Wear pattenr on valve tip
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Wear pattenr on valve tip

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    Senior Member flat screwd's Avatar
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    Default Wear pattenr on valve tip

    I pulled the V/C to loosen rockers for a timing gear change and noticed this . The roller tip chewed into the rocker body and left this odd pattern on the valve stem . Is the bow tie pattern OK ? or should they be straight ?Unfortunatly I didnt check lash prior to pulling rocker .




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    Some guy obnoxious001's Avatar
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    If those are Miller rockers, may want to check to see how loose the trunion bearings are. I just replaced a set that had super low hours but were next to impossible to set lash properly since they would appear to be set, but bearings would shift and they would have a ton of extra lash.

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    Senior Member flat screwd's Avatar
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    Yes they are Miller rockers . Do you feel that the valves should spin? I think I have a weak spring and the valve is bouncing off the seat. But that alone shouldnt cause the rocker issue.

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    steelcomp was here
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    Quote Originally Posted by flat screwd View Post
    Yes they are Miller rockers . Do you feel that the valves should spin? I think I have a weak spring and the valve is bouncing off the seat. But that alone shouldnt cause the rocker issue.
    The rocker shouldn't be causing that. I'd check that valve spring.
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    gn7
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    Quote Originally Posted by flat screwd View Post
    Yes they are Miller rockers . Do you feel that the valves should spin? I think I have a weak spring and the valve is bouncing off the seat. But that alone shouldnt cause the rocker issue.
    Like Steel said, check the spring. You cannot imagine the grief, hell and damage a weak spring can cause. There is too much spring pressure forn the valve to rotate or move back and forth like that unless the spring is unseating at some point. Bearing slop can't do that. Incedably slopping guide plate could. But there is NOTHING to hold the rocker aligned on a stock rocker except the guide plate and all the slop in the world at the skid ball and they don't leave a mark like that. The valve is moving.



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    Last edited by gn7; 06-24-2012 at 05:35 PM.

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    Senior Member flat screwd's Avatar
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    Yea, thats kinnda what I was thinking. Ill check into it this weekend and post up the results . Thanks

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    Some guy obnoxious001's Avatar
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    Quote Originally Posted by obnoxious001 View Post
    If those are Miller rockers, may want to check to see how loose the trunion bearings are. I just replaced a set that had super low hours but were next to impossible to set lash properly since they would appear to be set, but bearings would shift and they would have a ton of extra lash.
    My point was that I have a set of those sitting here that have maybe less than 10 hours on them and the trunion bearings are junk. I did some research and found that others had similar problems with these same "bargain" rockers, and was suggesting that you should check them out while you have them off the engine.

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    gn7
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    I agree Barry, he should check the rocker. But for the rocker to do that due to a bearing, it would have to be painfully obvious that it was seriously jacked up. The stock skid ball arrangment has ZERO alignment control and even wallows side to side like a deep v bottom, limited only by the stud in the slot, and does't leave a mark like that.
    Any roller rocker that has MORE slop than a stock skid setup would be very clearly JUNK!



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    Quote Originally Posted by obnoxious001 View Post
    My point was that I have a set of those sitting here that have maybe less than 10 hours on them and the trunion bearings are junk. I did some research and found that others had similar problems with these same "bargain" rockers, and was suggesting that you should check them out while you have them off the engine.
    The problem with those rockers, as I understood, was the aluminum body not the bearings. Wrong alloy or wrong heat treat...something like that. They were all over the place for real cheap for a while.
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    steelcomp was here
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    Quote Originally Posted by gn7 View Post
    I agree Barry, he should check the rocker. But for the rocker to do that due to a bearing, it would have to be painfully obvious that it was seriously jacked up. The stock skid ball arrangment has ZERO alignment control and even wallows side to side like a deep v bottom, limited only by the stud in the slot, and does't leave a mark like that.
    Any roller rocker that has MORE slop than a stock skid setup would be very clearly JUNK!
    I agree. I don't care how much the rocker can wiggle around...it's not going to cause a wear pattern on the valve tip like that. That's purely from the valve turning. Having said that, if the lash was excessive from the trunnion bearings going bad, that could possibly cause some harmonics that might upset the spring to the point where the valve might rotate a little. Lot of 'mights" there, but that's the only way the rocker could be responsible for that kind of mark on the valve tip. It would also be very obvious tht the rocker's bearings were that bad.
    Last edited by scott foxwell; 06-24-2012 at 09:55 PM.
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    Once again, I was merely trying to be helpful and point out that the rockers should be closely inspected, not that they were the cause of the problem. The set that I have here has very loose bearings,, with almost no time on them.
    Last edited by obnoxious001; 06-24-2012 at 10:02 PM.

