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Discussion Starter · #61 ·
do u also have to take into account the lifter will prob collapse a little under the spring pressure when its not a running engine ?
Since I'm rolling it around, I think so. I should pull that set out and throw them back in the peanut butter oil tub. I think for checking this, it was as good as it needed to be.
 

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Pushrod length is not going to have any effect on the sweep pattern on any rocker arm that is solidly bolted to the head. It mattered on old small and big block chevy's when pivot point height of the rocker was adjustable (like in the straub video), but not on anything where the rocker bolts solidly to the head. The pushrod length effects how far the adjuster is out of the rocker body, which you want to minimize.

I'm not there to look at your rocker in person, but I doubt you are going to be able to center that sweep pattern on the valve by only moving the rocker base up or down .050". That little movement with have minimal effect on the location of the sweep. I did 20+ Yates sbf jesel rocker setups at a previous performance shop I worked and I've tried lots of different stuff. You can't always get it centered with shaft mounts.

Sometimes you just have to make the best of what you have. As long as the valve starts and stops about the same line and mid lift is the farthest outside of your pattern, that's as good as you are going to get.
Then I thought I'd get all smart and turned the adjustment screws in 4 turns instead of the recommended 1-1.5, making it a shorter pushrod. I don't think it helped. If anything, it looks like a wider path.

Intake
View attachment 153133

Exhaust
View attachment 153134

I think I need to shave the pedestals down the .059" difference the checking tools showed. I'll wait to see what Crower comes up with. He said the previous pictures I posted were very good, so maybe I'll send him all these sweep pattern pictures and see what they say.

@Rubber Duck I think you forgot to post the video link in your last post, and THANK YOU for lending your brain on this.
Below is the video I forgot to post last night.

This video is always the one that I send to people setting up
a shaft system after I have them go through the video that
Foxwell made. After you watch the video by Foxwell one
should fully understand what one is attempting to achieve,
albeit using different techniques.


While the shaft system does not rely on the length of the
pushrod for proper 'Mid-Lift Geometry', I tend to continue
to monitor the 'Witness Mark' left where the rocker arm first
strikes the valve stem. Strike marks 'can' be changed when
changing push rod length. Once you begin to recognize
the above, it can help to lead one in the correct direction.

So in my opinion, pushrod lengths 'can' still be
important in a shaft mounted system.

Here with the OP, we are 'first' attempting to gather info
for Don @ Crower, and hopefully this can all be completed
with only one more phone call.

My feelings are; the stands are going to have to be
worked on in order to get the sweep pattern closer
to the center of the valve stem.

I personally believe that is where the
contact pattern belongs (JMHO)!

If that is what needs to be done, then I
believe Don should make that decision.

But for Don to make that decision, the OP will need
to provide him with all the info he requires in order
to make that decision.

Having the OP go through all of the operations I have
been putting him through, was to help him learn, as
well as collect sufficient data for Don.
 

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Discussion Starter · #63 ·
It ALMOST seems like if I could have bolted the pedestals where they sat BEFORE we had to open up the reliefs for the valve cover bolts, it would be almost perfect. Those contact marks with it shimmed the .045" they want was VERY small.
 

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It ALMOST seems like if I could have bolted the pedestals where they sat BEFORE we had to open up the reliefs for the valve cover bolts, it would be almost perfect. Those contact marks with it shimmed the .045" they want was VERY small.
The desired thickness of the contact / witness mark is highly debated.
What is not generally debated, is the requirement of geometry at Mid-Lift.

I personally don't feel that one requires a sweep mark that is thin.

But I do believe the correct geometry will deliver a sweep
that begins in the middle of the valve stem, and then returns
to the middle of the valve stem. . .Again, just my opinion.

Have you checked for proper mid-lift geometry again since you changed the shims?
I would think having that info when you speak to Don would be of great help. . . ..
 

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Discussion Starter · #65 ·
I don't know how I missed this last post.

The only midlift I checked was shimming it the midlift amount, which was the one picture that it was almost off the valve tip, which also must not have worked correctly, because I don't think when I rolled it around, the marks show different. I'm 1200 miles away from home until Wednesday I think, so no checking stuff for a while.
 

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I don't know how I missed this last post.

The only midlift I checked was shimming it the midlift amount, which was the one picture that it was almost off the valve tip, which also must not have worked correctly, because I don't think when I rolled it around, the marks show different. I'm 1200 miles away from home until Wednesday I think, so no checking stuff for a while.
For whatever it is worth, I would wait to call Don until you provide
him with your last couple of pictures you took, after removing the
shims and also the one where you shortening the pushrod.

