additional cooling

My existing cooling system becomes marginal in hot weather. I have room below my existing rad ( pic )to run another small rad ( like a trans cooler ). Any suggestions on how well it would work and how to plumb it in to my existing system? Thanks, John

john, out of curiosity, at the lower end of your grille shell, do you have a metal "scoop" like the factory shell had ? this aids airflow to not bypass the radiator by going under the car if the "scoop" was not there. just a thought. also, please refresh me on your fan setup. as my old man was fond of saying, : "he [i] don't know he [i] left the house yet !"........ "oldtimers" ya know.....

upon looking at your pic, try adding a "scoop" from the lower edge of your shell up to your front crossmember, closing that area, forcing more air to flow through your radiator. see, i looked and didn't see ! i hate when i do that.....

Cooling a vehicle in the AZ summers can be a challenge.......I moved out here 30 years ago and it's been a learning curve ever since.

As far as a secondary radiator......I did that once (52 Ford F6....big truck with a lot of under under hood room)I installed a complete small radiator with it's own cooling fan. It was a colossal waste of time! the only thing the second radiator did was cause it to take a little longer to get to the same temperature it got to before.

It's really kind of hard to make any suggestions without knowing what you're currently working with. What temperature does it run at in the summer. When does the heating occur; in town or going down the highway. Have you verified that the temperature the gauge is showing is accurate (I've had gauges read as much as 30 degrees off).

It would also help to know what type of radiator, number of tubes and with width of them. What kind of fan and do you have a shroud. What is the temperature range of the thermostat.

Pictures would help too.

I agree that an additional radiator will probably only add a little time to how long it takes to reach the high temp you are reaching. Your going to be pretty limited as to how you can add another radiator and pass enough air through it to make much difference. If you could add another cooling feature, I'd see if you can plumb it as a reserve to tap into when you need it. Adding a couple of quarts of cool coolant to hot system will bring down the temps for a while, maybe long enough, if your running close to range.

How hot is it getting? 210-220 is not out of an allowable temp range under a 16 lbs pressurized system. Gene

Radiator is a 22.5 tall 2 core aluminum rad to fit a 32 Ford chopped grill shell. Trans cooler in the bottom tank. Total cooling system capacity = 3.5 gal ( not including the heater core ). Fan is a Spal 16" electric fan = 1,604 cfm bolted directly to the rad ( no room for a shroud )- pic. I haven't been running a stat to try to improve flow through the rad ( less restriction ). Not sure if running without a stat is a good thing or not?? Fan controller is set to go on at around 185 / 190. With ambient temps in the mid / upper 70's, temps seem to hold around 190 - 200 both at idle and cruise ( 60 - 65 mph). Running a 3.55 gear so cruise a 65 = about 3,000 engine rpm. Any kind of load ( long hill, etc ) and the temp starts to climb. Seen it as high as 212. Haven't run it at 80 / 90 degree ambient temps yet, so ..... don't know what will happen temp wise? Also haven't run the A/C yet?? Think the gauge is accurate. Sender is located right next to the stat housing. Agree with some of what's been said so far on this thread. Hope this answers some of your questions.

after seeing the pic of your radiator/fan combination, i would look into a fan setup from a late model ?? that would incorporate a shroud covering the whole core. also, most factory fan setups are a two speed, having the high speed kick on whenever the ac is requested. i think that would go a long way toward easing your mind about the 80-90*temp/ac use issue. although the aftermarket fan manufacturers claim great things about their products, i'm not a "fan" of them [pun intended ], preferring factory setups instead. you may also consider a separate transmission cooler [with fan] to eliminate that heat source from contributing to the issue.

Nice build! Start with the simple things first.

The first thing I would do is buy or borrow a temperature gun.

http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=temperature+gun&_sop=12

You need to verify what the temperature actually is…….you don’t want to spend a bunch of time, money and aggravation hunting for a problem that turns out to be an inaccurate temperature gauge (over the years I’ve run into this three times so it does happen). You want to check the temperature at the thermostat housing to see what the temp of the coolant coming out of the engine actually is.