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    Quote Originally Posted by obnoxious001 View Post
    Once again, I was merely trying to be helpful and point out that the rockers should be closely inspected, not that they were the cause of the problem. The set that I have here has very loose bearings,, with almost no time on them.
    Sorry Barry, I thought you were blaming the rocker for the wear pattern. I mis-understood what you were saying. I agree on checking those rockers, anyway.
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    www.highflowdynamics.com LakesOnly's Avatar
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    Since 2005, High Flow Dynamics has been the west coast distributor for Miller Rockers, Precision Valve Systems (a subsidiary of Miller Rockers), and the Miller Products Group. Jim Miller and I speak almost on a daily and rarely less than 3-4 times per week; he's been here in California paying us a visit; I've been to his location in Florida on a few occassions to pay him a visit (most recently this very month June 2012); we have lunch together when we can and regularly talk so much about rocker arm geometry that I consider myself a bit of a disciple of his. Further, I am more intimately familiar with all the Miller products offered, the history of the company, know intimately the methods of manufacture relative to each product line, the quality control excersized both in-house and independently, and basically more than anyone else outside of the company who has not actually worked under their roof and more than some who have.

    And I'd like to respond to a few posts in this thread.
    __________________________________________


    Quote Originally Posted by flat screwd View Post
    I pulled the V/C to loosen rockers for a timing gear change and noticed this . The roller tip chewed into the rocker body and left this odd pattern on the valve stem . Is the bow tie pattern OK ? or should they be straight ?Unfortunatly I didnt check lash prior to pulling rocker .


    The above photo is not depicting a rocker arm problem, it is a valve train problem and one which is not being caused by the rocker arms. The cylinder heads are "el cheapo" offshore chinese cylinder heads which have a long history of poorly executed machining accuracies. The worn roller tip area of the rocker body is most likely being inflicted upon the rocker arm, not caused by it. Swap out rocker arms with another unaffected one and I'll bet the wear will begin on the new rocker arm that was just placed on the suspect cylinder. And don't worry, Chris, I view your above-quoted post as nothing more than an honest and sincere inquiry based on your curiosity. Also, thanks for the email today.


    Quote Originally Posted by obnoxious001 View Post
    My point was that I have a set of those sitting here that have maybe less than 10 hours on them and the trunion bearings are junk. I did some research and found that others had similar problems with these same "bargain" rockers, and was suggesting that you should check them out while you have them off the engine.
    Obnoxious001, believe me when I say to you that I am being more than polite when I state that you couldn't be more incorrect about Miller rocker arms using a "junk" bearing. The rocker arms pictured above are top-of-the-line, first rate Miller PVS rocker arms. And they are from the most recent production run and not a defective rocker arm in any way, not in the body, not in the trunnion, not in the bearing, etc. (I have personally inspected some of the rocker arms used in this engine.) Furthermore, the allegedly "junk" needle roller bearings that come in all Miller rocker arm products--regardless of division--are 100% American made, on American soil, by an American company, employing American craftsmen, running state-of-the-art American machinery which is being fed American sourced materials. The needle roller manufacturer that supplies the bearings in Miller rockers is the exact same supplier that Crane used for decades, that Harland-Sharp currently uses, that Scorpion currently uses, and the list goes on. When Miller rocker bodies are manufactured (the extrusions and the billets) samples are taken and diverted to an independent testing lab in Florida. The destruct level is greater than just about every other manufacturers' stud rocker arm bodies, save for a handful that use the same materials as Miller Engineering. In the case of the above pictured rocker arms, the 7075-T7 material has a destruct level of about 83,000 psi. Compare that to other manufacturers who use 6061 or 2024 which come in at about 65,000 psi (and which is plenty adequate for the application). The Miller destruct testing exceeds even one of the biggest rocker arm manufacturers today (who shall remain nameless at this time) that uses an aluminum material which I consider to be the absolutely crappiest shit on the planet for rocker body material--destruct comes in at 33,000 psi and it doesn't break, it mashes out like a marshmallow. The aluminum they are using was devleoped for a completely different, lesser application. And I see people on this forum talking up those truly inferior rockers like they are awesome, probably because the manufacturer has a flashy website and shiny rocker arms but mostly because the end user is none-the-wiser since most don't actually have experience with a vast range of rocker arm manufacturers nor are they familiar with the geometry practices of each or--mostly--the materials used in the manufacturing process. I'd say the material in Miller rocker arms performs above and beyond most out there.


