Iain's 1970 MG BGT

Pistons

The pistons were +60 thou. They were County Brand, bought from Octarine Services. They were the type with the fully floating gudgeon pin, secured with circa clips. This made it easy to fit the pistons to the conrods at home. For other conrod/piston combinations this would require a proper press at a machine shop.

There is an oil hole on the top of the big end. The piston is attached so that when the front marking on the piston faced forward the oil hole points to the distributor side of the engine (not the camshaft side). This allows lubrication of the thrust side of the bore.

The pistons were then fitted using a piston ring compressor, ensuring that the front marking faced the front of the engine.

Finally the big end caps were fitted and the tightened to 40 lbs/ft. New bearings had of course been used. Both the gudgeon pin and the big end bearings were lubricated with graphogen.