Pistons And Connecting Rods

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC

The connecting rods are manufactured from forged steel and have fracture split connecting rod bearing caps to provide precision re-assembly for bearing alignment. The connecting rod bearing caps are not selectable. Adjustment to take into account the large end bearing journal size is made by selecting the correct large end bearings after measuring the crankshaft journals.

There are a number of grades of large end bearing available. The crankshaft is laser etched with a string of 6 alpha characters in the order of crankshaft journals 1-6. A data matrix code contains the reference data for each large end bearing, installed to the engine. The correct large end bearings are sized with reference to a selection chart in order to achieve optimum running clearances.

For additional information, Refer to: SPECIFICATIONS 

There is only 1 grade of piston diameter. The pistons are marked to make sure correct assembly, with the marks facing the front of the engine. The top face of the piston has an arrow that must also point towards the front of the engine. The piston crown has a recess for optimization of the fuel/air mixture and combustion.

A 3 ring piston sealing system is used. The oil control ring is located in the bottom groove. The 2 compression piston rings are located in the upper grooves. The piston ring gaps must be positioned at 120° to each other.

The pistons are cooled with engine oil from 6 piston cooling oil jets installed in the cylinder block.

The pistons are attached to the connecting rods with a gudgeon pin, which is secured with 2 circlips. The gudgeon pin is located through the small end bearing in the connecting rod. The gudgeon pin allows the piston to articulate with the linear movement of the connecting rod. The circlips locate in grooves in the piston.