Radiator Choices - Cooling System Info

quote:

Is there a way to recognise from a picture a pre-74 radiator with vertical baffle from a later design with newer horizontal divider?

-Sami

No, but sticking a piece of wire in the right side bleeder valve will tell you. If the wire goes in all the way to the back of the tank, the rad has a horizontal baffle. If the wire only goes in about halfway, it has the earlier vertical baffle and should be changed. DeTomaso TSB Bulletin 2, article 35 shows the factory modification.
Corvettes, Z-28 Camaros and many other road cars have had stock aluminum radiators from the factory since the late '60s. The technology is 'mature'. Alloy rads remove a huge amount of front end weight: a stock '72 Pantera brass radiator weighs 64 lbs. A custom-built brass replacement weighed 45 lbs and a Fluidyne aluminum rad weighs 16 lbs. The Fluidyne cooled our engine much better than either of the brass ones (15F lower on long fast highway runs with no other changes).
The water you dump in the radiator will determine the assembly's life. Some areas have such corrosive water that an unprotected alloy rad has an operating life of a year or less. Most vendors now supply a bottle of 'No-Rosion' anti-corrosion fluid with all their aluminum radiators and there are others. They also suggest changing all the coolant yearly. Corvette shops stock anti-corrosion sacrificial anodes (Mag or zinc)to be put in the coolant tanks. The anodes dissolve rather than the radiator, cylinder heads or block.
Finally, home-handymen(?) tend to wind bleeder valves and other threaded parts into aluminum alloy with far too much teflon tape and force: I've seen NEW aluminum radiators with pipe-threaded aluminum bosses split wide open, returned under warranty as 'defective'. Cooling systems seldom see 20 psi; we are NOT sealing high pressures or explosive fuel here!

Thanks for the reply. The reason I asked is because used ones pop up for sale at ebay every now and then. But I guess I'd better start looking for a new ones because radiators aren't cheapest parts to ship overseas.

quote:

Originally posted by Bosswrench:

quote:

Is there a way to recognise from a picture a pre-74 radiator with vertical baffle from a later design with newer horizontal divider?

-Sami

No, but sticking a piece of wire in the right side bleeder valve will tell you. If the wire goes in all the way to the back of the tank, the rad has a horizontal baffle. If the wire only goes in about halfway, it has the earlier vertical baffle and should be changed. DeTomaso TSB Bulletin 2, article 35 shows the factory modification.
Corvettes, Z-28 Camaros and many other road cars have had stock aluminum radiators from the factory since the late '60s. The technology is 'mature'. Alloy rads remove a huge amount of front end weight: a stock '72 Pantera brass radiator weighs 64 lbs. A custom-built brass replacement weighed 45 lbs and a Fluidyne aluminum rad weighs 16 lbs. The Fluidyne cooled our engine much better than either of the brass ones (15F lower on long fast highway runs with no other changes).
The water you dump in the radiator will determine the assembly's life. Some areas have such corrosive water that an unprotected alloy rad has an operating life of a year or less. Most vendors now supply a bottle of 'No-Rosion' anti-corrosion fluid with all their aluminum radiators and there are others. They also suggest changing all the coolant yearly. Corvette shops stock anti-corrosion sacrificial anodes (Mag or zinc)to be put in the coolant tanks. The anodes dissolve rather than the radiator, cylinder heads or block.
Finally, home-handymen(?) tend to wind bleeder valves and other threaded parts into aluminum alloy with far too much teflon tape and force: I've seen NEW aluminum radiators with pipe-threaded aluminum bosses split wide open, returned under warranty as 'defective'. Cooling systems seldom see 20 psi; we are NOT sealing high pressures or explosive fuel here!

BW. What was in your car?

Curious since our cars are close in production.

I've seen Hall modify the tanks and leave a V in the middle of the right tank.
That would split the upper and lower sections of the radiator and make it a dual pass.

I'm not criticizing the use of aluminum radiators in the Pantera but I have heard of about a half dozen that failed around the one year old mark and were not repairable.

