Aluminum Journal Bearings and Chromed Shafts
Aluminum Journal Bearings and Chromed Shafts
(OP)
I am restoring a 1968 Honda DOHC motorcycle that has aluminum journals for the steel camshafts. The journal i.d. is 22mm. I am thinking about hard-chroming the male part of the new camshafts, and polishing the aluminum journal bearing. The original design is problematic and has produced an expensive aftermarket solution which installs needle bearings in the aluminum journals, and a sleeve on the camshaft mating part. Is this combination of hard crome and polished aluminum advisable? Thanks, John Boettger P.Eng.





RE: Aluminum Journal Bearings and Chromed Shafts
Rod
RE: Aluminum Journal Bearings and Chromed Shafts
RE: Aluminum Journal Bearings and Chromed Shafts
It's probable that you have a condition where the steel is really riding on alum. oxide, which is far harder than steel. The oxide will be very thin (microns), but it's still extremely hard and tough. But if something manages to wear thru it, the alum. underneath is soft, of course.
RE: Aluminum Journal Bearings and Chromed Shafts
RE: Aluminum Journal Bearings and Chromed Shafts
Cheers
Greg Locock
RE: Aluminum Journal Bearings and Chromed Shafts
RE: Aluminum Journal Bearings and Chromed Shafts
Also. has the head been surface ground.
If the head is a little bit warped, it is not always desirable to machine it flat, as the design and material of the head is not nearly so rigid as the cylinder block and crankcase, so on tightening down the head, it will conform to the deck of the block and straighten. This will pull the original cam bearing bores straight also. If you machine the head, you also need to line bore the cam bearing bores.
Regards
pat