SwRI: The roller follower wear test simulates camshaft axle wear.

	The engine is a General Motors 6.5-liter, indirect-injected diesel.
	At procedure end, the roller follower axles are removed and their wear is measured using a linear profilometer.
	Top image is FAIL; bottom image is PASS

The roller follower wear procedure simulates commercial and military applications. It determines the effect of lubricating oils on camshaft roller follower axle wear.

The roller follower wear test is part of specifications:

• API CG-4

• API CH-4

• API CI-4

Roller Follower Wear Test Equipment and Procedure

The test engine is a General Motors 6.5-liter, indirect-injected diesel. The engine is rated at 160 horsepower at 3,400 rpm and is run at 1,000 rpm with near maximum load for 50 hours without an oil change.

Make-up oil is added at 25 hours. Oil gallery and coolant-out temperatures are controlled to 120°C. New roller followers are installed at the beginning of each test.

Test Results

At test end, the roller follower axles are removed and their wear is measured using a linear profilometer. Samples are taken at 25 and 50 hours. The used lubricant is analyzed for:

• Viscosity at 40°C

• Viscosity at 100°C

• Total base number (TBN)

• Wear and additive metals as specified

The pass/fail limits for wear on the roller follower axle have been set at:

• 11.4 micrometers (0.45 mils) for CG-4

• 7.6 micrometers (0.30 mils) for CH-4 and CI-4.

For more information about the roller follower wear procedure capabilities at Southwest Research Institute (SwRI) or how you can contract with SwRI, please contact Jim McCord at jmccord@swri.org or (210) 522-3439.