Shell Lubricants recently tore down two Cummins Signature 600 engines (2000 model year) that had been pulling road trains in Australia. The field trial actually included six engines—three rated at 650 horsepower and three at 600 horsepower.
Tractor and multi-trailer combinations reached 174 feet long and weighed as much as 198 tons (roughly five times legal U.S. road weight). Test engines average about 2 miles per gallon, and the two engines that were disassembled had each logged 186,000 miles. The typical road tractor here in the States running at 6 to 7 miles per gallon would travel more than 600,000 miles before it burned an equivalent quantity of fuel.
Shell notes these teardown highlights:
- Injector rocker arm assembly, valve deck, front gear cover, gears and oil pan had minimal sludge buildup.
- Cylinder liner crosshatch pattern was preserved, and ring and liner wear were minimal.
- Wear on the injector rocker arm shaft was minimal.
- Piston pins were absent of scratches, scuffing and abnormal wear patterns.
- There were minimal deposits on the piston crown and bowl, and ring grooves and ring belt areas were practically free of carbon deposits.
The road trains operated in the Outback, where temperatures over 100 F required cooling towers for differential oil.
Factory-recommended Fleetguard products handled crankcase-oil filtration, and the engines were maintained according to factory recommendations. Oil analysis never showed elevated contaminant levels. The engines had run less than 1,000 miles before being switched to Rotella T.
Source: Shell Lubricants