Roller tip rocker adjustment?

[Lustle]

Properly centered with the minimum sweep will only happen if the fulcrum length of the rocker is correct for the shaft location, so no, centered is not the most important. You are applying a stud type design, with the correct fulcrum length and that is adjusted by varying the pushrod length, to a shaft system that is not, and rarely if ever has the correct fulcrum length.

You are correct though, that the contact us way to far from center for reliable operation.

But isn't a centered mark with minimum sweep a sign of proper geometry? That should mean that the rocker arm tip is located over the center of the valve stem through the full movement. With an equal intake/exhaust sweep. Isn't that proper geometry?

I realize I didn't mention sweep. But I figured that was understood with the centering.

 

[B3RE]

But isn't a centered mark with minimum sweep a sign of proper geometry? That should mean that the rocker arm tip is located over the center of the valve stem through the full movement. With an equal intake/exhaust sweep. Isn't that proper geometry?

I realize I didn't mention sweep. But I figured that was understood with the centering.

That's what is best, but a centered pattern does nothing for valvetrain stability. It just gives the largest amount of contact area between the roller and the valve tip. With minimal sweep, the valvetrain will be stable, even if the pattern is off center. That's why the narrow pattern is of primary importance, and the location of the pattern is secondary. If it's centered, great! If not, it isn't going to cause a problem unless it's off a good bit, or if titanium valves and/or very small stems are utilized.

 

[Lustle]

That's what is best, but a centered pattern does nothing for valvetrain stability. It just gives the largest amount of contact area between the roller and the valve tip. With minimal sweep, the valvetrain will be stable, even if the pattern is off center. That's why the narrow pattern is of primary importance, and the location of the pattern is secondary. If it's centered, great! If not, it isn't going to cause a problem unless it's off a good bit, or if titanium valves and/or very small stems are utilized.

So you're fine with a slightly off centered pattern. As long as the overall sweep pattern is less? You wouldn't want to continue to adjust the geometry until you had that smaller pattern more centered? I'm just curious.

I'm just always worried about how much deflection/movement there is between the valve and rockers and everything else under high rpm conditions. Anything off center just looks like trouble ahead to me.

 

[MOPAROFFICIAL]

And here is where this post went off the rails. Everything after this is wrong when using a roller rocker.

It's wrong in that your system can now correct the issue....but until you ame along it was mill and block and or if its not setting records...you shorten one or the other. Sorry I stepped on your prick by saying "butt load of money" in regards to your product, I think its a great product and fix....but would you say anyone with a mopar shaft mount 'no matter the level of performance' should be purchasing and utilizing it on their grocery getter with a .480 lift cam?
You could have had more tact/info in your post addressing a practical yet old hat appraoch, but I won't hold it against you.

 

[19blockhead72]

And here is where this post went off the rails. Everything after this is wrong when using a roller rocker.

 

[B3RE]

So you're fine with a slightly off centered pattern. As long as the overall sweep pattern is less? You wouldn't want to continue to adjust the geometry until you had that smaller pattern more centered? I'm just curious.

I'm just always worried about how much deflection/movement there is between the valve and rockers and everything else under high rpm conditions. Anything off center just looks like trouble ahead to me.

Like you saw in that video, things deflect. But, the side loading causes the deflection more than anything. When the minimum sweep is realized, that bending sideways of the valve stem is also minimized. Where the downward and sideways forces are applied isn't of much consequence, with the previously stated exceptions, of course.

But, you have to ale sure you have the absolute minimum sweep. That is going to depend on the rocker used, and the net valve lift. Consider that a small block, using a popular roller rocker, and .750" net lift, will only have .050" sweep when properly set up. Puts the whole .550" lift with a centered .100" sweep thing into a new perspective.

 

[SSG_Karg]

Valves sunk? What size valves and how many valve jobs have been done?

 

[B3RE]

It's wrong in that your system can now correct the issue....but until you ame along it was mill and block and or if its not setting records...you shorten one or the other. Sorry I stepped on your prick by saying "butt load of money" in regards to your product, I think its a great product and fix....but would you say anyone with a mopar shaft mount 'no matter the level of performance' should be purchasing and utilizing it on their grocery getter with a .480 lift cam?
You could have had more tact/info in your post addressing a practical yet old hat appraoch, but I won't hold it against you.

Pardon me for my lack of tact. My response was not out of anger. I just pointed out incorrect information. The old hat way you speak of was to center the pattern on a non roller type factory rocker, and guys continue to apply that to rollers. You can't mill the stand down .080" and expect to improve valvetrain stability with a roller rocker. It just ain't happening. Another point you are missing, is that with a stick rocker, the higher the valve lift, the further off the geometry became. But, with a roller rocker, it is exactly the opposite. Low net lifts need more correction than higher lifts, so if someone isn't willing to correct it, my only recommendation is to put stock rockers back on the motor. I've told plenty of people that over the years.

