454 (Bent) PUSH ROD or (Collapsed) LIFTER or (Flat Lobe) CAMSHAFT?

[savatreatabvr]

My mid 70's 454 was running really rough, like on 7 cylinders so I replaced the plugs, wires, cap & rotor, set the timing and adjusted the carb but no change! I decided to adjust the valves, (running adjustment) and after loosening and then cranking down the rocker arm nuts around 1/2 turn each after zero lash I noticed one of the push rods, (only one) was spinning! Well since it was running good I figured it was alright so I put the valve cover back on and went for a drive! After about 10 miles or so it gradually started running rough again, they were all adjusted correctly and none of them were clattering so how could this happen? Could the spinning push rod be the culprit and if so, why is it spinning?

[Jonboy]

I would say pull the cover and pull the pushrod out. If it isn't bent, I would think it might be a lfter, based on that it gets worse after driving. Souns like a lifter bleeding off to me. Double check that it seems to be moving the same amount at zero lash as the others (up and down while running). My experience with a bad lobe is that the rocker arm will barely move up and down.

[savatreatabvr]

Ok, now I'm really confused! I was told the push rods ARE supposed to spin, all of them and if they don't spin then it's a flat lobe issue? Any camshaft experts out there?

[INSIDIOUS '86]

Spinning is good. All of them should spin that means the lifter is rotating and still has a slight crown on the surface.
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