I would think that just about everyone buys their anti-freeze pre-mixed at 50/50 now and as such why would there be an issue with electrolysis with factory water?

I do remember a discussion I had with Gary Hall about this and as he said, "I can sell you any radiator you want, I have them all, BUT the only advantage the aluminum has is it is lighter and unless you are going racing and need to lighten the car as much as possible, use the brass radiator, it is repairable".

Still running the original stock unit. I'm sure it will need something some day?

Brassworks now makes a front primary radiator with fans and shroud Brassworks Radiators for Pantera

Years ago, I had a long conversation with Gary Hall. We discussed different cooling setups. The aluminum radiators while lighter but that advantage isn't worth much, the front of the Pantera is too light anyway, taking weight out of the front isn't a big help. He also recommended the use of a 160 degree thermostat. The 160 degree thermostat is what the '71 Pantera's had from the factory, the use of the 180 degree thermostat was used because of the smog requirements in later models. I have used the 160 degree thermostats, but finding them is very difficult.

My pantera is modified to 435hp, while the stock setup worked for the original it failed at the added horse power. I tried several setups with little improvements. Then I converted the AC condenser core into an aux cooler by rerouting the water from the heater core. This dropped the temperature 5-10 degrees. For the most part, the car runs at 160-165, going up hills it will reach 185 degrees. (That is when the first set of fans come on.)

quote:

Originally posted by Yakone:
Years ago, I had a long conversation with Gary Hall. We discussed different cooling setups. The aluminum radiators while lighter but that advantage isn't worth much, the front of the Pantera is too light anyway, taking weight out of the front isn't a big help. He also recommended the use of a 160 degree thermostat. The 160 degree thermostat is what the '71 Pantera's had from the factory, the use of the 180 degree thermostat was used because of the smog requirements in later models. I have used the 160 degree thermostats, but finding them is very difficult.

My pantera is modified to 435hp, while the stock setup worked for the original it failed at the added horse power. I tried several setups with little improvements. Then I converted the AC condenser core into an aux cooler by rerouting the water from the heater core. This dropped the temperature 5-10 degrees. For the most part, the car runs at 160-165, going up hills it will reach 185 degrees. (That is when the first set of fans come on.)

I had the exact same discussion with him. I had to check to see that it was you that was writing this and not me.

I run a 160 also with the stock radiator. Runs fine. Never goes above about 210-220.

Consider though that if you are running a 16 psi system, you are not over heating the car until about 250 degrees farenheit.

The 16 psi cap is in there for a reason.

Personally I think you NEED to run 235 to 240. All modern cars do by design. If you don't you will build up too much sludge in the oiling system which is detrimental to longevity also.

I am actually over cooling at them moment. You are too.

How does my cooling system function? While running at the cooler temperatures my gas mileage was 17.3 mpg. When the car's temperature ran high (185 or above) the gas milage dropped by 2mpg.

Physics backs this up, Boyles law states that the higher temperature reduces the amount of fuel that will enter the engine.

The big problem is that the cooling system is marginal at keeping the temperature at 160. I am always looking for cooling ideas.

Keep air out of the cooling system and increase the coolant flow rate, especially at low rpm.

-G

Hey George,

With regard to your self-bleeding cooling system mods, I have a few questions: why doesn't the suction line on the bottom of the header tank (formerly the overflow tank) drain the tank in seconds? Is it because it's a totally sealed system and the suction line can only draw out as much as the bleed lines can feed in?

If you reduced the size of the line from the bottom of the header tank to the water pump, from -8AN to -6AN, what effect would it have, if any?

Also, since I have bleed fittings in the back of my cylinder heads, should I connect those fittings to the header tank as well? If so, what size hose would you recommend? Perhaps -3AN or -4AN?

I just want to make sure I have a complete understanding of the theory behind the mods, before taking the plunge!

Thanks,

Dave

Dave, I ponder the exact same.

I'll like to hear others reply, however I have looked at it this way;
If all the coolant is sucked out of the header tank, where will it go in a full non compressiable system? thus what goes out has to go some where and the only compressable volume will be back in the header tank.

