S/B rocker arm geometry and contact patch
Ok YR, u have stated numerous times that shims are the wrong way of adjusting rocker shafts for valve tip alignment and sweep and push rod length. Is this not shims? Or am I missing something? Kim
When I said shims, I meant shims like Hughes is selling, among others. They are just a flat .015, .030 and .060 shim with a hole in it that has a curve to sit in the saddle.
That only does half of what you need. If the shaft needs to go up, it also needs to move AWAY from the valve. There is a mathematical formula for how much up and how much away you need. I don't know it, but Mike at B3 does.
When you buy his kit, the "shims" aren't really a shim at all. They had a radius for the saddle in the head and a radius for the shaft and the shim is offset. That means it's thinner on one side. So it will move the shaft up, and then away from the valve. And you have to offset the hole in the shaft so it can move away.
Just raising the shaft is only half of it.
That's why Mikes kit is different. It isn't just 3 different thicknesses of shim. IIRC my shims are .200 thick and then however much away they move the shaft.
I've seen pictures of his shims that correct the height much more than my puny .200.
That's the same principle as using stands like the W2 head does. With longer valves and different rockers...some with roller tips all require a different height and offset.
So, you can either mill the stands and use offset blocks and shafts, or just buy Mikes kit.
My first dealing with the offset stuff was on a buddy's T/A stuff he bought. It was late 1981 when he drug all that crap home. I no longer remember the name of the guy who turned us on to the W2 stuff for his T/A heads, but he did the original set of heads I've ever seen it done on. An we bought the parts on my dads account at Roy Burnett Chrysler-Plymouth.
It's not something that is new or unknown.
Edit: from the picture above its a bit hard to see what I'm saying about the offset of the shim. Maybe GLH can post some pictures with different angles so it's easier to see.
Also it looks like he didn't need a bunch of correction.