I would also include a new Mid-Lift picture, one which would
correlate to those last couple of pictures I spoke of just above.

Don is the production manager for Crower and he is very sharp.
Being he is the production manager, he really understands the product.

He can look at various rocker arm sweeps, and calculate the
solution regarding incorrect geometric angles in his head.

But he is also very, very busy..lol

Take care!
Bruce
 

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Discussion Starter · #68 ·
2 weeks worth of waiting and Crower said "try" taking .040" off the bottom of the pedestal to get the mock up tools to where the instructions say to get them.

I just dropped one off to get taken care of. I hope I can finally put this to bed, and get pushrods ordered. 😡
 

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2 weeks worth of waiting and Crower said "try" taking .040" off the bottom of the pedestal to get the mock up tools to where the instructions say to get them.

I just dropped one off to get taken care of. I hope I can finally put this to bed, and get pushrods ordered. 😡
Most likely that is going to have a big impact on your geometry.

If that doesn't do it, then you might have to additionally
modify the pedestals in another manner. . . .Just a Guess!

When your working with a cylinder head, along with a gross valve
lift that works best around 0.550" to 0.600" of lift, you don't want to
give up much when it comes to rocker arm geometry as well as
valve train flex.

In the end though, it will be worth it..:)

----------------------------------------------------------------

Just a comment for whatever it is worth.
Go to the best pushrod you can buy!

Your using an 1:8 rocker arm ratio.

On the valve side, if you have 300 psi of open pressure <= (just as an example)
it is not problem. But on the pushrod side, you multiply the
300 psi by 1.8 and the result is the pushrod is seeing 540 psi.

Heavy pushrods do not generate the same problem that
heavy valves generate. But pushrods that flex generate
problems equal to, or can even exceed the issues that
heavy valves generate.

In either case, you lose control of the valve motion
which has been engineered into your camshaft. . . .

The better pushrods have an outside taper, as well as an inside taper.
Some have multiple tapers. . . . .

These tapers not only help to strengthen the pushrod,
but also helps to control the natural frequencies, also
called resonances of the pushrod.

Cheers
 

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For those following this thread, but who also might still have questions, here is
some info from a rather technical article I have in my archives which might help.

I have only cut and pasted the pertinent data from this very in depth article,
which I feel is relevant to how this thread has moved along via the posting
from members to this thread.

I have both underlined and made bold some of the more relevant info
regarding this thread, in an attempt to bring an understanding to
this complex subject.

Enjoy.. :)

----------------------------------------------------------------------------------------

How Rocker Arms Work
Rocker arms are actually nothing but center pivot levers. They share the same physical behavior as other fulcrum type levers, including playground teeter-totters and pry bars.

The length ratios from where forces are applied on both sides of the fulcrum point determine the ratio of distance movement and ratio of pressures. Like many other things, the force comes down to a constant inch-pound ratio. If we alter the lever ratios to increase movement distance (or "inches"), we decrease the available force ("pounds") on that side. The opposite is also true.

Let's assume we have a simple lever:

Rocker arm lever




The simple drawing above assumes near zero distance movement compared to lever length. As the lever moves up and down, each end swings in an arc. If we moved the end far enough, it would actually rotate in a circle.

We see the basic functions of a lever above. We trade distance for force by the ratio of side lengths. The 1.6 length side moves the furthest, but has the least pressure. The 1 side moves the least, but has the most pressure. It doesn't matter what the units are, only ratio between the two lengths matter. Let's say the 1.6 is 2" and the 1 is 1.25". We still have 2/1.25 = 1.6 or 1.6 to 1 for the ratio. The sides can be any length or angle that works to align things so long as they are in the proper length ratios from contact point to the fulcrum.

At minimum,. the rocker shaft has the sum of tip pressure plus pushrod pressure. If the spring is 400 pounds and the ratio 1.6:1 (ignoring inertial and friction) the pushrod has 1.6*400 = 640lbs. The fulcrum or shaft has 640 + 400 = 1040 lbs. pulling it out of the head with perfect geometry. Of course friction and inertia add to this, inertial forces determined by acceleration of the masses in the system at both ends, with the largest effect from weight at the valve. Mass has the least effect in the area of the rocker shaft.

These forces are increased by geometry errors.

With a central pivot or support the length ratio between the two sides, where they are being pushed on or pulled on:

1.) The ratio determines the ratio of distance each side travels. The longer side moves further in proportion to the rocker ratio. The travel distances are in proportion to rocker ratio if contact motion is 90-degrees to the effective arm angle on each side

2.) The ratio determines the pressure or force. The shorter side has the most force in close proportion to the ratio if the force is applied 90-degrees to the effective lever angle.

