Weekend Workshop

Remove, improve and replace your cylinderhead in an afternoon

If you campaign a six-cylinder Triumph, you’re bound to have to replace the head gasket at some stage. The rugged cast iron engine block and cylinderhead mean that head gaskets aren’t prone to suffer major failures – but they can be provoked if the engine’s overheated. Head gasket oil leaks, however, are a very common problem. And, of course, you’ll have to remove and replace the cylinderhead if you are carrying out a decoke or fitting hardened valve seats.

There are two typical sources of head gasket oil leaks: the rear corner where a pressurised oilway carries oil from the main gallery in the block to the rocker shaft in the cylinderhead, and the relatively narrow section of gasket that runs along the pushrod side of the engine block, just below the spark plugs. Both leaks can be solved permanently by fitting a good quality replacement head gasket with a sparing smear of sealant in these critical areas.

This feature applies to the Triumph Vitesse, TR5, TR6, GT6 and the 2000/2500 saloon range. Make sure you buy the correct head gasket for your car. A change to a wider cylinderhead in 1968 dictated a change of gasket. There was a further change in 1972 when the ‘recessed block’ was introduced. This later engine had recesses machined into the top of the engine block around the cylinders. It requires a gasket with special sealing rings that locate in the recesses.