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cooling

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by bgwhlr, Mar 18, 2003.

  1. bgwhlr

    bgwhlr Registered Member

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    Hey just got the big block going, 4 core radiator keeping motor at 200 degrees, with a 180 thermostat, are 454's supposed to run hot, is this hot, for 50 degree weather, and what will happen in the summer at 90 degrees. What's a good pusher style electric fan to help with cooling, or do I need it? /forums/images/graemlins/confused.gif
     
  2. 71blaz

    71blaz Registered Member

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    check out this fan Old air products Kind of spendy, but complete and made for a 1st Gen.
     
  3. Larry_in_Tx

    Larry_in_Tx 1/2 ton status

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    I haven't been real comfy with the temp of my 454 on the couple of runs I've made since the engine swap. I plan on taking the trans. Lines out of the radiator all together and running them through a separate cooler and trying out some electric fans and see how it acts. I haven't figured out what fans I want to run yet but if you do a quick search on electric fans and check out what some people are running now and what they have to say about there set up, it should help with you're decision.
     
  4. chevyracing

    chevyracing 1/2 ton status

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    Puller fans are more efficient than pusher fans.

    John
     
  5. chevyracing

    chevyracing 1/2 ton status

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    also make sure you have a good fan shroud. Maybe you should consider a 160 degree thermostat too.

    John
     
  6. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    I'm running a 396 with the dual Flex-A-Lite electrics (220 model?) and a 4-row radiator. It runs cool on the street (180 or so)...but I've had it boil over a couple of times on slow trails...

    I think I need to explore a higher flow water pump. I suspect I have plenty of cooling potential....I'm just not moving the water quickly enough through the radiator to pull the heat out of it....especially at low speeds
     
  7. Tuff

    Tuff Registered Member

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    Greg,
    Did you build a custom bracket for your fans or did they mount right up? I want to go to electric fans, but I'm worried they won't be secure enough to the radiator to hold. I am hoping to find something that mounts right up.
     
  8. chevyracing

    chevyracing 1/2 ton status

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    [ QUOTE ]
    I'm running a 396 with the dual Flex-A-Lite electrics (220 model?) and a 4-row radiator. It runs cool on the street (180 or so)...but I've had it boil over a couple of times on slow trails...


    I think I need to explore a higher flow water pump. I suspect I have plenty of cooling potential....I'm just not moving the water quickly enough through the radiator to pull the heat out of it....especially at low speeds




    [/ QUOTE ]


    That is backwards actually, from what Popular Hot Rodding said. If the water moves thorugh the radiator too fast it does not have time to cool before it is returned to the engine. Maybe an underdrive pulley would help you out.

    Something I thought would be cool is if there were a way to tee of the top hose to bypass the t-stat for hot conditions. If there were two hoses with an inline shut off to the bypass hose that would be slick.

    John
     
  9. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    The dual fans are mounted on a plate already. I was able to drill a few small holes in the upper radiator lip to secure them, and I think I just used some big zip-ties on the lower area (for now!)

    Here's a pic of the setup:

    [​IMG]


    ChevyRacing,

    Interesting comment on the "too fast" idea....I suppose that could be true also. The only reason I suspected differently was because the overheating only seemed to happen at low speeds, never at higher RPMs.....

    I know they make "High Flow" thermostats....maybe that's something worth checking out too???
     
  10. Triaged

    Triaged 1/2 ton status

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    You can restrict coolant some from the heater core and it will be like you added a higher flow pump because you will increase the flow through the radiator.

    I believe they put a valve on the AC trucks to do this when the ac was on to cool the engine better when the AC was on. It is vacume opperated but you could get one from a europian car that would be lever opperated (or just bypass it all together).

    You do need to make sure that coolant can circulate through the block before the t-star opens so either leave the valve open while the truck warms up or drill a couple 1/8" holes in the t-stat (it will take longer to heat up if you do that but you live in CA so who cares!).
     
  11. Chris_T

    Chris_T 1/2 ton status

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    What about adding an electric water pump for the go-slow. That way engine rpm is not a factor in the movement of coolant through the system at low rpms?
     
  12. Roostr84

    Roostr84 1/2 ton status

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    I think electric are really not the ideal setup for a daily driver, in fact I don't think I know of anybody who has run them continuously. I realize you mean for low rpm but I don't know how feasible it is to swap water pumps often.
     
