>> The real pros would measure all the various components and then
>>calculate the
>>clearance.
Rubbish!!
The *real* pro uses 'plastigauge'. Most pros grind the crank to the
required tolerance and fit the bearings it says in the book. Most pros
couldn't calculate the difference between the main bearing housing diameter
and the diameter of a trashcan lid!
>I guess this means you would measure the thickness of main bearing
>pedestal, subtract
>the distance between the thrust surfaces, subtract the combined thickness
>of the two
>thrust bearings, and compare to specifications? I guess that requires
>inside mic...I
>only have an outside mic, but I would never have thought to do that.
>
>>BTY, you must have all the mains installed and the caps torqued to spec
>>for this
>>measurement to be accurate.
>
>Right, the manual was clear on that.
WRONG. If you need to measure the bearing clearance to this sort of
tolerance, you need the above-mentioned 'Plasti-Gauge'. This is a plastic
strip which you insert between the crankpin journal and the shell bearing,
you then torque down the cap, light the cigar, remove the bearing cap, and
measure the width of the Plasti-Gauge. You then compare the measured width
with a table provided in the plasti-gauge pack, and - hey presto! the
bearing clearance is revealed, to the nearest couple of tenths.
FLAME OFF.
With apologies.
Richard Smith
R.G. Smith Automobile Engineering,
Alvis & Triumph Specialist,
Historic race & rally preparation,
Lucas Injection centre.
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