[scott foxwell]

Looks like you have +.05 locks. Are these longer valves than came with the heads?
You don't need any where near a triple spring but that's another subject.
How are you setting up the stand height? Stand height dictates rocker geometry and rocker geometry is all that matters. It looks to me like you need more shim...more stand height but that may not be the case. Use the tool and follow the instructions to the T. Don't "guess". Do NOT use lash caps to correct a geometry issue.

 

[scott foxwell]

Cam specs are 286/300 @ .050”, .836”/.816”. Pretty sure I need a triple spring for that.
To use lash caps I would have to change the locks (which isn’t a big issue) but I will most likely need a new set of stands from T&D, or at least some longer bolts, since I’m using a thin (.040”) and thick (.080”) shim under the intake stand as is.

With .836" on intake you can find several choices of dual, smaller dia. springs that will set up with less installed height. That will solve your problem. If you have a stack of shims under the springs, you should be able to get rid of them and the +.05 locks.

 

[scott foxwell]

Wow, what diameter spring is that? I have no intention of turning my motor more than 7500.

PAC has quite a few 1.50" duals with those specs. Certainly nothing you need.
If you go to a smaller dia. spring you'll need new retainers.
Do you have a spring p/n for what's on the heads? It would be good to find a more reasonable spring that fits your retainer. The PAC 1324 is a 1.625 spring that is good for .850" and will install @ 2.00". If you don't mind buying new retainers, you have lots of options in the 1.50-1.55 dia range.

 

[scott foxwell]

The springs I have now are Comp #948: 1.645 diameter, 686 pounds per inch spring rate. They’re good for .910’ lift @ 2.1” installed height, so I’m thinking if I reduce the installed height to 2.05, by changing the locks to standard height, I should still be able to use the springs and retainers I have now and that should give me sufficient additional clearance between the retainer and the rocker, no?

What do you think the minimum clearance between the rocker body and the retainer should be?

I wouldn’t mind changing the springs, but these are brand new ones I just bought a few months ago, and I would need to change out retainers as well.

Personally I don't think you need near that much spring pressure. I would take the inner spring out and see what you have at your minim installed height. You'll need a spring scale to do that. Don't rely on advertised coil bind. Put one of your springs in a vise with the retainer and squish it till it coil binds, then measure it. I agree with Saviour68 on how to go about it. Find your actual c/b, add .05" for clearance, then add your net lift (gross lift - lash) and that would be your minimum installed height. IMO if you have 280 seat and at least 800 open, you should be good to go. You should be running no less than a 7/16 x .165 pushrod. Straight wall on the ex, single taper on the intake. Minimum between the rocker...would like to see .06" but I think once you get this all sorted out you'll have plenty.
Don't take this the wrong way but running the wrong spring just because they're new isn't a very good reason.

 

[scott foxwell]

Thanks again for all the advice. It is greatly appreciated.
I don’t actually have a lot of faith in comp springs, although I previously ran a set of these 948s in my old 565 without any issues.
I was thinking I needed this stiff of a spring due to running stainless valves?
I don’t have a problem changing the springs out, and would much prefer to run the right spring, and from what I read, PAC and PSI makes better springs?
I’m certain I can get .06” clearance just by changing the locks to standard height, but now I’m thinking I need to change the springs and installed height to optimize coil bind as well?
Thanks for the advice on pushrods. Believe or not, my previous setup was running these springs with .080” wall 3/8 diameter pushrods. I was planning to run 7/16 .165“ wall tapered P/Rs on the exhaust and at least a .135” 3/8” dia on the intake. But it looks like I need less spring and more pushrod?
Thanks again for the advice.

I've done several engines with big stainless valves and the pressures I quoted above, running in the mid to upper 7K range with no issues. Your 2.35 intake won't be a problem at that rpm. PAC and PSI are about the only springs I use these days. Comp gets their springs from several different suppliers. I wouldn't think their big triple is a bad spring so If you can get what you need out of it, I'd run it for now. If and when they give up the ghost, cross that bridge then. I would get an on-the-head spring checker so you can keep track of your pressures. Get a baseline when they're new and monitor any changes.
Pushrods are way important and way overlooked. The bigger the better. It's common where more spring pressure is added to try and control a problem caused by too-small of a pushrod so yes, bigger pushrods can lead to less spring pressure. You don't want the pushrod to be a secondary spring in the system.

 

[scott foxwell]

Okay. Thanks. So, you’re saying I should shim the exhaust spring a bit more to keep the spring gap at max lift as close to .050-.060” as possible, correct?
I’m planning to order some more shims as well, so that I can get the installed height correct.

