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Sbc temp question

Discussion in 'The Hokey Ass Message Board' started by DFW31, Jun 7, 2013.

  1. DFW31
    Joined: Apr 13, 2013
    Posts: 148

    from Texas

    I've got an sbc in my 31 coupe. It's .030 over, and pretty hot little
    Motor. I live in texas so obviously it's hot here. I run 210 normally but it can get to 250+ pretty quick in stop and go situations.

    I have the 32 radiator, and the small speedway electric fan. Fluids are good even when it gets pretty hot

    Any tips on what I may be able to do to keep the temp down in stop and go traffic?

    Thanks in advance
  2. Grudge
    Joined: Jun 26, 2008
    Posts: 435


    Need more info.

    What thermostat are you running?

    Pictures of your electric fan setup? Shroud? Fan specifications?

    What turns your fan on?

  3. jcapps
    Joined: Dec 30, 2008
    Posts: 473

    from SoCal

    250? Way to hot. Is your gauge accurate
  4. eppster
    Joined: Jan 26, 2011
    Posts: 223


    First get a laser temp gun and make sure your temp gauge is accurate, if it is then you can go looking for solutions. People seem to trust these aftermarket gauges to be accurate and some are'nt.

  5. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    Cooling always seems like a hot topic around here (pun intended :D) Either cars run too hot or too cold. 250 is WAY too hot.

    My first thought is to get rid of that Speedway fan and put the biggest SPAL fan you can fit on there with a shroud so the air is being drawn over the entire radiator.

    My second thought is that are you 100% sure you are really going to 250? Buy one of those Mr Gasket radiator caps that have a thermometer in them. Autozone and Advance Auto carry them, about $20 and they really are accurate. It showed me my gauge on the dash is 20 degrees hotter than it really should be, and I checked it with a thermal gun.

    You say you have a 32 radiator, was it an original that you had reconditioned ? Might be time for a new one in either copper or aluminum.

  6. The only problem with those Mr Gasket radiator caps is they are not measuring how hot the water is in the motor, they are measuring how hot the water is in the radiator - and there is a difference. We regularly see a difference in readings depending on where in the motor the sender is. Left cylinder head is always the hottest, front of the manifold will be different than rear of the manifold. Etc.

    it sounds like a fan issue if it only gets that hot during stop and go - you either need more fan, a better shroud, or Both
  7. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    Yes, but it is measuring the temp at the top tank, right where the engine dumps the water before it has had a chance to cool. When I shot the engine block in various places it was exactly what the Mr Gasket cap was showing. I could shoot the heads, intake, crossover, etc and they all matched up with the radiator cap reading.

  8. GassersGarage
    Joined: Jul 1, 2007
    Posts: 4,728


    Sounds like you need a shroud. My '31 had an aluminum radiator, unknown make, with a flex fan. The fan was about 4" away from the radiator, so I got a spacer to put it 1" away. I also installed a half shroud. Since I had a '32 grill shell, I hid a pusher electric fan behind the grill. In stop and go traffic on a hot day, the temp went from 215 to 180 with the pusher fan on.
  9. It doesn't cost you anything to check your timing,check it again. Then crank it up and let it idle and get to about 200-210,put a fan in front of it and see what happens. Go from there !!! Don has good points there also !!!
    Last edited: Jun 7, 2013
  10. DFW31
    Joined: Apr 13, 2013
    Posts: 148

    from Texas

    Thanks for the replys guys, sorry for the delayed response. The radiator is a new aluminum '32 style. The fan is on the front of the radiator and could probably be a bit bigger. I didn't realize this at first but when we put the '32 grille and hood on we had to push the radiator back about an inch. In doing so, the bottom hose became a bit pinched. Not bad, but enough to restrict flow. I replaced the hose and the motor seems to be running noticeably cooler. It runs at 210 for the most part. Keep in mind I'm in Texas and its hot as hell. I'll get one of the radiator caps and look into a bigger fan. Rising temps in stop and go conditions is an issue for everyone I assume. Especially us texas folks.
  11. Baumi
    Joined: Jan 28, 2003
    Posts: 2,690


    My 327 ran hot as hell until I found someone had just punched the old freeze plugs inside the block, left them in and just installed new ones. Removing them and giving the block a good wash until only clear water was coming back out dropped my temps from 210 to 180.
  12. Heating up in stop and go conditions, but not when driving, indicates an air flow problem. As suggested, bigger fan, better shrouding, room for hot air to escape, are ways to help. Your pinched hose is a good first item to fix and sounds like it was having an effect.

    I think just about any hot rod seems to have air flow issues at low speeds. I can keep mine at reasonable temps, but it is always a concern.
  13. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,260


    Pusher fans restrict air flow. Like Don said,throw that speedway fan in the trash and install a Spal puller if you have the room.
  14. wingman9
    Joined: Dec 30, 2009
    Posts: 804

    from left coast

    Pusher fans don't seem to work well. Are you sure it's even directing air in the proper direction? I'm not trying to be a smartass, just making a suggestion. Stranger things have happened.
    Gman seems to be a faster typist. :eek:
  15. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    1. Early Hemi Tech

    I agree about verifying the temp first. If you are using a new type temp gauge (autometer, etc), it needs to have a small type sender. It wont work with the old TS6 sender that GM used for 50 years. I installed new aluminum heads in my 70 vette & a new intake. The heads only had a provision for the small sender (& nothing in the intake). I found a small sender that's pretty close to the Ohm value of the TS-6. It's off a '75 Volvo. I also needed to add a 5 Ohm resistor to it. Anyway, my original temp gauge is very accurate now.

    A little trick to cool down your motor is to hook up your vacuum advance to a full time port. This will advance your timing fully at idle. I did the to my car & the temps dropped around 10-15* You need to use a performance vac can, depending on rough your camshaft is. I have a B-26" on my vette, which works good for a semi-rough cam.
  16. Joliet Jake
    Joined: Dec 6, 2007
    Posts: 497

    Joliet Jake
    from Jax, FL

    Here's what worked for my 32 and 30 Model-A here in Florida and works great, I also plan to use the same set up on the one I'm building, it's a 31 coupe with a stock 56 354 Hemi.
    Both run warmed over small blocks.
    32 grill shells,
    Twin 10" electric pusher fans in front of radiator,
    165 degree thermstat,
    Water pump lube and spring or distilled water,
    Good luck with yours
  17. txturbo
    Joined: Oct 23, 2009
    Posts: 1,771


    Unless the gauge is hooked up to the top of the radiator near the cap.....that 20 degree difference is probably correct. It all depends on where you are taking the temperature reading.

    Posted using the Full Custom H.A.M.B. App!
  18. Out of curiousity-are you running Vortec heads and/or a '96 and newer block?
  19. joliet jake already said it, but, distilled water will make a difference. my 57 chevy dropped 15 degrees just by changing to it.
  20. txturbo
    Joined: Oct 23, 2009
    Posts: 1,771


    either an air flow problem.....or your new radiator is plugging up. Next time , drive it until it gets up to operating temp.....then shut it off.....feel the center of the radiator core. If its cold in the center and hotter out towards the found your problem. Radiators clog in the center first and gradually plug towards the edges. Motor could have had a bunch of junk in the water jackets and now its in your new radiator.

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