Mains engine problem Brisbane - WORN

OUT

Even bearings operating under normal conditions will wear out and require replacement. When main bearings wear out pre-maturely the main cause is contamination. This can occur over a long period and will be evident by very fine particle scratches in the bearing face. These scratches are a result of oil having contaminants such as carbon or silicon. Complete elimination of these contaminants is impossible but will be reduced with shorter service intervals. If the scratches are severe, foreign material has found its way into the oil or the failure of another internal component has occurred. Quite often the contact position of the bearing has no bearing material left and has been reduced to the backing or underlay material. The crankshaft will also have corresponding marks, as the foreign material is generally harder than the crank or bearing. If the bearings wore out (fine scratches) soon after a rebuild or recondition the cleanliness of the engine on assembly should be investigated. Abrasive honing material is not successfully removed without the use of hot soppy water and soft brush. Petrol, kero or the like do not remove honing material from the hone marks or the rough casting of the crank webs and block. (A clean, oiled white cloth should be used as the test of honing material removal from the bore and a bright lead light for the rough castings.) Main bearing shells that show uneven wear indicate main tunnel alignment problems or out of round main tunnels. Line bore the main tunnels to eliminate this cause. Disclaimer Agreement : Every care has been taken in writing this information and procedures, but no responsibility can be excepted for errors, omissions or misuse of this information and procedures. The information available on this site is for your instruction only and cannot be copied for sale, © copyright 2001 UMR Engines