3.) Minimum wear and stress and maximum motion occurs when things are either at 90-degree angles or straight, but we can't always do that perfectly.

From this we can conclude if we use a properly constructed and installed 1.6 rocker arm, the maximum possible distance the valve can move is 1.6 times cam lift. The force on the cam and push rod is always more than 1.6 times the force required to move the valve, and that force is minimum when the push rod is at a 90-degree angle to the short side line. For best valve control and minimum wear and tear the push rod and valve should be 90-degrees from the effective lever angle on their respective sides of the fulcrum.

Rocker ends move in a circular arc. Any point on either end swings through a small portion of a circle, that circle being centered on the rocker's pivot point. The pivot point does not have to be what we physically see as the center of the body. The pivot point is the center of the shaft in any rocker with a shaft, either stud or shaft style rockers.

On a cup type pivot, the pivot point is the center of circular arc of the pivot.

Crower Rocker




The straight white line at the roller tip is the 90-degree alignment angle where forces in the entire system are minimum. The straight black line is the angle where wear and bending force on the push rod is minimum. The lines would respectively each be aligned with the valve and pushrod at half lift.

If we draw two circles, one with the radius of the valve tip contact point and the other with the push rod contact point centered on the fulcrum point, the radius (or diameter) ratios would be the true rocker arm ratio. We see this as:

Rocker arm arc


We can see the rocker arm tips and contact points have to follow each circle's radius, and how this forms an arc. The center of the circle is the same point as the center of the shaft in a shaft or needle bearing center stud mount rocker system. The circle's centers are ABOVE the pivot point in a standard OEM cup pivot stamped arm.

-------------------------------------------------------------------------------------------

Changing the height relationship between the fulcrum and valve tip changes the position of the contact and the width of the pattern on the valve tip. The ideal pattern sweeps outward from minimum lift, reaches peak outward distance at half lift, pulling back in toward the pushrod and fulcrum at both maximum and minimum lift_______"The ideal pattern centers on the valve tip."

If acceptable pattern width is not found with proper centering on the valve, the pivot point has to be moved laterally toward or away from the valve while maintaining ideal pattern. Lowering or raising the pivot or shaft height to center the pattern is only correct if the pattern width is acceptable.

Raising or lowering the stand away from narrowest sweep always moves the pattern toward the pivot point, but it also decreases lift and duration, and increases wear.


Improper geometry harms valve control, requiring higher spring pressures or lighter weight components to achieve the same RPM before loss of valve control or valve float.

-----------------------------------------------------------------------------------------------

Maximum safe RPM for given weights and springs and minimum wear occurs in the green area of sweep. This is also the narrowest sweep



Rocker height changes position
 

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Discussion Starter · #72 ·
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So here we are with .040" off the pedestal. The one with HALF the marker worn off is kinda nerve-racking. I'm tired of dinking around with this. This is where it will stay. I need to take the other pedestal in on Monday to get milled down, and then I'll measure the rest of the lengths.

At least the Summit tall valve covers clear the rocker arms. THAT was my next point of frustration I figured. There is a small sheet metal baffle inside and nothing hit on intake or exhaust when I checked #6.
 

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View attachment 153470 View attachment 153471 View attachment 153472 View attachment 153473 View attachment 153474 View attachment 153475

So here we are with .040" off the pedestal. The one with HALF the marker worn off is kinda nerve-racking. I'm tired of dinking around with this. This is where it will stay. I need to take the other pedestal in on Monday to get milled down, and then I'll measure the rest of the lengths.

At least the Summit tall valve covers clear the rocker arms. THAT was my next point of frustration I figured. There is a small sheet metal baffle inside and nothing hit on intake or exhaust when I checked #6.
Have you looked at mid lift geometry again?
 

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Discussion Starter · #74 ·
Nope. Crower hasn't really been helpful at all on this, except for saying he would give me a smokin deal on a new pedestal if it got worse after milling. That being said, he didn't offer any suggestions for changing ANY thing here. He said I habe the shortest arms available, and that Mast heads were hard to get right, and these are knockoffs on top of that. SO, even if the midlift isn't good, they aren't going to have any suggestions to actually make it better.
 

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Nope. Crower hasn't really been helpful at all on this, except for saying he would give me a smokin deal on a new pedestal if it got worse after milling. That being said, he didn't offer any suggestions for changing ANY thing here. He said I habe the shortest arms available, and that Mast heads were hard to get right, and these are knockoffs on top of that. SO, even if the midlift isn't good, they aren't going to have any suggestions to actually make it better.
Regarding the comment above. . .There is still more that can
be done regarding sweep patterns versus mid-lift requirements. . . .

