Register now to get rid of these ads!

help...sbc cooling problems in model t

Discussion in 'The Hokey Ass Message Board' started by ford9inch, Jun 9, 2009.

  1. ford9inch
    Joined: Dec 26, 2007
    Posts: 100


    I have a very mild sbc in my model t, it's got a milodon high volume waterpump, and whichever year mustang radiator that fits in a model A shell, with a nice spal electric fan (don't talk shit, it was my only choice, unless a manual fan a few inches bigger than my waterpump pulley would be an efficient means of cooling), anyways, I built a nice shroud for the fan as well. It runs around 190-200 in town with a 180 stat...but once highway speeds are reached it climbs to almost 240!! The rad is mounted lower than the motor, so my filler is right ontop of the thermostat, the highest avoid air bubbles, and my fan is mounted engine side, it's not working against itself athighway speeds...please help me's really lame only being able to put around town...
  2. RClark
    Joined: May 14, 2006
    Posts: 147


    Make sure the waterpump has the right flow direction. They make some to run with serpentine belts that are meant to turn backwards. And make sure that any air is purged from the system. An air buble will create all kinds of headaches.
  3. wildearp
    Joined: Oct 24, 2007
    Posts: 522

    from tucson, az

    If that isn't a 4 row radiator, that is the first thing I would change. Try drilling a couple 1/8" holes in the outer ring of your thermostat first.
  4. Steves32
    Joined: Aug 28, 2007
    Posts: 1,280

    from So Cal

    Check bottom hose for an internal spring to keep it from collapsing.

  5. 53sled
    Joined: Jul 5, 2005
    Posts: 5,818

    from KCMO

    are you reading temp at the head or the t-stat? how many lbs is the cap? I have a 305 with my original 53 radiator, 6 lb cap and a 24 oz official PBR overflow tank, 19" flex fan (no shroud) and I haven't overheated on any of the 91* 95% humidity days yet. A friend had a camaro that acted like that, it had air bubbles in it. he used a flush and fill kit to chase them out.
  6. miller
    Joined: Aug 5, 2006
    Posts: 484

    from New Jersey

    The electric fan is it running when your going down the highway?..It should be in the off position...Miller
  7. tgabbe1934
    Joined: May 20, 2009
    Posts: 64

    from smithtown

    It seems like you have your bases covered. I have had a similar problem. when the water pump is flowing too much water. If the water does not spend enough time in the radiator it will not cool effectively. I had a street stock circle track car that had a similar problem, I used an underdrive pulley to slow down the accesories, and it corrected the problem. just an idea
  8. timing would cause this issue also,i would run 18 initial,20 centrifugal and vacuum cannister at 14 total so you got 38 total +14 vacuum = 52 all in by 2800/3000 rpm,it'll make a world of a difference,180 t-stat with two 1/8" holes is good,fan should be roughly 3/4"-1" away from radiator also 4 core radiators help and a "water wetter" additive helps too,make sure coolant is 50/50 mix ethylene glycol and distilled water this should take care of most over heating probs.
  9. RichG
    Joined: Dec 8, 2008
    Posts: 3,919


    Is your shroud preventing free air flow at highway speed? You might want to try taking the shroud off first and driving on the highway, see if that helps. If it does, make some ports in the back of the shroud for airflow:D
  10. No hood top or sides?

    Air will flow around the radiator instead of going through.

    It takes the path of least resistance.


    While two 1/8" holes in the thermostat flange work ok, my experience with them is they extend warm-up times considerably in cold weather.

    One 1/8" hole works fine for relieving an air pocket and the engine warms up in about the same amount of time as it did when the thermostat flange was undrilled.


    Miller is correct about the fan being off at highway speeds.

