Big-end bearing set 320/09340 JCB Dieselmax +0.50 mm, genuine

For the JCB Dieselmax 444 engine: big-end bearing set 320/09340, +0.50 mm, a genuine JCB part. The card also lists 320/09207.

Big-end bearings are the most heavily loaded bearings in the engine: combustion pressure comes from the piston through the rod straight onto them. Dirty oil, overheating and running at low oil pressure speed up wear. It shows as the oil lamp flickering at idle on a hot engine and a metallic knock when the throttle is opened. They are always replaced on all four rods together. 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. An undersize set is chosen after the crankshaft has been reground, to the journal size given by the grinding shop. The catalogue also has the aftermarket version (320/09340) and aftermarket version (320/09207 JCB Dieselmax undersize) of this part. For the rod bolts see the connecting rod bolt 320/03040. Other parts are in JCB Dieselmax engine.

Fitting

On strip-down, mark which cap belongs to which rod. With the new shells fitted, turn the crankshaft by hand after tightening each rod to check for binding. Watch the oil pressure during the first minutes after assembly.