Mystery ticking noise

Discussion in 'Troubleshooting & Diagnosis' started by jnkman61m, Aug 13, 2008.

  1. kenny77

    kenny77 Veteran Member Lifetime Gold Member

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    Jul 31, 2001
    Ft. Lauderdale, FL
    The warped flange header leak that plagued me for months is the one that I speak of. It was on a bastard set of Dynomax headers. 4 and 6 spot.

    The ONE SURE SYMPTOM of it was it would not tick at all when the engine was just started cold. I switched to a super thick soft paper-like header gasket, that solved the problem for about 10 or so miles, then it returned. I thought for sure for weeks...without a doubt that it was valve train related. Nothing, I mean nothing pointed toward a header leak.

    BTW....during my escapade I also had no burn marks or carbon tracks, clear impressions on the gasket ect . The flange appeared straight also then I had a old timer racer guy explain that that meant squat. What was happening to that cheap POS header flange when the bolts got tight and the flange got hot was my real problem.
    He got me to thinking..Hmmmmmm


    I ended up switching to a set of Hedman ceramic coated elite headers with a real thick flange, even thicker than the newer version of Hooker super comps..and that was the end of that.


    The Hedman Elites' had by far the thickest flange to resisit the warped flange thing. I had the advantage of being in a speed shop that had several companys headers so I did a side-by-side comparison. I've been around a while and believe me, I don't bother posting or just throwing our random crap or ideas if I have no first hand experience on the topic at large. That just wastes peoples time and energy IMO. And you've earned a merit badge by now with this headache. I can relate.

    I'm also not one of the me-too...me-too crowd if you follow me.>>>>>>>>>>>Ken


    [​IMG]
     
    Last edited: Sep 14, 2008
  2. jnkman61m

    jnkman61m Member

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    Aug 12, 2008
    Okeechobee, Fl
    I actually have the same sries of headers on this car in a shorty version, Hedman 68608 Elite's........heard too many horror stories about cheaper headers and chronic leaks.

    At this point the car is back together, running and running well. Removed the hi-volume pump and put in a stocker I had on hand. Put on a set of stock rockers. Scorpion rockers look great sitting on my desk.

    Tapping still persists, I shall officially recant my adamant statement regarding the possibility of a header leak being impossible, as it could be, I just cant prove it.

    Current plan is to run the crap out of it until the noise worsens to the point it will at least leave some visible evidence somewhere. Which may never happen.

    Ken, I thank you for taking so much time to spell out your experience in detail with hope of helping me with my dilemma.....and thanks again to everyone else as well.
     
  3. jnkman61m

    jnkman61m Member

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    Aug 12, 2008
    Okeechobee, Fl
    Cam lobe looks STRANGE

    Was going to attach pics to this post but they are too big to post....oh well.

    I have found "chatter marks" on the number 8 exhaust lobe of the cam on the closing ramp. They extend from the nose downward about halfway through the ramp and stop short of the base circle. They are very visible, and can be felt both with a fingertip as well as a fingernail.

    I am of the opinion these are manufacturing chatter marks, not a wear mark.
    I have a theory that these marks are imparting some weird harmonics into the valve spring and at the very least contributing to the noise in this engine.

    After checking the INSTALLED height of the LT4 valve springs, the machine shop that set them up did not shim them to enough seat pressure and proper height. The height is too tall and the seat pressure is 20-25lbs too low. Perhaps a secondary cause,perhaps not. Not laying blame, just pointing out what I found. And in defense of the machine shop, I selected the springs and they really are not a good match for the particular heads I have as the spring pockets are deep enough that they really require what I feel to be an excessive amount of shims to get the springs to the right pressure, so again, no badmouthing on my part.

    I am installing a NEW LT4 Hot Cam, a different set of springs and using a spring tester and height mic and doing it all myself.

    I'll post results if there is anything useful to contribute.
     
    Last edited: Sep 29, 2008
  4. John Wright

    John Wright Veteran Member Lifetime Gold Member

    13,932
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    Aug 9, 2002
    Rustburg, Va
    Keep us updated as to what you find...maybe whatever is making the noise will show some evidence and the mystery will be solved. If your noise goes away with the cam swap, what do you think that it points to as the noise maker? cam? spring pressure?
     
  5. jnkman61m

    jnkman61m Member

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    Aug 12, 2008
    Okeechobee, Fl
    Darn good question. I would love to be able to change one thing at a time and prove the cam theory, but since the heads are off, it's going back together with a better set of springs.

    At this point, I am going to point a magical finger at the evil looking cam lobe.
     
  6. kenny77

    kenny77 Veteran Member Lifetime Gold Member

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    Jul 31, 2001
    Ft. Lauderdale, FL

    The springs would make a lot of sense, simply because IIRC heat changes pressure and if they are too light to start with....well........I'm watching this thread!
     
  7. rscamaro73

    rscamaro73 Administrator Staff Member

    Just from my friend's LT1 with the LT4 hot cam kit he had....that thing made some ticking noises ALL the time. Almost fool-proof the way that engine goes together too. But it did run like the dickens and the time slips proved it.

    Hope you found the issue with the cam/springs.
     
  8. jnkman61m

    jnkman61m Member

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    Aug 12, 2008
    Okeechobee, Fl
    Using a Rimac spring tester with the LT4 springs tested at their previously installed height, looks like they were set up with 75-80 lbs seat pressure. Spec on those springs is 101lbs@ 1.780" installed height.

    I substituted a set of Crane 99846 springs set to 120lbs seat pressure @1.788 average across all 16 springs, some a little taller and some a little shorter. Good thing about these springs is the retainers FIT correctly, there is ALOT more seal to retainer clearance and also much more room before coil bind...

    That is one thing that bugs me with specs on LT4 springs....the specs dont add up. Installed height is 1.780. Coil bind is 1.215-1.220. LT4 hot cam using 1.6 rockers is .525"(I am using 1.5).....do the math......1.780-1.215=.565"
    Common manufacturer advised coil bind clearance is .060".
    .565"-.060"= .505" max lift. Seems like these springs installed at that height with that cam are running very close to coil bind right out of the box and whoever sets up the heads and springs had better pay very close attention to details and assume NOTHING.

    Cam and heads are going on today and should fire it up tomorrow, I'll update as I can.
     
  9. jnkman61m

    jnkman61m Member

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    0
    Aug 12, 2008
    Okeechobee, Fl
    Fixed!!!!!!!!!!!!!!!!!!!!!

    Cam and springs did the trick. No more tick at any rpm in any gear. I think it must have been the low spring seat pressure combined with a cam lobe with a washboard finish.

    I can't tell you how much I appreciate everyone taking the time to read my posts and reply in kind. Thanks a bunch, hope I can return the favor someday.:) :) :)
     
  10. rscamaro73

    rscamaro73 Administrator Staff Member

    Glad you got it figured out and replaced and back on the road.
     

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