Two dynamic laws to keep in mind: (1) Fluids (such as coolant) are not compressible ... only gases (such as air) are compressible. (2) Both fluids and gases will flow from a zone of higher pressure to a zone of lower pressure. Never the other way around.

The air space above the coolant in the header tank cannot exist at a pressure lower than pressure of the coolant pump suction. If it did, it would draw coolant away from the coolant pump and into the header tank! So .... the air can collect in the header tank because it is compressible, but the coolant in the header tank cannot be drawn out of the header tank any faster than coolant is flowing into the header tank.

The cooling system is a closed hydraulic system. Every ounce of coolant drawn from the header tank is replaced by the same amount of coolant entering the header tank. So, what is happening, the coolant in the header tank is constantly "turning-over" but the level in the tank remains the same. If you don't believe this, open the hood of your daily driver and observe the coolant level in that car's header tank while the engine is running. Most header tanks are manufactured from opaque plastic these days. If the cooling system's pressure cap (radiator cap) is not located on the radiator, but on a tank, that tank is a header tank. You can verify this by tracing the large hose connected to the bottom of the header tank. It should connect or "tee" into to a portion of the plumbing that connects to the cooling pump's suction. The cooling pump's suction is the lowest pressure zone of a cooling system. There should also be one or more smaller air vent hoses connecting to the header tank, attached at the other end to various points where air may collect in the cooling system ... such as the top of one of the radiator's tanks.

The header tank is a feature found in the cooling systems of most (if not all) modern cars and it has been used in racing cars as far back as I can remember. There's a lot of experience there. Every Pantera owner who has "admitted" to making the mod has reported good results. All I have done is explained how easy it is, using existing components, to modify the Pantera's cooling system to duplicate such a system. I believe its easy to convert the Pantera's cooling system because the Pantera's system was originally designed to be configured in that way.

Why do I believe this ... well the "system tank" was obviously manufactured to be a "de-gas tank", aka a swirl tank, due to the way in which the inlet and outlet nipples are configured. Here's the part where the light bulb should turn-on for the typical enthusiast ... a de-gas tank (such as the Pantera's "system tank") cannot function without a header tank! The header tank is needed because it is the low-pressure point of the cooling system where air can be plumbed and collected successfully. The Pantera's "expansion tank" was obviously intended to be a header tank! That explains why the connection on the bottom of the expansion tank is so large!

Wow, thanks Professor P.

Now, I get it!

Two more questions:

1.) If you reduced the size of the line from the bottom of the header tank to the water pump, from 1/2" to 3/8", what effect would it have, if any?

2.) Since I have bleed fittings in the back of my C302B cylinder heads, should I connect those fittings to the header tank as well? If so, what size hose would you recommend? Perhaps 1/4" or 3/16"?

Thanks George!

Dave

I specify 1/2" hose for the connection between the header tank and the coolant pump to accommodate "surge" in the cooling system, which occurs when the speed of the engine rapidly accelerates or decelerates. I don't know if anything would happen if you decreased the size of the hose, other than the fact the level in the tank "may" be a little less responsive to surge. I was just being safe.

3/16" ID hose (or 3/16" OD metal tubing) should be fine for the air bleeds in the cylinder heads.

George,
First of all, thanks for all you knowledge dumps. The are great! So on the venting system modification. Is the connection to the suction of the water pump the same one the goes to the heater core? I've had my rad re-cored and what to make that mod to my system. Thanks ahead of time.
Ken

quote:

I run a 160 also with the stock radiator. Runs fine. Never goes above about 210-220.

I run a 180 stat. Quella triple-pass (Ron Davis) aluminum radiator. Weiand pump. Block bypass circuit is plugged. Hi-flow stat. Stock system otherwise.

And yes I know all about the "issue" with the lack of a bypass circuit, but in over 50K miles I have yet to notice a problem because of it.

YMMV.

I'll run 180-190 on a cool winter day at cruise.

Heavy summer city traffic runs 200-220.

