Valve clatter could it be timing?

Discussion in 'Classic Mustang Specific Tech' started by jeffnoel, Sep 15, 2007.


  1. D.Hearne

    D.Hearne Banned

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    I didn't mean it to say that it was "bad" noise, just too noisy to allow you to discern what you thought you were hearing. You want noise? try listening to my 77 Comet when I rev it. (If I could record and upload it I would) Stuff starts fallin off the shelves in my shop when it's cranked up. (331-sixpack, open Hedman long tubes with 24" long collector extensions, nothing else) It's loud and roudy, but nothing I'd want to drive everyday.:nice:
    #41
  2. jeffnoel

    jeffnoel Founding Member

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    Got the 91 in it yesterday warmed it up then and again today to mix the tank and get it to the fuel bowls I plan on taking it for s little drive tomorrow after work. I'm still running the Rotella with Crane cam lube that I had in it to break-in the cam should I dump that know before taking my joy ride?
    #42
  3. CraigMBA

    CraigMBA New Member

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    I think I'd leave the break in lube in for the first hour or fifity miles.

    Drive to Hanford or something. Say hi to my mom.
    #43
  4. jeffnoel

    jeffnoel Founding Member

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    I've got a 3-4 hours on it already.
    #44
  5. jeffnoel

    jeffnoel Founding Member

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    I'm about to take a little test drive but I did a couple things and took a couple pics I wanted to share first.

    I was reading up some on the MSD website and they say to use Copper not Platinum plugs so I went to Kragen and picked up some Autolite 25s and gapped them at 0.050 and installed them. When I pulled the Platinum plugs the #1 and #6 were black the rest looked OK (see pic below). Then I pulled the VCs and rechecked torque on all the rockers. I pulled the rockers on #1 and #6 to see if I had cracked another pedestal but no damage. I did however change from a thick shim to a thin shim on the #1 intake. Then I used a marker on the valve tips and reinstalled the #1 and #6 rockers and rotated the engine through a few revolutions to mark the top of the valve tips (see pics).

    After reinstalling the VCs I fired it up to warm the engine and then tried slowly revving it a couple times and I was getting a really bad miss around 2K rpm with the vac adv connected. So I disconnected the vac adv and tried again and it revved smoothly through 2K without missing like it did with the hose connected. It appears when the vac adv kicks in my advance goes to 40+ and that's why its missing. I say 40+ because my damper is only marked to 40.

    Link to fullsize pic of plugs http://www.supermotors.net/getfile/566259/original/100_1933.jpg
    [​IMG]

    #1 Valves
    [​IMG]

    #6 Valves
    [​IMG]
    #45
  6. jeffnoel

    jeffnoel Founding Member

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    Well I think it's the Vacuum advance on my distributor. I just got back from a little drive and with the hose connected it still pinged even with 91 octane and plugs gapped smaller at 0.050". Then I diconnected the hose and capped it at the carb and no more pinging. I was told the Duraspark distributors had an adjustable vac advance, but which way would I turn the allen wrench to advance or retard the timing? I didn't get video while it was pinging but I did after I disconnected the hose.

    [​IMG]
    #46
  7. D.Hearne

    D.Hearne Banned

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    Did you test the vacuum pod to see if the diaphram is busted ? I had one do that a year or so ago. I don't recall the symptoms, but it puzzled me till I found the vacuum pod leaking and changed it. You can buy new pods at the parts house to replace the old ones.
    #47
  8. jeffnoel

    jeffnoel Founding Member

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    If the diaphram was busted I would think that vacuum advance wouldn't do anything, mine is providing like 20 degrees.
    #48
  9. D.Hearne

    D.Hearne Banned

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    You still have mechanical advance in the distributor that works, test the vacuum pod, it'll cost you nothing to find out. Just pull the cap and rotor, unplug the hose from the carb and suck on the hose while watching the actuator arm on the breaker plate.
    #49
  10. CraigMBA

    CraigMBA New Member

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  11. jeffnoel

    jeffnoel Founding Member

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    D.Hearne I will check that.

    CraigMBA those are some great links.

    Thanks Guys
    #51
  12. woodsnake

    woodsnake Active Member

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    If you haven't gone over the process for setting up your valve train geometry, you should head over to sbf tech. http://*******.com/index.php/topic,317.0.html

    I have had nothing but trouble with my Edelbrock cam. Getting correct valve train geometry is critical for a proper running engine. I'm on my second set of roller rockers, third set of pushrods. I've had my heads completely rebuilt TWICE. All because my machine shop operator didn't ask the right questions about cams and such. This was my first performance rebuild, and I'm way over budget. ( I don't know the 'link' didn't paste, but go read the page!!)
    I just got my Cougar to start again, after breaking in my SECOND camshaft. I am dealing with the same noise under the hood that you are.

    It's FUN to build motors!!
    #52
  13. woodsnake

    woodsnake Active Member

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  14. jeffnoel

    jeffnoel Founding Member

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    My noise is gone, my vacuum advance was the culprit.

    Your link to the SBF tech forums is incomplete.
    #54
  15. D.Hearne

    D.Hearne Banned

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    Diaphram was busted ?
    #55
  16. jeffnoel

    jeffnoel Founding Member

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    Nope adding to much advance to early. I need to get the adjustable vacuum kit that Crane makes for the Duraspark.
    #56
  17. CraigMBA

    CraigMBA New Member

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    And then recurve it so you have it all in by 2500 RPM.

    Those head you have seem to like no more than 34 degrees total advance.
    #57
  18. D.Hearne

    D.Hearne Banned

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    Some of the vacuum pods are adjustable by using an allen wrench inserted into the hose nipple, or so I've heard, I've never found the need to adjust it. Or maybe I've confused this with the vacuum modulator valve ?
    #58
  19. CraigMBA

    CraigMBA New Member

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    You aren't confused and some of they are adjustable. Others.....aren't.
    #59
  20. jeffnoel

    jeffnoel Founding Member

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    Yeah I've heard some of the early models were adjustable, I did try and Mines not adjustable. Luckily the Crane kit is only about $28 at the local Kragen.
    #60

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