Anywhere between .05 and >.100 off c/b is going to be fine. Your actual coil bind within that set is going to vary anywhere from .010-.020 so fighting for .010-.020" of c/b is really a waste of time. Just keep it under .100 and anything under .05 you're going to want to measure every spring. That's not necessary.

 

[scott foxwell]

Thanks, I will follow your advice on that. I’m thinking I’ll shoot for 2.02 on the intake and 2.015 on the exhaust, or as close as I can get to that.
I’ve ordered the new retainers and some extra shims, although I have a bunch already. I’ve also ordered a spring rate measuring tool, so that I can see what the difference is without the inner spring.
I’m hoping to have that stuff by Wednesday and then I can start setting it up to see if these springs can work or if I need some other springs.
I also pulled all the springs off one head today and I put one in the vise and measured coil bind and it was right at 1.09” so you’re right about C/B not being as stated by comp (1.13”).

Did you check the coil bind in the vise with a retainer installed?
Some spring companies show a c/b with a safety margin factored in. That's why I always measure.

 

[scott foxwell]

No sir, I took the retainer off and put the spring by itself in the vise and clamped it until there wasn’t any space left between the coils.

Kinda thought so, You have to use the retainer. That inner step compresses the inner spring another .100".

 

[scott foxwell]

Wow. This thread sure changed directions.
Getting 90* geometry with shaft rockers is a challenge for sure, especially when they only give you either a .04 or .08 shim to work with...but that should also tell you something.
I haven't read the entire thread so forgive me if this is repeating something already said.
Rocker geometry is all about the relationship between the center of the rocker pivot (trunnion) and the valve tip and how much lift you have.
1) You NEVER use lash caps to correct geometry. That's not what they're for. At a minimum, you're just adding weight to your valve. Worst case, a hardened lash cap on a hardened valve tip is asking for a failure. Fix the problem right.
2) My rule of thumb for wear pattern location; if you're confident that your geometry is right and the pattern is in the center third of the valve tip, IMO you're golden. If not, you need to make some adjustments but don't compromise the geometry. if you feel you need to move the pattern front or back but your geometry is right, then order the rocker stands with the shaft moved one way or the other. Don't raise or lower the stand to change the location of the pattern unless the geometry requires it.

If you really want to get shaft rocker geometry spot on, you have to measure the sweep and adjust stand height till you get the least amount of sweep/narrowest pattern. This isn't easy. The little tool will work very well if you can use it precisely but that's almost impossible to do by yourself. If you can accurately measure from the top of the rocker shaft to the top of the valve, you can do some math and calculate what that dimension should be. For me, the easiest way is like I show in the pic below. I made a retainer that holds a dial indicator and reads the actual roller sweep on the valve tip. I use that in conjunction with measuring the lift to set my shaft rocker geometry. Using the method below, I set the sweep indicator at zero at zero lift. As I open the valve I watch the sweep indicator and it should reach max sweep at mid lift and then start back toward zero sweep asthe valve continues to open. At max lift the sweep indicator should go back to zero. That would be perfect 90* geometry...but it seldom happens. Depending on all the parts, a .04 shim will usually give me about a .010" difference in the sweep. If the sweep comes up short of zero at max lift, you add shim. If it goes past zero , you have to lower the stand. If I get the sweep to return within .005 of zero, I'm happy. At that point, you're picking pepper out of fly shit.
Once you get your geometry right, then you look at your sweep pattern. Again, IMO if it's in the center third of the valve tip, leave it alone. If not, then you either have to move it back or forward, but that shouldn't change the geometry. FYI, with ~.800"lift, I usually get right around .05 sweep on a BB Chev. One more FYI...Jesel does not build their rockers based on 90* geometry. You can't set a Jesel rocker like this. Reason being, the pushrod side geometry will be a mess. LOL...did I say pushrod side geometry?

I drew this years ago and it's been used all over the internet...gives you an idea of what you're shooting for;

 

[scott foxwell]

Re: Thread sealant for stand bolts, since the 4 intake stand bolt holes are open into the intake ports in my heads and since I wanted some kind of thread locking compound on the stand bolts, this is what I’m going to use:

Permatex® Seal & Lock Thread Compound, 35 ML – Permatex

www.permatex.com

Seals like their Teflon thread sealant, with the strength of their blue thread lock.

Found it at a local automotive store yesterday. Didn’t know it even existed.