Btw, I wasn't considering your buttload comment when I replied. It is what it is. When you know what your looking at, and it can't possibly be right without it, the cost becomes relative to how right you want your motor to be. That being said, spending extra money for "good" rocker arms that need just as much, or more correction than a cheaper adequate alternative is where the real money is wasted in my book.

 

[MOPAROFFICIAL]

Pardon me for my lack of tact. My response was not out of anger. I just pointed out incorrect information. The old hat way you speak of was to center the pattern on a non roller type factory rocker, and guys continue to apply that to rollers. You can't mill the stand down .080" and expect to improve valvetrain stability with a roller rocker. It just ain't happening. Another point you are missing, is that with a stick rocker, the higher the valve lift, the further off the geometry became. But, with a roller rocker, it is exactly the opposite. Low net lifts need more correction than higher lifts, so if someone isn't willing to correct it, my only recommendation is to put stock rockers back on the motor. I've told plenty of people that over the years.

Btw, I wasn't considering your buttload comment when I replied. It is what it is. When you know what your looking at, and it can't possibly be right without it, the cost becomes relative to how right you want your motor to be. That being said, spending extra money for "good" rocker arms that need just as much, or more correction than a cheaper adequate alternative is where the real money is wasted in my book.

Ok cool, just making sure... ;)
Ah ...well I'm not missing anything, I get it...though I have never had a roller tip sweep of .100 , that's with ridiculous lifts or more so exaggerating to make the point.
yes I understand the importance of translating the lobe profile and longevity of stem/guide/seat...I like your product, I just don't see this as a whole being a good path.

The machinist is getting a pass by all on this ,it seems. Are all the valves even at or near the same height +/- .020 ?
The old used cycled out mp rockers...I'd set them aside. Used I don't see them to be very "good" or expensive to the op at this point ...till you ad more **** to make it work.
with such a tiny cam...
Op...How much will those used old rollers really cost you after all the **** to set them up? and to end up with piss for lift....
Your money, time and life lesson...enjoy.

 

[Cudafever]

Here's a hot rod article that gets into it a little more.

Rocker Arm & Valve Train Geometry - Circle Track Magazine

Thanks for the link!!!

 

[yellow rose]

Who did the heads and where is the stem height set at? Around 1.917-37 off the top of my head is where it should be, taller the worse off when stuck with as cast stands...
Basically the taller the valve gets and or rocker shaft gets...the closer the two are to eachother. You can A. Cut the stem height down, B. Lower the rocker shaft by means of machining the stands about .080...Or C. Buy different rockers because sometimes they put the ratio on the wrong side of good and it hangs off the valve....Or D. Spend another butt load on B3 rocker shaft kit.
I call this skinning of the cat, meow now...

If the stems are too long, you damn sure don't lower the shafts. You raise them and move them away from the valve.

Also, it doesn't matter if it's .480 lift, the roller tip is enough to require geometry to be corrected. And yes, I've run cams with about that lift and had to mill the stands and use blocks to get everything correct until B3 came along.

The B3 kit is DIRT CHEAP for what you get.

Once again, for the record, I don't get his product for free, or even at a discount. I'm not hyping his stuff for any other reason than the simple fact his stuff WORKS, is COST EFFECTIVE and does EXACTLY what he says it does. The sad fact is, Chrysler guys have been geometry ignorant since before I came along, and to save pennies they cut corners, have issues or worse yet, don't even get they have issues.


It's 2017 now. Chrysler guys need to catch up. I'm glad the OP is working on his stuff and getting it figured out.

 

[19blockhead72]

So it turns out the rockers are intended for us with w2 heads. The seller is going to take them back and I'll try again. Thanks for all the help.

 

[B3RE]

Thanks for the link!!!

That is a good link. I only wish he had gotten into the accelerations, decelerations, and harmonics that get out of whack when the geometry is not correct. A loss of lift, i.e. inefficiency, doesn't break parts, but the harmonics and instability from incorrect geometry certainly will.

 

[nm9stheham]

Being centered, and the width of the patch, are two independent geometrical issues; narrow (good) or wide (not so good) contact patches can occur with the patch centered or not.

The width of the patch is related to the total angle though which the rocker tip sweeps relative to the centerline angle of the valve stem. (The rocker's part of that angle is from the centerline of the rocker shaft to the contact point of the roller to the valve tip....ooops, to the center of the roller axle.) If the geometry is such that this angle is exactly 90 degrees as the rocker passes through the center of lift, then that is the optimum geometry for that lift. The higher lift, the wider the patch will be, even when optimized, unless you make the rocker arms longer. This geometry can be messed up with valve tip height or rocker design. (Wish I was where I could draw something up and post it for illustration.)

