Atlas crankshaft end float or the lack of it

If the crank is free to turn, should it matter if there is no end-float when it is cold? When hot, some clearance should open up anyway as aluminium's coefficient of expansion is greater than that of steel. Should there be any end float with superblends fitted? Someone will have a definitive answer. The green book states .005" to .008" with ordinary ball and roller bearings but also states that it is not critical.

Previously gordon_johnston wrote:

If the crank is free to turn, should it matter if there is no end-float when it is cold? When hot, some clearance should open up anyway as aluminium's coefficient of expansion is greater than that of steel. Should there be any end float with superblends fitted? Someone will have a definitive answer. The green book states .005" to .008" with ordinary ball and roller bearings but also states that it is not critical.

Hi Gordon, Norton service notes give 0.010 nominal side play. One would put a DTI on the end of the crank shaft and lever each way to measure. Small dinks on the side cheeks caused by hammering off the inner races are a common cause of this problem. Did you Loctite the outer races and get adhesive under the mating face? Worth a check. A couple of thou. end float will increase to 0.004/6 with a hot engine. Minus end float will knock the bearings out. I used to machine Jet Engines, they grew 12" when hot, according to a Rolls Royce engineer!. ATB, Paul