Author Topic: MK crakshaft clearance and how to obtain it  (Read 560 times)

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Offline tck

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MK crakshaft clearance and how to obtain it
« on: 22 Dec 2020 at 11:40 »
I have now made the necessary spacer and have pulled the rear bearing in until it is the correct distance from the clutch release spigot and the bearing is snug to the end of the crank (oil thrower removed) the crankshaft revolves freely and now I have attempted to test what clearance i have at the front (no camshafts or crankcase gaskets etc yet) However when I when I tighten the 4 nuts in the clutch housing firmly (but not tight ) the crank will not move I suppose my only action now is to reduce the height of the front bearing flange on my milling machine one of the variables I would like advice on is the thickness to allow for an assembled gasket also unfortunately the spares did not have a top gasket so I shall have to make one, any pointers to this problem (NB I am aiming for 3 thou clearance twixt crank shoulder and flange.

Offline phil1

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Re: MK crakshaft clearance and how to obtain it
« Reply #1 on: 26 Dec 2020 at 16:21 »
Hi tck
           I have shimmed be twin bearing and crank. double check your bearing is fully home in the case and on the crank shaft, my shaft was excessively tight and had to polish .oo1/2 thou off so removal is lot easer when shimming up, then go for .005 clearance at bush end, use dry paper gasket for a Dumay run.  cheers Phil.

Offline Neville Heath

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Re: MK crakshaft clearance and how to obtain it
« Reply #2 on: 27 Dec 2020 at 18:52 »
tck
If you look in the latest "ConRod" page 30 you will see that Spannerama 33 was not published. Here it is. Might help.
Neville

Offline tck

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Re: MK crakshaft clearance and how to obtain it
« Reply #3 on: 30 Dec 2020 at 08:17 »
I think the crank clearance is sorted now I need to get a bit of end float on the cam shafts I have line reamed them so the stiffness must come from a lack of end float (there is none at the moment) I am not sure what 'perceptible' movement is but my guess is 10 thou

Offline eddie

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Re: MK crakshaft clearance and how to obtain it
« Reply #4 on: 30 Dec 2020 at 10:19 »
Tim,
       With just the 2 crankcase halves clamped up, there should be about 25 thou endfloat on the cams. On final assembly, fitting the camwheels controls the actual endfloat. According to the T35 handbook, the camshaft bearings should have a running clearance of 2 thou, but it doesn't give a figure for the endfloat - I would suggest a minimum of 8 thou - a tight cam bearing can make a motor surprisingly sluggish!

  Regards,
                 Eddie.

 

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