SwRI: Sequence IIIG test for gasoline engines, API SM, ILSAC GF-4

	The Sequence IIIG method at SwRI measures oil thickening and piston deposits during high-temperature conditions and provides information about valve train wear.

The Sequence IIIG procedure measures oil thickening and piston deposits during high-temperature conditions and provides information about valve train wear.

The Sequence IIIG test is part of engine oil categories:

• API SM

• ILSAC GF-4

The Sequence IIIG test simulates high-speed service during relatively high ambient conditions.

Sequence IIIG Test Equipment and Procedure

The Sequence IIIG test uses a 1996/1997 231 CID (3,800 cc) Series II General Motors V-6 fuel-injected gasoline engine.

Using unleaded gasoline, the engine runs a 10-minute initial oil-leveling procedure followed by a 15-minute slow ramp up to speed and load conditions. The engine then operates at 125 bhp, 3,600 rpm, and 150 °C oil temperature for 100 hours, interrupted at 20-hour intervals for oil level checks.

Sequence IIIG Test Results

At test end:

• All six pistons are inspected for deposits and varnish.

• Cam lobes and lifters are measured for wear.

• Kinematic viscosity increase (percent increase) at 40°C is compared to a new oil baseline every 20 hours.

• Wear metals Cu, Pb, and Fe, are evaluated.

Sequence IIIG Pass/Fail Criteria

 

PASS	FAIL

For more information about the Sequence IIIG procedure capabilities at Southwest Research Institute (SwRI) or how you can contract with SwRI, pplease contact Pat Lang at plang@swri.org or (210) 522-2820.