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Discussion Starter #1
let me know what i should change without spending alot of money to get my under hood furnace to stop creeping to 230+ in deadly dream cruise traffic, my current set up is; stock bore mild 454 with iron heads, 8.2 cr, new borgwarner long pump with impeller disk, stock pulleys, 18" 7 blade flex-o-lite heavyduty flex fan, 19x30 griffin aluminum rad, chevelle fan shroud, 160 replacement stat, core support trimmed to fit rad, 7 blade pusher fan offset to hot side, bypass hose blocked, car has stock hood.
 

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Discussion Starter #3
yes, i trieed everything short of duel electric fans, but not much room in a long water puimped bigblock
 

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Man I run a 454 with 10.5 compression a summit radiator, procomp aluminum water pump and a flex fan and I rarely see more than 165/170 even on the hottest days.

I'm not sure why really. The only odd thing about my setup is my Brodix intake with a restrictor instead of a thermostat.

Heck, I have problems actually getting up to temperature.
 

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I've never seen a flex fan that could keep a stocker cool. I used to run a 7 blade fan from a 4th gen. Nova police car(no longer available from GM) with a heavy duty clutch, and was the best mechanical fan I'd ever used. (I tried all the flex-fans, Plastic, stainless, fiberglass, all worthless) The electric that I use now(Lincoln Mk.8) works fantastic, but sucks up a ton of amps!
My 14.5-1 compression, half-filled 400 block, never got hot.
 

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Have you tried any coolant additives like water wetter? You can get it at most parts stores and it does drop water temps between 10 and 20 degrees. You just need to flush it out befor winter in the colder states. I run it in my 63 and it helps durring the summer.
 

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You getting good water flow? How's your timing? Carb too lean? A few things I would check before spending $$ on new parts.

(when I had the big block in my car I had an edelbrock victor H2o pump, griffin aluminum radiator, 160 t-stat and a flex fan--she still ran hot--11:1, big cam, 396/402. I went to a dual e-fan setup and my problems were over--Just FYI)

Hope you get her figured out,

Scott
 

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a 160 thermostat will never close. Get a 195 thermostat, maybe drill 1/8 hole in it and get a GOOD electric fan. The flex-a-lite black magic is the best one ive used to date. Its around $200. But pulls ALOT of air, and actually through the radiator. I had one set up as a pusher (way less efective) on my procharged 427 and it stayed cool with a small griffin radiator. I have one on my Nova now pulling air through the radiator & the intercooler... very effective.
People always argue with me about the thermostat thing, they run no thermostat or a cold one and the cooling capacity of their radiator is huge and la la la. But As they argue with me...my **** runs cool and thiers doesnt.
 

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A stock brass HD radiator,water pump and fan will easily keep a mild big block below 200 degrees under normal circumstances. Brass is a better thermal conductor than aluminum. It just doesn't look as cool and is heavier. I never could understand why anyone would want to run a 160 thermostat on the street unless they actually want the engine to run at 160 degrees. There really isn't any difference between a 190 and a 160 at the temps you're running since they are both open anyway. If a 160 degree thermostat keeps your car running at a temp significantly above the rated temp under normal circumstances, it's a glaring indication that you have another problem in your cooling system.

The purpose of the thermostat isn't just to keep the engine cool. It's also to keep the engine warm enough to run within the optimum operating temp. If it's only closed when you start the engine up cold and then opens as it reaches 160 and then never closes again, you might as well not even have a thermostat. It's just like a restricter.

I've had flex fans in the past. They always worked good for me. I prefer a clutch fan though if you have enough space to fit it in. That's the advantage of a flex fan. It doesn't protrude as much for tight spaces yet allows air to flow better when the car is moving at higher speeds.
 

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I'd have to agree with 64pronova that running a 160 t-stat is not a good fit for your car.When the t-stat is open and never closes the coolent doesn't get a chance to cool off.I went to a 190 t-stat from a 160 for just that reason.The coolent needs time to cool off. The radiator and fan can't do their jobs if the flow is constant.My 383 stays between 190-200 all the time.I use
a factory radiator and 6-blade flex fan and it works for me.
 

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My intake has a restrictor built into the thermostate boss. I posted about it before. I have a problem actually getting up to temperature. It sucks on cold days, but stays nice and cool on hot summer days.

Luckily I hardly take it out in the winter.
 

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I agree with 64pronova about the 160 therm depending on you're setup. BUT, in my personal experience I have to disagree with his comment about copper (Brass) being a better heat conductor then aluminum. From what I have found Alum radiators out perform copper by about 2:1... I have switched over to aluminum rad's on two past cars (My Nova is next) and both ran about 20 deg cooler then the OEM copper. Plus copper-brass radiators are soldered together, but solder is a poor thermal conductor and this reduces the ability of the fins to remove heat from the tubes. With that said, that offsets the alum rads being less of a conductor of heat and that's why you see the increase in cooling with an alum rad.
Little bit of fan info; mechanical cooling fans work best when the fan sets approximately halfway inside the fan shroud. I have a 7 blade OEM fan (no clutch) that works great for me..

