What Ben Franklin actually said is, "He is a fool for whom experience is the best teacher."

I've been disappointed with the way the XS282 solid lifter cam has rev'd in the 396, dropped off over 6200 RPMs something fierce, supposed to be a 2400-6800 RPM powerband. I thought it might have been the stock retainers on the Comp 924 springs, so I got a set of 741 retainers and 612 keepers (10 degree both) to see if that helped any. What I discovered while switching them out was that the intake springs had literally cut through the spring shims - from float. Absolutely not from spring bind, that was checked, lots of room left there.

I spoke with the engine builder who assembled the heads, he agreed it was valve float. He suggested a slightly thicker shim, since there was plenty of room travel-wise, to see how that would do.

Well, after putting it back together that way, not much better. May have gained 100 RPMs over previous. Still well short of the 6800 RPMs the cam is supposed to be able to spin to, and these are the springs Comp recommends for the cam.

When I put the cam in last year, I cheaped out and used Elgin lifters instead of Comp's. I didn't like the look of the cup being farther down in the lifter than the hydraulics I took out did, but figured lifters is lifters, especially solids, so went ahead and assembled it. This put the rocker farther down the stud, of course, and the intakes seemed to suffer more than the exhaust. Bad move.

So, I need to correct that geometry. Perhaps some day I'll learn from the experience of others without having to destroy my own stuff. . .

 

There were 2 quotes about experience by Tacitus, a Roman historian in the 2nd century, in his books the Annales (a history of Rome organized year by year as was common to do at the time). One was the familiar "Experientia docet", meaning "experience is the best teacher". The other was "Experientia docet stultos", which means "experience teaches even fools". There is also a quote from Livy, another Roman historian, of the 1st century BC, in his Annales; "Stultorum eventus magister est", "experience is the teacher {or master} of fools".

Ben Franklin's is a sort of commentary on all of these put together....

Experience keeps a dear school, but fools will learn in no other, and scarcely in that; for it is true, we may give advice, but we cannot give conduct. Remember this; they that will not be counseled cannot be helped. If you do not hear reason she will rap you over your knuckles.
— Benjamin Franklin

Seeme like there's alot of people among those who come to these boards that fit that description! Sorry to hear that you feel like you have joined them. But unlike some others, you will probably profit from it and move on, instead of trying to overcome reality by repeating the same mistake and expecting different results.

 

Uhh yea, boy I feel young for not knowing those quotes...
Anyway, that geometry can't be too far off can it? I would think between the .050" step that you can get different pushrods in. I mean I would think maybe .030" or something? I wouldn't think a slight change in geometry could make that much difference, ie. ~500RPM?
I would have thought perhaps valvetrain weight may have a bit to do with your upper RPM limit? Are the studs good and stiff as well?
Well pushrods are a quick easy change, do you think you'll have a chance to correct the pushrods and try it out again this summer?

 

The difference is more than .050". As in, visual without even looking that hard. Lash adjustment is difficult because the socket gets stuck to the rocker (Comp Magnums) when it gets close to the proper lash.

I don't know if I'll be able to get anything done about it before the season is over or not.

 

OH! Gotcha. Hmm, are you just that busy? I mean, a plastic rocker looking style pushrod length checker would work pretty good for that eh? Then a caliper, then call up and order the right pushrods. It's a pretty quick test, and an easy swap isn't it? But i'm not sure how much season you've got there either.

Damn, well, I'll learn from your mistakes at least

 

Custom length push rods are about 3 week lead time - the season will be over by then.