#2 & #3 mains

[TURBO D]

took my engine out to investigate metalic particles in the oil and found #2 & #3 main bearings wasted. #2 was the mos damaged not spun but it was like flaking off on the lower half. The thurst sides showed ware not to bad. #3 was starting to flake off and showed dark marks like being burnt. The engine has steel caps on #2 & #3 with a girdle. Rod bearings show signs of ware. Is this an alignment , oiling or detonation problem. Any ideas? TIA Dean

 

[qtr@atyme]

Could be any of the above .
Check the line bore for staightness along with the crank.
Buicks ars real sensitive to excessive clearance in the housing bore diameter. Make sure they are round and have no more than .0025" at the parting line. Have checked several and had th have the line bore redone belive its a problem with the machinist that installed the caps rushing the final pass and the caps being billet and the block soft, also check your clearance with a dial bore gauge taking the housing size - shaft size - brg wall thickness (measure with ball mic and multiply by 2 ). This gives you an exact oil clearance spec have seen plastigage vary by as muck as .0015" do alittle investigating and the problem will arrive.

 

[TURBO D]

Thanks, qtr@atyme, the block and crank are at the machine shop. He found the #3 cap a little loose. He will see if it can be saved, probably change cap and bore. Thanks for the info.

 

[Joe 1320]

Also, Buick used different sized oil feed holes on each journal. #2 and #3 are undersized. Have them opened them up for more uniform oil flow.

 

[TURBO D]

Thanks Joe, I read somthing about drilling the holes larger but didn't check what size they were. Do you know what size it was recomenced? Thanks

 

[Joe 1320]

#2 and #3 are 1/4", the front is 7/16", the rear is 5/16" from the factory. It is recommended that you increase #2 and #3 to 3/8". This will increase oil supply to the mains as well as the #2-5 rods as well.