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Technical gas boiling looking for peoples vapor lock fixes

Discussion in 'The Hokey Ass Message Board' started by cobalt333, Sep 17, 2016.

  1. i have a 1972 455 olds engine and its boiling the gas in my fuel lines...want to see pics of what others have done to insulate and stop the heat tranfer from engine to lines and fuel pump carb ect...thanks
  2. You can use the tried & true cloths pin trick.:D

    Seriously,you can re-route your metal gas line away from the headers or exhaust or use a insulation wrap . HRP

    Last edited: Sep 17, 2016
    e1956v likes this.
  3. e1956v
    Joined: Sep 29, 2009
    Posts: 2,390

    Alliance Vendor

    You Crack me up Danny.

    Sent from my SAMSUNG-SM-G890A using The H.A.M.B. mobile app
  4. boltupal
    Joined: Dec 27, 2010
    Posts: 293

    from western ny

    Plugging the exhaust crossover in the intake manifold solved my gas boiling.

  5. you can also move the fuel lines farther away from the source of heat
  6. saltflats
    Joined: Aug 14, 2007
    Posts: 12,596

    from Missouri

    Do you have a fuel pump with the vapor return?
    AHotRod likes this.
  7. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,194

    from oregon

  8. AVater
    Joined: Dec 9, 2008
    Posts: 3,150

    1. Connecticut HAMB'ers

    image.jpeg Special alumonium clothespins
    timmy2times and Hnstray like this.
  9. Oh come on man,you know as well as anyone aluminum cloths pins are not traditional! :D HRP
  10. G-son
    Joined: Dec 19, 2012
    Posts: 1,286

    from Sweden

    A fuel pump near the tank pushing the fuel to the engine is fairly insensitive to vapour lock, since the fuel isn't hot there. Even if the fuel gets hot near the engine the pump still feeds fuel to the engine, while a front mounted pump can't pump anything when the fuel already has turned into vapour due to heat and the reduced pressure in the suction line before the pump.
    1927graham, clunker and czuch like this.
  11. Knew a guy in high school that wrapped all his lines in aluminum foil and swore to the moon and back it worked....but he did pull the lines out away from the block to get his hands around them to wrap the foil on lol
  12. proartguy
    Joined: Apr 13, 2009
    Posts: 667

    from Sparks, NV

    GM used a fuel filter which routed the hot vapor back to the tank in the '60s. I ended up eliminating the mechanical pump for a rear mounted electric unit. Solved the problem for me.
  13. Exactly. 12v helper fuel pump just after gas tank, a return line to gas tank, mechanical fuel pump on line, pressure regulator before carb, never worry about vapor lock again.
    '51 Norm likes this.
  14. saltflats
    Joined: Aug 14, 2007
    Posts: 12,596

    from Missouri

    Sounds like a little planning ahead and it should never be a problem.
  15. HLB
    Joined: May 19, 2014
    Posts: 20


    • Insulated fuel line and installed 2 wooden clothes pins next step block off exhaust ports on bottom of intake my heat riser is already off
  16. 270dodge
    Joined: Feb 11, 2012
    Posts: 742

    from Ohio

    First off, what are your fuel lines made of? Ma Mopar always said to use steel, never copper or aluminum. It's got to do with heat transfer.
  17. AVater
    Joined: Dec 9, 2008
    Posts: 3,150

    1. Connecticut HAMB'ers



    These are pre "Jetsons"
    Check the name and patina on the cardboard
    hotroddon likes this.
  18. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 12,336

    Bandit Billy

    Clothes pins? Geez! I run a 11:1 455 in my Olds. I run an electric in-tank electric pump. I have a phenolic carb gasket. I reversed the carbs dual feed line so it points at the firewall rather pulling fuel up the front of the hot block. Fuel line runs down the firewall to a Holley regulator and back to the pump. Insolate everything near a heat source. Never an issue even on hot race tracks on hot summer nights. Clothes pins? Maybe if there is a bra and panties hanging under the hood.
    flatheadpete, Hnstray and clunker like this.
  19. thanks for the info :) and gonna work on it this week
  20. main line steel and some rubber the steel to the carb and im gonna take that plastic filter and change it out to a glass one and insulate everything

    Attached Files:

  21. EZ Cool
    Joined: Nov 17, 2011
    Posts: 265

    EZ Cool
    Alliance Vendor
    from Slaton TX

    I either use a mechanical pump with the return line or use a metal inline filter with the return line. With either one you have to run a 1/4" line back to the tank for the return
  22. How hot does it get under the hood? How about some louvers to let the heat out... would look cool even if it didn't work.
  23. chopolds
    Joined: Oct 22, 2001
    Posts: 6,214

    from howell, nj
    1. Kustom Painters

    Insulation helps, but you need to understand the problem to find a solution. Anything under pressure has a higher boiling point, than when it's not. Most boiling problems stem from the lines that are under suction (supply side), where boiling points are lower. That is why the return at the fuel pump work, it keeps cooler fuel circulating, instead of sitting and absorbing the heat. So, fuel return works. That's why a helper pump at the gas tank also works. Insulating the lines wherever they come close to a heat source is a great idea, too. We use insulation, at work, that fits over fuel size lines, that is aluminized, and split, with a Velcro seam, so it's easy to install, and long lasting. You could even cover that with some old fashioned wire loom, to hide it.
    On my old 55 Olds, I finally had to insulate the bottom of the gas tank, as it sat so close to the ground, it picked up lots of heat off the asphalt, when running down the road, on very hot days.
  24. belair
    Joined: Jul 10, 2006
    Posts: 9,015


    A glass fuel filter housing is not a good idea.
  25. Tim
    Joined: Mar 2, 2001
    Posts: 17,172

    from KCMO

    Yeah I agree, metal filters. Plastic or glass are just asking for trouble
    DirtyDave likes this.
  26. Tim
    Joined: Mar 2, 2001
    Posts: 17,172

    from KCMO

    On that note it doesn't look like on your photos that you have any line that runs near a hot spot? Does it get near the manifolds or other exhaust as it runs back to the tank? Figuring out where it's getting heat will help a ton.

    If it's not close anywhere you can see I'd be leaning towards the carb spacers as a possible solution?
  27. blue 49
    Joined: Dec 24, 2006
    Posts: 1,827

    blue 49
    from Iowa

    Picture is pretty poor but it shows a little bit of my fuel line with the end of an insulating sleeve that runs back to where the fuel line runs along the side of the exhaust. Also shows the heat shield I made where the line runs very close to the exhaust down pipe. I've never had any vapor lock problems. 020.JPG

  28. blowby
    Joined: Dec 27, 2012
    Posts: 8,661

    from Nicasio Ca

    I'll vouch for that. Came out this morning, gas under my truck, coming from the fuel pump right at the seam. )(*& ethanol I guess. Had a new one on the shelf but it lacked the return line fitting (SBC) so I just plugged the hose. Went from being an instant starter hot to taking 5-10 seconds of cranking. Bummer. Not sure exactly how that return setup works but it sure seems to.

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