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F head engine noisey

Discussion in 'Early CJ5 and CJ6 Tech' started by jeeper50, Mar 28, 2008.

  1. jeeper50

    jeeper50 jeeps 'till I die

    Engine runs smooth at speed, no smoke at all. 40lbs of oil presure at idle. My project 3B has a mystery noise when the engine is idling up thru 1500 rpms, sounds like it coming from the valve train (sounds to high up in the block to be a rod.) Tried to figure out which cyl the noise is coming from by idling the engine and pulling the plug wires one by one, per the engine noise diagnosis 101 website. Noise stays the same. I adjusted the intake valves to spec .018"they we're real close, tried to set exhaust valves, but need to remove fender to get good access around the exhaust mani. When you shut off engine, noisey rattle is last thing you hear over exhaust until engine stops spinning.

    Lets hear from the F head gurus- what the diagnosis doc? :hurrican:
     
  2. jeep2003

    jeep2003 Well-Known Member

    maby the timing chain?
     
  3. Glenn

    Glenn Kinda grumpy old man Staff Member

    Has timing gears, not a chain. Are the rocker arms getting oiled?
     
  4. jeeper50

    jeeper50 jeeps 'till I die

    Pretty sure but I'll make sure lots of new oil in valve cover when I adjusted the intake valve.
    We're these old valves one piece or did they have any caps on the stem that could have come off? I know they're supposed to rotate, but also wondering what I'm going to find.
     
  5. mrhp

    mrhp Member

    Noisy fuel pump? Bad pumps often make noise.
     
  6. 66cj5

    66cj5 Jeep with no name

    valvetrain clatter?

    what weight of oil are you useing?
     
  7. jeeper50

    jeeper50 jeeps 'till I die

    It has 30w in it. I'll see if I can get a video of it running and post it on youtube or some other host.
     
  8. jeeper50

    jeeper50 jeeps 'till I die

  9. blevisay

    blevisay Oh Noooooooooooooooo! Staff Member

    Check Timing and recheck valve lash. Sounds like you are a little loose.
     
  10. jeep2003

    jeep2003 Well-Known Member

    it sounds bad :shock: Hope its not a rod knock . Let us know when you figure it out. I wouldnt run it much more though
     
  11. 1960willyscj5

    1960willyscj5 Well-Known Member

    Wouldn't the rod knock be there when he revs it up, too?

    Sounds like a FarmAll Cub engine.


    What is your idle set at? Mine is set to 900, book says 700.
    might check the little line at the back of the block to make sure it is supplying oil to the valve train.
     
  12. jeeper50

    jeeper50 jeeps 'till I die

    Yes, per the "engine noise diagnostic 101" website, rod knocks can be localized by removing plug wires one at a time. No noise change at idle when this was done. I'm leaning towards exhaust valve tappet noise and will be reporting findings soon.
     
  13. 1960willyscj5

    1960willyscj5 Well-Known Member

    Mmmm! Valve train rattle. Might also check the torque on the pedestals the intake valve train rest on. Moses Ludel says a tad bit loose on the valve train components (except those pedestals) is preferable to having them too tight. Do the intake valves come close to the pistons, or are they off set enough to miss if they open too far?:?
     
  14. jeeper50

    jeeper50 jeeps 'till I die

    Adjusted valves over the weekend, quieted down some, looks like the intake rockers have some slop on the rail. Perhaps it's time for several new parts.
     
  15. bkap

    bkap Gone, but not long gone.

    I don't know. Mine sounds like that all the time. I haven't adjusted the valves yet, so maybe we share a common problem. It almost sounds like a bunch of marbles rattling around inside the timing cover. :)
     
  16. Glenn

    Glenn Kinda grumpy old man Staff Member

    If everything is perfect they can be pretty quiet. Once there is any wear though in the rocker arm assembly they start getting noisy. Obviously poor lubrication due to being dirty or plugged up makes a difference. Oil flows through the entire assembly. It could just be partially plugged too.
     
  17. 1964_cj5

    1964_cj5 I'd rather be Jeepin'

    I found that running a bottle of Lucas oil stabilizer in with my oil helped quiet my engine down alot. I know that's probably not the best solution, but it worked at the time. Their gear oil also makes the tranny alot more quiet as well.
     
  18. jeeper50

    jeeper50 jeeps 'till I die

    I can buy a intake valve set (rockers, rail, mounts) for $73 at Walck's also try some pushrods. We'll see how that works. I need to do a comp test also, just to see where I stand.
     
  19. evanjm

    evanjm Yeah, it's got an F-head.

    could be something on top of one of the pistons. i'd pull the head just to check and rule it out, not to mention it'll always appreciate a valve job.

    - evan
     
  20. JeepPower

    JeepPower Hopeless Gearhead



    Ditto on that-- mine has always sounded like that-- even after the rebuild. I have to say that I didn't replace the rockers or the rocker shaft. It will improve a little with a valve adjustment, but comes back sooner or later.

    Did this noise show up suddenly?

    is there any loss of power or a misfire?

    Again, it sounds great-- remember, this is a engine design that came out of the 30's (as far as I know)