Effects of Lubricant Composition on Wear in Methanol-Fueled SI Engines 932796
The effects of lubricant composition on low temperature wear were studied in low-to-medium temperature cyclic mode engine tests fueled with M-85. The wear characteristics on the cylinder bore, piston rings, bearings and cam lobes were dependent on the lubricant formulations, in particular the detergent chemistry. Calcium borate overbased detergents were found to be suitable for formulating methanol-capable automotive lubricants.
Cylinder bore wear could be prevented by preserving the alkalinity of the lubricants during the tests. Valve train wear in M-85 engine tests was correlated with JASO motor-driven valve train wear tests using emulsified oils. The piston ring wear was at a similar level to that of gasoline fuels. Bearing wear was not significant and could be well correlated with the wear scar of the used oils measured with the four ball tests and was found to be of an abrasive nature.