    If the prop is rotating on a dead engine lightweight airplane in a glide it creates more drag than if the prop was stopped.
  11. atomickustom
    Joined: Aug 30, 2005
    Posts: 3,388


    I'm with Electrodude - try it without the shroud. You might be stopping the flow of air through the core.
  12. musicrodder
    Joined: Aug 24, 2006
    Posts: 65

    from Upstate NY

    Lots of good ideas, the shroud could possibly be the culprit. My T has a sbc, Walker radiator, no shroud, 1/8" drilled thermostat, mechanical driven fan, complete stock hood w/side panels. The coolant mix is 50/50 and it runs cool even on the hotest summer days. The only time it was hot was the first start up after reinstalling the radiator it had an air pocket which is long gone now.
  13. lawful27
    Joined: May 8, 2010
    Posts: 10

    from Salinas

    I had the same issue for my T roadster running cooler in town and heating up on the freeway, then a custom radiator was made, now it cools well on the freeway but runs hotter in traffic 205-230 on cool days. So now my issue is airflow through a thick radiator.

    I was running an underdriven crank pulley, but it cooled better when I went back to 1:1 crank/water pump. Sounds like a bigger radiator might help, but you might end up where I am currently fighting the heat at slow speeds.
  14. 10secondA
    Joined: Apr 8, 2009
    Posts: 104


    wrong pulleys on your balancer and pump, you are spinning the pump to fast which causes a cavitation in the water pump thus not flowing water at freeway/highway speeds put a smaller pulley on your water pump
  15. lawful27
    Joined: May 8, 2010
    Posts: 10

    from Salinas

    I cooled better by 10 degrees by removing the underdriven crank pulley. Having the water pump spin almost 1 to1 with the crank HAS COOLED MY engine BETTER. There was not enough coolant flow.
    If cavitation is prevelent in 1 to 1 water pump turns why do the manufactures produce them that way. They spend lots of dyno time to ensure enough coolant flow through the engines to prevent overheat. All of the overheat situations I have ever had have been on modified cars, not factory vehicles.

    In my situation speeding up the water pump helped not hurt. Most people under drive accessories to gain HP, I have a 1900 LB car with 500 HP, did not even notice the loss of few HP that it might take to spin the water pump faster.
    Last edited: Jun 26, 2010
  16. Ace50coupe
    Joined: Apr 7, 2010
    Posts: 122

    from Indiana

    Check the timing on the engine. If you are running a decent cam you need to be advanced anyway probably around 30 degress. The timing can play a big role in your over heating problem also look into to see if the engine is running real lean. Try to make it so the stociometric ratio is around 14.7:1 thats the optimum fuel air ratio for an engine. If running real lean your engine will run hot. And usually you dont need to run a high flow water pump unless on boosted applications or very high static compression.
  17. 10secondA
    Joined: Apr 8, 2009
    Posts: 104


    lawful27 you are right 1-1 works great on a stock pump but running a milodan high volume as ford9inch stated in his post can create problems with cavitation at higher rpm, ive had the same problem with almost every high volume pump ive ever ran fixed by simply slowing the water pump down, im just saying it has been my expierience
  18. Also wouldn't hurt to switch to a 160 degree thermostat. Henrietta the '38 Ford pickup runs a 160 thermostat, original flathead radiator with extra outlets plugged and a 4 lb cap, driving 60-65 MPH in 100 degree weather, my temp gauge is on about 175 -180 all day long. If I'm idling or stuck in slow traffic, it might climb up to 185-190 tops.
  19. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    1. Early Hemi Tech

    I think the filler on your thermo housing is keeping you from filling it all the way. Pull the guts out of an old thermostat, install it & take it out for a drive.

    I also agree with ensuring the lower hose has a spring in it to prevent collapsing.
  20. pdq67
    Joined: Feb 12, 2007
    Posts: 787


    ALL good idea's!!

    1. drill a hole in the T-Stat flange to help "burp" her.

    2. spring inside suck hose.

    3. 50/50 mix and water-wetter.

    4. 4-core rad. or 2-core aluminum jobber.

    5. pop-rivet plate the open side of the impeller in your water pump with one of the kits out there.

    6. 160 degree T-Stat.

    AND do run whatever fan setup you can fit!

    Now, I can NOT comment on the hood and side doors, so please go from there.

    As always, just trying to help.

    Good luck.

  21. lawful27
    Joined: May 8, 2010
    Posts: 10

    from Salinas

    Just curious how you determined the pump was cavitating.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.