I got my A/C system finished on Friday & we went to the Red River Rod Run in Shreveport, LA on Sat. & Sun.
I have gone to a 16" electric fan (puller) on the radiator set to go on at 200 & off at 185. I have a 190 degree thermostat. I also have a 10" pusher fan in front of the A/C condenser.
So yesterday it was 86 degrees & about 90% humidity out & the car was running about 220 on the temp gauge. I was freaking out until I got home & was looking in a Chilton book which indicated that 245 to 260 degrees was OK for a small block Chevy. Isn't that a little high?
What is a good operating temp to look for under the conditions I noted?

I had a friend of mine tell me if it doesn't burb anything up it"s fine. He would run his car at 220/235
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I'am interested in the Early 40s style
look !

Erb; I don't have an answer for you but I would try taking the 10" pusher off if it's in front of the radiator. Just a thought. RP peggys other half
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Peggy Diegan

Mine runs around 200, Where do you have the sending unit mounted at? Also where you running the A/C?


Rick
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awsum34

What kind of fan was it that you bought and what is the CFMs and/or current or wattage? And.....it runs 220 at idle? ......or going down the road? ....and...where is your temperature taken from...head...intake...other..??..head sensoring will run 10 to 20 degrees hotter than intake water outlet temps.

If you are cruising at 220 and that is different from the idle or slow speed, then I would say the car is running lean, and in some rare cases the pump is not working correctly or the radiator is plugged. If you are idling and slow speed at 220, I wouldn't worry too much....unless your losing coolant, then you have to secure the system. I would start to worry at anything over 240 and still going, most systems aren't fully designed to keep the coolant in at that temp......the temp won't hurt the engine though until 260 ish....then regular oil begins to think about lower adhesion. If it will stabilize there....and hold the coolant then everything is fine...I would go my merry way.

Also, remember......even at idle and slow speeds....the more horsepower......the more fuel....the more fuel....the more heat.......the more heat....the more that heat that has to be carried away...........you get the idea!

Steve Jack
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SOUTHEASTERN GOODGUYS REP

Oh one other thing......where is the placement of the fan switch. If it's on the lower/bottom part of the radiator it's on the cool side of the radiator and it may not be coming on until it gets to an indicated 220 at the temp gauge......just a thought!

Steve Jack
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SOUTHEASTERN GOODGUYS REP

The temp gauge comes off the water neck on the intake manifold, the fan switch comes off the stock temp gauge fitting on top of the manifold.
The 16" fan draws 8.9 amps @ 2147 cfm. The 10" pusher fan on the A/C condenser only runs when the compressor is running and is rated at 900 cfm. And yes, I have a shroud. Nothing has puked out of the system yet. Runs up to 220 - 225 degrees when in town, 200- 210 degrees on the hwy.
But we haven't seen those 100 degree days yet.

ERBSSR......I know those Texas summers can get pretty hot and I am looking forward to coming to Texas to the Goodguys again this late summer. I loved meeting all the people from Texas and Oklahoma etc.

As long as your system holds at 250 or less and is stable at that, then you are okay. But, I too like to see something less than 240 on a regular basis.

Anyway....back to the problem at hand. It sounds as if you have done everything right, but the shroud statement confuses me? Most electric fans have their own shroud. Can you explain.

And for the bad news. Unless you mis-stated the fan CFMs, the almost 9 amps will not produce enough wattage (117 watts)to move 2147 CFMs. To give you an example, the Derale 16 inch (part no. 16516) produces 2175 CFMs, but takes 18.4 amps to accomplish this work. Another example is the SPAL 16 inch (part no VA18-AP13-59A) produces 2070CFMs and takes 18.5 amps to do this. These are the most efficient fans that you can buy, so the statement of 8.9 amps is concerning. I figure around 1100 CFMs depending on blade design.

If it is true that your fan is only 9ish amps...then the problem is somewhat there. You will need more than 117 watts of power (an estimated 1100CFM) to keep that rod cruisin in the Texas sun! Can you shed some light on the main fan that you have. Do you have any mounting restrictions...space etc.

