While I was playing with the hardness tester

SkipSchloss said:

So, we haven't really addressed the issue of the toasted needle bearings that Jim mentions. Insufficient lubrication? Or is the needle bearing concept just wrong, when bushings will carry more load with less lubrication? Was Paul Dunstall being too cute with the needle bearing recommendation?

Click to expand...

I think its one engineers concept working against another. One will spend the R & D to sell their products long life but the new one "needle bearings" doesn't take into account what happens down the line. if everything stays the same. Who then gets the blame?

SkipSchloss said:

So, we haven't really addressed the issue of the toasted needle bearings that Jim mentions. Insufficient lubrication? Or is the needle bearing concept just wrong, when bushings will carry more load with less lubrication? Was Paul Dunstall being too cute with the needle bearing recommendation?

Click to expand...

Norton cam journals are not hard enough to run on a needle bearing for very long.

Cast iron cams have much softer journals than Norton cams.

Dunstall cams were made of gear steel and the bearing journals were hardened to >RHC 62
which is the minimum hardness for a needle bearing. [or a roller lifter]

Dunstall cam [as good as they get IMHO]



The lobes are still mid 50's RHC