Thanks Nippymog, for posting the link back to the original BB discussion from the pics contained therein I was able to gain more of an idea as to the layout of the components.
Dan, many thanks for taking time to respond to my ramble, I come here to pass time, chat and hopefully keep the old grey matter active to some degree...I am NO expert, and have only seen pics a M3W.
Seems that a bevel box lacks the complexity of a diff, no planetary gears as in a normal diff or clutch mechanisms and the likes as in an LSD..? T
he BB seems more akin to the bevel drives to the OHC on old Ducati`s that I owned many years ago, boy they made some noise when the mesh on the bevel gears developed play as the resultant hammer in the drive from the valve-gear operation would crush the shims over time to increase the play in the mesh of the bevel gears which would then further increase the noise/hammer effect...
Seems to me that in the M3W BB set-up a similar hammer effect may be experienced by the shimming utilised to adjust the bevel gear mesh, as the result of acceleration and deceleration loads....? Again only working from the pictures, I am still left wondering at the need for pre-load as determining that the bearings have seated correctly..OR indeed the accuracy of the mesh adjustment..?
Looking at
http://www.talkmorgan.com/ubbthreads.php/ubb/download/Number/24422/filename/025.JPG that to me looks like a shim designed to determine the mesh of the bevel gears..?
Looking at
http://www.talkmorgan.com/ubbthreads.php/ubb/download/Number/24372/filename/034.JPG I can see the general layout of the BB from which it seems possible that the mesh of the bevel gears could be affected by whether or not gasket material was utilised in the joint between the input bevel gear casing assembly and the main body of the unit..?
If no gasket is used in this machined joint then my assumption would be that the longitudinal position of the bevel gear shaft in the input assembly casing would be critical and as such pre defined by precise machining with at least one shim utilised to adjust for manufacturing tolerances in terms of determination of the critical mesh between both gears..?
With any play in the mesh, then I suspect hammer(clunk) will become obvious when in the transition from acceleration to over-run and vice versa..?
With no play and too much pressure applied in the mesh of the gears I suspect they will generate excessive heat as the result of the increased friction incurred...?
I note in the original thread that Peter J typed of cush drive.... Ideal for removing shock from drive trains. Lotus utilised rubber doughnuts in their half shafts to achieve this and old m/cycles oft times had rubber inserts built into the clutch centres to take the shock out of the drive line, with something like this it would seem that the possible hammer effect on the BB system could be considerably reduced, unless there is some other similar system built in elsewhere...?
I suspect the belt drive may be an improvement on the whip effect that a chain drive could feed back into such a system....?
Overtightening the belt would seem to also add a degree of stress into the output shaft BB bearings and those of the swinging arm bushes..?
Interesting stuff... Thanks for posting, happy to continue discussing if thought to be food for thought...?
