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Valvetrain wear

Discussion in 'Engine Building' started by 99sidude, Nov 15, 2011.

  1. 99sidude

    99sidude Moderator Moderator VIP

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    This week I hit 3500 miles on the build. Time for the first oil change following the break-in period. I ran the oil through a strainer - no metal particles. Good. I decided to pull the valve cover just to check things over, and found THIS:

    [​IMG]
    [​IMG]

    On the exhaust cam, cylinders 2 & 3, the vtec lobes are wearing BAAAAD. The cam is literally crumbling. You can see a little shard in the picture. Good thing my oil filer is picking up this shit. This is unacceptable for a street driven car with 3500 miles. I checked the lash and its still right on. It's like whatever heat treating they did to harden the camshaft didn't quite get to the center of the cam.

    The setup is skunk2 stage 2 tuner series cams, skunk2 valve springs. fresh lma's. Hell, the wiper pads contacting the bad lobes looks like new. Usually the wear is the other way around - over a much longer time period. I had the rev limiter set at 8k up till 2 weeks ago when I raised it to 9200. I paid over $650 for these brand new:(

    Any of you guys experienced something like this?
     
  2. 99sidude

    99sidude Moderator Moderator VIP

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    Now that I think about it, during WOT pulls in 3rd and 4th gear, the car has this strange frequency in sound and pulling power from 7k-redline. It's been getting worse - I assumed that the cold temps were throwing off the tune. I'm guessing that my new low-lift cam profile on 2 of the cylinder is the culprit.
     
  3. Myztiq

    Myztiq New Member

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    what type of oil are you using did you check the camshaft bearings there is a key on the last of the bearings might want to check that out mine did the same thing until i replaced that (i had stock cams lol) it almost looks like a screw.....
     
  4. CAFROG

    CAFROG Honda Minion VIP

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    Are the wearing spots finger nail grabbers?
     
  5. Magana559

    Magana559 The Warden

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    you know my buddy was telling me this about a year ago, warned me about the skunk cams. I also seen and hear about crower cams breaking.

    Seems like everybody is makng shit aftermarket cams.
     
  6. Magana559

    Magana559 The Warden

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    I would check your bearings. Most metal gets caught in the soft lead and makes oil clearances tight or uneven.
     
  7. 99sidude

    99sidude Moderator Moderator VIP

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    Just Penzoil 5W30. Same crap I have always ran in my Hondas. The key is fine.

    Yes, on the edges of the lobes, not where it contacts the rocker. The cam lobes themselves are wider than the pads on the rockers. Its like the lobe material is compressing where it contacts the rocker and is pushing material outward. Kinda like when you push down on a balloon and the sides push out.

    Great. They have no warranty either. I bought them on reputation and success for over 10 years. I am a sucker. I'm going to send them pics and micrometer measurements and hope for the best.

    I hope your wrong, but it's a good idea to check. Once I take measurements and see exactly how much material is gone I will decide whether or not to tear into it more.
     
  8. Briansol

    Briansol Admins Admin VIP

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    Are these regrinds or fresh billit?
     
  9. 99sidude

    99sidude Moderator Moderator VIP

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    Not regrinds.
     
  10. 99sidude

    99sidude Moderator Moderator VIP

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    Heading out now to pull the cams. I'll post pics later. The plan is to do some harness testing at work. I'm going to compare the hardness at different points across the cam, and compare to the harness spec for OEM cams.

    The plan is to put together an irrefutable case that these cams are shit, then hope that Skunk2 sends me a new set.
     
  11. Briansol

    Briansol Admins Admin VIP

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    So you can have the same problem again in another 3500 miles? get your money back and choose a different brand.
     
  12. vtecsir1

    vtecsir1 Senior Member

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    I know you said you had the valve set right but what is that at?

    I had Pro 1s and when I pulled them when my motor let go they were perfect pretty much. I will see if I have a pic to compare to.

    To the comment about cams breaking and having issues, that happens with every manf..

    Im running Brian Crowers with no issues and ran Skunk pro1s without issue.
     
  13. josh_crewdson@y

    josh_crewdson@y New Member

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    I had a Brian crower stage 3 snap on me..
     
  14. 99sidude

    99sidude Moderator Moderator VIP

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    Soooo... I renamed the thread because I am not sure the cams are to blame now. The cams on the other hand seem pretty much fine. The sharp edges I described earlier appear to be part of the casting process and do not contact the rocker. The visible marking is not detectable by feel. I'm going to mic them and throw them back in if they measure out OK.

    I got the cams out and it seems like the culprit is worn vtec rockers on the exhaust side. The wear is very uniform at each rocker. The rockers are worn FAR worse than the cams. There is a good 1mm deep indentation. The wear is on the side where the valve would be closing. The markings on the cams are also on the valve closing ramp.

    Got the top end apart
    [​IMG]

    This is a good pic of the damage. Notice the deep wear on the contact pad, toward the left.
    [​IMG]

    In this one also shows the wear
    [​IMG]
    [​IMG]

    This is a pic of an intake side rocker assy. Looks just fine.
    [​IMG]
     
  15. 99sidude

    99sidude Moderator Moderator VIP

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    These pics are taken around an exhaust vtec lobe.

    This is the valve open side. Looks just fine
    [​IMG]

    This is looking down on the peak. Notice the transition from good to shitty right at max lift.
    [​IMG]

    This is the valve close side. Not pretty.
    [​IMG]
     
  16. Matts96HB

    Matts96HB . Moderator VIP

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    Wow, I have never seen that before. I still would think that the camshafts might have something to do with it, given that the wear was not evident before the aftermarket camshafts were installed.
     
  17. 99sidude

    99sidude Moderator Moderator VIP

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    There is a number of causes. I listed my ideas in order of likelihood.

    1. oil starvation. the consistency of the wear on the exhaust side only leads me to this. I need to double check and make sure all dowel pins and oil system parts were in place.

    2. the rockers were worn from the start. I didn't look too hard when I put it together. TISK TISK. Time to do some detective work in my massive photo album.

    3. valve float. At high rpms the rocker could separate physical contact with the cam, then slam back down. I doubt this because:
    a. I am running stronger valve springs
    b. The motor has only seen 8k all year until 2 weeks ago, and 9k only a handful of times

    4. Shitty cam material. The transition from good to shitty occurs along the parting line of the casting. Sometimes material can get micrscopic air bubbles in this area due to material cooling before it has joined in mold. This causes material to be weak.
     
  18. Magana559

    Magana559 The Warden

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    the rockers seem damaged pretty bad, It might have been caused by the cam. Also looks like there was over heating, maybe not enough oil to the rockets or the cheap penz is not enough.
     
  19. 99sidude

    99sidude Moderator Moderator VIP

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    I took this pic at the start of the build back in March. The rockers appear fine then.
    [​IMG]
     
  20. 99sidude

    99sidude Moderator Moderator VIP

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    Yea. I'll be ordering 4 vtec lobe rockers tomorrow. Hopefully it doesn't set me back too badly with the associate price. Online, it looks like I can only get it as an assy (primary, secondary, and vtec) for around $160 each. x4. OUCH. Who has a junk B series head with decent rockers???

    I doubt the oil itself was to blame, otherwise there would be damage on the intake side as well. The intake side see more force as the cam lift is greater.

    It has to be either shitty cam or oil starvation. Surprising that the cam journals and primary/secondary parts look fine :confused::confused::confused::confused::confused::confused:
     
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