Restoration guide Expert advice

01 Engine

Scout engines were side-valve, 42-degree V-twins. The crankshaft was built-up, with eight bearings and a ‘knife and fork’ big end arrangement to keep the cylinders in line. The stroke was 31/16in(G) or 3½in (GP), the cast-iron cylinder bores were 2¾in (G) or 2⅞in (GP) for the 37 and 45 cu in capacities. The timing chest contained a camshaft for each cylinder, as well as the gear drive to the adjustable oil pump, providing a positive feed to the big-end assembly. The single cam per shaft operated both valves via lever followers acting on pushrods, with adjustable tappets