I have a 97 Pontiac sunfire 2.4L as a winter beater. I mest up a rod bearing last year. Not super bad, just a slight knock. I retired the car for the winter and just decided to put it back together (bought a 06 cobalt to use in the winter months). I looked the crank over and it seemed ok so I threw in a new set of rod bearings and all was well for about 10 minutes. Then the knock returned. I dropped the pan again and found that the number 3 bearing was TOAST. All the other bearings were ok, but showed slight signs of FOD from number 3 coming apart. Now my question is did I line something up wrong on the bearing. I am not a engine guru but in the pic below it almost looks like I misaligned the oiling hole on the bearing... is that even possible? Does the oiling hole remained lined up as the crank rotates? Anyways here are a few pics. I'll grab a few extra bearings and plastigauge the rod bearing and see how far out of spec I am. Also which rod bearing tends to die first if the oil pump is under performing? Any input is appreciated.

You can't only go byt eue for the crank. You need to mesure it. It is most likely worn and out of spec witch is why you toasted the bearing again.



Gilles
2.3 Ho

I plastigaged the number 2 and 3 rod bearings. I took the measurement on number 2, and then I took the rod bearing out of 2 and put it in the numer 3 (since #3 was totally screwed up as pictured above). They seemed to spec out ok. #2 is at .002 and #3 (the bad one) is about .002 on the right side of the bearing and .003 on the left side. I plan on polishing the #3 journal with some fine Emery paper just to be on the safe side. The motor will get all new rod bearings on the next and final assembly.

Here is a pic of #3. You can see the slight FOD from crap that came through the oiling hole as the bearing fell apart.