Main bearing set 320/09335 JCB Dieselmax standard, aftermarket

Main bearing set 320/09335, standard is an aftermarket part for the JCB Dieselmax 444 and 448 engines. The card also lists 320/03243.

Main bearings are the plain bearings in which the crankshaft runs in the block on a pressurised oil film. The set holds the upper and lower shells for one engine; the upper shells carry oil holes and grooves. Worn main bearings cause low oil pressure, knocking from the bottom of the engine and, at worst, a spun bearing. The size follows the crankshaft: standard for a shaft that has not been reground, undersize for a reground one. The shell size is marked on the back of each shell, showing standard or the undersize value.

Specifications

Compatibility

The part is listed for JCB 3CX and 4CX backhoe loaders. The set is for standard main bearings with side locks; for engines with the lock in the middle of the upper shell choose the main bearing set 320/09202. The catalogue also has the OEM version, genuine version (set) and genuine version (shell 320/03243) of this part. Other parts are in JCB Dieselmax engine.

Fitting

When the new bearings go in, clean the housings, keep the backs of the shells dry and oil the running surfaces with engine oil. Check the crankshaft end float together with the thrust washers. Change the engine oil and filter after assembly; the oil pump and passages must be clean.