Hi Gentleman-
I believe I may have a rod bearing issue after a my top end re-fresh. My friend Franz and I re-worked the top end on my 80SC while he was vacationing on Kauai, he is a 30 year veteran Austrian 911 air cooled mechanic/shop owner.
At the time we started we didn't have time nor the indications, 118 K, that the bottom end needed attending to. During the process he stated that the case had been split at some point, well a month after he left I noticed a mechanical noise that seems to be deep in the case, also have found a thick silvery sludge on the drain plug. The sound doe not seem to be timing chain related. It is burning a much more oil than in the past and today I noticed a number of small air bubbles on the dip stick. The sound has remained constant but doesn't give me a good feeling. Like a sewing machine and it remains constant at all engine speeds. Seems to be more pronounced at a low idle 750.
I spoke with Franz on the phone and he thinks that when the PO split the case that perhaps they cut corners and re-used the rod bolts, after we added more compression with fresh heads and rings this may have cause the bolts to stretch.
I just wanted to inquire with the experts as to your thoughts. I have heard that I can send the oil for analysis to determine if it contains rod bearing material. At the end of the day I guess I know the answer, I was just hoping to get a few more opinions before diving into the fix on my own. Thank you for your time and knowledge.
Regards-
JS