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Q & A: Shim Thickness

I have a 1968 MGB with synchro transmission. I am in the final stages of assembling the transmission, and have some questions:

I am trying to calculate the shim thickness between the front cover and input shaft bearing, and the wording and method used in the factory manual is confusing me. Maybe because I don't speak the King's English all that good. I'm at work now and don't have the exact specs in front of me, but In simple terms, am I trying to create a gap between the bearing and front cover, or am I trying to put on a slight preload with the front cover, thereby bending the cover inwards with the studs?

If you read it yourself, you can see it's written to indicate preload. First you measure front cover cavity depth, then add in for the compressed gasket. Then measure bearing height. Then they tell you they want you to add shims until the bearing height is more than the front cover cavity depth! Do you agree? Wouldn't that crack the front cover? Shouldn't there be a gap instead?

John!

I usually simply replace the shims I removed - with this extra step. I use a prick punch and a hammer, and put about 100 little tiny prick punch marks in the front cover on the annulus that meets the bearing. This rai... read more