I would run it to see what happens.....you might get away with it as long as you keep moving, but....in those 100+ degree Ft Worth days.....forget it....I don't think it will keep its stability with the amount of flow.

Steve Jack
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SOUTHEASTERN GOODGUYS REP

Steve;
You are right my fan does have a built in shroud.
I goofed up on the fan amperage. Actually, I don't know what teh rating is but it is a heavy duty S-blade fan by Vintage Air I got at Parr Automotive and it is rated at 2416 cfm not what I stated earlier. I looked at a lot of cars over the weekend at a car show and most had smaller fans than mine but some had two 10" fans on their condensers.

Whew!...I am glad that you cleared the amperage thing up. Vintage usually provides pretty good stuff, but I am not familiar with what they do in fans. Kinda new products.

I see alot of folks run two fans as well on the condensers, but if you are running them in front....I would run them all the time with the other. Just makes sense! You could put another on and see what happens. I know it will improve the airflow!

Going to Orlando on Thursday......catch up with you later.

Steve Jack
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SOUTHEASTERN GOODGUYS REP

When I still had the studebaker, I had a heating problem at slow speeds, and so installed a pusher fan (the big one from Vintage air) and that seemed to cure the slow speed hot (250+ in parades. It semmed to cause a cruising heating condition, I think because of blocking some of the air throught the radiator. I then removed it and built a shroud. Everything worked great until the top tank (the original from 1940) broke and I had a new top put on. I lost about 2 quarts capacity, and had heating problems from then on. Not bad ones, just ran hotter than it used to all the time. I think one thing we forgot to check is the total water capacity of our cooling systems. I seems to take a certain amount of water to disapate the heat, no matter how many tubes in the radiator.

My 2cents worth
Doug
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The Land Yacht specialist

Can someone tell me if my thinking was off then on this??

Dont you actually want your engine to run about 195 or so to get the proper combustion, yet you want your fuel to be as cool as possible for the proper fuel/air atomatization?

Im thinking I seen this on the Learning Channel where you actually want your engine to run warmer for combustion, you want your fuel cool for atomatization and you want your engine cool for parts maintaince and performance? So what you kinda have to do is average the three wants for optium effenciency? Where did I see that, I know it was on TV on either the discovery or learning channel?????
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Damn, I wish I had more time.
35 Ford Pick-Up

One more item. Is there such a thing as having too much anti-freeze in the system?
Will this effect temperatures?

ERBSSR......go and read the article that I wrote for the SRS Articles file undercooling www.streetrodstuff.com/Articles/March_2001/Top_Ten_Cooling_Tips.php .

The direct answer to your question is there in more of a scientific analysis, but to answer it here it is a resounding YES! The glycols (either one you pick) actually dilute water's ability to remove and carry heat. The specific heat number of water is 1...there is no better conductor and carrier of heat. The specific heat number of ethyl glycol is .5ish, meaning it can only carry about half the calories that water can. So mixing it with water makes the cooling removal harder, albeit protects from corrosion, freezing, boiling to a certain extent, and does lubricate the system. My recommendation is only use what you need at a minimum. For the hot summers in Texas, I would only put 20% in with a 16 to 22 lb radiator cap.

Steve Jack
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SOUTHEASTERN GOODGUYS REP

In response to hotrodsrj
Steve;
I HAVE READ YOUR COOLING ARTICLE AND ADOPTED MUCH OF IT.
WHAT IS YOUR TAKE ON PRODUCTS LIKE "WATER WETTER" OR "40 BELOW"?
I USED WATER WETTER IN MY OLD FLATHEAD 49 LAST YEAR & IT HELPED A LOT. WHAT IS THE SCIENCE BEHIND THESE? DO THEY CHANGE THE FRICTION COEFFICIENT OF THE WATER? THEY APPEAR TO BE VERY SLIPPERY FLUIDS.

I just posted a whole dialog on this very subject on another site just in the last week or so. The ads must be getting around!

The manufacturer of water wetter makes a claim of up to a 20 degree drop in temperature of your cooling system, etc, and that could very well take place if you have certain ills with your system that water wetter could help. In most cases you won't see a drop at all, but in fact, more heat could be escaping your engine.

