Gordon Misch
MEMBER
Toledo, Wa (KTDO)
It was interesting to me that the break-loose torque to remove the cylinder base nuts varied some (considerably?) when I took this engine apart. That was especially true with the large nuts, and they stayed tight for several resets of the base wrench. That struck me as strange, and I think would be consistent with the case mating surfaces being non-flat at the time it was assembled (stud tension remains high until case distortion is fully relieved). That's a subjective finding of mine, and I didn't keep track of which nuts were real tight, but I'm suspicious.This brings up something I have pondered over the last two years:
After an overhaul or cylinder change is there any reason to re torque the case/cylinders at 10, 100, or 1000 hours? Should the prop resistance be checked before and after a re torque? It appears that this would show up fretting and would be a good time to check exhaust and induction for cracks inside the pipes. Any resistance change would dictate a tear down of course.