I was taught by the old Mopar drag engineer group at their drag race seminars that wedge motor single shaft rocker arms should start with the contact pattern on the valve stems to start on the inner third of the valve stem and then sweep outward across the center of the stem to the outer third at max lift, does yours do that now?
It better not, or Mike botched his kit!
Two current schools of thought on rocker geometry:
1. Have the rocker arm perpendicular to the valve tip at 50% lift, which means the rocker tip starts slightly inboard of the center of the valve tip, sweeps out across the center at mid-lift, then sweeps back slightly inboard again at max lift. This approach yields a narrower overall sweep pattern and -- if components are designed properly -- will have this sweep pattern centered over the valve tip. I'm pretty sure this is the approach Mike at B3RE takes w/ his kits. Although T&D's bolt-on kits don't achieve this, this is the "ideal" geometry T&D describes in their catalog.
Brad,
Once again, you are spot on. The reason the T&D rockers (or Jesel)don't achieve perfect geometry with the single shaft, is because they can't. They make a compromised rocker, for the guys who want to just bolt something to the existing stands, just like everyone else. I've talked with their engineer multiple times, and he admits that is true. But, they will tell you, "we have a paired system that has correct geometry". Yes, but you will have to use pushrod or spray bar oiling, likely have to bush the lifter bores with the pushrod oiling, cut off the stands on the heads, and class racers like Stock Eliminator aren't allowed to do that.
The Jesel set up may center the roller at the highest spring pressure, but does not decelerate the valve as much at full lift, or accurately transmit the cam lobe to the valve. So, what is more important, loading on the valve tip, or stability and accuracy?