The next step is to get a thermostat in the engine. Besides its function of quickly bringing the engine up to operating temperature, the thermostats’ most important function is to act as a restriction in the cooling system. That restriction is vital in keeping the coolant in the radiator long enough to transfer heat from the coolant to the outside air.

Thinking on what is an ideal operating temperature has changed considerably over the years. In the old days we felt that a car was running hot when the temp gauge hit 200 degrees. For most modern engines that could actually be considered on the cool side. Personally I’m perfectly happy seeing any of my cars run in the 190-210 range and can even live with 220-230 if I can’t get it any better. Keep in mind that the coolant mix (anti-freeze and water) will raise the boiling point of the coolant and the radiator cap further raises the boiling by 3 degrees for every pound of pressure added to the cooling system. As long as your cooling system is in good shape (hoses, clamps, radiator etc) running a 16 pound radiator cap is no big deal.


That being said personally I would start with a 190 degree thermostat and feel perfectly comfortable seeing an operating range in the 190-220 degree area.

If you feel that that is too high then your alternatives boil down to increasing coolant capacity or increasing air flow thru the radiator.


Increasing coolant capacity means a radiator with a more coolant tube surface area. Brass/copper actually transfers heat more efficiently than aluminum. The problem is that the brass/copper is relatively weak limiting the size the tubes to a small size. Cooling capacity was added to these radiators by adding more rows of tubes (i.e. 2, 3 or even 4 row radiators). Aluminum is a more rigid material than brass/copper and because of this the tubes can be made much wider exposing more surface area and allowing a more efficient radiator. The reason I bring this up is that many aluminum radiator companies have started producing radiators with 3 and even 4 rows of tubes. The problem is the tubes are much smaller (usually 3/8”). If you are currently using a 2 row radiator with 1” tubes(2" worth of surface area), going to a radiator with 3 or 4 rows may actually end up decreasing the cooling capacity rather than increasing it. (A 4 radiator with 4 3/8" tubes actually only gives you the equivalent of 1 1/2 inches worth of tubes). Basically I don’t think you are going to get much more coolant capacity than you already have.

Increasing the airflow thru the radiator is also going to be problematic with your space limitations. Most of the aftermarket electric fans just do not move a huge volume of air. The problem is 2 fold…keeping the fan slim means limiting the pitch of the blades (less air flow) and thin motor (less power/speed). Using a bigger more efficient fan to the front of the radiator might be an option but I suspect you run into space issues there too. moparx is absolutely correct about the factory fans, if you can fit one in.

One final option is to slow the engine down. 3.55 gears are fun, but the faster the engine is turning the more heat it’s producing. A few years ago I gave my wife a car I had built several years before as my DD. She doesn’t drive a stick, so I pulled the overdrive 4 speed out and installed a non-overdrive automatic……operating temperature went up 10 degrees. Just say’n.


Sorry about being so long winded.

Airflow thru the radiator at 65 mph is driven by road speed not the fan, unless the fan is blocking airflow itself.

Generally speaking temperature issues at highway speeds are water flow issues not airflow, but that assumes a factory designed cooling system as well.

I see you have aftermarket pulleys, that may be affecting the water flow. Looking at the pulleys they look like might be underdriving the water pump. If you happen to have a stock set of pulleys you might swap them in and see if that clears it up.

How many vanes on the water pump impeller? impeller count and pulley ratios are interdependant, if you run non-AC pulleys with an AC water pump you run into issues like you have. The non-AC pump was more impeller vanes so it runs ate a lower speed. AC pumps have less vanes and run at a higher speed to move the water.

Had 454 '37 ford, have 460 f1, know about trying to cool.

160 degree stat, remote trans cooler, 200 is not hot.

