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Discussion: Purpose Of Stay Cable

Discussion in 'Early CJ5 and CJ6 Tech' started by ITLKSEZ, Oct 30, 2018.

  1. Oct 30, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    I didn't want to hijack Juffer's thread with this discussion.

    I'd like to bring up for debate the practical purpose and original intention of the stay cable.

    [​IMG]

    I keep seeing the popular opinion going back to mitigating clutch chatter. This never made sense to me, and still can't wrap my head around the concept. I don't understand how a longitudinally placed cable that is supposed to be loosely adjusted is going to help calm a torsional movement.

    According to what Juffer found on the CJ3 page, it's explained in a manual to keep the drivetrain in place under hard braking or collision: "On page 34 of the Maintenance Manual for Willys Model MC-38 (a military sibling of the CJ-3A) it is explained. Here is what the manual has to say...
    "The engine is prevented from moving forward on the rubber mounting, when a sudden stop is made, by the engine stay cable which is attached to the left side of the flywheel bellhousing in the front and to the frame cross member at the rear. The length of the cable is adjustable to provide correct tension through a threaded end mounting. Do not overtighten the cable. It should be adjusted to provide 1/2" up and down movement by thumb pressure.""

    Taking into consideration its proximity to the rubber mounts, if adjusted to those above specs (with added warning not to overtighten), the engine would almost have to spin out of the bay before it acquired enough tension to tighten under torsion.

    The most publicly accepted theory I've seen on this site is this one: Mystery cable on bell housing

    I find flaw in this theory in two ways. One, the chatter starts before the vehicle will begin to move, so vehicle inertia is a moot point. Without fore/aft inertia, the engine only has torsional inertia, bringing us back to my first point. And two, some of the records of people complaining of clutch chatter are ones with late-model V6s that have a clutch cable rather than linkage. I'd think this would isolate the movements from the pedal from the engine a little more than the mechanical linkage, taking it out of the equation.

    Thoughts?


    :ninja:
     
    Beach66Bum likes this.
  2. Oct 30, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    I once caused the engine of a M38A1 to move forward & through the radiator by running it nose first into the bottom of one of those bumpy things they put into tank training grounds.

    The stay cable did not seem to be effective at preventing this. :whistle:
     
  3. Oct 30, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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  4. Oct 30, 2018
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    Don't know how it works but many of these Jeeps simply WILL NOT back up without the cable in place. Some have said that it has to do with the rotational force of the engine turning one way and the driveshaft turning the other way when in reverse. I have a steep driveway in front of my garage and you simply cannot back up my driveway without the cable in place. The adjustment isn't 1/2" of slack, it is a 1/2" of deflection which means the cable is supposed to be pretty tight.
     
  5. Oct 30, 2018
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

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    Following this as my Jeep bucks pretty hard when doing anything but very easy backing.
    Are any of these parts available to purchase?
    It seems the mount in the photo is welded on as well as a large rivet. My cross member does not have that mount.
     
  6. Oct 30, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    The anti-chatter theory has been discussed since at least the late '60s that I know of. It was around '67 or '68 that I heard this at the Jeep dealer so it obviously does make a difference, although keeping the engine from going forward seems the most logical purpose.
     
  7. Oct 30, 2018
    Twin2

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    my question is why was this cable deleted when the clutch system went to the cable clutch . mine has never bucked in reverse . with any of transmissions I have used
    and now with the T18 it is just too slow going backwards
    so the only theory I see is it keeps fan from hitting radiator . going back to my corner :poke:
     
    tcfeet likes this.
  8. Oct 30, 2018
    colojeepguy

    colojeepguy Colorado Springs

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    My 70 with cable clutch doesn't have it, and it backs up fine.
    My dad's 69 with a linkage clutch definitely has chatter in reverse, he bought it when it was 10 years old and had only 11,000 miles on it, and he says it's always done it.
     
  9. Oct 30, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Was the cable on any of the V6 Jeeps? I always thought it was only on the 4 cylinders, never paid any attention to whether or not it was on the V6's.
     
  10. Oct 30, 2018
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    Noone has to believe anything. If YOUR Jeep bucks in reverse, install a cable or rod or ratchet strap and it will probably fix it. A lot of Jeeps have had to back out of my driveway and your's without a cable would probably buck in reverse here too. Doesn't matter if your one Jeep works without one, this is to help everyone else.
     
  11. Oct 30, 2018
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    Yes.
    Used on both F4 and V6.
     
  12. Oct 30, 2018
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

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    Above is a great photo of how it attaches to the X member. Anyone have a good pic of how it attaches to the Bell Housing?
     
  13. Oct 30, 2018
    gunner

    gunner Member

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    Every time I crawl under my jeep to just generally check on things, I'm confident that I understand how every component works as part of the overall system.

    Except for that stay cable. I look at it, give it a few seconds of thought, then:shrug:
     
  14. Oct 30, 2018
    rusty

    rusty Well-Known Member

    norfolk,va
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    My 75 bucks only in reverse. Everything else is just fine. I have looked everywhere for a cause. I understand the Jeep did not have one from the factory . Wonder if one would help?
     
  15. Oct 30, 2018
    dozerjim

    dozerjim Member

    western New York
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    I say put one in and extend the discussion....Daryl don't you have one to sell ?I don't recall if the trucks and wagons use one......
     
  16. Oct 30, 2018
    Daryl

    Daryl Sponsor

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    Whole pile of them on the shelf. I just hate shipping stuff.
     
  17. Oct 30, 2018
    55_Willys_CJ5

    55_Willys_CJ5 Nephews Visit 2017 2024 Sponsor 2023 Sponsor

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    Picture of the stay cable attached to bellhousing for the F134 engine with t-90 transmission at this link:

    20181030_163953.jpg
     
  18. Oct 30, 2018
    oldtime

    oldtime oldtime

    St. Charles,...
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    I've always contended that the cable stay functions as described in the USM.
    Basically to prevent one from tearing the insulators.
    2 insulators at the engine, 1 at the transmission and 1 at the transfer case.
    T90 insulators have been known to separate...especially old and oil soaked insulators.

    The cable stay was eliminated with later transmissions due to different transmission insulators.
    That's why the insulator design was changed.
    T98-A insulator on CJ's was the first insulator not to require the cable stay.

    The stay cable is not to be confused with the anti chatter cable.
    The anti chatter cable is simply Jeeps cable actuated clutch control system.
     
  19. Oct 31, 2018
    garage gnome

    garage gnome ECJ5 welder

    Western MA
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    This makes sense. Ted, who has a T18, doesn't have the stay cable. He doesn't chatter in reverse, maybe due to the more modern mount. Both my stock jeeps have the stay cable.
     
  20. Oct 31, 2018
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    I have one on my Jeep, I agree that it helps keep the motor and trans from moving in the motor mounts, and ripping the mounts apart. Just my opinion, but it makes sense to me. My Jeep does not chatter at all. Good Luck
     
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