Still FRICKIN Hot.... what about Aluminium Radiators

[John Wais]

Clois
After installing a new fan in my Cobra, I was overheating in 60 degree temperatures. I walked in front of the Cobra for some obscure reason and felt hot air on my legs.
Dumb me had the fan wired backwards and was pushing the hot air from the engine into the radiator.
John W.
When in doubt, follow instructions!!

[Clois Harlan]

I am running an expansion tank, my current and new fan (when it arrives today) will be puller fans. I am thinking about running both fans, small one as a pusher and the larger one as a puller. My thermostat is a 180 degree. I am also wanting to do something about my top rad hose. The radius is extremely tight (5" or 6") from the expansion tank to the first 180 degree bend and then another quick 180 degree bend back into the radiator. I know the hose suffers from this configuration even though it is pre-formed to some extent.

I received a call from a friend of mine (who has raced and ran bb Fords for quite some time) last night and he thinks I may be expecting too much from the old engine.

Last night I purged all the water from my block and will be trying the Purple Ice and maybe 1/2 gallon of anti-freeze with distilled water in my cooling system. I probably won't be be firing this baby up until Saturday.

As soon as I get another take on the changes I will let everyone know. Everyone has given me some great suggestions and I will be trying most of them this weekend (except the aluminium radiator for a while). Thanks again.

[Frank Coppola]

Clois,

Do you know if you're gauge is correct? I gave up on S&W mechanical gauges and went with another brand that was more accurate. Put the sensor in some boiling water and check the calibration.

My cobra ran hot, so I bought the dual aluminum fans from Enzo for pusher fans and a Mr. Gasket 16" fan as a puller. I went for a dual core Griffin aluminum radiator and the cool flex hose. If my car is not in motion the fans (all 3) have to be on. I installed a permacool thermostat/ relay which allows me to turn the fans on manually.

Haven't had a problem since.

I know it was mentioned before, but I too think you should check your timing.

Good Luck!

[Jim Weatherall]

I have a 428 CJ too and my heating problems were precicely as you describe. I finally installed an aluminum radiator and now it cools within acceptable limits in Houston heat (200-210).
Conventional wisdom about better heat transfer properties of copper/brass aside, the alum units cool way better because the tubes have huge surface area where fins are connected. They use just two inch-wide tubes to maximize that. This design can not be built out of brass because it is too soft and the tubes will deform.

Two good brands are BeCool and Griffin. Griffin uses epoxy to attach the header tanks which has poorer heat transfer, while BeCool welds everything. I don't think this is a very significant difference. My Griffin is very satisfactory and it was custom made for Everett Morrison and about half the price of BeCool.

[CobraEd]

What is the deal with 428s??? It is becoming apparent that this cooling problem is very common.

Why didn't all the factory mustangs and police cars have this problem? Why don't the 352, 390s, and 427s have this problem? Why the big deal with 428s in Cobras?

Ed

[Jim Weatherall]

I also want to mention you must be sure to have a spring inside your lower radiator hose to prevent it collapsing. The thermostat is important in this application not for its temp rating, but to restrict flow of coolant. The bends you mention in your top hose will not be a problem and in fact will even help.

I have the high volume water pump like you and this actually flows coolant too fast so it doesn't have time in the engine to pick up heat and time in the radiator to dissipate it.

There are a number of counter-intuitive things going on here. Basically we just have a marginal cooling engine pumping out massive amounts of horsepower to make it even worse.

[chopper]

CobraEd:

FWIW, the 427s DO have this problem, probably worse than the 428s. I've been fighting this on my car since the day I bought it. I ran into a fellow in NJ who had an original Shelby car, completely restored, at a show at a local Ford dealer. He pulled in, turned off the engine and it puked about 1/2 pint of antifreeze out the overflow on the expansion tank all over the ground. He walked up to my car and started to ask what I did about the overflow when mine did the same thing. The original 427-engined cars were reknown for overheating. I have since installed a catch can with a return line and am in the process of talking to Griffin about replacing the original copper/brass radiator with an aluminum one to try to resolve the overheating-in-slow-traffic problem.

