Piston And Connecting Rods

Fig 1: Exploded View Of Piston 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 make sure precision re-assembly for bearing alignment. The connecting rod bearing caps are matched to there connecting rod and are not interchangeable. Adjustment for 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. Each size of the bearings is color coded and inkjet marked with a letter on the running face of the bearing. The crankshaft is laser etched with 4 alpha characters in the order of crankshaft large end bearings 1 to 4. Also a data matrix code containing the same data. To make sure that the correct running clearance is obtained use the connecting rod large end bearing selection chart.

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.

The pistons use a 3 ring piston sealing system. An oil control ring is located in the lower groove. The 2 compression piston rings are located above the oil control ring. The piston ring gaps must be positioned at 120 degrees to each other.

The pistons are cooled with engine oil from 4 piston cooling oil jets installed in the cylinder block.

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