Mechanical tensioner pulley 320/08729, aftermarket, option 2

For the JCB Dieselmax 444 engine: mechanical tensioner pulley 320/08729, an aftermarket part. The card also lists 320/08694.

Unlike an automatic tensioner, a mechanical one does not take up belt stretch by itself, so belt tension is checked at every service and readjusted if needed. The pulley bearing is sealed. The belt from the crank pulley drives the alternator, water pump and other ancillaries; a slack belt reduces their output and an overtight one loads the bearings. Correct tension matters for belt life and proper charging. If the arm pivot or adjusting slot is worn, the tension will not hold and the arm is replaced. The pulley face suits the back or the ribs of the belt. The arm has an oval slot for adjustment.

Specifications

Compatibility

The part is listed for JCB 3CX and 4CX backhoe loaders. The catalogue also has the aftermarket version of this part. Other parts are in JCB Dieselmax engine.

Fitting

After fitting, set the belt to the deflection or tension figure in the service manual and tighten the bolts. Run the engine and check that the belt runs without flutter. Fit the belt according to its direction arrow.