SwRI: Ball Rust Gas Test (ASTM D 6557) evaluates a lubricant's ability to prevent engine corrosion, particularly rust.

	At test end, the hydraulic lifter balls are removed from the rig, washed according to procedure, and rated for surface discoloration using an optical rating/computer/video system.

The ball rust procedure, ASTM D 6557, replaces the Sequence IID procedure (ASTM D 5844) and evaluates a lubricant's ability to prevent engine corrosion, particularly the formation of rust. The Sequence IID procedure has been correlated with vehicles used in short-trip service prior to 1978.

Ball Rust Equipment and Procedure

The ball rust procedure uses procedures for engine oil categories:

• API SL

• API SM

• ILSAC GF-3

• ILSAC GF-4

The ball rust procedure fixture is a custom-built bench rig based on a temperature-controlled shaker table. A syringe pump is used to inject acid into the test oil, while a compressed air manifold system supplies clean, dry air into the oil at a controlled rate of 40 mL/min.

Ball Rust Test Parameters

	Tests are run for 18 hours with the test oil environment controlled at 48 °C.

Tests are run for 18 hours with the test oil environment controlled at 48 °C. A solution of Acetic, HBr, and HCl acids and deionized water is injected into the oil at a rate of 0.193 mL/hr. 

Ball Rust Test Results

At test end, the hydraulic lifter balls are removed from the rig, washed according to procedure, and rated for surface discoloration using an optical rating/computer/video system.

Each candidate oil is run in pairs during a single test. Up to 5 oils can be run simultaneously, with one or more of the oils as a reference oil.

Ball Rust Pass/Fail Criteria

An average gray scale value of 100 minimum is required for the ILSAC GF-3 and ILSAC GF-4 and API SL and API SM engine oil categories.

For more information about the ball rust test (ASTM D 6557) capabilities at Southwest Research Institute (SwRI) or how you can contract with SwRI, please contact Pat Lang at plang@swri.org or (210) 522-2820.