The 1500cc upper engine components are entirely different from the A-Series and no parts are shared between the two. The rocker cover arrangement changed during production, early 1500 engines (to approximately 1977) used a cover with conventional studs and a cork gasket, while later engines adopted an O-ring sealed cover with different mounting studs and nuts. The two types and their fixings are not interchangeable, and the correct type must be identified before ordering.
1500 Specification
The pushrods and cam followers on the 1500 are specific to the Triumph engine and cannot be substituted with A-Series items. The rocker arms are individually handed, numbered 1 through 8 from the water pump end, with odd numbers on one side and even numbers on the other. Each arm has a different geometry to suit its valve position, so they must be refitted in the correct sequence. The rocker shaft is supported by four pillars with different functions, the locating pillar ensures correct oil feed to the assembly and must be identified during reassembly.
1500 Sealed Breather System
The 1500’s sealed breather system routes crankcase gases from the rocker cover back to the carburettors via a T-piece and hoses. If an aftermarket rocker cover is fitted that does not replicate the sealed breather connection, a blanking arrangement must be provided to maintain the closed circuit. Running the 1500 with an open breather results in oil mist in the engine bay, increased oil consumption, and potential emissions issues.