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Thread: 496 overheating

  1. #1
    Member MASTER JOURNEYMAN
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    496 overheating

    Hello, the car is a 1972 Ventura. I originally had a be cool radiator with two one inch tubes, the radiator is 26X19" and the core is 22X19. I had a 2700 cfm electric fan with a shroud on it and the motor would creep to ~230-240 and I would shut it off. The weird thing is that if I let the car sit at an idle, and dont drive it, it never gets over 200. As soon as I start driving it, it slowly starts creeping up. We figured that the radiator must be clogged as it was an old radiator so we bought a new triple pass FSR crossflow radiator. We are still using the same fan and shroud and it runs a little cooler, but still gets to 220-230. I am wondering if a mechanical flex fan with a shroud would have a good chance of solving the problem. I think the electric fan and shroud may be causing more airlfow restriction than anything and that the mechanical fan would help. Below is the fan and shroud I am thinking about as well as the fan and shroud I currently have. Does anyone have any experience with a mechanical fan and shroud like the one I am looking at?

    This is the exact fan and shroud I currently have.
    http://cgi.ebay.com/ebaymotors/64-67...mZ150125394870

    This is the flex fan I am considering
    http://www.jegs.com/webapp/wcs/store...44431_-1_10115

    This is the shroud I am considering, I may run two, one right side up on top and the other one upside down on the bottom.
    http://www.jegs.com/webapp/wcs/store...56129_-1_11483

    If it matters, I have a march pulley kit with a long water pump

    Thank you
    Adam

  2. #2
    Administrator RACING JUNKIE bjuice's Avatar
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    1st off you did good by getting another raditor....i think your problem lies in the speed your running water thru the block...
    at this time is sounds way too fast.......this explains why it heats up when you start moving the car in gear.The manual water pump speeds up with the crank speed therefore starts circulating the water faster...The water is not in place long enough to draw heat away from the block..

    what size pulley do you have on the water pump and what are you using where your thermostate goes ?.......Your gonna need a restrictor in place to slow the water down.....most people just take the center out of the thermostate and place it back under the water neck..
    try this 1st before changing pulleys...the next step would be to change the pulley to a slower rpm pulley...but i think the restrictor will help a bunch

    Brian
    Bjuice..

    "I'M YOUR HUCKLEBERRY ! "

  3. #3
    Member MASTER JOURNEYMAN
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    It currently has a 180 thermostat. The water pump pulley is 5 inches and the crank pulley is 7 inches which would spin the pump pretty good. I will have to try a restrictor plate. Do you have any experience with the mechanical flex fans? Is there a reason that you say it is a good idea that I got a new radiator?

    Thanks,
    Adam

  4. #4
    Senior Member MASTER BUILDER
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    Do you have the fan sucking or blowing, that can make a difference when driving.

  5. #5
    Member MASTER JOURNEYMAN
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    I originally had one sucking, now I have both. Going with both make a little difference but not much.

    Adam

  6. #6
    Senior Member MASTER BUILDER
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    If you have the fan pulling air into the radiator through the grille, I would agree with bjuice, its probably thermostat related, the water is traveling through the radiator and block too fast to be cooled down when rpms are up.

    Have you tried it without the shroud, that looks like it would trap alot of heat, but I have never ran one like it.

  7. #7
    Administrator RACING JUNKIE bjuice's Avatar
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    Adam...no paticular reason for the radiator you had..however the cross flow is an ideal radiator.. i run one of those also with no over heating problems...many do not know of this company but a few guys left "Griffin" radiator and opened up their own Raidiator shop here in the upstate of S.C.....their name is "KARRHOUSE" out of Anderson S.C....they will custom make any radiator for anyone..i have a custom CROSS FLOW MADE with 2 ros of 1.5 inch tubes...for $330.00......

    take out your thermostate and take the center of the thermostate out ..this should just leave a flat metal shim with a 3/4 inch hole...

    try this 1st..its quick, inexpensive and may just work.....

    if it doesn't help enough your going to have to slow the water down by placing a different pulley on the water pump that will slow the water down...


    yes i have had some luck with the flex fan's..they are good on a true street car that see's a lot of street driving...keep your electric fan on the car and make sure what ever side you have it mounted on thats its pushing or pulling the right direction.

    i think you will find that when you slow the water down you will not need a electric fan.

    i have a 511 bbc in a 3,000 lb camaro...i run a CSR water pump and i have an adapter ( see jegs part#555-53087 page 70) that comes off the top radiator outlet that allows me to run a #12 braided line into a #12 fitting that bolts over the waterneck...so you can see how i restrict it..
    i can make a full pass and come right back around into stagging for another pass and it never gets above 185 degree's

    take a look at ( jeggs part#555-51105 page 71)..this is what the restrictors look like if you bought one instead of making your own..


    i have Years of round track experience as a Pit man and garage monkey, we have diagnosed and fixed many overheating problems..,from spiining a water pump to fast to fabricating a high tech shround with vent ducts etc...

    i would bet A SHINING PENNY...you place a restrictor in place of your thermostate ...1st.....then 2nd if it doesn't cool it down enough...get a pulley to slow it down..

    thanks- Brian
    Bjuice..

    "I'M YOUR HUCKLEBERRY ! "

  8. #8
    I'm having the exact same problem? :evil: I have a 10 1/2:1 540 in a 3100 Monte Carlo, Griffin radiator 3000 cfm electric fan..had it pulling air from the back side of the radiator, now in the process of moving it to blow thru the radiator. I also had a 160 thermostat, then put a 190 in and no luck. Also, tried taking out the antifreeze and put in straight distilled and water wetter..which I believe kinda helped? I did put a March underdrive pulleys on, which still didn't help...HELP!!!??? Think taking out the thermostat and running just a restrictor will help me too? Thanks in advance for the good info already!

  9. #9
    Administrator RACING JUNKIE bjuice's Avatar
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    yes i think it will...water moving to qucikly thru a block is the culprit in many situations...try the restrictor..also make sure your cooling system is purged really well...One air pocket will cause you a heap of problems.

    when i purged mine i left my electric wtaer pump on for 30 to 45 minutes straight with cap off front wheels elevated 3 inches off the ground.

    deadenbear makes a bolt on water neck that will purge for you but its expensive plus its something you can do on your own..

    BRIAN
    Bjuice..

    "I'M YOUR HUCKLEBERRY ! "

  10. #10
    I have a question. If I gut out the thermostat wouldn't it flow at the same rate, but now all the time? By the way thanks again.


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