Good evening all,
I've read a couple of conflicting reports on allowable end float on a 650ss. I've got my 1963 engine apart at the moment, just before I split it I measured 0.019" (.5mm) end float on the dial gauge. I'm going to put new main roller and ball bearing so, if bearing are the same width as the ones I took out, I plan to add 3 x .003" shims to get the float down to .010". I'll put 2x shims between the roller and crankshaft lobe on the driveside and 1x shim between ball bearing and crankshaft lobe on the timingside. Is my plan a good, bad, somewhere in-between or unnecessary? Any feedback most appreciated.
Matt
Hi Phil, Thanks for the tip…
Hi Phil,
Thanks for the tip.
The timing side ball bearing is in good nick, no discernible side play but going to change it anyway. I'll check the depth of the bearing housing and hope it's a good match to the width of the new bearing to confirm its going to seat correctly.
I'll then recheck the float with the new bearings installed and add shims if still exceeding .012".
Matt
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Make sure that the mainshaft ball bearing is in good condition. If it worn then it will have side play which may affect your measurements. Up to 1963 most of the Bracebridge Dominator engines were properly machined and generally left the factory with only a 12 thou maximum of end float. As a rule, unless the timing side bearing housing is badly worn, the crankshaft is pulled up tight against the ball bearing and does not move. The 10 to 12 thou of end play being primarily to allow for expansion of the differing metals used in the bottom-end.
However, this design feature does not work too well when roller bearings are banged onto each end of the crankshaft. Then you can get serious crankshaft end-float and a need for shimming.