I caught an approaching and nearly catastrophic failure of my valvetrain on my 493" RB a few years back during a routine inspection of my valvetrain. All my exhaust roller bearings in my T&D rockers were at some stage of being completely blown out. It was a mystery for a few weeks as to how that could be occurring only on my exhaust rockers.
I contacted Dwayne Porter, and he quickly deduced that my intake pushrods were being dampened by ever so lightly touching the intake port castings on my Indy EZ heads. He also reviewed my original dyno sheet and pinpointed the rpm at which my valve springs lost control of my valve train at about 5800rpm. I had been running a hydraulic roller, and Dwayne found that the root cause of my dilemma was that the valve spring installed height was slightly incorrect resulting in lower than recommended seat pressure and that the springs had also lost some tension.
Dwayne went through my heads cleaned up some epoxy work on the intake port ceilings (non-Max Wedge port openings) and changed all my hard parts. He also recommended a solid roller cam and spring set for my combination. While I was at it, Dwayne helped me with the calculations to swap out my 12.2 to 1, flat top Ross pistons for a weight matched set of reverse dome 10.2 to 1 Ross pistons. The things only weigh 528grams, so it was at the limit of Ross to pull off the fresh set, but they nailed it.
I then contacted Mike at B# Racing and had him review my valve train geometry. Mike sent me a kit and ordered me a set of custom T&D roller rockers. I also upgraded to an upsized set of Manton Stage 5 set of 7/16's " pushrods.
Now that the motor has been all back together and running for over a year now, I can say that an entire magnitude of vibrational harmonics is gone from this new build. It runs and rev's so much smoother than any thing I have ever run before. It's astonishing how much harmonic vibration has been eliminated from this motor.
I can only speculate that since the only thing that has been altered aside from an exact same weight piston is the valve train set-up, geometry correction and components. It is actually pretty amazing how much smoother the motor rev's. Food for thought.
I'm glad you posted pictures. That's a bunch of correction. That's how far off you were and it's NOT your fault. I blame all the people who fight about correct geometry at every turn. They talk about how their [censored] has been running for years and how they've always done it blah blah blah. Correct is correct. I'm glad Porter helped you out. He doesn't miss much.
I can tell you that my personal junk has about that much correction. I was stunned. I knew it was wrong, but that's a long ways off. I'd bet lots of money there are way more out there that are wrong than heads that are correct. And it's a damn shame people put up with this [censored].
I like T&D but they will tell you the same thing...there stuff is bolt on and will work. Any time the rocker shaft placement is fixed, you can bet it's most likely wrong. Statistically it has to be wrong way more than its correct.
I'm glad you caught it all before you had a serious problem.
