- Jun 24, 2010
- Reaction score
I've wondered about this aspect myself. All the rocker arms I have come across on commercial 4S engines are steel, which I assumed was maybe more about wear than strength? The valve springs around this size equate to probably 2-3 pounds max depending on pre-load. The rockers on the O.S. 4S engines I've seen almost look forged, not machined. Maybe that's a function of their minimal mass with the inverted 'T' section profile. I unscientifically ran a file across the material on valve end (not the pad itself) and it seemed quite hard.