Valve geometry hell Options

[malcolm2]

Help me out here. Working on the subject and can’t figure it out.

9590 cam. 0.426 lift on the card. Adjustable pushrod tool.

I get to 0.426 lift. But the geometry between the swivel foot and the valve is wack. That is shortening the PR.

Stretch out the PR and i get 0.430 lift and almost straight valve to adjuster. The foot is too tight to the 1.7 rocker boss.

Bought some shims to lift the rocker stand and try that.

Question is: why am I so far off the card lift? Does it matter?

[Mark Henry]

Don't worry about the lift vs the card.
Instead worry about getting the geometry correct.
I take more than .060 off and the countersink must clear the foot in all directions.
I don't use shims, at least not much shim.

I cut the swivel foot down and recut the slot, as the screws can/could hit the valve cover.
The cool trick for doing this is to put two 32T blades in your hacksaw, first cut the slot deeper, then grind off the excess thread.

[malcolm2]

Don't worry about the lift vs the card.
Instead worry about getting the geometry correct.
I take more than .060 off and the champher

Cool. That is the direction I was heading. Don't really have much choice otherwise.

[Mark Henry]

Don't worry about the lift vs the card.
Instead worry about getting the geometry correct.
I take more than .060 off and the champher countersink

Cool. That is the direction I was heading. Don't really have much choice otherwise.

Take the .060 off the smallest rocker then match the rest.
After a generous countersink it won't look like much thread left, maybe less than a 1/4", but it's never been an issue.
To get very little shim you only have the screw about 1-1/2 turns in, that's why you need a generous countersink and thus you have a lot of thread sticking out the top.
If you need reassurance it's how Raby does them.

The geometry... well I see some of the threads and giggle at all the complication (IMG:style_emoticons/default/biggrin.gif)
At one half of measured lift the the adjuster screw should be in line with the valve stem. The rock (degrees) of the swivel foot from open to close should be equal. That's about all you need to know.

Just an FYI If you have well machined heads, like Len's, then all the valve stems are equal, if you start into needing different lengths of PR there's something wrong with the head machining and/or case deck.