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Loud tap? Bent valve?

Discussion in 'General Tech and Maintenance' started by Alvin, Nov 30, 2003.

  1. Alvin

    Alvin Junior Member

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    Hello,

    I just bought a 91 prelude and the motor has a really bad tap to it, I can't find it probeing around but by ear it definately sounds like its coming from the head.

    the valves have jsut been adjusted and trippled checked and the noise didn't change.

    Someone mentioned to me that it could have a few bent valves. Is this possible? The car drives and acts great it just taps like crazy.

    It doesn't seem to knock but tap. Theres no metal in the oil and it doesn't change by pulling spark plug wires off.

    Any help would be greatly appreciated.
     
  2. brian11to1

    brian11to1 Senior Member

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    first of all you pull the spark plugs out... so there isnt any pressure on the piston/rod. But Im leaning towards a bad rod.
     
  3. ludegirl

    ludegirl Senior Member

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    sounds like a rod knock to me...
     
  4. iluvepills1985

    iluvepills1985 Member

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    check out the rollers or what ever there called i had the same problem in my zc and i tightened up the rollers i know thats not what they called big brain fart but what you do if you dont have a torque wrench is take off the head cover and start the car follow me on this then you tighten them down till you hear the engine bog down then back it off a quarter of a turn it worked for me in the civic and in the stang so give it a try if it doesnt work then hey you know its not tht
     
  5. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    are you reffering to camshafts? cam gears? and valve cover?
    please elaborate.
     
  6. brian11to1

    brian11to1 Senior Member

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    Dude they are under the cams... they open and close the valves as the cams rotate
     
  7. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    valve seats? valve springs?
     
  8. brian11to1

    brian11to1 Senior Member

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    what about them?
     
  9. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    the rod that goes thru the valve seats?
     
  10. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    what part is he talking about? rocker arms?
     
  11. brian11to1

    brian11to1 Senior Member

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    rocker arms pivot back and forth on on top of the VALVEs, the VALVES then stretch down into the combustion chamber via the VALVE STEM, and pass through the VALVE GUIDES. The valves actually seats and seals on the VALVE SEAT. Got it?
     
  12. NotUrAverage_Si

    NotUrAverage_Si Senior Member

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    :wtf2: I already knew that you idiot! OMG nevermind I don't even care what he was talkin about anymore.
     
  13. jamesA

    jamesA Well known pissed off telephone guy VIP

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    :huh: Talk about your ultimate thread hijack of stupidity......

    Anyway, have you checked your oil lately? older cars tend to burn oil, causing a loud tapping noise when the cams hit the lifters. I used to get that all the time in my Escort. If it's not that, then something is out of alignment.
     
  14. jamesA

    jamesA Well known pissed off telephone guy VIP

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    to add, if it's a bent valve then it won't close and you won't be able to keep compression. Get a compression check, and tell us what the numbers are...
     
  15. sportlinecrx

    sportlinecrx Banned

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    a really really dumb question but..

    have you checked your timing? i know that when mine is advanced too far, the engine starts making a tapping noise.
     
  16. ryanwolfe911

    ryanwolfe911 Senior Member

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    You have rods that go through the valve seats? thats got to be one strange looking engine!! Anyway, I had the problem you're describing one a JDM b16a that I bought from nippon motors,(ps, don't buy from them, EVER) One of the valve keepers on the #4 cylinder, I beleive it was an intake valve, was missing apparently, but the whole springs assembly managed to stay together, but was letting the valve open too far, just barely enough to tap on the piston. After a good 2 weeks of this, (I never could pinpoint the source of the noise) It finally punched a big ass hole in the top of the piston and I lost all compression. From what I have heard from the local honda techs, this is actually a common problem on OBD 0 engines. See if you can borrow a borescope from someone, and look in the cylinders to see if ther's any piston damage
     
  17. sportlinecrx

    sportlinecrx Banned

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    dam that aint good news. wouldnt a compression check show a problem if there was piston damage?
     
  18. B16

    B16 Super Moderator VIP

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    wtf are you talking about? adjusting valves? he already said he did that bro.
     
  19. sportlinecrx

    sportlinecrx Banned

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    yea that does sound alot like adjusting valves :hmm:
     
  20. lude68

    lude68 Senior Member

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    and this kid has no clue what puncuation is! lol! A whole paragraph w/ not a single period. Sorry if you think im flaming of any kind but this shit has got to go!
     
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