At a minimum, gasoline should meet ASTM specification D 4814 in the United States or CAN/CGSB-3.5 or 3.511 in Canada. Some gasolines contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT).
We recommend against the use of gasolines containing MMT. See Additives for additional information.
Gasoline Octane
California FuelChevrolet Cobalt Service & Repair Manual. Crankshaft Main Bearing Clearance Measure
Method A
1.
Measure the crankshaft bearing journal
diameter with a micrometer in several places, 90 degrees apart.
Average the measurements.
2.
Measure the crankshaft bearing journal
taper and runout.
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