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MG TD TF 1500 - XPAG crank thrust bearing clearance

Hi all,
A little question regarding the crank of my MKII engine.
In disassembling and measuring I found the following strange(in my view..) results.
The main and big ends were all reasonably within tolerance. (0.001-0.003) but the thrust face showed a tolerance of 0.01" . Meaning that the crank can enter the driveway almost before the car does !
Is this common wear,that will be corrected by a new set of bearings, or is something else going on ?
Greetings
Gert Nijhof
GD Nijhof

Gert - I had the same problem in our TD, there was so much thrust bearing clearance that I would get a knocking whenever accelerating. A new center bearing cured the problem. If that doesn't do it, I suppose that the next thing to do would be to have the thrust surface on the crank built up and ground to spec. Cheers - Dave
David DuBois

Gert

I would be ensuring the width of the crankshaft main centre journal is to spec and the faces parallel.

Other things to look at are that the flywheel bolts and taper pins are not fouling the rear main cap, these will completely compromise the thrust clearance on the centre main bearing and create a source for non design wear.

If the crank journal is worn and irretrievable your options are limitted to buying a new crank.
G Evans

From the Moss Motors catalog: Main bearings have oversized thrust faces on the center bearing to compensate for wear. Clean up thrust faces in block if necessary. Use glass plate with 320 grit or finer sandpaper on bearing to achieve 0.002" endfloat. Clean all grit from bearing

The crank can be welded and brought back to size if needed, if no cracks, etc. George
George Butz

George

Is 0.002 correct my original workshop manual states 0.004 clearance on the centre crankshaft main.
G Evans

Somewhere there is a John Twist Univ. Motors machine shop data list for the XPAG that would have that spec, I can't find it. My dim recollection when we did my engine that the WSM specs were generally on the loose side for bearing clearances. I'm sure not expert on this for sure, what do others think? George
George Butz

Thanks all,
It would be very helpful if indeed the moss center bearing comes oversized on the thrust surfaces.
First I will check if the faces are parallel as mentioned.
Should it be 2 thou as stated ?
Cheers and thanks
GD Nijhof

Gert, The WSM shows the centre main bearing - end clearance as .0014in. to .0037in. (.035mm. to .095mm.) Cheers Phil
Phil Atrill

This thread was discussed between 27/11/2011 and 30/11/2011

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