Norton Service Release Database N20

SERVICE RELEASE N20

NATURE OF RELEASE: Timing cover gasket interchangeability MODELS AFFECTED: PARTS AFFECTED: Timing cover gaskets, T2236, 060719, 061092. DISTRIBUTION: Worldwide (Information for general use) EXPLANATION: On all Commando engines, the pressure release valve in the timing cover discharges surplus oil through a drillway in the timing cover and crankcase back to the inlet side of the oil pump, instead of merely allowing it to escape through an open hole into the timing chest as on all earlier Norton twin cylinder engines. As this drillway oroeses the timing cover to crankcase joint face, the gasket used must have an additional tab or loop to seal it and gasket part number T2236 does not have this. Therefore T2236 must not be used in any Commando engine. We learn that certain spurious gasket sets currently available and identified as suitable for the Commando contain a timing cover gasket to the T2236 form which is quite unsuitable. Commando timing cover gaskets 060719 and 061092 differ in that 061092 is intended for engines with the camshaft driven contact breaker and thus has an additional tab or loop to seal the drillway for the contact breaker low tension feed wire. It will be noted from the above that 061092 gasket will service all previous Norton twin models 7, 77, 88, 99, 650 and Atlas. This gasket is thicker than previous conditions and effects the compression of the rubber seal between the oil pump outlet and timing cover.   ACTION: Before renewing a Commando timing cover gasket, make sure that it connects and prevents leakage at all holes in the joint face. Using the thicker 061092 it may be necessary to shim up the rubber seal at the oil pump to achieve 0. 010" of compression through in the majority of cases it will be found that the correct compression is achieved by the use of the seal without shims. October 1970 Norton Villier Canada Limited