Re: Crankshaft Bearings for 34 Standard 8 Engine

Posted by Owen_Dyneto On 2008/8/4 7:44:56

Been thru this a number of times. When I did my 34 1100 engine (at 89,000 miles) it was after the faintest of rod knock noticeable at a warm idle, though oil pressure was still acceptable. #8 rod showed some babbitt failure and I redid the engine sticking with the original babbitt.

MANY years back when you could still find original rod bearings for the 35-39 320 engines, one alternative was to find a set of rods from those engines to replace the 34 and back rods, but since the 80s or so those bearings were unfindable. Those bearings were flanged to control end play. I now believe one of the major Packard vendors has had them remanufactured.

The third alternative, which has been widely documented over the years involved the conversion of the 34 and earlier rods to take a modern simple insert (PM me if you want some more info). This took a bit of machining on the rods, on some conversions it required notching the rod bolts, and as the bearings didn't have the thrust flanges to ride on the crank cheeks, nubs or buttons were welded on the rod side faces and machined to control end play. Some people swore by these conversions, others had buckets of troubles, the differences perhaps depending on the skill of the mechanic doing the conversion.

I drive my car sensibly in recognition of it's original capabilities and thus stayed with babbitted rods and mains.