For the most part water wetter is a sufficant that changes the way the water molecules (and any compounds thereof) react with adjacent medias, such as air and solids. As a result, you are absolutely right about the stuff, it's slippery as all get out and feels like soapy water (soap is a sufficant too). This slippery feel is what makes the surface tension of the water flow more evenly and smoothly as well as spreads out in a thinner layer and penetrates into smaller spaces/pores, essentially bathing the cooled surfaces with the coolant. This surface tension trick helps eliminate hotspots in blocks, and will cause the water to pick up heat FASTER (notice I said faster, but does not increase the waters ability to carry MORE heat away)meaning that if you have a fast flowing coolant it will excape with more heat (if the coolant is not at the corrected vapor point). Hotspots are the culprits of most cooling problems whereas when one gets started it produces gassing that makes it bigger and the domino effect occurs and before you know it you have quarts of coolant on the ground. Of course temperature reduction cannot be seen in a system that is basically governed by a thermostat, but the thermostat will open and close more frequently as a result of the hotter water making it do such. As a result more heat getting carried to your radiator. Now the issue is letting the radiator get rid of it!

The real good thing about the water wetter is the prevention of hot spots. Hot spotting can occur for several reasons, inadequate flow, eddy currents at low pressure points, trapped air, cavitation air, slow moving coolant, but water wetter makes coolant flow more easily into the nooks and crannies of your engine and esp the fine holes in the castings, also allows air to escape with less surface pressure and actually helps cavitation. Water wetter is also a great lubricant for the cooling system and a preservative for rubber parts! I use it just for that!

To give you an example of a great fix that water wetter can take credit for......I have a buddy with a 502/502 that constantly overheated due to the fact that he was puking in traffic at high temps. The temperature gauge said 230...but there were definitely spots somewhere in the block that were alot hotter and producing gassing that exceeded the radiator cap pressure. These hot spots where formed by either trapped air or cavitation air from the pump. I suggested water wetter to see if it could stop the hotspots. He added two bottles( big system) and off he went. The temperature gauge still reads 230, but the thing stopped puking because of no outgassing pushing the coolant out. The water wetter obviously fixed the coolant from boiling off for one reason or another, regardless of what they were caused by it has stabilized the system.

Water wetter in my opinion has some redemming qualities that make it worth the extra $$. It is not a substitute for a poorly designed system though.

Forty Below is another story. I don't recommend it. I have never seen any claims of theirs met. Remember, pure water is the best conductor and carrier of heat.......period. Forty Below cannot absorb or carry any more heat away from the engine. I think it's a waste of $$. Others may have a better experience or explanation of this.....I'm all ears and have my chemistry book near?

Evans coolant in another coolant substitute that does have some redeaming qualities. Evans is a non-aqueous based glycol that has extremely high boiling and freezing points. The down side is that it is expensive and it has requirements of alterations to your mechanical cooling sytems in some applications. The extremely high boiling point and the fact that it will not produce any outgassing means it stays put.....that's good. But, it has a significantly lower specific heat number which means that it removes less BTUs from the sytem which in and of itself can produce a run-away cooling system in some cases. I have seen these systems go right to 250 degrees...whereas a correctly designed or corrected system with conventional coolant would stay at 220 easily. So, there are big ups and downs to this coolant substitute...you decide.

My 2 cents worth of cooling chemistry.

Steve Jack




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SOUTHEASTERN GOODGUYS REP

I notice you mentioned time in contact with the surface being cooled. If I remember rightly from college thermodynamics, a fluid can flow so fast that it will not pick up sufficient heat in a heat transfer application. So, if it flows through the block and/or radiator too fast, that's not good either. Correct?

Fred,.... it depends on the coolant and the design of the cooling system really. If a liquid/coolant is not utilised to the fullest extent of it's capacity or range to maximally absorb BTUs from the source, the "too fast" thing could theoretically happen. This is very heavily dependent on surface tension of the media as well I might add.

