mixed main bearings

[vl1500]

While replacing a rear main seal I decided to replace the main bearings also,my question is has anyone ever seen mixed bearings in these engines? All of the bearings were stamped with the GM markings without any sizes stamped on them therefore indicating a standard size but when I got to the #1 main I found the top bearing stamped .001 with the GM marking and the bottom bearing did not have anything stamped on them but the GM markings(no numbers).Has anyone ever seen this????

 

[bison]

While replacing a rear main seal I decided to replace the main bearings also,my question is has anyone ever seen mixed bearings in these engines? All of the bearings were stamped with the GM markings without any sizes stamped on them therefore indicating a standard size but when I got to the #1 main I found the top bearing stamped .001 with the GM marking and the bottom bearing did not have anything stamped on them but the GM markings(no numbers).Has anyone ever seen this????

Yes i have seen it and done it myself. The factory has done it also. I did this a few times on FWD 3.8 cars pre 3800 to prevent bearing noise after installing new timing chains.

 

[vl1500]

Question,Since the top main bearing was .001 and the bottom main was standard could the top main be replaced with a standard as well because I can not find a .001 Clevite main bearing and what can I expect??

 

[bison]

Question,Since the top main bearing was .001 and the bottom main was standard could the top main be replaced with a standard as well because I can not find a .001 Clevite main bearing and what can I expect??

Any store that sells bearings can order a .001 bearing

 

[newkid87GN]

Im in the same boat as you.Just pulled the motor apart to reseal it and found 001 oversized bearings on the cap side only on #3 and 4 mains..You can order 001 bearings from clevite or any other manufacturer..Good luck

 

[machinegun]

Yes this was actually quite common. The factory made sure these engines were set correctly from the factory for correct bearing clearances. Well not sure if you noticed but their engines repeatedly lasted 150K plus miles. I have done this too to get the clearances just the way I want them.