piston ring groove deposits. (Same as for API CE performance)
* Mack T-7 multi-cylinder engine test. Evaluates the oil viscosity increase. (Same as for the API CE performance)
* CRC L-38 Test, Labeco single cylinder engine. Evaluates the bearing corrosion, oxidation and deposit formations. (Same as for the API CE and CD performance)
The oils meeting these engine test requirements are generally oils which have been developed for the newer USA emission specifications. But these oils also perform much better at the higher temperatures in today's higher output engines. As Caterpillar has developed engines for increased power output, piston temperatures have increased. Oils must be used which will perform under these higher temperature conditions. The illustration shows how the test performance for oils has increased with the temperature conditions in today's engines.
X axis = various engine designs. ("A" is earlier engine designs, and "B" is newer engine designs.) Y axis = temperature, from lower temperatures toward the bottom to higher temperatures toward the top. "C" is the relative piston crownland temperature in the 1K engine test. "D" is the relative top ring groove temperature in the 1K engine test. "E" is the relative piston crownland temperature in the 1G engine test. "F" is the relative top ring groove temperature in the 1G engine test.The information in the illustration shows the need for another Caterpillar single cylinder engine test. The piston temperatures in the 1G test were lower than the temperatures that were actually experienced in the field engines. The 1K engine test also upgrades all the engine hardware (direct injection fuel system and piston design) to better emulate today's engines.
The temperatures shown in the illustration indicate the reason for the recommended change in engine oils. The piston in today's engines and the new engines now being produced are operating at higher temperatures. The oils must be capable of operating at these higher temperatures.