Inspect 2/6 rod bearings with TB off and crank locked at 45° BTDC
10-06-2017, 11:37 AM
#61
Rennlist Member
Hi FredR! Thanks! That has kind of been my guiding philosophy: pain now for better later. At least that is what I tell myself.
Let me clarify something: the Plastigauge readings are for the NEW bearing sets. I only Plastigauged the old bearing set from #1 connecting rod. Subsequent discussion in this thread suggested this was not needed. I moved on to fitting new bearing shells.
I do agree. Based upon what I saw on the bearings, and oil pressure readings, those bearings could have continued on for years. Prudence and WYAIT dictated their replacement.
Let me clarify something: the Plastigauge readings are for the NEW bearing sets. I only Plastigauged the old bearing set from #1 connecting rod. Subsequent discussion in this thread suggested this was not needed. I moved on to fitting new bearing shells.
I do agree. Based upon what I saw on the bearings, and oil pressure readings, those bearings could have continued on for years. Prudence and WYAIT dictated their replacement.
The significant thing about your work to date is that the new bearing have what appear to be good consistent clearances- nothing marginal/suspect. For the original set that you did plastigauge they were in the same ballpark and that suggests negligible wear. It would have been of more relevance to measure the 2/6 bearings given the propensity to fail first but with plain bearings either they work or they do not and there is no mistaking when they do not so yours have worked to the point they were removed. As Greg says, at 160k miles they do not really owe you anything but I am pretty sure there may well have been another 100k miles or whatever in them especially with the new damper.
The only thing you now have to do is reset your goal to SITM 2018!
The figures for the new bearings are way more important than for the old ones that would have been of interest but somewhat academic nonetheless.
10-06-2017, 01:53 PM
#62
Rennlist Member
Thread Starter
Thanks, FredR!
That was my take away, as well. I saw no horror show, no carnage, all the old bearings looked relatively evenly worn.
Based upon the consistency in the clearance readings of the new bearings, I can safely guestimate that the old bearing clearances were similar to that of #1 cylinder, at 0.038mm.
I would like to have measured the clearance of all the old bearings, but the time just wasn't there. H*ll, it took me months just to get the new ones installed.
Well run in 928 engine, worn but not worn out bearings, showing no major issues. Moving on...
Yes, my next goal is SITM 2018!
That was my take away, as well. I saw no horror show, no carnage, all the old bearings looked relatively evenly worn.
Based upon the consistency in the clearance readings of the new bearings, I can safely guestimate that the old bearing clearances were similar to that of #1 cylinder, at 0.038mm.
I would like to have measured the clearance of all the old bearings, but the time just wasn't there. H*ll, it took me months just to get the new ones installed.
Well run in 928 engine, worn but not worn out bearings, showing no major issues. Moving on...
Yes, my next goal is SITM 2018!
10-09-2017, 12:54 AM
#63
Rennlist Member
Thread Starter
Martin, in my reply to your post, I said something to the effect that I didn't consider checking the rod bearings to be drastic operations.
Having replaced all 8 rod bearing sets, I now would like to retract that statement. That was pretty drastic.
10-14-2017, 11:21 PM
#65
Rennlist Member
Thread Starter
Thank you, Chris! I try my best. 
Note, all further work done to the engine and accessories on the Red Witch will be documented in this thread:
https://rennlist.com/forums/928-foru...l#post14536481
Note, all further work done to the engine and accessories on the Red Witch will be documented in this thread:
https://rennlist.com/forums/928-foru...l#post14536481
Last edited by skpyle; 10-14-2017 at 11:56 PM.