Journal: Greg's Journal

I got tired of waiting for Moss Motors to develop a supercharger package for the MK1 3-main MGB so I explored the options.
Moss says they have'nt produced a supercharger for for the 3-main engine because it has a unique water pump which would be too expensive to adapt to a serpentine pulley for such a limited production. However it is possible to install the (150-058) SC for the '65-'67 mgb with the suppled pump (and the provided serpentine pulley) with some modifications. The down side is that the engine block would need some minor grinding at the pump opening to make room for the newer style pump but it would improve cooling.
I chose not to modify the block. Instead, I had a water pump pulley turned at a machine shop to fit the original pump. The supplied pulley was welded to a billet aluminum fabrication.
The Moss supercharger kit supplies a serpentine generator pulley that sits 1/4" farther out than the original. Therefore, the machined water pump pulley height was reduced by 1/4" to line up with the idlers and serpentine crank pulley correctly. The pulleys lined up pretty well so our new water pump pulley turned out to be a good fit.
No real problems but admittedly no easy task getting this kit onto a 3 main MGB. The aftermarket header needed grinding at the head studs to clear the SC casting and there was some anxiety about the water pump pulley dimensions but it was all by the book after that. The new throttle cable has no provision to route securely behind the bonnet hinge so I used a lid switch (part#90016) harness clip from a Whirlpool direct drive washer. With minor alteration it clips the cable securely behind the hinge, preventing damage when the bonnet is raised.
After everything was installed it started quickly needing only timing, mixture and idle adjustments.

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