My 2 cents..


Just an FYI, each therm will be full open 10 degrees over the rated temp. So, if you're running a 180 its fully open at 190. I would not run anything over a 180 in any V8..
 

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Well we're both wrong. Aluminum has better thermal conductivity than brass but copper has a higher thermal conductivity than aluminum according to the Machinists Handbook. You got me thinking there after I made my post.

Thermal Conductivity

Aluminum 136 Btu/(hr-ft-F)
Brass 69.33 Btu/(hr-ft-F)
Copper 231 Btu/(hr-ft-F)
 

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Then we both stand corrected:D Most alum rads that are installed in muscle cars are larger as well in thickness. So, you get more surface area then the copper.

Comparing apples to apples.. If you were to get a 2 row copper / brass radiator that had the fins braised (I think that is the way it would be done) and not soldered. Then get a 2 row alum of the same size, the copper would do better then the alum in cooling. However the Copper / Brass radiator would be super expensive and therefore not cost effective.

Ya think we beat this topic to death LOL :)
 

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I'd have to agree with 64pronova that running a 160 t-stat is not a good fit for your car.When the t-stat is open and never closes the coolent doesn't get a chance to cool off.I went to a 190 t-stat from a 160 for just that reason.The coolent needs time to cool off. The radiator and fan can't do their jobs if the flow is constant.My 383 stays between 190-200 all the time.I use
a factory radiator and 6-blade flex fan and it works for me.
Stopping the flow of coolant will reduce the efficiency of the cooling system by quite a bit, which is what happens when the thermostat closes.
There is no 'time' involved in a closed system, for every unit of coolant cooling in the radiator, there's a unit getting hot in the block. Slowing the flow simply increases the temperature drop across the radiator, raising the temperature at the outlet of the engine, which will show up as an increase in temperature of your engine.
The real time constraint of the cooling system is the rate of heat exchange, which is highest when the radiator is the hottest. This is why your engine arrives at an operating temperature, the heat lost is equal to the heat produced.
 

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here is a way to solve your problems but not too cheap
1 a becool aluminum 4 core rad
2 a becool dual electric fan
3 a 55 gal meziere elec water pump
you will have a problem getting it to temp after all of this but it will run cool
i have about 6 of these setups out there from 13.5 comp small blocks to 14.5 comp 572s and they all run super cool
 

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Although there are exceptions to the rule, it's is common for overheating at highway speeds to have an undersized radiator and overheating at low speeds to have inadequate airflow through the rad. This rules is for the cooling system on an engine that is tuned correctly and the cooling system components are good. If the engine is tuned correctly. I would look at increasing the air flow through the rad and at the same time using a high flow thermostat(drill two 3/16" holes on the outboard side of the thermostat opening). I went through a number of flex fans and electric fans on the last engine. What worked was the GM stock flex fan from a mid seventies Cadillac 500 c.i. engine. 7 blade and no clutch and used in conjunction with a shroud. At idle, I could feel the air being drawn with my hand on the front of the grille. As the engine speeds up, the fan would flex and not draw as much. I was now at the point that I would never have to look at the temperature guage again and enjoy the car rather then constantly keeping an eye on the gauge and wonder if I can get to a spot where I could get the car moving fast enough to bring the temps. down.
 

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Frist off about the radiators, copper/brass radiators are better heat exchangers than aluminum, but aluminum is stronger. The stronger material allows for bigger tubes. Larger tubes give you more surface area for the cooling fins to remove more heat from the coolant. That's why the aluminums perform a little better, but a properly sized brass/copper will cool just fine as well on a mild engine.

As for the fans, in my Ventura we couldn't keep the 307 in it cool for nothing. We finally went to a Summit fixed blade steel fan. It helped considerably. Since this car isn't about HP, the fixed blade fan wroks great. On my Firebird (400) which is pretty stout, and my Nova (427) which is also a little more than mild, I run a stock 7 blade clutch fan on both and have no cooling issues. The Firebird runs a copper/brass radiator while the Nova uses a Griffin aluminum. I run 180 high flow thermostats in each. Both these cars will run high 11's and can cruise around all summer.

Now when my Firebird was really radical (400, 255/265 @ .050 cam, 11.5 compression, big carb, big convertor, lots of gearing, 10.75's) I tried to run a flex fan. Did nothing but overheat around town. Then I tried adding an electric fan to help. This did nothing. Then I tried swapping to a clutch fan. No change. Then I was working on the car and had the electric fan off the car and had to move the car. I was worried about running with only the clutch fan due to the overheating issues, but once I got going I noticed that the car was running considerably cooler. Once I got home I reinstalled the electric fan and noticed that the temps went back up.

What we learned is that the electric fan was actually hindering airflow thru the radiator. The clutch fan was capable of moving more air than the electric fan and the two fans were actually fighting each other for air.

What I recommend is using a stock GM clutch fan with a heavy duty thermal clutch and the proper fitting shroud, or a good electric fan set up, but not both. Definately ditch the flex fan garbage.
 
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