- BOOK, NEW, OLD?, ME? Colin Sims analysed that the length of the eccentric rods appears to be wrong as follows: “The eccentric rod issue I worked out in the following way: Link radius is 7.5″, with a ‘backset’ (not the right term, I know) to the pin holes of 3/4″, leaves a dim of 6 3/4″ from the pin to the crank centre. If I add the dim from the centre to top face of the eccentric strap to the foot to pin hole dim on the rod, I get 6 5/8″, i.e. 1/8″ short. This will not affect the valve travel, as this is determined by the eccentric throw, but it would affect the quasi-SHM of the valve movement subtly. Yes I know it is not true SHM, as the mechanism is effectively a slider-crank form.” editor’s note: I have made the rods to the drawings, and they seem to fit, but I agree with Colin that the math sais they may the wrong length.
- Having now assembled the valve gear (February 2014) I fear that this is proven – moving the gear from ahead to astern cannot be accomplished without the valves being deflected in mid gear, no matter where the crank is set. I think this is wrong, ah well, time will tell – I have managed to time the engine to run on air, but pretty roughly so far….