  13. Rusty68

    Rusty68 1/2 ton status

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    I thought I would throw this in, My 383 truck use to get real hot in traffic during the summer. I even had a new 4 row cooler and flo cooler pump. I put the original fan shrowd back on and it dropped down about 15 degree to about 205. Still to hot!! Turned out that my new replacment fan clutch was not working very good, because when I swapped it out I have never been over 180 even while trail running. As far as a thermostat goes, you might try going up in temp to like 195. This would hold the water in the radiator longer and let it do its job.
     
  14. Chris_T

    Chris_T 1/2 ton status

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    I have to admit I don't know too much about it, but I was under the impression that's not the case. You can get electric pumps to put on your street machines to free up the HP lost to the pump. I wasn't thinking about swapping pumps every time you want to go offroad. If it works in high rpm engines, why not at low rpm, especially if water pump speed is independent of engine speed. What I like about the concept is in theory you could have coolant flowing even when the engine isn't running (depending on how the pump is wired). I think the trick would be finding the right pump.

    That said, I won't be doing it on my Blazer since it doesn't see that much slow going, nor do I have cooling problems.
     
  15. '72brett

    '72brett 1/2 ton status

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    well, I saw the post on using a smaller pulley with the water pump. Now, when I think about it, wouldnt a smaller pulley make is turn faster? The way I see it, is like the rear gears on a bicycle, the bigger the gear, the more totque you have and the slower you go. so, if you would like the water to flow FASTER, then go with a smaller pulley. AM I correct on this? (bigger=slower) (smaller=faster)
     
  16. chevyracing

    chevyracing 1/2 ton status

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    [ QUOTE ]
    I have to admit I don't know too much about it, but I was under the impression that's not the case. You can get electric pumps to put on your street machines to free up the HP lost to the pump. I wasn't thinking about swapping pumps every time you want to go offroad. If it works in high rpm engines, why not at low rpm, especially if water pump speed is independent of engine speed. What I like about the concept is in theory you could have coolant flowing even when the engine isn't running (depending on how the pump is wired). I think the trick would be finding the right pump.

    That said, I won't be doing it on my Blazer since it doesn't see that much slow going, nor do I have cooling problems.

    [/ QUOTE ]

    If you were refering to my post about the underdrive pulley's what the do is turn the item slower. That is why if you put one on an alternator you may have charging issues at idle. Underdrive pulleys slow down the part with a bigger pulley. You also gain a certain amount of power at higher RPM's with them.

    John
     
  17. TED

    TED Registered Member

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    Yeah, I believe smaller would cause the pump to turn faster. I put a hi-flow pump on mine and it works great. Ive been through Fresno in 105 degree weather, sat in traffic and the hottest it got was 205. I have a hi flow t stat and a four core radiator with an electric fan. I made my own bracket because the bracket that came with the fan was worthless and it looked like crap.
     
  18. supersize75

    supersize75 1/2 ton status

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    I have a set up just like greg's. I have a 396 and 4 core radiator.

    My plans are to the parts tyard on 1/2 off day and pic up 2 electric fans, the larger the better. Then I just want to wire them to a switch. I live in AZ so I think I will wire them into my ignition so every time the truck is running they are on, but have a cut-off switch for winter. I figure I will just fab something up fro angle iron or flat stock and just make shure the fans are the same. As for an air shroud I plannned on making custom brakets 4 the radiator then installing tabs to make a "box" design around it to direct air.


    Any idea's /forums/images/graemlins/ears.gif I also plan on ditching the factory fan no need 4 me to loose fingers. /forums/images/graemlins/thumb.gif
     
  19. Chris_T

    Chris_T 1/2 ton status

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    [/ QUOTE ]

    If you were refering to my post about the underdrive pulley's what the do is turn the item slower. That is why if you put one on an alternator you may have charging issues at idle. Underdrive pulleys slow down the part with a bigger pulley. You also gain a certain amount of power at higher RPM's with them.

    John

    [/ QUOTE ]

    No, I was referring to roostr68's post about swapping water pumps back and forth from mechanical to electric.

    The more I think about it, the more I like the idea of both an electric water pump and electric fans. You could be standing still, with the engine off, and still be running both.

    Since pulleys came up, I'm pretty sure you can get an electric pump that has a pulley mounted on the front that is merely an idler, so you don't have to change your belt configuration
     
  20. RingMaster4x4

    RingMaster4x4 1/2 ton status Premium Member

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    My K/5 does the oppsite. In low speeds my 427 runs 180 degrees and it runs 200 at highways speeds. I have a stock waterpump, stock 4 core rad., and dual Prema-cool 14" fans (like BobK).
     

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