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Old 07-30-2020, 08:02 PM
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ignaro ignaro is offline
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Default Am I measuring pushrods wrong?

I'm building a 461 stroker with Speedmaster heads and I need to order pushrods.

I initially used the method where you put a dry erase marker on the end of the valve (thanks Fast Monty's Garage!) and the rocker arm wears the ink off-- I got 9.135" on all valves.
Before ordering, I asked Butler to help me make sure I was doing it properly since they're hydraulic roller lifters and there are a lot of opintions out there. The Butler tech said he was certain I would wind up needing 8.800" pushrods and I must have done something wrong. I decided to keep learning and measuring until I got closer to that "known-correct" goal.

I thought that maybe the lifters were collapsing? I swapped to the checking springs and did it again. Got the same result.

More research, I found this video from Straub that explains the whole goal is to have the rocker arm be square to the valve at 1/2 lift. That makes a ton of sense.
I reset everything, drew a line on a rocker, have my checking springs, got it as square as I could by eye, and the pushrod came out to (drumroll please)... 9.135"! Literally the exact same as Monty's video.

The Johnson lifters want .035" +/- .010" of preload, so I think I need 9.170". They come in .050" increments so call it 9.150" pushrods.

Am I doing something wrong or is the Butler guy just remembering measurements from different lifters/rockers/heads?

461 with 10.230" deck height.
Speedmaster 72cc heads, round port.
.027" head gaskets
Johnson lifters 2112OPR
CompCams 1.5 ratio roller rockers CCA-19060

Thanks!

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Old 07-30-2020, 08:06 PM
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Photos showing the travel of the rocker arm and the witness mark on the valve. (Thanks, Monty!)

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Old 07-30-2020, 08:58 PM
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Was Butlers' guess based on their experience with ProComp cylinder heads?

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Old 07-30-2020, 09:10 PM
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Quote:
Originally Posted by NeighborsComplaint View Post
Was Butlers' guess based on their experience with ProComp cylinder heads?
They said so but I don't know. I'm also not sure whether or by how much they differ from E-heads

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Old 07-30-2020, 11:12 PM
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I would go with the length you got to yield that swipe mark on the valve stem.

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Old 07-31-2020, 12:27 AM
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You got it correct. The Comp Cam rockers are designed differently than most other Pontiac rockers.

I recently built a motor, and had both Crower and CompCam (1.65) rockers handy. Iron heads, but HR cam/lifters. Crower rockers needed an 8.800" pushrod, Comp rockers needed 9.150".

FWIW, I think Butler is a GREAT source for parts, but not nearly as great for advice on street-oriented builds.

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'67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T-II, full exhaust (3" w/Dr. Gas X, Xlerator mufflers).

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Old 07-31-2020, 01:35 AM
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FWIW- At half lift, the line that should be square to the valve centerline goes from the rocker's pivot center to the roller tip's center- not to the tip of the valve. This gives minimum "pattern" width, and also gives maximum valve travel at full lift. Note that this may not center the "pattern" on the valve tip- but that's not a concern.

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Old 07-31-2020, 05:46 AM
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If your running any type of Hydro lifter remember that the amount you preload the lifter by will shorten up on the measurement you made with your adjustable push rod, so you need to factor that back in to the needed lenght of the push rod you order up to maintain perfect geometry.

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Old 07-31-2020, 11:03 AM
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Agree on any phone advise. Trust but verify. The pushrod pocket on those comp lifters looks higher up on the rocker body, like it would want a longer pushrod than say a HS or a Crower Enduro rocker.

When I checked the length on my setup, it wanted 8.850" pushrods IIRC.
H-J lifters, Voodoo HR cam, iron heads, long valves at 1.8 IH, Crower enduro rockers. I used the Straub technique.

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I could explain all this to the girl at the parts store, but she'd probably call the asylum.

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Old 07-31-2020, 02:15 PM
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Quote:
Originally Posted by Old Man Taylor View Post
I would go with the length you got to yield that swipe mark on the valve stem.
X2, looks good.

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Old 07-31-2020, 02:30 PM
grandam1979 grandam1979 is offline
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Is that guide plate bent or is it supposed to be like that?

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Old 07-31-2020, 02:33 PM
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If you use light checking springs on the valve will you get a more accurate measurement and not have to calculate in lifter plunger travel or will a light checking still depress the plunger.

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Old 07-31-2020, 03:22 PM
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Depends. My setup would collapse the HR lifters even with the light checking springs. The straub technique doesn't require rolling the motor through with a pushrod. However when you do roll it through to look for the tip wipe, the lifter was wanting to collapse. I used a set of washers on the adj pushrod locknut to hit the lifter body to keep it from collapsing. There is a margin of error, but not much if you do it right.

My wipe pattern was just outboard of the center, but since I'm using longer valves, its to be expected. Longer valve moves the contact patch outboard of center, since the valve is angled toward the rocker stud.

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I could explain all this to the girl at the parts store, but she'd probably call the asylum.

'67 LeMans. 407/TH350/Ford 3.90.
Bests:
13.0@102.5 N/A
11.82@110.1 50N/42F
Then it broke. Rebuild in process.
  #14  
Old 07-31-2020, 08:01 PM
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Quote:
Originally Posted by Lee View Post
You got it correct. The Comp Cam rockers are designed differently than most other Pontiac rockers.

I recently built a motor, and had both Crower and CompCam (1.65) rockers handy. Iron heads, but HR cam/lifters. Crower rockers needed an 8.800" pushrod, Comp rockers needed 9.150".

FWIW, I think Butler is a GREAT source for parts, but not nearly as great for advice on street-oriented builds.

Sooooo, I build a combo. Want to switch from 1.5 to 1.65 rockers and there is a chance I may need different pushrods?

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Old 08-01-2020, 10:10 AM
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Quote:
Originally Posted by ponjohn View Post
Sooooo, I build a combo. Want to switch from 1.5 to 1.65 rockers and there is a chance I may need different pushrods?
If you are using the same brand/style of 1.65 rockers as the 1.5's, then you SHOULD be ok. It never hurts to measure and check, though.

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'73 T/A (clone). Low budget stock headed 455, 222/242 116lsa low-lift cam. FAST Sportsman EFI installed.

'67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T-II, full exhaust (3" w/Dr. Gas X, Xlerator mufflers).

My webpage http://lnlpd.com/home
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Old 08-01-2020, 10:45 AM
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https://www.youtube.com/watch?t=24s&...-fZyVI2ihwYBg4

If you want to check your previous work using a different method to see if it comes out close. This video helped me when I put my BBC together. I thought it was easy to follow.

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Old 08-01-2020, 01:12 PM
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Quote:
Originally Posted by chiphead View Post
Agree on any phone advise. Trust but verify. The pushrod pocket on those comp lifters looks higher up on the rocker body, like it would want a longer pushrod than say a HS or a Crower Enduro rocker.

When I checked the length on my setup, it wanted 8.850" pushrods IIRC.
H-J lifters, Voodoo HR cam, iron heads, long valves at 1.8 IH, Crower enduro rockers. I used the Straub technique.
Thanks, an interesting way to check valve geometry, seems more accurate than others.

https://www.youtube.com/watch?v=o5is9BsH5OU

(Jeremy treed me on the video)

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