Because of the size constraints and the size of the gears I intend to use, the centres of the 2 upper idlers do not quite fall on the same centres as the existing tapped holes for the roller spindles.
There is however, sufficient meat in the bosses on the support plate for them to be drilled and tapped slightly off centre for the idler spindles.
The central idler between the crankshaft and the inlet camshaft will run on a spindle this is mounted in the area currently occupied by the spring tensioner device. The plate is tapped 7/8" UNF (14 T.P.I.) and i have made up a threaded plug to fit this thread which I have loctited and pinned in place. This plug will then also be drilled and tapped to take the idler spindle.
Note:- As the idlers will all be running anti-clockwise, they will all be screwed in using a left hand thread so that the natural tendency is to always tighten them up when the engine is running.