Thanks for all the reply's!! Lots of good info for me to chew on / try. Increasing coolant capacity and / or air flow really helps put it in perspective for me. I will start by verifying my existing gauge. Agree on the fan thing. I will keep looking for a factory unit that will fit my application. I will put a stat back in it too see if that helps. I do see wide temp swings without a stat ( temp can drop down to as low as 150 with cooler ambient temps ). Separate trans cooler is another option. I am running an 8 blade A/C pump and I think the pulleys ( although after market ) are the factory diameter. I will verify again on that. Thanks again for everyone's input.

Will increasing capacity, not the core size help or is it a temporary fix until the extra liquid heats up?

Ran a few more tests today - all at idle in neutral. Used an infrared thermometer and verified the temp gauge. Temp was measured right next to the temp gauge sender in the intake manifold and the #'s were within about 5 degrees. I'm calling that accurate. Without a stat, temp seems to level off at about 195*. Installed a 180 stat and the temp came up to 180 quicker, but seemed to level off a little higher than without a stat at around 200*. I'm thinking that it is due to the flow restriction caused by the stat? Anyway, the temp went right on by the 180 stat. After the temp leveled off at around 200, I kicked on the A/C. This added about 10 - 15 degrees and the temp leveled off at about 215. Ambient temp in the garage was in the upper 70's. Sooo, it appears that my existing system will hold the engine temp (@ idle rpm with no load )at around 190 - 215*. I think my next move is to install a separate trans cooler.

Good question - for which I do not have a good answer.

i will go out on a limb here [with chainsaw in hand] and say this will just delay the inevitable, unless it will be a sizeable increase. i think the answer to the issue is [in no particular order] water flow, increased air flow from the fan system, removing excess heat from the transmission cooler, and possibly removing excess heat from the engine compartment, in which to do this, i don't have any suggestions, other than the basic hood louvers or running without hood sides. as the water temperature is the hottest coming in through the upper hose, the fan should be directing a bunch of airflow in that location. one example of this was the introduction of a water pump riser for the "brand "x" small block. this was a good fix [at the time before electric fans] when it was discovered the engines sat drastically lower in the chassis than the original inline sixes, or flatheads, causing the water pump driven fans to, therefore, suck the air through the lower part of the radiator, not cooling the upper, hottest, part of the system.all OEM's position mechanical fans at the top of the radiator for maximum airflow in this area.

Increasing capacity, unless it's due to increased radiator size, will not solve the problem.

Thanks again for the feed back guys. Gonna look for a separate trans cooler today that will fit below my existing rad and in the grill air stream. Don't know how much it will help ( getting trans oil heat out of the bottom tank ), but it sure can't make the situation worse. Might try and get some temp #'s at speed today ( 65+ mph on the highway ). This info might tell me if more rad air flow is the way to go? If the steady state temp #'s go down, I will be looking for a better fan ( OEM fan that will fit in my confined space ). John

Some ducting / air flow into the trans cooler that also forces more air into the rad?

The best OEM electric fan, if you have room, is the Lincoln Mark VIII, (hands down) I have one on my 460, comes with a trimmable short shroud, but it desperately needs hood louvers on hot engine cool down to get the hot air out.

Removing hood sides on '37 did not help much.

http://www.fordmuscle.com/archives/2006/10/Mark8Fan/index2.php

Mark (big amps) and Taurus. I will see if I can get a pix of the 460 mark fan installed.

http://www.qsl.net/wd4ngb/markviii.htm

With dimensions and p/n's.

Warmer weather will probably bring higher temps. You might consider changing your coolant to the Evans Coolant so the higher temps don't build dangerous system pressures.

http://www.evanscoolant.com/vehicle-types/hot-rods-muscle-cars/

Looking at that stuff John. Presently running a 10 lb cap with 60 / 40 mix - water/ glycol. My next step is changing the crank pulley from my existing 5.750 aluminum pulley to a stock 7.25 OEM pulley. This should speed up the pump about 200 RPM. The additional flow through the rad might just be enough. Step in the right direction anyway. Gonna do this before I install a remote trans cooler.