    Quote Originally Posted by steelcomp View Post
    The problem with those rockers, as I understood, was the aluminum body not the bearings. Wrong alloy or wrong heat treat...something like that. They were all over the place for real cheap for a while.
    There was never a problem with the aluminum in Miller Rockers, and in fact some use the strongest billet aluminum for any stud rocker arm of which I am aware.

    In 1998 (read: 14 years ago), the very first production run of the PVS Big Block stud rocker was manufactured with a clipless, self-centering trunnion and a different roller-tip pin. They were made of 2024 material and this specific production run used a completely different source foundry for the extrusions. In an effort to save the production run, they were re-worked with upgraded sub-assemblies by Miller Engineeering, then all sold to a single distributor as reworked rockers and with the understanding that distributor was to sell them as such. The distributor essentially offered them as Grade A rockers (by not depicting the reworked status) and so Miller dropped the distributor immediately.

    These 1998 1st Gen rocker arms are eeeeeeasily identifiable a mile away because they have different features, a differnt color, and different overall look to them than all subsequent manufacturing runs. Unfortunately, Miller did not change the part number with next subsequent production run and so when others see the part number, they mistakely assume they have defective rockers.


    Paul Kane
    High Flow Dynamics
    Performance Components for the 429/460 Engine Family


    This post © Copyright 2007-2017 Paul Kane. No copying, linking, printing or otherwise without express written permission.

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    gn7
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    Quote Originally Posted by LakesOnly View Post
    __________________________________________

    .


    There was never a problem with the aluminum in Miller Rockers, and in fact some use the strongest billet aluminum for any stud rocker arm of which I am aware.

    In 1998 (read: 14 years ago), the very first production run of the PVS Big Block stud rocker was manufactured with a clipless, self-centering trunnion and a different roller-tip pin. They were made of 2024 material and this specific production run used a completely different source foundry for the extrusions. In an effort to save the production run, they were re-worked with upgraded sub-assemblies by Miller Engineeering, then all sold to a single distributor as reworked rockers and with the understanding that distributor was to sell them as such. The distributor essentially offered them as Grade A rockers (by not depicting the reworked status) and so Miller dropped the distributor immediately.



    Paul Kane
    Thanks for posting that Paul. I bought a set of the "cheap" PVS rockers from the SOLE distributor. Although they did not say they were re-worked, they did not, when I bought them, sell them as grade "A" rockers. I knew they were reworked from something Jim had on his website at the time. As I remember the rocker was identifiable because the color was more of a bronze color than gold. I was also aware that they were 2024 which isn't the worst alloy for a rocker, although I knew the new ones were were 7075. The supplier never did say why the rockers were less expensive than the "gold" rockers, but they did sell both generations at the same time, so it was pretty obvious that something was different. Never had any trouble with the rockers while I had them, and with the "G" tool, they were by far the easiest rockers I ever owned to setup.



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    Last edited by gn7; 06-30-2012 at 11:23 PM.

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