Richard Hudgins:

Not meaning to cause dissention here. but I talked with some of our engine folks at work (I work for a helicopter manufacturer and we use radiators as cooling units for the engine and transmission oil). Their statement agreed partially with yours, in that, all things being equal , copper/brass is superior to aluminum from a heat transfer standpoint. However, as usual in engineering, all things are not equal, and the use of aluminum allows the manufacturer to build cooling tubes which are wider than possible with copper/brass, due to the increased structural rigidity of the aluminum. This allows the aluminum radiator to have more direct cooling surface area than the copper/brass. Also, the secondary cooling fins on the copper/brass radiators are soldered on; I understand that the solder inhibits the heat transfer from the primary cooling tubes to the fins, resulting in loss of efficiency. At work, we also use aluminum because it is lighter, and that is a much bigger factor in aircraft than cars.

I have talked with Bill Parham from Southern Automotive about the overheating 427 problem on several occasions. Bill built my engine and has one which is essentially identical in his Superformance demonstrator. He claims he runs it around Atlanta all year round in all kinds of traffic and never exceeds 195 degrees coolant temperature. The only difference I can see is the Superformance cars have a really nice aluminum radiator setup and my older model ERA still has the original copper/brass unit. I do note that ERA has switched to aluminum radiators in their later model Cobras and GT-40s.

[Clois Harlan]

Hey Frank,

I don't want to order a radiator unless I have to but when/if I do we have a source here in Tulsa that the race car drivers are using ACCO Aluminium Radiators made in Indiana. My price is $209.00 for a 19" tall x 26" wide two core. What are the diminisions of your radiator? I figure if I order one of these ACCO Radiators there will be about 375 square inches of cooling surface (15"x25"). What do you think.

Of course there is Summit and PAW for Griffin and BE COOL at around $450.00.

[Coloradocobra]

I run a 428 in my car and went with a 19x26 Griffin from the start. It runs 180 to 190 most of the time and rarely sees 200 at a stop light on a hot day. I ended up having my inlet and outlet on the driver's side. To do this, Griffin put a block in the left header tank halfway up so my radiator is a dual pass. This leaves the upper right side vulnerable to air pockets so there is a bleed up there. I run a hose from the bleed to the expansion tank tube that is off of the corner of the tank - not the overflow. I had Griffen fabricate the fan mounts when it was built so the fan bolts directly to the radiator. The only times my motor overheated is when I went lean trying to get the jets sorted out and another time when my ignition retarded when the Pertronix unit went out of alignment.

Griffin will make a radiator to your exact requirements including overall dimensions, inlet and outlet sizes and orientations, bleeds, drains, and temperature or fan switch ports. The cost with the fan was very reasonable. We just faxed them a drawing of the layout and the built it to match.

How many miles on the motor? It could be a little tight right now. Also, I have heard that a runaway temperature problem can be due to improper ring and/or piston sizing. Do you have the specs?

Lastly, there is a Mile Hi Cobra Club member with a 427 that had temperature problems as you describe. A new radiator, new fan, and a much better tune allows it to run cool now.

Good luck,

Gary

[Clois Harlan]

The weekend plan is to re-intall everything including both fans and see how it performs. Then if I still have problems I will pull everything down and starting with the pistons and rings re-check everything. But I really hope I don't have to do all that, I am going broke buying gaskets.

One thing I haven't done yet is re-check my fuel mix, I know my initial setting was fairly rich so not to burn anything. I will also check my timing again although I think it is right on the mark +10.