Thanks a lot for this info.

Ok, ran the car today in the garage at idle with the larger crank pulley and no stat. Dropped the temps by at least 10 degree's. I can now get the temp to cycle off the fan on/off setting ( between 180 - 190 ). As soon as it warms up outside, I will drive it at speed (65+ ) with the A/C on and check it that way. If it is good with ambient temps in the 90's, I may not have to use a remote trans cooler.

I still think, if you insist on no stat, you should at least put in a re-stricter to slow the flow through the rad some.
You can play with it to dial in the ideal opening size.

I think that running without a thermostat or with a restrictor only are both poor ideas for any car that is anything more than a dedicated trailer only race car.

Just because racers do something it does not mean it is a good thing, especially when you do not know why they do it.

Why do racers run without a thermostat or with just a restrictor?

It sure ain't because they are overheating with a thermostat, they don't run long enough.

It's because the restriction of the thermostat, coupled with high rpm's were blowing hoses and such loose. It's a crutch to fix a unique issue.

Much like the old wives tale about needing a thermostat so the coolant has time to get the heat out of the block is false. Whomever says this doesn't know about heat transfer. The number one factor, by far, in heat transfer is the differential between the high and low temps involved. Not the time in contact.

The bigger the difference in temp between the block/heads and the coolant the quicker the heat transfers. This is something that is not commonly thought about, the same it true about the difference in temperature between the coolant and the AIR going thru the radiator.

Turbulence in the coolant can increase the efficiency of the heat transfer. Best way to create turbulence in our applications is to increase flow, but not to increase it so much that the pump cavitates. If you were to compare an intercooler to a radiator (both designed to remove heat from a "fluid") you will see that intercoolers use internal devices to create turbulence thru the intercooler, this increases efficiency. Radiators don't generally do that because you can increase flow without detriment unlike in an intercooler where too much flow (boost) can cause all sorts of interesting things to happen.

As to the OP's specific situation, a 10 degree drop by swapping the pulleys is fairly large. You are probably ok now. If you need a bit more I would suggest a high flow pump with an anticavitation impeller, or at least putting an anti-cavitation plate on your stock pump.

what were your original pulley sizes ? do you know what the factory sizes were for your engine ? as was said, 10 degrees is a sizeable drop.

Interesting stuff. Thanks. Not sure I understand it all. I would prefer to run a stat, but before I made the pulley change, I was not able to run on a 180 stat. The temp would just blow right by it, so the stat would just run wide open all the time and not regulate anything. In that case, it became nothing more than a flow restriction ( in my simple mind), so I removed it. Seemed to help with temps slightly lower without it, and I attributed it to better flow through the rad ( coolant passed through it more often in a given time period ). BTW,I have been trying to read temps ( inferred temp gun ) in the same spot all the time( intake manifold right next to the temp gage sender and thermostat housing ) for repeatability purposes. Without a stat, I do see wild swings ( 160 to 215 depending on engine load and ambient temps. I know, not good.
With the pulley change (5.75" aluminum pulley to 7.25" OEM steel pulley) I will probably be putting a 180 stat back in and give it a shot.
Attached pic is of the air deflector I fabbed to try and direct more air from the bottom 1/4 of the grill opening to the rad. This change will only work at speed of course - if it works at all - doubt I will be able to measure it, but can't hurt.
Hammer away Supercuda! I really do appreciate your input.

I believe the factory size crank pulley for my engine was what I am running now ( 7.25"). The aluminum pulley I was running was 5.75" diameter. Think that equates to about a 200 rpm pump speed change. BTW, I do have a modified pump ( added an anti-cavitation plat to the impellers ) that I haven't tried yet.

Pic I forgot to add of grill deflector.

Oh, I wasn't trying to hammer, just inform.

the thermostat's job is to regulate minimum temperature, which as you've noticed can vary wildly without the thermostat in. I think you are on to it right now anyway.

