cooling a sbc 350

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cooling a sbc 350

Postby finest20 » Sun Jan 24, 2016 11:18 am

Hello everyone
I received lots of help earlier on overheating my sbc.

I have since switched to a 2" blade fan and a smaller water pump pulley and "most" of the issue has gone away.
The last thing I would like to do is the final suggestion I received, which is to separate the heater core hoses from the water pump. I was told that having both supply and return from the heater core connect to the water pump is not good. This is my setup now, along with a temp sensor located in the intake manifold.

My question is this: Is it ok to have the temp sensor mounted on top of the water pump? I have never seen them like that before. If it is ok I can just swap a heater hose and the sensor and I am all set. If not then where are the ideal locations for the heater core hoses and temp sensor?

Thanks again!!!
Rob
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Re: cooling a sbc 350

Postby blownvega1 » Sun Jan 24, 2016 1:00 pm

I have the temp sensor in the head for a gauge and the efi use's a sensor beside the thermostat the head is always @ 12 degrees hotter I would not put a sensor on the water pump, that would give you a temp of water going into the block from the rad you should consider feeding the heater core from the block then drain it to the rad even if you have to solder a fitting on the rad . Alex
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Re: cooling a sbc 350

Postby Monza Harry » Mon Jan 25, 2016 12:19 am

The stock set up take water from the manifold (hottest water) to the heater core and from there to the suction side of the water pump. This set-up helps when the t-Stat is closed as the heater core is part of the bypass system then, the original arrangement didn't use a water shut off back then. I have some numbers for senders if you need different from stock 1/2NPT for aftermarket heads (3/8NPT). I will post them up tomorrow or I can PM them for you if needed. And there is a reason GM puts them in the heads, that is where the action is so to speak. Harry
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Re: cooling a sbc 350

Postby SeniorSavage » Mon Jan 25, 2016 4:36 am

for what its worth I used to have an F-body Firebird that we had replaced the 2.8 V6 with a 300+HP SBC 350 and it had real bad overheating as its like our H-bodies in that it had essentially zero front air openings to the rad and no airdam underneath so in the summer it was a real pain, especially idling thru downtown traffic. We fixed it by using electric components and it worked very well, an electric rad fan and an electric water pump pulley which could be controlled automatically or manually, like we did it - with a switch under the dash which i could simply click on for cooling and off to warm up the motor faster. we used a Ford solenoid relay to activate it all and to handle the current.

cheers.
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Re: cooling a sbc 350

Postby finest20 » Mon Jan 25, 2016 7:34 am

So for this air dam issue: this is just a metal air deflector pointing down from the radiator toward the oil pan so that as air blows by it, it creates negative pressure in the engine compartment that draws away hot air? Can anyone take a quick picture of what they have and post it here so I get an idea of how to fabricate it?

Much appreciated!!!
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Re: cooling a sbc 350

Postby SeniorSavage » Mon Jan 25, 2016 11:25 am

i'm not convinced that adding an ad-hoc airdam will be the answer you're looking for .. it will look out of place if you just ad an airdam of your own construction to the vehicle - perhaps for a pro-street car maybe not as much out of place but finding other methods is best. i did drag race that Firebird at the local track a lot and again, the electric water pump motor worked very well for us (though i imagine that after you put so much effort into finding that smaller stock pulley you might not want to do that eh?)

on that note, the '79 Spyders had an airdam of sorts ..

http://www.jegs.com/c/Cooling_Electric- ... 5/10002/-1

cheers.
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The fleet;
1975 Buick Skyhawk 3.8 V6 turbo - total restore ongoing (soon!)
1996 Fleetwood Bounder 36' Ford 460 TBI motorhome
2004 Harley-Davidson Heritage Classic 88ci 1450cc. - custom original.
2005 Ford 500 Limited (wife's car) - working original.
2006 Chevy TrailBlazer EXT LS VorTec 4200
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Re: cooling a sbc 350

Postby Smiley » Mon Jan 25, 2016 7:32 pm

have you changed your crankshaft pulley also yet ?
Try a double groove crank pulley that is correct for small block corvettes without power steering from 75-82
Measures 7-3/4" in diameter and has the part number 469558. usually some on Ebay.

heater hoses: 1st gen small blocks running a thermostat and a heater should have one hose from the intake and one to the side of the water pump.
Temp sender should be in the head or the intake.
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