Big End engine problem Brisbane -

FLOGGED / SEIZED / PICKED UP

The big end bearing is a highly stressed component. Extreme loads are placed upon the big end bearing as the con rod transfers the up and down motion of the piston in the cylinder bore to the crankshaft where the motion is converted to rotating motion. The con rod bearing is subject to extreme pressure and force due to compression and combustion along with added load that is required to move the vehicle.  If the driving conditions are extreme, the engine timing is too advanced, the engine revs are excessively high or the fuel is of poor quality, the slightest failure in the lubrication system will quickly destroy the big end bearings. Big end bearings are housed in the con rod and have bearing nip specifications that are extremely important to the life of the bearing. The con rod big end has to be round and the sizing has to be within manufacturers specifications. At UMR Engines we recondition the con rods with a Sunnen rod hone machine. The process is referred to as "close and hone" the con rod. The process is carried out by precision grinding the big end cap and rod mating surfaces. This is closing the rod to an undersize and then the undersized big-end is precision honed to the correct manufacturers specs.   It is very important that the maintenance of engine oil and oil filter is carried out at regular intervals. Engine oil is degraded over time due to carbon deposits and fuel contamination. Good quality oil of the recommended grade should always be used. Oil levels should be regularly monitored and maintained. Oil pressure has to be kept within manufacturers specifications to avoid premature failure of big end bearings. When rebuilding an engine the bearing oil clearance has to be measured during assembly to ensure the bearing will have a long life. At UMR Engines the assembler is responsible for checking the oil clearance on all con rods, as this will double check the crankshaft size, con rod tunnel size and bearing wall thickness. 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