If the above is off, then the patch will also coincidentially move off center, but the patch will move towards the inside, not towards the outside (shaft system). And the Lunati linked article does not apply here unless you can move the shaft DOWN (mill the stands) or lengthen the valves; this Lunati article applies to stud rockers where the adjustments DO move the rocker fulcrum vertically.

Interesting video clip but you can't make conclusions in roller tip centering from that. The internal vibrations in the springs are internal resonances in the spring and valve mass. The rollers being on or off center have nothing to do with those motions or vibrations.

 

[B3RE]

Ok cool, just making sure... ;)
Ah ...well I'm not missing anything, I get it...though I have never had a roller tip sweep of .100 , that's with ridiculous lifts or more so exaggerating to make the point.

Well, maybe you haven't, but it's no exaggeration. I've seen .130"-.140" with lifts in the .500s. The valve stem heights are critical on a single shaft system, but only between intake and exhaust, and they won't always be the same. I couldn't care less how long the stem protrusion is, because I'm going to put the rocker where it needs to be, provided it will fit in the space I have available. Sometimes, a longer valve is the only way to get the needed installed height, which really throws off the geometry. Quite the opposite of what HS says on their website.

Like I said before, if the motor is worth installing roller rockers, even in mild applications, it should be worth installing them properly. Otherwise, I agree, don't waste your time......use the stockers.

 

[B3RE]

The width of the patch is related to the total angle though which the rocker tip sweeps relative to the centerline angle of the valve stem. (The rocker's part of that angle is from the centerline of the rocker shaft to the contact point of the roller to the valve tip.)

C/L of the shaft to the C/L of the roller axle. The contact point is used for non roller rockers.

 

[nm9stheham]

So everybody humor me here: What bad thing can come from the roller being this far off of the top center in this set up? What unreliablity can occur? I keep reading that there are issues being perceived with this, but I can't see it. And forget the patch width for the moment; let's assume that we can adjust the shaft position for minimum patch width.

Please, no answers of 'just because'. Think of where/how the forces are being applied and how things react to that.

Edit to add: And B3RE provided one answer, when he points out that certain light valves and thin valve stems will be more effected. The contact patch gets smaller, and the contact forces increase. But in the OP's pix, I can't see the contact patch being smaller than about 15% or maybe 20-25% at the worst. So the contact forces are not all that much higher, and if the springs are typical 1st level hod rod springs with <300 lbs seat pressure at the full .480" lift opening, I would not expect the mildly increase contact forces doing anything bad at all.

 

[nm9stheham]

C/L of the shaft to the C/L of the roller axle. The contact point is used for non roller rockers.

I think we went through this before.... LOL ... I am sure you are right. Thanks.

 

[B3RE]

I think we went through this before.... LOL ... I am sure you are right. Thanks.

No worries! I just don't anyone to get confused.

 

[nm9stheham]

No worries! I just don't anyone to get confused.

Agreed.... it's to everyone's benefit to get past a lot of misconceptions on this matter.

 

[MOPAROFFICIAL]

With it that far out toward the exh, he could gain some lift, off the top of my head..

Everyone remember the early days of trying to run .660 solid roller and not finding a spring that would work at any installed height near the working relm of a mopar rocker arm...? If you get B3's kit, it won't matter where the stem height is 'just make them all the same' the kit allows adjustment of shaft to compensate.
And for the guys running roller rockers with under .600 lift who are lite in the wallets... the stem height range is 1.907-1.937 with with 1.917 being the sweet spot for a Comp,Harland wide body aluminum rocker, sweep for mine was like maybe .030 w/.575 lift. Fwiw

 

[19blockhead72]

Lots of good info. Learning alot from this experience but I think to save money and time I may just go with some 273 adjustables. The engines been running and don't really want to dead line it any further.

 

[Cudafever]

so what makes the geometry set up different from a rocker arm that slides on a valve to one that has a roller tip.?
I realize that the roller cause the rocker are to set higher on the valve.......but you could have slide rocker arm that had higher valve install height, and then the playing ground would be equal right? or what am i missing.

 

[19blockhead72]

Well from what I know standard rocker will have more contact area on top of the valve so not as big of a deal as roller tip that would have to be more precise because of the small amount of contact. That's my thinking but there are much bigger brains on here than mine so maybe there's more to it.

 

[yellow rose]

Well from what I know standard rocker will have more contact area on top of the valve so not as big of a deal as roller tip that would have to be more precise because of the small amount of contact. That's my thinking but there are much bigger brains on here than mine so maybe there's more to it.

If you actually have W-2 rockers then half of the rockers should have the adjuster offset. Is that what you have?