General Pushrod/Rocker Theory
11-18-2025 | 12:09 PM
#3
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VIP Member
Joined: Jun 2021
Posts: 3,461
Likes: 2,089
From: SW Ohio
Go on you tube
search
Powell Machine and camshaft
dude is a no nonsense genius
Explains everything easy and educates
https://youtu.be/jXu4Bga8Q6E?si=s6MZ3pMcjnPkMrY-
search
Powell Machine and camshaft
dude is a no nonsense genius
Explains everything easy and educates
https://youtu.be/jXu4Bga8Q6E?si=s6MZ3pMcjnPkMrY-
I’ve done a ton of YouTubing, albeit I haven’t come across Powell (I’m aware of him). So far, all I’ve seen/heard/read is that you want the left image sweep with the right image contact patch. Unfortunately, with stud mount rockers, that’s not always possible. Sometimes, you just have to choose one over the other. So I’m asking the brain trust their druthers.
Thanks. Brad.
11-18-2025 | 12:39 PM
#4
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Joined: Oct 2005
Posts: 221
Likes: 124
powerboatr,
I’ve done a ton of YouTubing, albeit I haven’t come across Powell (I’m aware of him). So far, all I’ve seen/heard/read is that you want the left image sweep with the right image contact patch. Unfortunately, with stud mount rockers, that’s not always possible. Sometimes, you just have to choose one over the other. So I’m asking the brain trust their druthers.
Thanks. Brad.
I’ve done a ton of YouTubing, albeit I haven’t come across Powell (I’m aware of him). So far, all I’ve seen/heard/read is that you want the left image sweep with the right image contact patch. Unfortunately, with stud mount rockers, that’s not always possible. Sometimes, you just have to choose one over the other. So I’m asking the brain trust their druthers.
Thanks. Brad.
The math and phyics from cam to valve stem is deep
I have been an aircraft engine guy since 81
Those engines are set in stone
For longevity, reliability etc .
11-18-2025 | 06:41 PM
#8
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Joined: Oct 2005
Posts: 1,073
Likes: 251
From: Waldorf, Md
Brad,
I feel differently than most. I always try to get the pattern centered. I would rather give up a little lift to have the valve pushed down as straight as possible. But every time it has also ended up with the narrowest pattern. One thing to take note of is that different rocker manufacturers will give different results. You can put a Brand A 1.7 Big Block rocker on a head and it can be almost impossible to get a decent pattern. Take it off and put a Brand B rocker on and it will be perfect. And it can vary from one head manufacturer to another
You asked for opinions . . . . .
I feel differently than most. I always try to get the pattern centered. I would rather give up a little lift to have the valve pushed down as straight as possible. But every time it has also ended up with the narrowest pattern. One thing to take note of is that different rocker manufacturers will give different results. You can put a Brand A 1.7 Big Block rocker on a head and it can be almost impossible to get a decent pattern. Take it off and put a Brand B rocker on and it will be perfect. And it can vary from one head manufacturer to another
You asked for opinions . . . . .
11-18-2025 | 06:41 PM
#9
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Joined: Mar 2020
Posts: 372
Likes: 182
From: East Tennesseee
Scott Foxwell from Straub Technologies gives the best set up in this YouTube video:
As to where the sweep cones out on the valve, be it centered or inside/outside a little doesn't matter. Ed Iskendarian put it best when he said, " thats why theres a roller on the rocker tip." Just so it's not coming off at one extreme of the sweep you'll be just fine.
As to where the sweep cones out on the valve, be it centered or inside/outside a little doesn't matter. Ed Iskendarian put it best when he said, " thats why theres a roller on the rocker tip." Just so it's not coming off at one extreme of the sweep you'll be just fine.