[Frank Coppola]

Clois,

My old radiator was brass and sat in front of the steering rack and behind the sway bar. My new rad is so wide that it wouldn't fit there so I wound up putting it in Front of the sway bar. If I had to do it all over again, I would have had a rad made to my specs as Gary said. If you're not going to use coolflex hose, you can even get a larger port put on your custom rad to match the larger diameter of the water pump inlet. My rad is vertical but some like to shoehorn them in on an angle. Call your place in Indiana and see if they make custom rads. If you do go the new rad route just take your time and make one out of cardboard and test fit it. You don't want to get stuck with a $400 rad that won't fit which you can't return.

Also, check out the formula on the purple ice bottle, the less anti-freeze the better. Fill your entire system with water, then drain and measure the volume so you can get the right ratio.

My new cooling system cost alot of time and money, but it is nice to drive now with both eyes on the road instead of one stuck on my temp guage.

ps, I was so obsessed with keeping cool that I even put an oil cooler in. --That was definate overkill.

[Wayne Maybury]

Just wondering what temperature you guys feel is too hot. My 351W ran at about 190 in traffic last summer. I always had one eye on the temp but it never seemed to go higher than that. I tried a 180 thermostat as well as no thermostat but the temp stayed more or less in the same area. I was running a 50/50 blend of antifreeze and I have a CSI electric water pump as well as a 16" puller fan.

I plan on running a 90/10 water/antifreeze blend this year with water wetter and I am considering putting a switch in the fan circuit to be able to shut the fan off when on the highway since the engine appeared to run a bit hotter at 60 MPH if the fan was running than if it was off. I am not sure what the capacity of the fan is but it sure appears to move a lot of air. Anybody notice if their engine runs a bit hotter with the fan running on the highway?

Wayne

[Clois Harlan]

I could live with 190 or even 200 in July!

[DAVID GAGNARD]

Clois;

What size radiator and fans do you have as well as diameter of your crank and water pump pulleys?????

Here is my setup;19x26 aluminum Griffin two core radiator,20" puller electric fan from a Caddy or big Olds,not sure,and a 12" pusher in front. Crank pulley is 6.5 inches in diameter,water pump pulley is 5.75 inches in diameter.

I fought with heating problems for a year and did everything except call in a witchdoctor,also spent more money than I care to admit, all for the sake of driving in parades.

Here is what I found,small 19x19 oringinal Mustang radiator was marginal for street use and no good for parades,so I switched to a bigger radiator 19x26. That helped but she still ran hot,went thru 3 after market electric fans with poor results,I find they are not shrouded very well and most blade configuration is not the best. Got the Caddy electric fan free at a body shop. It had one to the four mounting "ears" broken off and they replaced it and were going to throw it out,so I took it and it has a very good shroud as well as blade shape and beats the a/m ones hands down,no contest. Did better in parades but still got hot. Put a high volume aluminum water pump with same results as before. Called their tech line and went thru whole scenario with tech guy and first thing he asked was pulley size. They recommend for street use pulleys of same diameter and THEY WERE RIGHT. Took off my crank underdrive pulley replacing it with stock pulley and have had no heating problems since. Idles in 100 degree heat parades for 45 minutes at 180 and after 45 minutes it slowly climbs to 190-195 and pretty much stays there.

The underdrive pulleys are designed for racing and not street use although they may advertise them for the street. With my underdrive pulley,once the car was warmed up,open the radiator cap,idling 800rpm and the water would just trickle out the flues,with the stock size pulley,it flows out an inch to two inches. Quite a big difference in flow.

I'll gladly give up the 5-10 hp of the underdrive pulleys for cool running and peace of mind for not having to worry about overheating........

David

[Dave Samson]

Wayne,
I run an electric water pump too and control the pump rate using a thermo-sensitive switch which restricts the voltage to the pump and has the same practical effect as a mechanical water pump. My fan is also controlled by another thermo-sensitive switch so that I can dial in different temperatures for each unit.
This system automates the heating/cooling process regardless of season.