For thread sealant, look up a product called Gasolia. The white teflon paste will also work fine. You don't need thread locker on rocker stand bolts, They get torqued to 45-50#. I use anti seize on the ex stand bolts.

 

[scott foxwell]

Yes, thanks very much for taking the time to explain in detail how it’s done. Very grateful for that.
I think your diagram confirms the Manton instructions as well, which dictate that roller tip starts on the “inboard side” (closer to rocker fulcrum) of the valve stem and as the valve opens, it moves outwards away from the fulcrum so that by mid-lift, it’s an equal distance across the center on the “outboard side” of the stem, then rolls back to where it started.
It’s very useful to know what the width of the sweep should be (0.050”) so many thanks for that.
The only reason I‘m considering lash caps on the exhaust valves is because I couldn’t get the exhaust stand low enough to meet the T&D instructions, which call for my exh rocker shaft to be .033” lower (.816“ lift) than the tip of the tool. So I added the lash caps to lengthen the valve and then shimmed the rocker stand to try to hit that number, and I can get real close to it (~0.035”) doing that.
But the strange thing is that I can’t see a better pattern doing that anyhow, although the lash cap is harder to read. But I’ve looked at this damn thing now until I’m cross-eyed, so I’m going to put it together with the recessed locks on the exhaust - so that I can use lash caps if I “need” to - but will use a test spring and roll the motor over until I can get a reading on the valve stem and see what that gives me.
Because at the end of the day, it’s where the roller meets the valve stem, and how much it moves across it that matters.
Thanks again for all the help.

Wait…”pushrod geometry“ you say??? JK, I’m confused enough as it is now, lol.

All sounds like reasonable compromises and lets face it...an engine is nothing but a series of compromises. I would mill the stands myself and not use the lash cap.
Pushrod side geometry...yes...the pushrod side of the rocker needs to have the same geometry as the valve side to be "right". The imaginary c/l of the rocker on the pushrod side needs to be 90* to pushrod at mid lift. See if this makes any sense;

 

[scott foxwell]

This drawing makes perfect sense to me, makes it easy to understand what you are trying to achieve.
Scott, with the rocker adjuster being 1 turn down from full up make the pushrod end a true 90 degrees? Wait,.... I think it would only make the pushrod longer or shorter....or did I just get more confused?

It makes sense to me as well.

I suppose the way to explain the need for it is if that 90*/90* relationship doesn’t exist, then you not going to get the lift from your cam that the lobe and rocker ratio predicts?

xlcr77, I was wondering the same thing. I’m thinking that if the adjuster is extended too much, it will lower the pivot point of the pushrod, so (in addition to starving the oil flow into the rocker), that will also adversely affect lift, no?

What I see; moving the adjuster in or out can be a way to adjust pushrod-side geometry. The numerical ratio of the rocker is a function of the distance from the center of the cup to the center of the trunnion. If that changes, the ratio changes. Since we're working with linear vs radial movements here, it would be real hard to move the adjuster and not change the ratio (some) unless it was moving along a radius as well. So...saying that, the change in ratio is also very slight within the adjustment range of the adjuster. However, the change in geometry will be more obvious. A change in geometry can definitely effect how the information from the lobe is dictated to the valve. That's why all this geometry stuff is important and mid-lift, 90* geometry is, as well. We're trying to convert linear motion to radial motion, back to linear motion, with the least amount of lost movement or lost information. There is a horizontal element and a vertical element to the movement. On the valve side, we can see the horizontal movement in the sweep on the valve tip. When we optimize this, we get the least amount of horizontal movement (narrowest sweep) and the maximum vertical movement (lift). We work on the valve side because poor geometry can have really detrimental effects on the guides and possibly the valve and spring causing bad harmonics and we can easily enough address that but the pushrod side is another story. It can have detrimental effects as well if the geometry is whacked, but it's not necessarily going to wear parts out or cause other issues but it can definitely effect what the valve sees as far as timing of events. We have the same vertical vs horizontal movement we're trying to optimize for the same reasons.
LOL... and to top all this off, all this is static thinking, static checking. None of this takes into consideration what's going on dynamically although the Jesel rocker design does seem to address some dynamic issues.
Now multiply all this by 50-60 times a second or more.
You can watch the movement of the pushrod side to see if it's close. Because the rocker is moving in a radial motion, the pushrod cup will "sweep" just like the roller tip and you basically want the same movement. It's an A-B-A movement and you also would like to see the adjuster and pushrod in-line with eachother at mid lift although that isn't 100% critical. The pushrod movement is.