But,within the conventional automotive cooling system, a point has been perpetrated on rodders for years with regard to the "if you hold the water in the radiator longer it will cool better" is a myth, if that's what your talking about. I have heard this time and time again and it makes my blood boil (talk about overheating) everytime I hear it. I think this started with the use of restrictors instead of themostats in radiators. When an engine was not cooling correctly and some people would remove the thermostat and found out that it wouldn't produce the results that they wanted, the introduction of restrictors caused a slight and noticable reduction in temperature. The conventional wisdom was to blame this cooling effect on slowing the water in the radiator(which was purportedly better)when actually it was introducing turbulance to the entrance of the radiator system eliminating laminar flow problems and mixing the media better making for more heat removal. Turbulence is critical.

In a closed loop automotive radiator system, the longer the water is in the radiator getting rid of BTUs, the longer the coolant is in the block picking up BTUs as well, BUT, and this is important.. not as many BTUs as the radiator is capable of dumping because of the point the coolant is at in the block (you theroretically want the water in the block to pick up as many BTUs as you dump). The fact is, the higher the flow the better! This will always be the case in a properly designed system! The radiator has the capacity to remove more BTUs than the engine (if it's designed correctly) can produce through conductivity and surface area, which means that the faster and therefore more volume of hot water flows across the superior cooling media will always reduce the temperature by a disproportional amount at the radiator outlet. This provides cooler water at the outlet of the radiator compared to slower moving cooling media. The mechanics of this is also dependent on the fact that water will absorb calories disportionately faster when the ambient temperature of the water is furthest away from it's corrected vapor point than water or coolant that is nearer it's corrected vapor point. So essentially, the radiator will always have the capacity to dump more calories per unit volume (because of area and conductivity) and provide cooler water that will absorb calories faster (for the engine) than the a warmer water in the engine can absorb as the water gets close to the corrected vapor point. If you let the water stay in the block too long the water cannot absorb and remove as many BTUs (due to the coolant progressing ever so closer to it's corrected vapor point) making for a runaway situation eventually.

Another important point about faster flow is the turbulence that it produces throughout the system which is critical to thorough heat transfer as I have previously mentioned. See my article on cooling and refer to the "jumping in the lake" analogy. Mixed water does inherently better than water that flows smoothly for heat carrying capacity.

Now, that's not to say that you can't create problems with very high pressure and flow that would create unproductive eddys, but the conventional high performance pumps available in the aftermarket will not come close to doing such. High flow pumps are a must on high performance engines in my opinion.

I know this got too lengthy and wordy......but I hope it helps you with your question.

Steve Jack
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SOUTHEASTERN GOODGUYS REP

Thanks for all the help from everyone.
I am going to reduce the percentage of glycol in the system and wire the 10" pusher fan to run on temperature with the 16" puller.
Hopefully, I'll stay cool that way. When those 100+ degree days hit & it still runs hot, I will try switching to an aluminum high peformance radiator.

You do want your engine warmed up for several reasons and not just combustion issues. The first of which is the friction of an engine at lower temps is greater, the cylinders/rings/pistons actually seat better under warmer conditions (depending where the engine is DESIGNED TO RUN and ever hear a true forged piston engine clatter when cold) and depending on the fuel that you are using, the best ecomomy MAY be at 195 vs 170 let's say. But, engines have run at 165+ for ages with great efficiecy and what you really want is the engine within its DESIGNED parameters as far as temperature is concerned and the cooler part of that zone will produce more power due to the incoming charge (induction) kept as cool as possible as well as the fuel...hence open aircleaners, outside air feeds, airgap intakes and the such.

If you throw a bag of ice on an intake at the dragstrip you are likely to get a few more hundredths of a second due to the inductive charge being denser and able to produce an effective higher peak cylinder pressure. We used to use cooling cans to keep the fuel cold whilst rocketing the quarter.....and ram air does work......but the engines of all of these must be within their operating temperature tolerances to produce the right result.

I operate most if not all my cars in the 175 to 185 range. That is acceptable as is 215 for some engines and combos. The upping of the temperature in todays V8s (and others)in the late 70s was a product of emission issues moreover than anything else, but isn't required. Certain oils are now made for higher temps as well and perform poorly in so far as frictional viscosity at lower temps......hence 0 weight oils etc.

My 2 cents.....

Steve Jack
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SOUTHEASTERN GOODGUYS REP