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V6 Valve Noise? Pictures?

Discussion in 'Early CJ-5 and CJ-6 Tech' started by Strider380, Aug 15, 2019.

  1. Aug 15, 2019
    Strider380

    Strider380 Can I have a zip tie?

    New England
    Joined:
    Jan 12, 2006
    Messages:
    1,111
    Hello let me preface this with, i know nothing about motors except how to pull them out and put them in. I have heads that are “ported and polished” in fact the whole motor was built for racing. The motor is tight and runs great but around 2000 rpm and up i get a lot of valve noise. I dont think you can adjust valves on a v6. But these heads are different. They look to have adjustable push rods. Each valve has two springs on it. The rocker assemblies are different then the ones on my stock motor. Can someone shed some light on what i have? And if i can adjust valves to quiet them down? I can post more pics if needed. The first two pics are the current ported and polished heads. The second two pics are my old motor and stock heads

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  2. Aug 15, 2019
    mike starck

    mike starck Member Sponsor 2019 Sponsor

    salem,oregon
    Joined:
    Jun 22, 2006
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    Yep ,someone has fixed you up with adjustable pushrods. Check with camshaft manuf. for adjustment specs. Comp Cams spec is .30" after zero lash .That comes out to 1 turn on adjuster with a 10-32 adjuster screw.I bought the adjustable pushrods for my engine from Smith Bros Pushrods.Very nice product and well worth the money. mike
     
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  3. Aug 15, 2019
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
    Joined:
    Jul 16, 2007
    Messages:
    528
    The pushrods do indeed look to be adjustable. Seems as though there would be no harm in attempting to adjust them.
    Note, considering that the engine is not stock the lifters could be either hydraulic or solid.
    Typically, hydraulic lifters are set with preload, the distance between the retaining snap ring and the plunger seat when the valve is closed.
    Solid lifters are set with mechanical clearance, a.k.a lash.
     
  4. Aug 15, 2019
    mike starck

    mike starck Member Sponsor 2019 Sponsor

    salem,oregon
    Joined:
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    Not knowing the exact parts used to build your engine does leave you at a disadvantage. Some research will be needed to hopefully find out what camshaft you have. Good luck with your project.
     
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  5. Aug 16, 2019
    NCRenII

    NCRenII yellow fever Sponsor

    Far Nor Cal
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    Sep 22, 2017
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    might also verify if you have hydraulic or solid lifters before changing much.
     
  6. Aug 16, 2019
    OzFin

    OzFin Vintage Jeep Guy

    Michigan
    Joined:
    Jul 16, 2007
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    Note: Since you are asking for advice here we will presume that you are unable to ask the builder of the engine for the info, also the presumption is that this engine has been "broke in" and we are not dealing with a fresh rebuild that has not had any runtime on it.

    Okay, with that out of the way...a possible course of action would be to run the engine until warm then listen at the tailpipe for whatever exhaust tone is present, make a note of what it sounds like

    Then adjust the exhaust valves to zero lash plus an additional 0.30" as in Mikes example.
    Then run the engine again and listen carefully to the exhaust at the tailpipe...if they are solid lifters you may be able to hear a distinct "popping" . The popping would be the solid lifters holding the exhaust valve slightly open during the ignition of the cylinder gases. Don't run it long this way or valves can be burned from not fully seating during the ignition/combustion process.

    I would think that if they were hydraulic lifters in good condition there would be up to 0.30" of adjustment from zero lash and the valves would fully close and therefore no distinct popping noises out the tailpipe.
    I would only try this on the exhaust valves, if done on the intake there could be a similar popping (backfiring) in the intake manifold. Backfiring through the intake/carburetor can cause damage to the carburetor's power valve.

    If you have solid lifters and they are out of adjustment you may be able to quiet them down with the proper adjustment but there will likely always be some lifter chatter present, especially during cold idle.
     
  7. Aug 16, 2019
    CJ Joe

    CJ Joe Truckhaven Tough!

    Vista, CA
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    Nov 9, 2002
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    OzFin is right, some lifter noise is preferred. "Its better to hear them, then smell them".
     
  8. Aug 16, 2019
    Oldriginal86

    Oldriginal86 Member

    Pasadena, Md.
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    Nov 5, 2014
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    If you push down on the pushrod end of the rocker arm the lifter should bleed down after a reasonable amount of time. If they are solid, no movement should be evident.
     
  9. Aug 17, 2019
    53A1

    53A1 Member

    Kern Co. Ca.
    Joined:
    Jun 17, 2008
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    I agree. My amateur observation is there is more valve noise at idle and get's better when oil pressure builds. I assume this is because oil pressure adds more resistance to the lifter? What's your oil pressure at 2K? Another scenario, maybe you have lifters and the pushrods were adjusted before the engine was primed and you have too little clearance at 2K?

    One thing I am confident on is If you adjust the pushrods and you have lifters I would prime the system before adjusting. Pull the dist and use a drill motor and chopped off screw driver. Don't drop the priming tool down into the timing cover.
     
  10. Aug 17, 2019
    Keys5a

    Keys5a Sponsor Sponsor

    Florida Keys
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    If you have those adjustable pushrods, they were used for a reason. Most likey, you have a solid cam in there too, and you are required to have a clearance between the rocker and valve stem. Usually, the exhaust side has a larger clearance than the intake side. You really need to know what cam you have to know the manufacturer's specs for the clearances. At least check the clearances you have from cylinder to cylinder to see if they are consistent. You need to rotate the engine to check each valve when the lobe is opposite the rocker. You can probably check 3 valves at a single crank position by observing which are opposite the rocker. Be sure to mark each one measured before rotating to a different position so you don't miss any of the 12. Typically, a solid cam will make a bit more valve clatter than a zero-lash hydraulic cam with the engine running.
    -Donny
     
    Last edited: Aug 17, 2019

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