Wear checks by oil analysis„,a—ton
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• Any wear of any part of a power unit or transmission produces traces of metals and these traces are found in the lubricating oil. Regular analysis of the oil can be used to determine the type and extent of the wear and enable maintenance to be scheduled well ahead of need.
Wear-Check is the name given to a method of checking wear of all types of Dower unit (and transmission) by Wear:heck International, Technical Service Laboratories, 355 King Street West. foronto 2B, Ontario, Canada. A service is ving offered in this country to all users of 3ower units, including commercial vehicle )perators. Pending the establishment of a aboratory in the UK, samples will be sent o Canada for analysis. Currently and in he future, samples will be handled by Near-Check International, 24 Warplc Zoad, Wimbledon, London SW19.
It is recommended that checks of cornnercial vehicle engine oil be made at every bird change up to 75,000 miles and then at ;very oil change. Oil-change periods can, lowever, appropriately be based on the mounts of wear indicated by checks, and it s said that this practice may enable oil • osts to he reduced by 50 per cent. A spectro-chemical procedure is employed to measure the proportions of various metals in the oil. It is possible to determine a proportion of metal as low as 0.0001 per cent; and at the same time checks are made of the physical properties of the oil such as viscosity, sludge content, pH rating and dielectric. Nine metals are listed on the report form which comprise copper, silicon, aluminium, chromium, iron, tin, lead, boron and silver. Probable wear and other sources indicated by the presence of the corresponding metal include wear of bearings, piston, piston rings, cylinders, crankshaft and camshaft, while other sources include dirt entering the air intake, and oil contamination by tetraethyl lead (in the case of petrol engines) or antifreeze solution.
The analyst's report indicates: (1) if wear of the part is normal and no action is necessary; (2) if wear is abnormal but not serious, and no immediate action is necessary (in this case a certain type of servicing may be advocated or the operator advised, for example, to cease overloading or to change operating conditions); (3) if wear is occurring at a serious rate and the procedures required to restore the equipment to a normal condition.