Test Method Summary
The JASO M331:1991 specification test evaluates the low and medium temperature
detergency of lubricating oils for automobile gasoline engines. Depending
on the oil quality, the test duration is either 200 hours (regular
grade or equivalent to API SE) or 300 hours (premium grade or equivalent
to API SG).
Test
engine
Nissan VG 20E (gasoline)
Test
Fuel
Class 2, as specified in JIS K 2202,
but the fuel must not contain any gasoline additives
Test
conditions
One cycle consists
in the following 3 stages:
I
II
III
time (mins.)
24
24
12
speed (rpm.)
800
1800
3500
load (Nm)
20
99
99
Oil temp
(oC)
522
962
1172
(temperatures are also specified)
The oil level is
checked every 25 cycles.
Test
duration
200 or 300 hours depending on the oil
quality
Measuring
items
Includes .... rating of sludge and
varnish / blocking of oil strainer / oil consumption
/ wear / deposits on valves / deposits in combustion
chamber / used oil analysis
2
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