Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

she cuts out

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by ChadL, Jun 30, 2001.

  1. ChadL

    ChadL Registered Member

    Joined:
    Mar 31, 2001
    Posts:
    13
    Likes Received:
    0
    I have a 71 with a 300hp 350. when the shop rebuilt the motor we put on an intake from a 65 impala (with the crossover exhaust ports); I installed headers and didn't want my carb iceing in winter (colorado). now the problem: When the engine gets hot it wants to cut out especially if I'm getting on it. I figure the headers are boiling the gas before it reaches the carb. I'm not sure about the best way to insulate the l lines. Thanks for any help, it is very scary to have the blaze cut out when going up some of the passes around here.
    More info: tried a holly hp fuel pump (mech 7.5psi) but press would flood carb; went back to std 4.5psi. This did seem to help prob but didn't go away.
    Had the carb prof redone-Baker Auto, Buena Park,CA (714)994-2355. Tom Baker is a walkin Chevy bible.

    Am I missing something? How do I insulate the fuel line for extreme heat? Thanks for any help!!!!! ChadL
     
  2. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    One of the first things to try is a phonic carb spacer. This will keep the heat out of the carb.

    '71 Blazer CST with alot of rust
     
  3. Steve_Chin

    Steve_Chin 1/2 ton status

    Joined:
    Mar 6, 2001
    Posts:
    1,126
    Likes Received:
    0
    Location:
    Foster City, CA, USA
    Hmmm.. I have a functioning exhaust crossover and headers with no vapor lock problems. The fuel lines in the Blazer are acutally routed pretty well for keeping them away from header heat. If the problem is due to header heat, putting in a bigger mechanical pump isn't going to do too much for you because the heat soak in the lines is happening in the low pressure side of the lines. Liquids boil more readily at lower pressure... You might need to install a low pressure pusher pump close to the fuel tank so that the line pressure leading to the mechanical pump is at least at atmospheric pressure (increasing the temperature at which boiling occurs). Also check how close the muffler is getting to the supply line between the transfer case and the front spring eye, as a lot of dua exhaust installations position the muffler REALLY close to the little kink where the rear hard line joins the front hard line.

    A phenolic spacer might help if the source of the problem is the heat in the intake manifold. GM sells a carburetor heat shield that is more effective than a spacer alone. The heat shield was originally intended for the '82-'85 305 H.O. Z/28s and Trans Ams. I have the P/N at home and will try to find it.

    Another quesiton I would ask is how hot does your engine get? Maybe you need a bigger radiator and/or lower temperature thermostat as well...
     
  4. ChadL

    ChadL Registered Member

    Joined:
    Mar 31, 2001
    Posts:
    13
    Likes Received:
    0
    I have a low temp thermo. in the truck now. My radiator is a two core; a mistake inthe first few days of my project. I just have had other things to spend the dollars on that seemed more important. I will check the routing near the junction and see if the fuel lines are close. Any suggestions on what to insulate with? I'm also thinking of getting a shield for my starter but do not know where to look for that either.
     
  5. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    PAW and Summit both carry the insulation for hoses and starters.
    http://www.pawinc.com

    '71 Blazer CST with alot of rust
     

Share This Page