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Cooling System Tank Modification

George PGeorge PAdmin.
I believe when the Pantera's cooling system was initially designed it was intended by its designer to have a functional swirl pot and a header tank. The header tank is needed anytime the ability to vent air is needed in a cooling system. Without a header tank a swirl pot cannot function, and a radiator vent has nowhere to vent into. Obviously somebody altered the design before the Pantera began mass production. However, because the Pantera's cooling system tanks were intended to be a functional swirl pot and a header tank, it is very easy to alter them and make them functional.

The Pantera's radiator vent has never functioned, and the Pantera has always had a problem with air trapped in the radiator. Air trapped in the radiator is the Panteras second biggest cooling system problem, next to the wrong thermostat being installed in the motor.

I had intended to fully modify the cooling system in my Pantera, turning it into a high flow style cooling system. But after I realized what the real problem was, I decided to go a different route. I decided to simply modify the tanks to restore their originally inteneded functionality, thereby allowing the radiator to self purge continuously. Coupled with a good radiator and a pair of good fans, I believe this is all that is needed for a Pantera to have a top performing cooling system.

Here's the basic drawing of the modification.

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C crxmanMember
I am working on 6915 for a customer who recently bought it.it was supposed to have restored,but far from it.One of its problems is as soon as it is started the swirl tank starts filling up the overflow tank.i finialy figured out the fill neck seat is warped and not sealing,i found a cap and with a little adjustment got it working ok. next problem,overflow tank is full of rust, you can see were this going.it has a stock radiator and cooling fans,wired reversed,new tubes and hoses .no air bleeds,also inlet tube to pump,on drivers side comes out of the lower part of rad. with the return from swirl tank to upper right side of rad.i installed a r/s t-stat, blead system,had to bypass heater core,tubes plugged . i drove it saturday about 10miles,waited at light to get on interstate about 3min .90mph for 5miles and back to shop stayed 200to210 all the way.this is in central fl.and 95degrees out.i have pitchures and will post soon ps. have to add A/c next week
angelobangelobMember
George, help me out here. What is the reason for the line to the pump inlet? Would the venting issue be resolved by moving your air bleed from swirl tank to the bottom of the overflow tank, eliminating the line to the pump? The system would still vent and with the swirl vent line in the bottom of tthe overflow tank, as the system cooled it would draw liquid back into the system. I'm just a little fuzzy about the pump connection.

Angelo
George PGeorge PAdmin.
quote:
Originally posted by ANGELO B:

... What is the reason for the line to the pump inlet?

Angelo


It converts an expansion tank into a header tank. It allows coolant entering the tank from the vents to recycle into the cooling system, while air remains trapped in the top of the tank. It establishes the tanks pressure as the same as the pressure at the coolant pump suction, which is the lowest pressure zone in the cooling system.

quote:
Originally posted by ANGELO B:

... Would the venting issue be resolved by moving your air bleed from swirl tank to the bottom of the overflow tank, eliminating the line to the pump?

Angelo


No

quote:
Originally posted by ANGELO B:

... The system would still vent and with the swirl vent line in the bottom of tthe overflow tank, as the system cooled it would draw liquid back into the system. ...

Angelo


It would only vent until the tank filled up or the pressure in the tank equaled the pressure of the vents, then coolant would stop flowing.

The venting system works as drawn ... this coolant system design is not mine, it has been used by race car constructors for decades (since at least the 1960s if not before), check out Carrol Smith's books. Half the cars on the road today have header tanks as shown in the diagram. Venting the coolant system to a header tank is what allows modern cars to use such small radiators. The Edelbrock coolant pump has an extra port on the right hand side which connects to the pump's suction, this extra port makes the connection to the header tank very easy to accomplish.

-G
George PGeorge PAdmin.
The -8AN fitting on the bottom of the header tank is used in conjunction with 1/2" ID hose, that's not all that small. I doubt if the outlet of your funnel is any larger.

Filling a Pantera is not something you can rush through, its about a 5 gallon system, and the radiator is at the opposite end of the car from the fill point. As you fill the system you'll begin to realize just how many places there are where air can be trapped.

After filling the next step is burping the air from the system, and that takes time too and it can be a headache. You start the motor so the coolant warms up and the thermostat opens, then you raise the rear end, raise the front end, back and forth until you think you've burped all the air from the radiator and the engine. With the vent system working that headache will be eliminated, just start the engine and let the system purge itself.

-G
larrywlarrywMember
When this system is properly filled, purged and at operating temperature, is the header tank completely full of coolant? Or do we want a header tank coolant operating level somewhere just above the swirl tank top, leaving a little air space within for expanded coolant? There won't still be a need for an unpressurized overflow tank of some kind so if she burps some hot coolant it will be drawn back into the system as it cools?
zr1panterazr1panteraForum Sponsor - SACC Restorations
quote:
Please let us know if you really don't have to jack up the rear several times to rid the system of air.


I can verify the system works as George describes. As I said earlier, my system is almost exactly the same design as the one George is doing and it self purges itself completely. Sitting flat on the ground...
George PGeorge PAdmin.
quote:
Originally posted by larryw:
... is the header tank completely full of coolant? Or do we want a header tank coolant operating level somewhere just above the swirl tank top, leaving a little air space within for expanded coolant? There won't still be a need for an unpressurized overflow tank of some kind so if she burps some hot coolant it will be drawn back into the system as it cools ...


The header tank should be operated with an air space above the coolant, never full.

The header tank should be the highest point in the cooling system.

The header tank will only burp coolant if the coolant level is too high. The header tanks in the last 2 cars I've owned did not have recovery tanks. BUT it wouldn't hurt to have a recovery tank if it would make you feel safer. Some race tracks or racing associations may require a recovery tank.

-G
morionmorionMember
Looks very good and efficient. If you have the old caps left and cannot find any use for those I would like to buy that. