Camshaft drive by chain is lighter than gears or a bevel shaft and more tolerant of dimensional change due to heat expansion. Like the first ohc AJS racing engine of 1927, the G50’s drive features the Weller tensioner patented by John Weller of AC cars for a 1919 ohc car engine. Chain flutter is restrained by a tensioner blade faced with a rubbing strip and kept bowed by a spring that holds it against the forward run. To deal with reversal loads from the valve springs, the blade is connected to an oil-damped slider on the rear of the timing cover.
An oil-damped slider steadies the cam chain tensioner blade