[Dan Lancaster]

I suggest that you recheck the timing. First check to make sure the mark on the dampner is pointed to the right location. To do this, take out number 1 spark plug and turn the engine to top dead center. I think I have seen a tool in Summit Racing or Jegs to help with this. Summit's number is 800-230-3030 and Jegs is 800-345-4545. Or build your own out of an old spark plug and a bolt. You have to break out the insulator, drill the metal hub and tap it for a bolt. The end of the bolt is screwed down into the engine so the piston strikes the bolt. Mark the dampner in this location and rotate the engine (by hand) in the opposite direction. Again when the bolt strikes the piston, mark the dampner. Half way between these to marks you made on the dampner is the actual top-dead center. Now retime the engine to spec.
In my earlier days, I had a Mustang which overheated when in the city. I would have to cool it down at 60 MPH. Turned out the timing was too far advanced. I found this out after several water pump replacements and many thermostats.
Hope this helps. Looks like you have tried everthing else. If you have any trouble with my explanation, let me know...

[Richard Hudgins]

Hi Chopper,

You stated "Not meaning to cause dissention here. but I talked with some of our engine folks at work (I work for a helicopter manufacturer and we use radiators as cooling units for the engine and transmission oil). Their statement agreed partially with yours, in that, all things being equal , copper/brass is superior to aluminum from a heat transfer standpoint. However, as usual in engineering, all things are not equal, and the use of aluminum allows the manufacturer to build cooling tubes which are wider than possible with copper/brass, due to the increased structural rigidity of the aluminum"

I agree with some of what you are saying, however, a couple of points.

1. Thermal conductivity of Copper = .00404 btu's per second per Sq.in.
Thermal conductivity of Aluminum = .00203 btu's per second per sq. in.

Copper is almost twice as good as aluminum.

2. What is critical in a radiator is cooling surface area relative to fluid area. In other words, you wish to have the maximum amount of radiating area relative to the amount of fluid. (area of fluid as small as possible and radiating surface as large as possible). The simple explaination here is that you wish as many molecules of coolant in contact with the largest possible amount of radiating molecules.

If you will look at the illustration below you will see that a larger tube is not a good thing from an area to area ratio standpoint.



Secan is the major source of radiators in F1 cars. Their units are copper/brass. But nobody could afford to use their units in our type of cars.

Now, I personaly like aluminum radiators. They are much stronger, cheaper to fabricate and lighter than Copper/brass units. But therm to therm/btu to btu, they co not compare for pure heat transfer.

[Wayne Maybury]

Richard

A very quick question. My copper rad is painted black, just like most radiators. In your opinion, how much effect do you think the paint has on the thermal conductivity of the copper? Wouldn't we be better off if we removed the paint? Just a thought.

Wayne

[Andy FIA]

David G - You have just confirmed what I have been thinking about the under drive pulleys. They are promoted because of the potentially "free" horsepower increase due to reduced friction of rotating components and fluid. Race cars have a relatively small alternator load compared with your average street "tank", and they don't normally have to run in traffic. so good cooling at idle is not a primary concern.
My 302 has a high volume pump and under drive pulleys, and runs fairly hot, most likely because the pump is not running at "design speed".

I think I need to do some pulley gearing sums!!

Andy

[Richard Hudgins]

Originally posted by Wayne Maybury
Richard

A very quick question. My copper rad is painted black, just like most radiators. In your opinion, how much effect do you think the paint has on the thermal conductivity of the copper? Wouldn't we be better off if we removed the paint? Just a thought.

Wayne

Hi Wayne,

Actually, I do not know what the real effect of paint has on the heat transfer capability of the radiator. It would seem that any coating would reduce the transfer rate unless this coating had a equal or better thermal conductivity rate.

As most black enamels these days are polymer based and use carbon black as the pigment, I would think that they would reduce the thermal conductivity quite a bit.

But, I do not have any good data on this. I do know that the F! radiators are not painted other than with a small logo in the fin area.