However, as work progressed, it became apparent that it wasn’t all as good as it seemed. There was burnt oil residue on the pistons; the piston skirts were no longer in factory specifications; the cylinder walls were worn, with slight ovality; there was excessive play in the valve guides, more than the factory recommends; holes had formed in the valve and valve seat working surfaces due to oil burning; and there was slight copper showing on the connecting rod bearings—the engine was worn beyond average.
Based on the customer’s request to gain horsepower, we replaced the pistons and bored the cylinders, and additionally installed a MILLTEK exhaust manifold. We used aftermarket JE Pistons to raise the compression ratio. Instead of the factory 10.5:1 compression ratio, we achieved a new ratio of 11.6:1 with the new pistons. The cylinders were bored and honed from 84mm to 84.5mm. The oil pan sealing surface and block sealing surface were polished. We removed the blind plugs from the oil passages to thoroughly wash the entire block, removing the burnt oil that had stuck to the walls of the oil passages, and installed new plugs.
In the cylinder head, we replaced all the guides. We machined the valve and valve seat working surfaces. The sealing surfaces of the cylinder head were also milled. In the future, we will replace the camshafts with ones that have a longer opening duration and greater lift.
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