Hi Richard,
Trevor beat me to respond to your last Q
So, is this then saying that no matter how loose the inner race is it will not spin with a well-tightened cush nut?
This leads to my next question. With a loose inner race, are we depending on friction between the compressed shims to be sure the inner race keeps turning at exact shaft speed?
Finally, should I just give up and admit that shim destruction only occrs with a loose cush nut?
Try and imagine this scenario
The cush nut will clamp the bearing race and shims endwise,
Suppose there is even a 1- 2 thou radial gap between the bearing inner and crank mainshaft
The pressure holding the bearing inner depends on the friction between the end faces of the bearing race
and crank oneside and spacer on the other
I can see engine power pulling the crank towards the gearbox?
the power stroke pushing the crank downwards against the bearing?
engine vibration acting in a couple of different directions? (vectors)
I can see all these forces overcoming the clamping friction and the crank moving realtive to the beairng inner
by our supposed 1 - 2 thou
This tiny amount of movement over thousands of engine revolutions would eat away at the shims
Of course as the shims wear and clamping pressure from the nut is lessened so the shims wear more until they break up *sad2
Then you go to clean the sump filter and find the remains there
You then embark on a strip down only to find the cush drive nut loose and blame yourself for not doing it up properly
When in fact it is loose because of the loss of the shims and the resultant wear on adjacent parts
Aside from the temperature considerations of using loctite,
Does it have the mechanical strength of steel to withstand the mechanical stresses mentioned above ?
I very much doubt it
I have heard of bearing races being electro plated to increase their interference fit ?
But I have no experience of this !!
John's 2 cents worth