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Discussion Starter #1
Is there a standard of how much to take off a shaft rocker stand to move the pattern toward the center of the valve?
I have begun assembling my motor and was mocking up everything. My rocker arm rollers are sitting on the outboard side of the valve stem at rest. Plus the roller contact is toward the outer 1/3 of the valve stem.
Thanks for any ideas?
https://www.flickr.com/photos/[email protected]/shares/44HdK8
 

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Discussion Starter #3
That would be useful info if I had stud mounted roller rocker arms.
But I have shaft rocker arms. The geometry is built into the rocker arm you can only move the contact patch by adding shims under the stand = move contact farther toward exhaust( outboard) side or remove material from the stand to move contact inboard,hence my question how much material needs to be removed from a shaft rocker stand to move the contact inboard? I'm hoping for x amount removed= y amount of movement on the valve stem.
 

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That would be useful info if I had stud mounted roller rocker arms.
But I have shaft rocker arms. The geometry is built into the rocker arm you can only move the contact patch by adding shims under the stand = move contact farther toward exhaust( outboard) side or remove material from the stand to move contact inboard,hence my question how much material needs to be removed from a shaft rocker stand to move the contact inboard? I'm hoping for x amount removed= y amount of movement on the valve stem.
Raise or lower the valve stem tip
 

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or

slot the pedestal so the roller is more centered.

you have to reveal ,...
...what head
... what rocker .
..and what stem length
...as well as what total lift movement at the valve.

what is the pivot length of the rocker that you have.
 

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Discussion Starter #6
Well I'm seeing how slotting the pedestal could help but that would require 10 times the machine work than just taking some material off the bottom of the stand plus there is no guarantee they wouldn't shift when in use.
Trick Flow High Ports. 5.160 valve lengths on both intake & exhaust. .700 lift at the valve. Harlan Sharp shaft rocker arm S90026K 1.6 ratio.
 

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Discussion Starter #11
Are lash caps out of the question? Seems like the easiest solution.
I've been researching this route. Sheldon had a reply to a thread several years ago about doing this very thing when milling the stands wasn't an option but he was replying about some slotted or offset stands.
My keepers are designed for the ability to use lash caps but I hate to add weight. It seems to me that kind of defeats the purpose of using titanium retainers to reduce weight.
 

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I've been researching this route. Sheldon had a reply to a thread several years ago about doing this very thing when milling the stands wasn't an option but he was replying about some slotted or offset stands.
My keepers are designed for the ability to use lash caps but I hate to add weight. It seems to me that kind of defeats the purpose of using titanium retainers to reduce weight.
have titanium locks as well?

some times getting what you want is a PITA
 

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I just set up my Sbc for geometry and pushrod length. .025 shim made a pretty good move in pattern location and width of the sweep.

You could take .050 or .100 ish off and then use shims to get where you want. To get the exact amount off will be tough. See what shims are available and then use those as a guide as to how much you can take off max and use a shim to get back.

Personally I would advoid slotting the stands unless you plan on pinning them to stop movement.
 

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I ran into this with both stud & shaft rockers with + .100" valves.The only 3 ways to move the contact pattern inboard w/o affecting sweep are...1) shorten the valves 2) use shorter pivot length rockers 3) slot the pedestals & move the rockers inboard (if you have room to do so). Lowering the shafts will move the contact patch inboard but will also affect the sweep.
 

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Discussion Starter #17
I called the manufacturer today. They have had this problem on a couple(like 2 or 3) other sets of shaft rocker arms on High Ports. According to them it's from some variable in the head manufacturing because all sets of their shaft rocker arms are trial/test fitted on a head before leaving the building. They had me ship all the stands back along with a set of the shaft rocker arms to take some material off the bottom of the stands and make sure the geometry is right. I'll update the post when I get the parts back and bolted on and see what I have. Thanks for the thoughts.
 

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Discussion Starter #19
Thanks for the link. The one thing that is a bit different between his set up and mine is my sweep is over .100. The pattern starts on the edge and rolls to the center. Its not a max movement at 1/2 lift kind of deal,then back to starting point at full lift.
 
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