Re: Alum bronze cam bearings 55-56

Posted by Jack Vines On 2013/12/15 16:46:54

Very interesting thinking, Riki and one modification I've never seen or even considered.

If restricting oil to the cam bearings is desired, it's easy to install the cam bearings with the oil holes out of line with the block. Then, new oil holes of the desired smaller diameter can be drilled to create a restriction.

FWIW, the cam bearings and journals are one of the few wear areas seldom a problem in the Packard V8s. Thus, restricting oil probably doesn't hurt anything and may raise pressure to mains.

In order of problems usually found in Packard V8s:

1. Main bearings - always going, often totally gone. I usually drill the main bearing holes and feed passages to 9/32". I've never been able to prove it helps main bearing wear, but a carefully machined and assembled build with good oil is going to last a long time anyway.

2. Rod big end bearings - wear but don't usually fail. When the mains start pounding, the rod journals usually also require a regrind.

3. Rod small end bushings - about average wear. I've seen one engine with oversized pins installed in the pistons. Now, I have to dial bore check all the rods just in case.

4. Rocker arms - high miles or severe neglect will show worn shafts, rocker ID, wear in tips.

5. Cam lobes/lifters - about average wear

6. Pistons - always cracked where the barrel turns to the flat if engine is run hard, as in Studebaker Golden Hawks with overdrive.

7. Valve spring retainers - Early soft retainers should never be reused in anything other than a trailer queen rebuild. They will fail eventually.

8. Cam bearings and journals - seldom to never a problem. So how will Riki be able to determine if bronze cam bearings are worth the effort? It would almost require a test of oil pressure with DuraBond bearings, then replacing them with custom bronze.

jack vines