End float

[rick]

Hi,

Can any one tell me what the crank shaft end float is on a BSA 350 L29 Sloper engine

Thanks

[john.k]

Im not familiar with vintage slopers,but any motor with a spring cush drive,should have no endfloat when the drive is assembled,as the spring pulls the flywheels against the bearings.If there is float with the assy done up,then the bearing may be loose in the crankcase.Before the spring is tensioned the crank assy will have from 005 to around 025 or more.There must be some.Regards John.

[chaterlea25]

HI Rick, & John K,
The BSA's of the period  I have worked on have do not bolt the cush drive solid to the main bearing
A sleeve with tapered bore bolts onto the crank end to take the cush drive, the crankcases and sleeve have slightly conical faces to match each other, a felt washer is fitted  between the sleeve and crancase
As for end float, I would aim for 10 to 20 thou
As long as theres some end float so as the bearing rollers are not pinched endways it will be ok
The crankcases will expand more than the crank as the engine heats up and clearance will increase

HTH
John

[rick]

Hi both, I think both of you are on similar lines The L29 does have a Cush Drive the Cush has a tapered internal which matches the external taper on the flywheel shaft the Cush is then held by internal nut, the felt washer I guess is the oil seal between the Cush and the flywheel shaft. Ihave actualy now joined both the crank cases together and there is no end float on the fly wheels bearings shafts the face of the flywheel shafts pulls up right to the inner bearing runner face.
Now got a problem with the gudgeon pin on my new/old piston it will not quite fit the hole in the piston It says in the work shop manual that the pin is floating I could possible warm the piston to expand it but this would then lock the pin to the piston Any ideas on this one

[john.k]

With the piston heated in boiling water to 100degC,the pin should slip in with thumb pressure.The pin should have around .001 clearance in the smallend bush.If the pin wont enter a hot piston,ideally the pin bore should be honed out with a honing machine such as a Delapena,or Sunnen.,to the correct fit.Never sandpaper the pin/sandpaper the pin bore as pro restorers/Norton Guru s are prone to do.Regards John.

[rick]

Thanks John worked a treat.

[chaterlea25]

Hi Rick,
I have found out in a BSA book,  maximum end float for the taper fitting cush drive crank assemblys is 0.005in.
HTH
John