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Poly Oil Gauge Line Starts Fire!

Discussion in 'Jeep Truck and FC Tech' started by 70cj5134f, Aug 21, 2020.

  1. Aug 21, 2020
    70cj5134f

    70cj5134f Member

    East Tn
    Joined:
    Aug 18, 2018
    Messages:
    749
    62, built over 100 engines, first fire!
    Oil gauges used to come with copper line.
    To save 1.25$ they now come with poly line.
    I spent extra time routing and tieing line away from headers.
    During cam break in, 3000rpm, bout 5 min in, nice and hot, Flames.
    Then the key off wouldn't kill the engine(No diode in GM alt yet).
    Shorted out coil with ext to kill.
    Took the shop fire ext and the 1 out of the truck to get fire out.
    I figured I'd melted a line?
    But upon investigation, I find the line blew out of the Ferrell and nut.
    And yes nut was tight. Oil pressure @3K was around 60 warm, good for AMC.
    I'll never use poly again, I'll pay the 12$ extra for the copper that should come with.
    Glad it happened in shop bay, even though it damaged the ceiling slightly, if it would
    Have happened on a test drive, it probably would burnt to ground?
    A bunch of toasted wires to patch now, nothing major lost.
    Oil makes a dang big hot fire.
    Until it cooled I wasn't sure what killed the engine, was Nervous the bearings
    Might have seized. Got lucky put a socket on ballencer and over she turned,
    Only 2 qt low on oil, don't think any internal damage!
    Please use copper line folks!
     
  2. Aug 21, 2020
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    WOW
    That sucks. I"ve got 3 jeeps with poly line
    Glad you saved it
     
  3. Aug 21, 2020
    Snoops

    Snoops Making progress, slow but at least it's forward! 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Idaho
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    I've read threads on this site that recommend stainless overbraded poly instead of copper. Maybe someone remembers the source?
     
  4. Aug 21, 2020
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Aug 3, 2003
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    I've had a poly line break from fatigue. Don't care for it.
     
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  5. Aug 21, 2020
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Northern California
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    The only instance I can think of where I would use the poly oil pressure line would be on my mother in laws vehicle.......
     
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  6. Aug 21, 2020
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    :rofl:LOL:rofl:
     
  7. Aug 22, 2020
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    And if you use copper line, put a few coils in it (like you see in steel brake lines under the master cylinder) to act as a shock absorber. If you don't the engine vibration will eventually cause it to break DAMHIK.
    Even better, use a braided steel line.
    Or even better, keep the oil in the engine & use a good quality electric gauge....
     
    ITLKSEZ likes this.
  8. Aug 22, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    Another tip... run fuel hose over the copper line anywhere it *might* come in contact with metal. That stuff loves to pretend it’s a ground strap, and it doesn’t take much to arc through it and cause a hole.
     
  9. Aug 22, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sep 21, 2002
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    Personal opinion but I'll take my chances with nylon tubing any day of the week. Even when coiled copper is subject to vibration. Original poster said the nylon tubing blew out so something went wrong on installation it would seem. It's easy to forget to remove the line and check that the ferrule is holding good. This is an instance where as colojeepguy noted a good electric gauge is the best bet.
     
    Ol Fogie likes this.
  10. Aug 22, 2020
    baldjosh

    baldjosh Member

    pacific north west
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    Oct 24, 2017
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    451
    x2
     
  11. Aug 22, 2020
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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  12. Aug 22, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Definitely a nice kit.
     
  13. Aug 22, 2020
    70cj5134f

    70cj5134f Member

    East Tn
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    Yes the Ferrell was in right flat end against nut, cone end into fitting, at least 1/4 in line in past Ferrell . Nut was tight, threads not distorted upon disassembly. It was a bastards size line and fitting from China, us pipe thread male X China poly compression. My other leftover poly kit parts would not fit it. It was a bad experiment on my part, I bought the cheapest 3 gauge kit off eBay from China, took 3 weeks to ship, looks nice but odd size fittings, water temp sender odd also . My 401, bout 500hp, blueprints oil pump runs 60psi warm, most AMC 8s don't get that high, it still should have bit the Ferrell into the tubbing and not blown .
    Anyway it sounds real good, lol.
     
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  14. Aug 22, 2020
    Admiral Cray

    Admiral Cray I want to do this again.. Staff Member

    Bainbridge...
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    The only thing I use poly for on vehicles is the boost gauge on my truck. If it blows nothing will happen...
     
  15. Aug 22, 2020
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    I’ve had good luck with copper. Been running it on my CJ-5 since 1989-90 but the run is long and it can distribute the flex over a very long distance. I do check it periodically. I’ve seen far too many failures with poly. Back then the electric gauges were not reliable and were not sealed well enough if they got wet. The new ones are far better.
     
  16. Aug 22, 2020
    Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Silver Hill,...
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    X2 & X3 !
     
  17. Aug 23, 2020
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Virginia Beach, VA
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    the PO did a mechanical oil gauge
    it puked all over floor once . never again
     
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  18. Aug 23, 2020
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    I still prefer the instant and sensitive response of a mechanical gauge. It can tell me a lot more about a situation.
     
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  19. Aug 23, 2020
    CHUGALUG

    CHUGALUG Member

    Silverton, OR
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    When did Gauges come with copper line. I can remember the SUN oil Pressure gauge I put in my 67 chevelle in 1978 having a nylon line. And so has every gauge I have used since I believe. On my Willys Build I am using a -3AN braided hose going too the Fuel pressure safety switch and the SW Oil pressure gauge.

    [​IMG]
     
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  20. Aug 23, 2020
    Admiral Cray

    Admiral Cray I want to do this again.. Staff Member

    Bainbridge...
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    Wow...

    Why haven't I seen this engine before?... :susp:

    Is there a build thread?...
     
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