The front timing cover at first glance looks like a mirror copy of the rear timing cover, but on closer inspection one can identify some features we would like to include in our model. The front timing cover is thinner than the rear timing cover as well.
Features of note on the front Timing Gear Tower:
- A – a raised lip around the edge of the front cover that extends out past the edge of the rear cover.
- B – Sizable radius on edges of the front cover, much smaller on the rear cover.
- C – Countersunk mounting hardware joining the two timing cover halves. Also there is a boss that extends above the edge radius noted by B.
- D – raised round boss and support web to house main idler bearing. This is a double gear so the bearing housing extends further forward.
- E – Raised Boss for larger mounting hardware holding timing covers to the block
- F – There is a raised boss that the camshaft gear cover mounts to.
This is also a good time to define the stack up of the timing gears, their bearings and the bearing supports machined into the timing covers. I am in the US so I am most familiar with imperial dimensions and parts, but metric components are just as easy to obtain here. In some instances metric parts are cheaper and more readily available, bearings are a good example. I am thinking of using a 1/4″, 3/16″ or 5mm shaft size for my timing gears. Since the gears are 48DP (imperial) I will start with imperial dimensioned shaft and bearings. A quick search on the internet and 3/16″ X 3/8″ X 1/8″ bearings and 3/16″ shafts should be a good place to start. Gears 7/32″ wide with small shoulders should fit well.
I know what cosmetic features I want to add to the Timing Gear Tower, but this is good enough for now. No sense putting in that detailed work if I need to reconfigure everything later. I am also missing the bevel gear housing for the magneto, but that will not impact the general layout, so that will have to wait.