Like Doug said, oil needs to be hot to boil off moisture. 180 is the generally accepted low for oil temp, and oil temp generally runs less than coolant temp.

If your cooling system, stock or modified, never boils over after shut-off or when stuck in traffic, everything is fine.

Just like the Wizard of OZ said - "Pay no attention to (that temp gauge in the console".) It will just make you nervous.

quote:

Originally posted by Italian hot rod:
[QUOTE]
Just like the Wizard of OZ said - "Pay no attention to (that temp gauge in the console".) It will just make you nervous.

I'm much taller than that picture would indicate.

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Originally posted by HayDude:

... Is the connection to the suction of the water pump the same one the goes to the heater core ...

Yes. The two aftermarket coolant pumps I am familiar with (Flow Kooler and Edelbrock) both have TWO threaded ports for the pump suction, one is needed for the heater core, the second port makes a ideal place to plumb the header tank.

George(or anyone), I have a question about the continous radiator venting.
your illustration shows the vent on the far common tank, thus there will be a slighly higher pressure here than if it was on the exit tank. Is that intentional?

on my increasing getting longer list of things to do, I was planning on having a local radiator shop inspect/rebuild my original radiator and possibly reuse it. another question I am having is the use of the original bolt on fan switches. Is there an adaptor to use the more common threaded switches.

with all due respect to your experiance...I question a statment you made concerning placment of the fan switch.
"The fan switch should be located in the radiator's inlet tank (the lower tank) so as to sense the coolant temperature regulated by the thermostat."
I was thinking if the switch was located in the outlet tank, it could determine if there was air flow causing the exiting fluid to be cooler than the thermostat regulated radiator inlet temp and thus start and stop the fan based upon car speed. it appears the original design's intent was to do this (with a 10c and 20c drop for a 192F thermostat), but the horizonal tank baffle modification defeated that for one of the switches. Is there experance to indicate this does not work?

quote:

Originally posted by JFB #05177:

... your illustration shows the vent on the far common tank, thus there will be a slighly higher pressure here than if it was on the exit tank. Is that intentional? ...

Yes

quote:

Originally posted by JFB #05177:

... Is there an adaptor to use the more common threaded switches ...

Since the radiator is being rebuilt, I would personally have the OEM temp switch "bungs" removed from the radiator and replaced with M22 threaded "bungs" rather than to use an adapter. I'm sure the M22 threaded bungs are available.

quote:

Originally posted by JFB #05177:

... I was thinking if the switch was located in the outlet tank, it could determine if there was air flow causing the exiting fluid to be cooler than the thermostat regulated radiator inlet temp and thus start and stop the fan based upon car speed. it appears the original design's intent was to do this (with a 10c and 20c drop for a 192F thermostat), but the horizonal tank baffle modification defeated that for one of the switches. Is there experance to indicate this does not work? ...

I pondered this question myself. I have no experience with the temp switch installed in the outlet tank, other than Panteras. And that was a bad example . But I know for certain that mounting the temp switch in the inlet tank works.

I checked-out various older European cars (with emphasis given to the way the Germans do it) and found they installed the temp switch in the inlet tank. It occurred to me the thermostat and the fan switch comprise a closed loop control system, and from that perspective mounting the temp switch in the inlet tank makes more sense. In that configurations there is less time lag between the action of the thermostat and the fan control, and they are working together to control the same variable, i.e. the temp of the coolant exiting the engine block. The fans won't turn on until the thermostat has opened fairly wide, and that alone has proven insufficient to control the engine outlet temp. I can't say if that's why the OEMs chose to do it that way, but it would be my best guess.

Installing the switch in the outlet tank may sense the temp rise sooner, but now the fan control and the thermostat are attempting to control two different variables; i.e. one the radiator outlet temp and the other the engine outlet temp. You could get into a situation where the dog is chasing its own tail (control oscillation).

Best wishes for success what ever direction you decide to take.

looks like a good place to share this info;
http://pantera.infopop.cc/eve/...670077164#4670077164

Mark