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Discussion Starter #1
First time doing this, but think I did it right. Was able to get 90 degrees at half lift. This put the roller on the outside edge of the stem. At full lift it was almost center. The pattern is wide and from center to outside edge. My pushrod length came in at 8.850 almost .600 over stock. I noticed in the video Scott also had a similar high number of 8.725

Is this right?
 

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What engine, head, rockers?
 

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Also are you going roller or staying flat tappet? I believe he was using a roller lifter which you wouldn't be near with a flat tappet
 

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What engine, head, rockers?
489, AFR 265, Scorpion 1.7


Also are you going roller or staying flat tappet? I believe he was using a roller lifter which you wouldn't be near with a flat tappet
Solid flat tappet

I was also concerned about riding the outside of the valve with a pattern that almost took up half the valve stem. AFR footnotes state that typically .200-250 over is required. So I set my adjustable pushrod for this and got more of a traditional wear pattern. I didn't use any marking compound and was just eyeballing nor do I remember what degree the rocker was at. So I may redo that test.

I did message Scott yesterday and he mentioned this is common and AFR heads need a shorter rocker. I never heard of such a thing, but I guess Harland Sharp makes them for AFR. So I'll probably set my my pushrod at .200 longer and check rocker degrees and wear pattern again. Then decide to buy the Harland Sharp rockers or not.
 

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702070



It's not a real clear pattern with just a checking spring and moving up and down by hand, but possibly looks better then I described. Just needs to be centered and narrowed slightly.
 

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Discussion Starter #7

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I have heard needing shorter rockers on some heads, even mine could possibly use them.

I mine is slightly more toward the center than yours currently(I am hydraulic roller)
 

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That what builders have been saying for quite a while AFR BBC heads need a back set or shorter rocker, not sure if intake only or both I & E.
 
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It didn't work for me either, same pattern as in your pic. Small block 355 with AFR 195's solid roller, .600 lift, Crower 1.6 roller rockers. His method came in at 8.100. I ended up with 8.000 to get the center of the valve, and a narrow pattern...
 
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With aftermarket heads, you have longer valves and longer rocker studs. The distance between the 2 is shorter because these are intersecting angles. On BBC the intake is the worst since the valve is +.250" longer. The rockers we supply AFR are 8 intake and 8 exhaust. This allows for the pattern to be narrow and more centered. Some brands of rocker are worse than others when using the half lift method. A centered but wide pattern on the valve, over .060", will lighten your wallet by over $1K after about 1500 miles on the heads.
702098
Geometrycomp.jpg Geometrycomp.jpg
 

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With aftermarket heads, you have longer valves and longer rocker studs. The distance between the 2 is shorter because these are intersecting angles. On BBC the intake is the worst since the valve is +.250" longer. The rockers we supply AFR are 8 intake and 8 exhaust. This allows for the pattern to be narrow and more centered. Some brands of rocker are worse than others when using the half lift method. A centered but wide pattern on the valve, over .060", will lighten your wallet by over $1K after about 1500 miles on the heads. View attachment 702098 View attachment 702098 View attachment 702098
What is worse, having the valve near that position at 0.030 sweep(mine is slightly more toward the center) or having a wide sweep pattern in the middle at a 0.060 sweep
?
 

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The scorpion rockers will end up with the pattern towards the outside. You are following the video correct? Then checking pattern with checking springs in place and rolling the engine over?
The AFR 265 heads I have done, all need the different rockers. Save yourself some time and get the Straub/AFR/Harland ones. I also strongly recommend changing the rocker studs to ARP 235-7205. This gives more shank inside the rocker fulcrum, and especially on the exhaust rockers, helps prevent premature wear on the rocker stud and movement/play. I actually use the stud 135-7202 on the intakes for maximum shank intersection. (machine .030" off the threads which go into the head).
 

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With aftermarket heads, you have longer valves and longer rocker studs. The distance between the 2 is shorter because these are intersecting angles. On BBC the intake is the worst since the valve is +.250" longer. The rockers we supply AFR are 8 intake and 8 exhaust. This allows for the pattern to be narrow and more centered. Some brands of rocker are worse than others when using the half lift method. A centered but wide pattern on the valve, over .060", will lighten your wallet by over $1K after about 1500 miles on the heads. View attachment 702098 View attachment 702098 View attachment 702098
Are you making the afr rocker Scott developed? I thought Harland sharp makes them?

Another reason to use Brodix heads since they use oem lenght valves with their heads up to at least .700” lift. After that lift you usually need shaft rockers because of the spring pressure needed with a roller cam with that lift that are head specific. At least I wouldnt use stud mounted rockers with 200+ seat and 500+ open. Another option that has worked for me withafr is backset Crower stainless roller rockers so I can use rockers that are made of steel and will last on the street.

With Brodix and Std lenght valves std BB roller rockers works fine and gives a narrow pattern thats decent centered with mid lift method. Brodix also cast their head not like afr that buys castings from edelbrock and now even from China(land of covid -19).
 

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Never seen this problem with a quality steel roller rocker like Comp or Crower.
 

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Im not alone likning steel roller rockers and looks like more than me manage to get them to work.

 

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Never seen this problem with a quality steel roller rocker like Comp or Crower.
Just need to go up a few post then.
 

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Are you making the afr rocker Scott developed? I thought Harland sharp makes them?

Another reason to use Brodix heads since they use oem lenght valves with their heads up to at least .700” lift. After that lift you usually need shaft rockers because of the spring pressure needed with a roller cam with that lift that are head specific. At least I wouldnt use stud mounted rockers with 200+ seat and 500+ open. Another option that has worked for me withafr is backset Crower stainless roller rockers so I can use rockers that are made of steel and will last on the street.

With Brodix and Std lenght valves std BB roller rockers works fine and gives a narrow pattern thats decent centered with mid lift method. Brodix also cast their head not like afr that buys castings from edelbrock and now even from China(land of covid -19).
Sharp makes the rockers. Chris doesn't make anything.
One of my biggest gripes with AFR is the valve lengths they use. In most cases, they're unnecessarily long. A valve only needs to be long enough to give you the necessary valve spring installed height.
200 seat and 500 open is nothing for a good quality stud mount rocker with a girdle. I have customers running high .700 lift cams with 250 seat, 700 open and stud mounts with a girdle; some to almost 8000 rpm. Shafts are nice but not always necessary.
 

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View attachment 702070


It's not a real clear pattern with just a checking spring and moving up and down by hand, but possibly looks better then I described. Just needs to be centered and narrowed slightly.
That's not going to fly.
Here's how I check where my pattern; ink up the end of the valve tip with the sharpie, like you did. Then, at zero lift, just put a little pressure on the roller end of the rocker and roll the roller like you're doing to burn-out on the valve tip. This is going to leave a very narrow mark on the valve tip and will be the starting point of your wear pattern. If your geometry is right, the width of the pattern will be what it is. Ideally, you want the starting point to be slightly behind center of the valve. You have the center third of the valve to work in to be safe.
 
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