If you had that large of space below the rad that allowed air to bypass going through the rad, that you have closed off, it should make a huge difference in the amount of air flowing through the rad at any speed. That should help a bunch in the hot weather. Gene

Hope so Gene. The car has a very long grill opening. Wish I could have used it all for the rad, but as the pic shows, the rack is in the way.

i'll take a pic of an original shell and that ducting in a little while and post later. as it was positioned, the factory straight axle was in the way, similar to your [or any, really] front suspension.

here are a couple of shots of my humpback grille & shell. obviously, the headlights are not in the stock location. however, the radiator ducting is still [mostly] there. this was used with the flat six and the 4 blade fan. i'm guessing the top speed was 60 [?] mph, but as it was a delivery vehicle, it probably spent most of it's life idling.

Thats a cool thing. (no pun intended) !

Wow! That's pretty close to how my air deflector looks. Got a couple hundred mile trip to go on this week end, ( should be in the low 80's ) so I will see how it works at speed. Thanks for the post.

john, how did your trip go ? any cooling improvements ?

I don't know where you got your pulleys but CVF Racing offers a high flow pulley. I believe it's 6.4" diameter.(if you want to go back to an aluminum pulley) Not as large as the one you're trying now though.

https://www.cvfracing.com/chrysler-small-block-pulleys-s/44.htm

I've read that some electric fans can be a restriction to air flow at cruising speeds.(while they are running) I wonder if hooking the fan up to a toggle switch and shutting it off while on the highway would be a good test to see if the temps stay lower.

Not real sure that setup is "high flow".

If you read the specs the water pump and crank pulleys as the same diameter, which means 1:1.

Stick with stock.

Yah, "high flow" is their description. It's high flow compared to their under drive pulley that usually comes in the kit. I was just trying to give him an option since all of his other pulleys are aluminum. If the problem ends up being the fan, maybe the 6.4" pulley would work?

The trip turned in to a low 60's temp with possible rain, so we took the wife's 79 300 instead of my 33 - and it did rain on the way home - so I haven't had a chance to try it yet. Weather here has been goofy lately.

Ya, Thanks for that info. If the weather ever warms up around here, I will give a report on the 7.25 OEM steel crank pulley that I have on there right now. I would like to stick with all aluminum pulleys, so if the 7.25 works real good, I might try going to the 6.4 aluminum pulley you mentioned.
As a side note, I actually had to trim about 1/32" off the O.D. of the steel pulley I am using to keep it from hitting my existing water pump pulley. I should know pretty quick if the water pump bearing ever starts to fail.

My 34 ply ran hot. What I did in steps, was remove 340 pulleys and put on 360 pulleys, relocate trany cooler from bottom tank, to under the running board, and the thing that helped the most was putting on a 7 blade engine driven fan, not a clutch fan. That alone took 15 degrees out of the probelm. Also did that on another car and it did the same. Brass radiators will remove more heat than an alumunim radiators,

Just a Quick up date on this thread. Did the Route 66 fun run a few weeks ago and got to drive in just about all weather conditions over the 3 days we were gone. The big test was the first day when the temp ran in to the mid 90's. We were pulling a small trailer to add to the situation. Hottest it got pulling up a long hill at 92 degrees ambient with the trailer was 220. Level surface at the same temp it hung around 205. The little air direction scoop I put at the bottom of the grill seemed to really help at speed. Ran a little cooler at 65mph than 55mph. This, again, was with no stat in the system. We ran in to some 60 degree temps on the way home and the temp dropped below 180 at times. Obviously too cool. So, per many's suggestion, I put a 180 degree high flow stat in. I will be trying it that way in a week or two. Thanks all again for your many suggestions.

glad it's working out for you ! [i just love that color with the sun on it !]

Not sure if this matters, or has been mentioned, but some marine inboards use a 140 degree stat. Slows down the coolant but also opens sooner?

John, I have a double pass Ron Davis radiator in my Hemi Model A and have no problems in the AZ heat.