Using an indigenous gasoline engine of popular car, Maruti 800 in India, two dynamometer tests, namely Maruti IIID and Maruti IIIE have been developed as an alternate to the standard ASTM Sequence IIID/IIIE tests used for assessing high temperature thickening characteristics of crankcase engine oils. Various changes in engine hardware and operating conditions (blowby, speed/load, air to fuel ratio, ignition time etc) have been incorporated to achieve the adequate level of test severity to discriminate oil of different quality levels.
An engine oil of API SF performance level has been used as reference oil for developing the Maruti tests. An attempt has been made to correlate the Maruti IIID/IIIE test with the ASTM Sequence IIID/IIIE test by generating data simultaneously on the Maruti and the ASTM test benches using four commercial engine oils of different performance levels.
The Maruti IIIE test has been found to be more severe than the Maruti IIID test with regard to oil viscosity rise, whereas in sludge and piston deposit rating both the tests have shown the same level of severity. A good correlation has been obtained between the Maruti IIID and the ASTM IIID tests with regard to oil viscosity rise.