Jaguar 4.2 Build: The Bottom Part II

With the crankshaft and distributor mounts in place, the next step was to install the pistons & conrods. For comparison we show one of the high-compression 9.0:1 pistons used for the E-Type and the 8.0:1 used on the saloon cars. The carbon buildup on the dirty piston is typical of oil burning and rich mixtures in the chamber. In extreme cases this can build up, increase compression and cause detonation.

The pistons and rods looked to be in good shape but some elementary mistakes were made during the last build. For instance the gaps in the piston rings were lined up which increases chance of blow by. In the manual jaguar recommends to replace all the connecting rod bolts.

Below is one of the new bearings and an old one that is indicative of problems that can arise if oil is not changed regularly. Near the oil supply hole, a rigid line was carved out of the bearing from particulates in the oil. Such a scenario can increase heat and create resistance. The last bearing shows typical wear on a main bearing.

The last step was to check all the ring gaps and install the pistons using a ring compressor.

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