Roller Rocker geometry questions

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71swing

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Working get my 408 put together. Today I worked on checking valve to piston clearance for the new cam. Plenty of clearance. But I looked into my rocker geometry. I have Crane 1.5 gold roller rockers. Below is a picture of my heads that shows where the roller are on the valve stem. The roller markings were to light for the camera so I used a black marker to help them show up. As you can see the roller is slight passed center. What do you guys think, Can I live with it? I understand I can shim the roller shaft but I believe that moves the roller out further on the stem if you do that. New rollers are so damn exspensive to keep buying sets to find one that give the right geometry. Plus Im so over budget at this point on this build I can't really front for a new set at this moment.

Also I'm running ARP studs. With the studs screwed all the way into the block like they should be and the head installed the top bolts dont use all the threads on the nuts. Has anyone alse come across this problem. should I just unscrew the studs a few threads to gain it back for the nut? picture below to so what it looks like on the nut when the heads are installed.
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You get the right stud kit? Iirc mine grab all the treads on the nut.
 
I'll double check the part number but there is only one set of ARP's for the Eddy heads so I can't really mess that up unless they set me the wrong set, but I dont see that happening since it has the 3 different leagnths the Eddys need in the kit.

Now I only torqued them down bare for the mock up to check the valve clearance. So maybe on finally assembly with ARP lube will get me the rest of the threads, but on the other hand the bottom bolts didn't have any problems using all the threads.
 
When I ordered my stud kit I got the correct part number (on the box) but got the stud for the regular heads. Call arp talked with them and they sent me the correct ones.
I'm not saying a mistake was in your kit but it did happen to me.
Now that I think about it, I think the nut and stud are different but I'm not 100% on that anymore cause that was a few years ago and in the middle of me find a roller cam with an intergrated cast iron gear (oh, how much fun that was).
 
Double checked the part #. It marked correct but I wll contact ARP to make sure they didnt mix them up. Thanks
 
Had the same geometry problem using Crane Gold rockers on a buddy's 408. Had to use lash caps to correct the tip contact area.
 
I can't see the pics here at work - but - geometry is set by the valve job. So what heads are on it? I have not had issues with geometry and Crane golds in the past on big or small blocks but I have made sure the valve jobs were always highest quality. I have had to minorly clearance for springs before.
 
I would go ahead and put shims under the shafts. That line should be in the middle of the stem as you know and if not you are asking for trouble - why chance it?
 
The Hughes tech section has a good article on rocker geometry. Maybe in the rocker assy instructions which is also online.
 
I have a lash cap on order from summit. I will see what that does for geometry. I only ordered one because i'm not sure if that is the right direction. If not I'll look into and talk to my machinist about shortening the valve stems. Frankly my head hurts from all the thinking and reading about rocker geometry I've done over the last few days.
 
Now I'm home - From what it looks like they are too tall already. I think lash caps will make it worse. The pattern should be more centered and be wider and I don't believe shims are not the right way to fix it. The factory Edelbrock valve job should have been corrected.

PS - the head studs are too short if that's where the nut lands when they are bolted together with the head in place.
 
Valve tips are too low or rockers are too long. Either lash caps, cutting the seats .060 deeper, or .050 longer valves are the solutions. Which of these makes the most sense on a budget. Good luck ! : )
 
Dude, the angle of the rocker stand vs valve stem, u lower the stem and the distance between the two increases and the the pattern moves toward the center/intake manifold side of head.

I Run into this all the time as with many valve jobs and half *** machinists forget to grind AND equalize the stem heights within factory spec.
Best thing you can do is ..with one valve just bolt up the rocker shaft with one arm and do a sweep/dye test and grind the stem a lil at a time till its right...then measure and grind the test to that height.

And quit with the "wrong again"****, you're not a game show host and this isn't a competition.
 
I'll be stopping by the machinist tomorrow with my heads and rollers to see what's up. I'll let you all know what happens to help others that may come up with the same problem later. So many threads that I search through never got resolved because nobody took the time to for final updates after the problem was solved and what it took to fix it.
 
Lots of theories here but the bottom line is this "that is as good as it's going to get with the Crane golds" Every set I've ever used on eddies and iron heads has this exact same problem. If it is the 'bad' valve job etc. etc. them why isn't there a problem with Hughes rockers and lots of others.
And as far as 'fixing' it with lash caps goes, you will still have the same problem but it will look better because you will be looking at a bigger diameter. The roller will still be off centre the same distance as it is now.

My advice run it as it is just like thousands of sets of Crane golds run and that is 'a little off centre'.

