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The clearance specs are basically minima for ‘as new’ parts, Derek - most clearances increase with wear. Point being that spec clearances are there to allow for thermal effects on parts - excessive clearances, within reason, are sort of harmless…
The pistons ‘rattle’ about in the bores, it is the rings that provides the sealing - and cause the friction noticed, which relates to ring tension, when turning the engine. While the ring gap allows rings to compress - they must also fit in the piston grooves with spec clearances. There are no specs given for turning forces - but even 23 ftlb seems perfectly OK to me; pistons/rings are not expected to move frictionlessly…
There is not much gained by musing on what went wrong, examinations after the fact offers limited clues. Varying damage to the main bearings may throw some light on the ‘out of line’ importance - but whether cause or effect will remain unknown…
You have done a grand job, maybe even above and beyond strict necessity in the suspect areas!
So let her rip, Derek - with due deference in the run-in period. And don’t forget to retorque the head after some 1000 miles. Loosen each nut at a time in torque sequence half a turn - and retorque it to specs…
And like the rest of us in similar situations; you have to live with the feeling ‘what have I forgotten’ - it goes with the territory…
Frank
xj6 85 Sov Europe (UK/NZ)
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