Solving heat soak gas vaporization with elec fan

Heating, Cooling & AC

  1. sputnik 440

    sputnik 440 Capt Jim FBBO Gold Member

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    I am having a severe problem with a 440, with headers and with minimum air space, overheating when turned off. The compartment gets so hot that I cannot grab on to the Holley filter which is placed 4 inches ahead of the fuel log for the Holley DP 4150. The fuel boils out of the carb and the car is next to impossible to start (WOT and crank for 15 sec and leave "idle" at 4,000 rpms+ until bowls fill back up). I have looked at wrapping the headers, insulating the fuel line and filter and fuel log. I have evaluated putting in a return line from the carb to the tank by use of a regulator with a return outlet. Here is why I am placing this on the heating , cooling section of the form. I'm thinking that the simplest way to get the engine compartment cooled down when I stop the car is to bring cooler air into it and displace the heat from the engine and headers. Question: If I replaced the stock fan with an electric fan(s), can I regulate the fan staying on until the temp in the compartment comes down to a point where it will not boil the fuel (approx 170 degrees)? If that concept works, will it be too big of a drain on the battery? What kind of thermostat would be needed to kick the fan on and off until the ambient temperature in the engine compartment is cooled below the 170 degrees? Any other ideas to solve the "overheating problem"?
     
  2. BIGSHCLUNK

    BIGSHCLUNK FBBO Gold Member FBBO Gold Member

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    I ran a thermostatically controlled pusher fan on my HEMI for years. Finally when my rad started to get the "green" death I had Bob @ Glen Ray just make me a heavier duty unit.............

    as I recall I got everything from JEGS
     
  3. SDCoronet

    SDCoronet Well-Known Member

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    I have a similar experience with my 318. I got the Edlebrock heat-insulating manifold gasket and that helped alot with the hot starting issues, but the carb still gets too hot in my opinion. Eventually, I will get a Holly Sniper, and I suspect it will fix all of these issues.
     
  4. 67belvedere/225

    67belvedere/225 Well-Known Member

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    ceramic coating the headders is the way to go . I like the idea of the cooling fan running on after to keep temp down
    If I rember vw jetta like a 89 had a sensor on the head and ran the fan relay.
     
  5. Glenwood

    Glenwood FBBO Gold Member FBBO Gold Member

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    Went through this same type of issue last fall and I'm still fine tuning the cooling system.

    https://www.forbbodiesonly.com/moparforum/threads/underhood-heat.138369/

    The ceramic coated headers helped a lot as my hp manifolds would retain a lot of heat. The shroud made a difference in my case as the heat was sort of just being circulated under the hood instead of channeled below the motor somewhat. Timing and carb tuning all seem to contribute to engine heat, but the shroud and headers probably made the largest improvement. Still gets quite hot under there on hot days though.
    A phenolic carb spacer is a must for my eddy carb due to the fuel bowl location. It didn't help that the exhaust under the carb was not blocked off either. The new heads do not have this passage thankfully.
     
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    • Yatzee

      Yatzee Well-Known Member

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      By using a quality electric puller fan, a relay and one of these, you can have your fan stay on for up to 3 minutes after shutting the engine off:
      http://www.dakotadigital.com/index....t_id=852/category_id=403/mode=prod/prd852.htm

      I use these on both my classics and have had them on for five years. You can feel the heat come out from under the back of the car.
       
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      • 5.7 hemi

        5.7 hemi FBBO Gold Member FBBO Gold Member

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        This helped my dads car.......take off the inspection plates on either side to allow air in. The plates I’m referring to are for adjusting the uca.
         
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        • multimopes

          multimopes FBBO Gold Member FBBO Gold Member

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          I have 2 electric fans that run off an adjustable Derale controller. I spliced in a manual run through 2 separate switches so I can switch on one or both fans at will. Had it that way for many years. I especially like to run the drivers side when fueling up with engine off to help cool the starter, which used to bind from header heat. I also wrapped my headers years ago. Much better now.
           
        • 66 Sat

          66 Sat Well-Known Member

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          I don't know what set up you have with the hood and your thoughts on originality, but I've converted my twin hood scoops from fake blanked off scoops, to functioning. They aren't connected to the carb, so no "ram air" type effect, but they let cooler air in during driving and then hot air out when stopped. I cut a hole under each with a holesaw, probably 3" diameter.
          Another thought is the location of the fuel filter. The large surface area of the filter picks up far more radiant heat than the fuel line - I had to re-position my filter near the chassis rail (before the fuel pump), instead of having it sitting over the intake manifold.
          I don't think there is one simple fix - if you live in a hot climate it is a combination of lots of small upgrades that lead to a big difference.
          If it's not a daily driver and you have a few minutes spare, even popping the hood for 5 minutes when you stop might help?
           
