INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Why do I keep trashing the same rocker arm?

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Old Apr 10, 2011 | 03:23 PM
  #41  
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Yup.
By chance did you or former BFF. drop the rail or any rockers?
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Old Apr 10, 2011 | 05:48 PM
  #42  
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Ok so here is my verdict after inspecting and retorquing my D/S rockers and checking lifter preload... All of the wipe patterns were damn near dead in the middle of the rocker tip. Preload was 1.5 turns till I hit 22ft lbs except for two and they were around 1 7/8 of a turn till I hit the correct torque. This head is the first head that I installed the springs on with this spring compressor I remember noticing when I started on the P/S installing the springs that the cheapo bolts that it came with started to wobble and walk around coming out of the head to move it for installation of the next two springs. After the first four springs on the P/S which were cylinders 6 and 8 intake and exhaust, I changed to new bolts bc the old ones were getting sketchy and I didnt want to gall my heads. So that would explain that the one rocker that keeps getting bucked is the last ones that I did with that sketchy set of bolts. I noticed this when I started tightening the rockers back down and they looked to me like they were walking everytime I turned the bolt like a warped bolt or crooked threads in the head.... I may try a new set of rocker bolts and a Shi-ton of Loctite to hold it in there as straight as possible but this certainly would explain why my rockers are riding untrue on the rails...... Thanks for all the help guys... At least my truck LOOKS good sitting in the parking lot of my barracks with the PT.NET decal on the back window... hahah Anyone had any bad luck with this compressor?
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Old Apr 11, 2011 | 04:17 PM
  #43  
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Originally Posted by afterburn84
Every single rocker tip that I have off on the P/S looks identical except for one.. The tips are all scored on the forward side, meaning that the rocker arm is somewhat twisted to the rear which makes the tip of the rocker ride on the rear side of the valve. What is causing this to happen? You think that it could be as simple as the rocker rail is faulty causing the rockers to be seated in a not so straight fashion. ?
Your push rods may be misized.

I just reread your post and got confused... Do the tips ride toward the intake or exhaust side of the head?


Color the tip on the number 1 and 2 valve stem, replace the rockers and spin the engine by hand a couple of turns. Then see where the wear spot is on BOTH banks.

Last edited by TurboBerserker; Apr 11, 2011 at 04:23 PM.
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Old Apr 12, 2011 | 09:04 AM
  #44  
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Where is all the about being able to determine preload based on bolt head rotation coming from? Is this really just a **** poor attempt at circumventing the purchase of a $30 push rod length measuring tool? What was the install height of your springs and what type of spring are you using? Does the hole that keeps eating rocker arms show coil bind?

Last edited by MPFD; Apr 12, 2011 at 09:31 AM.
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Old Apr 12, 2011 | 09:14 AM
  #45  
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make sure the hole in the pushrod isnt stopped up.
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Old Apr 12, 2011 | 09:15 AM
  #46  
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Its not a **** poor method of counting turns. It has actually been working many timea for countless people for many builds. Its simple and it
Works. Nuff said! TR builds this set up everyday with the exact parts that I have used to build mine on the same platform and this is the
Rod they recommended for this build. The PR's are the correct length and I dont need a 30$ to determine that.
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Old Apr 12, 2011 | 09:29 AM
  #47  
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Thats what I thought, did you even measure install height? It looks pretty plain to me by the swipe pattern on your rocker, that clearance is lacking somewhere. The tip looks like the rocker is going into a bind at full lift causing it to slide out of alignment and make that odd lateral wear pattern. Till the trunnion finally gives way and you "eat" as you put it, the rocker arm. Hope you get it figured out...

Last edited by MPFD; Apr 12, 2011 at 10:15 AM.
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Old Apr 12, 2011 | 11:22 AM
  #48  
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Sorry wasn't trying to step on toes earlier. I just ordered a PR length checker. I figure what the hell? Right? This has got me stumped that is why pt.net is the Holy Grail for us gear heads. Im just really tired of hearing the fiance shake her finger and tell me I should have left it alone. Haha. As we all know that is impossible for us even with DD trucks ( like me). @MPFD, the more I read your last post the more its making sense. As budd hayes put it on the very first post. He said VT geometry. I will be checking the correct height when my tool comes in as a final effort before I have to do the unthinkable and put it on a trailer. That would be a WIN for her and a DEFEAT for me. Thanks for the input guys. Can't thank everyone enough!! Semper Fi to PT.net
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Old Apr 12, 2011 | 11:24 AM
  #49  
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There's something to be said for not modding a DD. In hindsight I would have rather left mine bone stock, the turd it was, and just get a project reg cab for something on the side.
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Old Apr 12, 2011 | 11:40 AM
  #50  
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Originally Posted by afterburn84
Sorry wasn't trying to step on toes earlier. I just ordered a PR length checker. I figure what the hell? Right? This has got me stumped that is why pt.net is the Holy Grail for us gear heads. Im just really tired of hearing the fiance shake her finger and tell me I should have left it alone. Haha. As we all know that is impossible for us even with DD trucks ( like me). @MPFD, the more I read your last post the more its making sense. As budd hayes put it on the very first post. He said VT geometry. I will be checking the correct height when my tool comes in as a final effort before I have to do the unthinkable and put it on a trailer. That would be a WIN for her and a DEFEAT for me. Thanks for the input guys. Can't thank everyone enough!! Semper Fi to PT.net

I came off as blameing you for this idea, sorry. It is not only you. I am reading about people trying to figure preload be thread pitch and rotation on Tech also and it's not an accurate enough way of checking just to save $30. What thinkness of shim did you use under your spings to come to the correct install height? And what is the height recommended by the selling company?
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