As far as your studs go they are wrong, you need the 'EDDY' ones or W2 ones
 
Alright let's get some theories on this. I did just get these back from the machinist for new valve springs that my new cam required. They required milling of the seat since they had a higher install height. they asked if I want the an angle job. I Told him I didn't think it needed one with the low milage the heads had seen. They did pressure check them to make sure and everything was sealed tight.

I ran these roller rockers for about 5 years on these heads prior. Car hardly ever gets drivin. Maybe 3000 miles on the heads with a few trips to the local track. For the original install I don't recall if they were off center then, but very well could have been maybe then I just thought it was good enough.

Now my head guy did find SLIGHT wear from the guides on the stems and mentioned the guides were tight, but only on the exhaust valves. Which I found to be a common problem with Eddy's on here in other threads so he fixed that. But he had me stop in to show me something he had never come across before. The stock springs that came on my eddy heads that they removed were slanted. I had asked him if rocker geometry could have done that and he didn't think so. I cant see it happening either. Looking close at the springs it's like they came that way from the Eddy factory. What do you guys think? Picture below. Hope it's not to big it was taken with my phone at the shop.
 

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Lots of springs are like that and lots are not. Last set of Manley springs I used were really jilted. If your springs pressures test good for your cam run 'em.
 
This pic should help clarify the effect of valve tip height vs rocker arm height. If the pattern is on the intake side of center you raise the shaft.If the wear pattern is on the ex side of center you lower the shaft (which us mopar guys cant do) so we use a lash cap. In the case of the OP's situation the Crane rockers are likely a bit longer than they should be (as Raymond noted) causing the scrub pattern to be out toward the exhaust side. In reality it probably would never give you any issues running the way it is, but I'd rather make it as good as I could within reason.
ctrp_0611_06_zrocker_arm_geometrygood_VTG_diagram_zps558c4b1f.jpg
 
holly crap hope that helps. I just logged onto my computer and seen how big the picture of the spring was. I resized it to fit better.
 
QUOTE=skrews;1969867027]This pic should help clarify the effect of valve tip height vs rocker arm height. If the pattern is on the intake side of center you raise the shaft.If the wear pattern is on the ex side of center you lower the shaft (which us mopar guys cant do) so we use a lash cap. In the case of the OP's situation the Crane rockers are likely a bit longer than they should be (as Raymond noted) causing the scrub pattern to be out toward the exhaust side. In reality it probably would never give you any issues running the way it is, but I'd rather make it as good as I could within reason.
ctrp_0611_06_zrocker_arm_geometrygood_VTG_diagram_zps558c4b1f.jpg
[/QUOTE]

Now I'm back at work and can't see your picture...lol.
But I disagree with your statement of them being too short for two reasons based on the pics from the OP I saw:
1. The path followed by the rocker tip is an arc. As a result the pattern should be centered and wider with a slight bias to the intake side of the stem. Put into motion - on the seat (valve closed, "0" lift) - the rocker tip contact should be just to the intake side of the tip of the valve stem. As it lifts the valve it should move accross the center of the tip, crossing the center and going slightly towards the exhaust side at 1/2 it's travel (mid lift) - then it moves back towads the intake side of the stem. The width of the swipe is dependent on the total lift, the rocker ratio, and the height of the valve stem tip. That pattern is narrow, telling me the rocker is not traversing the tip, but rather still moving accross the tip towards the exh side of the stem.
2. The distance between the center of the valve stem tip and the rocker shaft centerline gets narrower as the height of either of those is raised. As that pattern starts on the exhaust side, it's already too tall... meaning the rocker shaft centerline and valve stem tip are too close together because the tip is too tall.
Adjustments should be made by the valve tip unless the rocker system and heads being used have flat support blocks. Those can be safely and accurately shimmed. Shims in the rounded saddle are fine for light duty work, but IMO are not acceptable in anything that has to rev or make big power. the repair is to fix the valve job.
To the OP - Your shop may not have to cut the seats, but by placing the head in their seat machine they can measure the heights very accurately and correct the valve lengths as needed. I'm not sure on the springs you're using but if the spring seats had to be cut to get a taller installed height it's my opinion that the seats should have been cut first. I've never had to cut spring seats on RPM heads. This is why I say RPMs need to have the valve job corrected prior to use. They all always had issues if one looks hard enough.
 
Sometimes I wonder about all of the complex solutions that come up to solve easy problems. The stems are too long - put shims under the shafts.. Don't mess around grinding the stems.
 
stumper said:
Sometimes I wonder about all of the complex solutions that come up to solve easy problems. The stems are too long - put shims under the shafts.. Don't mess around grinding the stems.
Click to expand...

The shaft is at an angle to which if you raised it the sweep would actually move closer to the exh even more.

You're stumped, stumper...
 
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