--------------------------------------------------------------------------

-these are quotes from Don-
After you get you your stand height right, you can mark your valve and check your wear pattern. If you think that it can stand to move one way or another, you can always notch the stand mounting holes slightly and slide the stand over to get the roller in the center of the valve. Since you aren’t changing the height of anything, your geometry is still correct.”

One final step that Flanagan says they get a lot of calls on, is the centering of the roller tip on the valve. This is achieved not through the altering of the height of the stand, which would throw the geometry off, but rather by setting the height and then slotting the mounting holes of the stands, if need be.

I eluded to this in several of my posts above.
But I also thought that it should be Don who determined if this should be done, not me..lol

-----------------------------------------------------------------------------------

The work you have been doing has made things much better.
If it were me, I would now once again look at the mid-lift geometry.

I am a bit concerned about the wipe pattern on a couple of the
valves that appear to be wiping on a somewhat 'Canted' Angle'.

But sometimes simply making sure things are rigid and torqued
correctly before whacking the valve with a rubber hammer, before
turning / rotating that cylinder over a couple of times will clear that up.

If not, then I would check to be sure that the pedestals have
been milled perpendicular / are square / and at the correct angle.

You could check that easily by exchanging one of them with
another stand where the wipe / sweep pattern is correct.

I would go to two or three of the cylinders that shows the best
sweep pattern now, and check the mid-lift geometry on those
cylinders once again.

--------------------------------------------------------------------------------------

Your getting close here with the sweep / wipe pattern, and many
would consider it fine. But now you need to verify the mid-lift geometry,
as the mid-lift geometry is more important than is the width of the
sweep pattern.


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Discussion Starter · #76 ·
Yeah, all DJ has said is "You're not THAT far off". 2 weeks ago after the first go around with checking the patterns he said give him a day to talk with the rocker arm guys, then it was wait until Monday. Then it was wait a couple more days and email the other pictures. Then it was I will email them to the rocker arm guys and cc you on the email (which didn't happen) and then I waited all this week for the call back until I called Friday afternoon. It seems he's just waiting for me to get tired of getting blown off, which I think is where I am now.
 

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Yeah, all DJ has said is "You're not THAT far off". 2 weeks ago after the first go around with checking the patterns he said give him a day to talk with the rocker arm guys, then it was wait until Monday. Then it was wait a couple more days and email the other pictures. Then it was I will email them to the rocker arm guys and cc you on the email (which didn't happen) and then I waited all this week for the call back until I called Friday afternoon. It seems he's just waiting for me to get tired of getting blown off, which I think is where I am now.
You might not be far off, but you won't know until you find out
how accurate your mid-lift geometry is.

Originally, the rocker arm sweep pattern was about to fall
off of the end of valve stem. And as I recall your mid-lift was
'Also' not correct. . .Right!

On your best sweeps now, you are about in the center of the valve.
So mid-lift now needs to be checked once again.

Your prime priorities are:
A proper mid-lift geometry,
along with the sweep pattern in the center of the valve.

If you end up with proper mid-lift geometry now, but
the sweep pattern is not in the center of the valve, then
you might consider slotting the stands, allowing you
to move the rocker arm towards the center of the
valve stem.

Your sweep pattern has been improved now.

However, since we understand that mid-lift needs to be correct, then
why don't you check it again, and then see where you are now. . .

Cheers,
Bruce
 
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Discussion Starter · #78 ·
I can't get my dial indicator base to the rocker arm with it magneted to the block. I'll look for something hopefully close on Monday.
 

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I can't get my dial indicator base to the rocker arm with it magneted to the block. I'll look for something hopefully close on Monday.
Shaft rocker arms setups usually take a bit of time to install them correctly.
One or two more steps and you'll have it..;)

Thought I would attach this simply because the use of a laser is somewhat novel.

However, he also goes through setting up some Yella Terra rocker arms, which many on this forum use.

While your out tomorrow, you might want to purchase a laser..lol
Actually, it looks like a giant pain in the ass to me. . . . .

Generally when I see a video I might desire to watch, I always read the comments below first.

Here is an interesting comment as this guy seems to get it!
Mike Curtis
3 months ago
Great information. I've always used dykem and a square. Thanks 😊!!

And below I have posted a picture I captured from this video where
he uses both the square and a laser.

Product Gesture Font Screenshot Line


Cheers,
Bruce
 

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Discussion Starter · #80 ·
I was going to go grab a couple of those lasers tomorrow, but they aren't going to work with an LS, I don't think.
 
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