Pajero Owners Club of South Africa

4ePajero wrote:... I'm convinced that I am not imagining things!

When a lubricant degrades, it forms reaction products that become insoluble and corrosive. So too, the original properties of lubricity and dispersancy can become impaired as the lubricant ages and additives deplete. Much has been published about the risks associated with overextended oil drains and the buildup of carbon insolubles from combustion blow-by.

However, surprisingly little has been said about the impact of fine abrasives in a lube oil as it relates to fuel economy over the engine’s life. One can imagine numerous scenarios in which solid abrasives suspended in the oil could diminish optimum energy performance. Below is a list of several scenarios:

•Antiwear Additive Depletion. High soot load of crankcase lubricants has been reported to impair the performance of ZDDP antiwear additives. Some researchers believe that soot and dust particles exhibit polar absorbencies, and as such, can tie-up the AW additive and diminish its ability to control friction in boundary contacts (cam nose, ring/ liner, etc.).
•Combustion Efficiency Losses. Sooner or later, wear from abrasive particles and deposits from carbon and oxide insolubles will interfere with efficient combustion in an engine. Valve train wear (cams, valve guides, etc.) can impact timing and valve movement. Wear of rings, pistons and liners influences volumetric compression efficiency and combustion blow-by resulting in power loss. As has been previously reported in this magazine, particle-induced wear is greatest when the particle sizes are in the same range as the oil film thickness (Figure 2). For diesel and gasoline engines, there are a surprising number of laboratory and field studies that report the need to control particles below ten microns. One such study by GM concluded that, “controlling particles in the 3 to 10 micron range had the greatest impact on wear rates and that engine wear rates correlated directly to the dust concentration levels in the sump.”1
•Frictional Losses. When hard clear- ance-size particles disrupt oil films, including boundary chemical films, increased friction and wear will occur. One researcher reports that 40 to 50 percent of the friction losses of an engine are attributable to the ring/cylinder contacts, with two-thirds of the loss assigned to the upper compression ring.2 It has been documented that there is an extremely high level of sensitivity at the ring-to-cylinder zone of the engine to both oil- and air-borne contaminants. Hence, abrasive wear of the ring/cylinder area of the engine translates directly to increased friction, blow-by, compression losses and reduced fuel economy.
•Viscosity Churning Losses. Wear particles contribute to oxidative thickening of aged oil. High soot load and/or lack of soot dispersancy can also have a large impact on oil viscosity increases. Viscosity-related internal fluid friction not only increases fuel consumption but also generates more heat that can lead to premature degradation of additives and base oil oxidation.
•Stiction Losses. Deposits in the combustion chamber and valve area can lead to restriction movements in rings and valve control. When hard particle contamination agglomerates with soot and sludge to form adherent deposits between valves and guides, a tenacious interference, called stiction, results. Stiction causes power loss. It causes the timing of the port openings and closings to vary, leading to incomplete combustion and risk of backfiring. Advanced phases of this problem can lead to a burned valve seat.2

4ePajero wrote:
Marius,
I don't think the oil filter would make a performance difference. The oil pump can't be rated at more than 200W max. (my guess only). It will have a by-pass valve as well.