[T3] Engine Rattling.... Update...

[J. Jonik]

Re/  71 sqbk FI Std shift....with a seemingly worsening rattle in engine area.

A  good diagnosis and explanation came in over the phone from a mechanic who's worked on the old bombs for decades. He knew just the sound I described...tinny, like a rattle-snake, when changing  gears and at idle...not when driving steadily.

Yes...(as explained here not too long ago) it's about too much play in the crank shaft, as seen by moving the fan pulley in and out.   It's largely about old age of the engine....as the bearing dowel holes in the case have gotten a bit elongated and are not holding the bearings, and the crank, snugly any more.  How four dowel holes can wear out is a mystery.
  He figures the case is shot.   But, to be picky, a few more questions...

* Exactly what thin-sounding metal parts are rattling together?  
*  Any chance it's not the case, but the bearing shells? Or do both dowel holes get out-of-shape at once?
*  No leaks from oil seal...yet....but will that be drastic (can't drive home) or gradual?
*  Engine does not have as many miles on it as some others.  This one had only 60 thou, or less, when I got it...and I may have put that much again on it  AFTER new pistons and cylinders.  What is normal life span vis a vis mileage?  Or does this have anything to do with careless assembly ten years ago, or bad driving practices?
*  Would it have helped if case nuts (top and bottom, front and back) were checked and re-torqued (if needed) every so often?  (Don't know yet if they aren't as tight as should be.)

    I have a spare engine in '73 parts car.  I haven't checked its crankshaft play yet.  Fingers crossed.  Didn't rattle when I parked it ten years ago.