Big-end bearing set 320/03270 JCB Dieselmax, standard, aftermarket

Big-end bearing set 320/03270 is an aftermarket set of standard-size shells for the four rods of the JCB Dieselmax 444 engine; the card also lists 320/03018. The photo shows the half shells of the set.

Big-end bearings are the thin shells on which the connecting rod runs on the crankpin, carried by a pressurised oil film. A worn bearing lowers oil pressure, causes knocking under load and at worst spins in the rod. The standard size is for a crankshaft that has not been reground; a reground shaft needs undersize bearings. They are always replaced on all four rods together.

Specifications

Compatibility

The set suits Dieselmax 444 engines in JCB 3CX and 4CX backhoe loaders. For comparison the genuine JCB set 320/09470 is also listed; other engine parts are in JCB Dieselmax engine.

Fitting

Before assembly the crankpin is measured and the oil clearance checked; the bearing tabs are seated in the rod, and the rod bolts are torqued to JCB figures. Bearings go in oiled. If the main bearings are worn too, they are renewed in the same strip-down; the crankshaft 320/03336 is also in the catalogue if needed.