Re: OFFICIAL: New 911 GT3 (991)
nberry:
Fritz, that makes a lot of sense. But one would think that the torque calibration issue could have been identified early on and which engines were involved. Am I missing something?
Early on? As far as we know, only two engines suffered damage as a result of this, and there wouldn't have been enough of the two conrod/bolt assemblies concerned left "in one piece" to provide clear evidence of the root cause of the problems. The only way to check on the fastener torques of the engines which had not (yet?) failed would presumeably be to strip them all down to check in a materials lab whether the bolts had "stretched" (if over-tightened), or needed to be tightened further (if under-torqued).
I suspect that the "tool" concerned would be a pneumatic wrench, or similar, which has to be set to the prescribed torque, and needs to be recalibrated at regular intervals, for instance, before every shift . If a previously incorrect setting was not noticed and recorded during the recalibration process, then there would be no "evidence" of it being the cause of the failures and no paper-trail to allow any conclusions to be drawn regarding how many engines - and which engines - had been assembled with incorrect torque settings.
This is all speculation, of course, but this scenario would be one which could explain why it took a while to reliably establish the cause of the issue with the two cars involved. A totally "safe" course of action in this mooted situation would be to review the procedure for ensuring correct calibration of the tools and then to start building replacement engines for all the cars already in the field.
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fritz