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F134 Exhaust Tappet Sticking

Discussion in 'Early CJ5 and CJ6 Tech' started by Scott Sherraden, Sep 30, 2020.

  1. Oct 1, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    First let me say that I'll definitely investigate that possibility before I pull the motor. Removing the head is a lot less work of course! And I will verify the valve moves freely on its own before going too much further...

    ...But keep in mind I've had the valve cover off and played with this. It's pretty easy to tell that the tappet sticking is what is happening here. It doesn't want to rotate very freely even when it is not under load from the spring and when the valve is down. Trust me, I know it's hard when you can't see it for yourself, but the tappet is sticking in its bore.

    All of the other 3 tappets rotate/spin easily and move easily in the bore. This one does not. You can get it to move with a wrench, but not with your bare fingers. The spring rotator is very free, it's fine.
     
    Glenn likes this.
  2. Oct 1, 2020
    47v6

    47v6 junk wrecker! 2020 Sponsor

    Washington DC.
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    Ok, then you're going to need to pull the cam. No way to get to them unless you pull it. When I last looked at buying rotator tappets they were unavailable. That was almost 25 years ago though.
     
  3. Oct 1, 2020
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    Rotators are separate from the tappets, at least on the F4.

    Willy's jeep parts has them listed-

    Engine Valves
     
  4. Oct 1, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    Yes from what I can tell the tappet is just solid 1 piece (except of course for the adjuster which is separate), Kaiser Willys and others have them in stock NOS. The cam lobe gives the solid tappet a rotating motion in addition to lift. The spring holder up above the tappet also rotates (it's called a spring rotator on Kaiser Willys site). Mine all rotate fine.
     
  5. Oct 1, 2020
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    :)

    Commercially they're called Rotocaps.
     
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  6. Oct 1, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    Advice and questions have been helpful! I've got a few suggestions to try out regarding spark. I'm also going to just give it a few more short road trips, hoping that maybe the Marvel Mystery Oil in the crankcase will do some magic and free up the tappet.

    If it doesn't, I'll have no choice really but pull the motor, pull the cam, replace the tappet and probably hone out that tappet bore.
     
  7. Oct 1, 2020
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    You can pull the cam without removing the motor, it's just not fun. :(
     
  8. Oct 1, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    I've looked into it before... long story in an earlier thread :) lol. There is the radiator support beam or whatever you call it in the way, agree it is possible, but not pretty!
     
    Glenn likes this.
  9. Oct 1, 2020
    47v6

    47v6 junk wrecker! 2020 Sponsor

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    When I rebuilt my F134, 24 years ago, before the internet, this stuff was impossible to find, and if you did, it was really expensive. I remember sending my crank out to the grinder with the special flywheel bolts. Of course they didn't come back, nor did the thrust shims. It was like trying to find hens teeth... Had to make my own shims out of shim stock to set thrust. Built that engine in my living room.
     
  10. Oct 1, 2020
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
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    Regardless of the cause, I suspect driving with the exhaust valve not seating will overheat and possibly burn it. The seating part of the cycle transfers heat from the valve head to the block. Although having no compression may reduce the effect of hot gases.
     
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  11. Oct 2, 2020
    Keys5a

    Keys5a Sponsor

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    I wasn't thinking! I still guess this is a valve sticking in the guide.
    I'll go back to my corner.
    -Donny
     
  12. Oct 2, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    That's what seems logical. But he can turn the tappet with a wrench and it frees up.
     
  13. Oct 2, 2020
    baldjosh

    baldjosh Member 2020 Sponsor

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    Crap...sounds more and more like the tappet...was hoping for an easier fix for you...super curious to find out whats causing this
     
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  14. Oct 3, 2020
    kenb

    kenb Member

    Detroit
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    Intermittent problems are the worst.

    Have you flooded the area around the sticky tappet with some penetrating oil? Something thin like kroil. Perhaps if there is some crud that could help break it up.

    As discussed I would certainly pull and inspect the valve before pulling the whole engine.
     
  15. Oct 3, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    Hi all! Well I tore into this more last night and things took a different (but good, I guess) direction. I was WRONG - (I admit it lol) - after really looking and studying carefully, my problem is NOT a sticky tappet. The problem was the valve sticking due to a combination of a few things, which many of you suggested earlier. I guess when I tried to move the tappet earlier, it still had spring tension.

    Last night I pulled the head so I could have a good look at all the exhaust valves. Here is what I saw after removing the spring and valve on #3,

    1. worn valve guides, really on all 4 exhaust valves. But #3 is the worst, that's the one that was sticking.
    2. The #3 valve is really burnt, galled really, I can't see how it could have seated properly.
    3. At some point one of the keepers on #3 wasn't seated and came loose, it didn't fall off, but it was on crooked and had a lot of wear. The spring rotor cap was either crooked or not properly seated, it was in a different lower position than the other valves. That was my first clue. The part of the valve that holds the keeper looks like it was damaged, either before or after this.

    So basically this exhaust setup on #3 was just a mess due to several problems, worn guide, valve keeper not in correctly, etc. I'll put the blame on my assembly last time I had this out I guess.

    So my next step will be to replace all 4 exhaust valve guides, install 4 new valves with new springs, new keepers etc. I won't have to take the cam out. I saw a clever video online showing how to make a tool to remove the valve guides from the top.

    This should all be relatively easy. The only thing that could bite me in the rear is that the exhaust valve seat on #3 is a bit rounded off. I'm not going to pull the block and take it to a machine shop, I'll lap it as best I can. I just hope it will seat well enough.

    If anyone knows a clever trick to clean up the bevel on an exhaust seat, with the block in the car, that would be nice :)

    Thanks everyone for the tips, to me it's pretty clear the way forward now.
     
  16. Oct 3, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    Oh just to add one more thing. Once I had the whole valve assembly out, the #3 tappet moves quite nicely just like the others, it isn't bound.
     
  17. Oct 3, 2020
    Scott Sherraden

    Scott Sherraden Member

    Kansas
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    Oh and another thing, if anyone can point me in the right direction, I need to find the right tool online to install the valve guides once I have the old ones out. It's a valve guide driver or drift tool. I see a lot of them online but not sure what size is needed.
     
  18. Oct 3, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Well, glad you finally figured it out. With your valve guides being worn you might not be able to just lap the valves as you hope to though. New guides could prove the seats hammered and off center.
     
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  19. Oct 3, 2020
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
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    In the old days there were sets of cutting tools and guides that could do that. Still are. Maybe you could locate one, or recreate one.

    Merely lapping is likely to leave the seat over-wide, and it will tend to not seal well and/or fail more rapidly.


    Valve tool- Bousfield Valve Seat Tool Set-In Box, Made in USA -REDUCED | eBay
     
  20. Oct 3, 2020
    Keys5a

    Keys5a Sponsor

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    Your valve seat is likely the most troubling part to repair. I used Neway seat cutters, but often the resurfaced faces will be recessed too far below the deck. If you have a badly pitted/damaged seat, a hardened seat needs to be installed. This entails cutting the block to accept a pressed-in seat. Just from the shavings created, the engine needs to be out for this work to be performed. I'm used to doing this work on heads, but a block (because f-134 exhaust in block) makes things a bit harder to work with.
    Original valve guides can be reamed to accept bronze sleeves that are ball-broached in place. I would pursue this method before replaceing the guides. The guides need to be refreshed before any valve seat work is performed due to mandrels inserted in the guide are what center the valve seat cutters or stones.
    -Donny
     
    Last edited: Oct 3, 2020

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