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Cooling System ?/thoughts

4K views 23 replies 11 participants last post by  toobroketoretire 
#1 ·
With the heat of summer here in south florida I have noticed what a difference the running temp on the highway and in town is depending on a head wind or a tail wind.

I know all about the less than favorable design the C3's have for air flow and all the sealing trick and such but I'm wanting to know if anyone else noticed the temp change simply by wind direction and if you attempted anything to compensate for it.

Driving with a head wind the car runs a cool 180ish turn around and put the wind at your tail and it goes up to 198-200. I understand why this is happening and I was thinking of putting an electric pusher fan on the front of the radiator to create wind flow when the wind is at my back.

Before I sink the cash and time into this I was wondering if anyone has bothered with it since from what I've read my numbers are fine and normal, I would simply rather stay at 180 all the time if possible.

My setup is a warmed over 350 with 9.6-1 compression, No A/C, aluminum heads, cam, intake, carb, ignition. New Aluminum 4 row radiator/cap with dual electric spal fans with the medium sized thermostat restrictor plate, new antifreeze 50/50 and royal purple coolant additive. Like I said, with wind it cools no problem at all, no wind it gets hotter just like riding a bicycle with the wind at your back not an ounce of wind to cool your face but you'll go faster than riding into the wind feeling the breeze and staying cool but peddling is a real fun treat.

Thanks in advance for your thoughts, ideas or trial and error attempts.

Eric
 
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#4 ·
Its the electric fans, at hiway speed when they don t run, they cause a restriction to airflow..the front of a C3, unlike later years, was not designed to flow sufficient air thru radiator without the help of a mechanical fan,. even at cruise speed a clutch fan still rotates at 40-70 percent of engine speed, depending on which clutch you use, standard, HD, or Severe duty..but toobrokes right 190-200 is OK...I wouldn t let mine get over 200, but mine never does excede 180...traffic, A/C , 110 degree day, it will not go over 180.
 
#5 ·
I agree with Fishslayer, it is the electric fans that are causing the problem. Either do away with them and go back to good mechanical fan and clutch or try wiring them to be on constantly.I work part time at a custom shop and we have had to do that on several cars to eliminate overheating problems on tuned motors with electric fans.The problem is that they provide a sever air flow restiction because of the housing and the fan blade design as oposed to the origanal machanical fan and housing.Sorry but electric fans may look cool but are not all they are cracked up to be.
 
#6 ·
i dunno...i ran two 14" electric pusher fans and no engine driven fan on my 79 with the 496 ( that would be a .060 over 454 with a 1/4 crank...) on a factory replacement 4 core radiator and never got over 180, thats sitting in bumper to bumper traffic at high noon for over an hour--and that car went 11.87 @ 128mph.....but they gotta be REALLY high cfm fans, dont cheap out and buy crappy ones--you need some serious airflow, the ones i used were 2500cfm each. probably gonna do exactly the same on the 78 when it gets the bigblock swap....
 
#10 ·
Thanks for all the input guys :thumbsup: I finally bit the bullet and ordered a new fan shroud, since after the last time trying to install the original by myself with the hood on I destroyed it and went with the electrics.

Fishslayer was right, it was the electrics that weren't causing an overheating problem but not allowing for the temps I wanted. I picked up a fiberglass shroud from corvette central and planned the install out for a few days and figured out how to make life easier, pull the upper control arms. It took longer but wasn't bad at all and made the install so much easier.

I tried my flex-a-lite fan first but no go with that so back to the original clutch fan and now the car cruises on the highway between 2600 up to 3200 rpm and never saw 180 degrees. It was running 176-178.

It does heat up once you exit the highway and gets up to 190 but slowly comes down to 185 with some air movement in town.
 
#12 ·
Your right there! I pretty much knew the answer to my question, I was just hoping someone might have a simple cure that I had overlooked to avoid going back to the fan shroud but it's never an easy solution with cars :doh: but that's why we love them :thumbsup3:
 
#19 ·
a typical small block doen't make full horse power until it gets above 180 degrees and you don't have to worry about detonation problems until it gets over 225 degrees. remember that all modern engines all run at 225 and detonation problems start at 240. But if you are concerned about running alittle hot, remember that in hot enviroment like 100-110 degrees and specially if there is low humidity, if a carburator is running to fat or lean will make them run hot. usually hot and dry and they run hot they are runnig rich because of the thin air. But like in ohio if it is 90-95 with lots of humidity and they run hot
its usually because the air is thick and heavy so they run lean

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#23 ·
Cooling system / thoughts

Eric,
I have a 1977 Vette with a 383, and run 11.1:1 comp ratio. I live here in Bradenton, so I know all about Fla weather.The sealing rubber, larger front spoilers, license plate openings, really don't do much for a car with the radiator higher than the engine water jackets.I run an automatic trans with a 3000 stall converter. To keep my temp at 180 deg, I use a 180 thermostat with 3 - 3/16 holes drilled into it.( Stewart water pumps sells them for there Stage II performance pumps ) a mechanical flex fan, a small pusher electric fan on a toggle switch, ( in bad city traffic )and a big trans cooler. Real big !!!
 
#24 ·
Keeping It Cool

The very best thing you can do to keep your engine temperature within reason is run a 4-tube radiator. All three of my C3's (two of them are 454's) have those big 4-tube radiators and I never have any heating problems whatsoever. Not even on a 110 degree day. Yes, they DO cost a little more than a 3-tube radiator but it's well worth the additional money.
 
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