SwRI: Mack T-8 tests oil filter plugging for soot, viscosity

The Mack T-8 procedure, which simulates field-service, heavy-duty operation, stop-and-go operation, and high-soot loading, evaluates the soot-handling capability of engine crankcase oil with regard to viscosity.

	Series of pictures above:  The Mack T-8 procedure which simulates field-service, heavy-duty operation, stop-and-go operation, and high-soot loading, evaluates the soot-handling capability of engine crankcase oil with regard to viscosity.  Photos were taken at various phases of the procedure.

The Mack T-8 test is part of specifications:

• Mack EO-L

• Mack EO-L Plus

• Mack EO-M

• Mack EO-M Plus

• API CG-4

• API CH-4

• API CI-4

• ILSAC DHD-1

Mack T-8 Test Equipment and Procedure

The test is conducted on a Mack E7-350, fixed-time, in-line, 6-cylinder configuration 11GBA77623, direct injection, 4-stroke, turbocharged, intercooled, compression ignition engine. The bore and stroke are 4-7/8 × 6-1/2 inches. The engine is rated at 350 brake horsepower at 1,800 rpm.

Each test is 250 or 300 hours long under constant-rated speed and load conditions with controlled water-out, fuel, intake air, and intake manifold temperatures. Exhaust back pressure and inlet air restriction levels are also controlled.

Between tests, the engine is flushed for two hours with the next test oil.

Test Results

At the end of the test, oil filter plugging is evaluated.

Oil samples are taken every 25 hours and analyzed for matic viscosity at 100 °C.

Pass/fail criteria include:

• Maximum viscosity: increase at 3.8% soot (11.5, 12.5, and 13.0 centistokes for 1, 2, 3 tests)

• Oil filter plugging: less than 138 kPA

• Relative viscosity: 2.1 for the T-8E at 4.8% soot

• Oil consumption: 0.304 g/kWh, max.

For more information about the Mack T-8 test capabilities at Southwest Research Institute (SwRI) or how you can contract with SwRI, please contact Ryan Johnson at rjohnson@swri.org or (210) 522-2892.