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          • sputnik 440

            sputnik 440 Capt Jim FBBO Gold Member

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            Yatzee -- that is what I am looking for, I think. I think 3 minutes ought to be enough time to expel the heat and cool the headers to a point that they won't contribute to boiling the fuel. Any idea what kind of battery drain you see? Ever have a problem? do you have a recommendation for a puller fan? I am running a '67 Satellite with 440 and 2" Hooker headers. I have an over sized 4" dual cold air intake system that takes up a lot of room in the compartment (they actually go all the way to the radiator support where a hole has been cut the size of the filters, also, the photo doesn't not show the filter and fuel line running in front of the intake manifold).. The 440 has a 26" radiator. Are you running the system now? What speed is usually enough to not have to run the fans? Guess I need to get smarter on what is out there.
            Satellite engine with cold air intake.JPG
             
            Last edited: Aug 23, 2018
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            • sputnik 440

              sputnik 440 Capt Jim FBBO Gold Member

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              66....that is exactly what my restoration guy said to do. I remember looking at the scoops when I first got the car and wondered why they were not functional. I see them feeding cool air into the compartment which would benefit the temp of air being sucked in through the intake filter, but I don't know if it will expel enough to remedy the heat soak when stopped. It should help to take away some of the temp created when running, thereby reducing the source of the heat. You are right, no simple fix. A little of this and a little of that. I do like the elec fan controller mentioned by Yatzee. Any thoughts on that? I insulated the filter and line. Just one of the "little of this" to stop the boiling.
               
            • sputnik 440

              sputnik 440 Capt Jim FBBO Gold Member

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              Multimopes, what make and size of fan do you run and for what size radiator? Do you run the fans when cruising? At what speed would you turn them off? Any idea of battery drain and max number of minutes before enough is too much on the battery?
               
            • sputnik 440

              sputnik 440 Capt Jim FBBO Gold Member

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              They are coming off. The car never, never goes out on a bad weather day and we have no dust problem. Ever think of adding a deflector of sort to eliminate road dirt from coming through?
               
            • Brewzer67

              Brewzer67 Well-Known Member

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              This is exactly the setup that I have employed. I use an electric water pump, dual electric Spal fans, a phenolic spacer, and thermotec wrap on the fuel line and no more hot start issues. When I shut the car off I let the fans and pump run for 2-3 minutes and that is more than enough to keep the fuel from boiling out of the carb. I have never had any issue with the drain on the battery being too much.
               
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              • coloradodave

                coloradodave FBBO Gold Member FBBO Gold Member

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                Take your hood off and see if it still hot soaks. If that works, make a couple of aluminum spacers to go between the hood hinges and hood to allow hot air to escape the compartment below the windshield. When I was a Corvette guy, in the summer I used to run with the hood 'popped' (rear opening) to ventilate the engine compartment. Ceramic coated headers (BIG difference in under-hood heat), carburetor phenolic spacer, custom aluminum shield under the fuel filter should all help. Leave the filter on the output side of the mechanical pump.
                Have you ever used an infrared temperature gun pointed at your headers near the exhaust ports? Retarded timing will put ALOT of heat in the headers that then gets radiated into everything under the hood. An engine running too lean will add to heat build up as will a newly rebuilt engine.
                 
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                • sputnik 440

                  sputnik 440 Capt Jim FBBO Gold Member

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                  I have a one inch wood gasket which is good for stopping conduction of heat from engine, but I think I am having more of a problem with convection. I have a FAST efi on a 383 in a duster and have no problems. I ordered a Holley Sniper for it, but thought I would give the FAST a better chance than I have given it. I would go to the Sniper.
                   
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                  • sputnik 440

                    sputnik 440 Capt Jim FBBO Gold Member

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                    'nough said, just got to open up the pocket book and let'er fly. Thanks Brewzer and all contributors. Man this forum is "hot".....sorry 'bout that.
                     
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                    • sputnik 440

                      sputnik 440 Capt Jim FBBO Gold Member

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                      67Belvedere, agree, the ceramic headers are the way to go from the beginning. I am to old to pull the engine to get mine off and coat them. By the way, I read on the fuel thread that Summit offers a coating that is wiped or painted on both the inside and outside of the headers and it is supposed to reduce 90% or radiated heat from headers. Sure would like to hear from someone that has used it for the purpose we are talking about. come to think of it, even my Kawasaki Mule has an electric fan that stays on to cool the engine temp after it is stopped.
                       
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                      • multimopes

                        multimopes FBBO Gold Member FBBO Gold Member

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                        Multimopes, what make and size of fan do you run and for what size radiator? Do you run the fans when cruising? At what speed would you turn them off? Any idea of battery drain and max number of minutes before enough is too much on the battery?

                        My fans are 11". Not sure of CFM as I am at work currently. My battery is an Optima red which is trunk mounted and is 7 years old. I run a 95 amp alternator. I have a 73 Satty RR clone and there are access panels at each shock tower that I used to remove to help dissipate heat. I also has removed the rear hood to cowl seal to let the heat out the back of the hood while driving or stopped. For some folks this would also let that heat enter the car via the heater box, which I don't have so I blocked off that opening in the passenger side above the kick panel. I will attach a picture of my fans which as I said run automatically or by my manual switches. I also installed little fan run lights under the dash so I know if the fans are on when running down the road. Because of my headers and 3" exhaust I can't hear the fans when tooling down the road. DSCF3564.JPG
                         
                      • sputnik 440

                        sputnik 440 Capt Jim FBBO Gold Member

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                        I like the set up and the little lights under the dash. Yep, those 3" pipes rumble a lot. I like to auto and manual control. Thanks for time you are taking at work. Tell your boss I said for you to take the rest of the day off.
                         
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