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Discussion Starter · #1 ·
I have afr heads with 1.73 comp cams ultra pro magnum xd roller rockers. I am running a .510 lift hydraulic cam. I ordered pushrods based on compromising between the rocker angle and contact point on the valve. I am attaching pictures with and without the lash caps. Is this to close to the edge? (Ands are lash caps a horrible idea for a hydraulic street motor?)

Thanks
 

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Yes too close to the front edge, pushrod too long.........needs shorter pushrod. Just remember it dosn't need to be perfectly centered on valve. A little back from center or a little forward of center is ok

Lash caps are more for ti valves, your build does not need them, but you can run them if you like.

Cheers, Bob
 

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I have afr heads with 1.73 comp cams ultra pro magnum xd roller rockers. I am running a .510 lift hydraulic cam. I ordered pushrods based on compromising between the rocker angle and contact point on the valve. I am attaching pictures with and without the lash caps. Is this to close to the edge? (Ands are lash caps a horrible idea for a hydraulic street motor?)

Thanks
If your rocker arm & valve train geometry are optimized, then leave it as-is. There is nothing wrong with the physical placement of your roller wheel’s position atop the valve stem and it will actuate the valve perfectly.

If you want to use a lash cap then there’s no harm in that—just keep in mind that geometry is affected. So, assuming geometry is optimized and then you add an 0.080” lash cap, you will have raised the nose of the rocker arm up 0.080” and so you should also add +0.050” longer pushrod since 0.080” / 1.73 = 0.046”.
 

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We have built numerous AFR headed combinations with Comp XD rockers and have never had to utilize pushrods long enough to place the roller tip that far outboard.

What is your push rod length(s) I & E?

1830-16 rockers?
75 cc or 85 cc chambers which have .045" more on the deck surface?

I do not generally recommend lash caps with hydraulic lifters. I've seen occasions where they end up in the rocker valley of the heads.







Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
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ParklandAutoMachine.com
R-H-P.biz
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(253)-988-6648
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Discussion Starter · #5 ·
1830 1.73 rockers. 8.775 intake, 9.325 exhaust. D9 block not decked. 85cc heads.
Just tried a 8.900 pushrod I had on a shelf and it is a fraction short of being dead center on the exhaust. Looks like intakes could be a bit shorter to cemter them as well.

I am probably screwing up on geometry angles and measuring wrong. I will search for a geometry explaination by The Mad Porter or Paul Kane, print it out and start from zero. (So many different theories and opinions to choose from).
 

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Discussion Starter · #6 ·
1830 1.73 rockers. 8.775 intake, 9.325 exhaust. D9 block not decked. 85cc heads.
Just tried a 8.900 pushrod I had on a shelf and it is a fraction short of being dead center on the exhaust. Looks like intakes could be a bit shorter to cemter them as well.

I am probably screwing up on geometry angles and measuring wrong. I will search for a geometry explaination by The Mad Porter or Paul Kane, print it out and start from zero. (So many different theories and opinions to choose from).
 

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Interesting.

We use the mid lift by drawing a line from the center of the roller tip axel to near the top of the push rod cup and have that line perpendicular to the rocker stud at half the valve lift.

If you freeze the vid at 11:37 or so you can see that at 1/2 lift a line drawn from the PR cup to the roller axel is damned near 90* to the rocker stud at 1/2 lift.


The next build I do I am going to check it both ways to confirm.







Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
ParklandAutoMachine.com
R-H-P.biz
"Parkland Performance Auto Machine" Formerly RHP
(253)-988-6648
Log into Facebook
 

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Yes! Please comment back on this Scotty!!! This takes a lot of the confusion out of it the way he explained and went over it! This is the first YouTube I've seen that does it this way and I believe this is the easiest way to do it as you guys have related about getting the correct geometry. Please do comment back on using this method!!
 
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