cam clearance for reverse rotation 350

[davewann]

Hello,

I am replacing a reverse rotation cam, port engine on 1964 30' Connie. The engine is a 350 long block with the original 283 manifolds. The CC casing has a brass adjustment stud with a locking nut to set the end clearance for the cam on the gear end. What gap should I have here for expansion of the cam?

I appreciate any help I can get here!

THANKS

[charlesquimby]

The cam does not expand. The reverse rotation tends to move the cam forward, or toward the timing cover. This is known as cam walk. The bevel gear at the opposite end of the cam tends to push the cam out of proper mesh with the distributor drive. Slight walk effects ignition timing. Severe walk tends to push the cam lobe centers out of alignment with their corresponding lifters. The cam button keeps this movement in check. I would adjust the button against the cam to zero end-play at the distributor end, then back the button out to allow .010-.015" end-play. To verify this adjustment, you may want to contact one of several marine engine specialists who advertise in the Bell for confirmation on this. I know that roller cams require .005-.010" adjustment to prevent cam walk. CQ

[drrot]

My book says .002-.004"

[davewann]

Thanks for the information, I really appreciate it!!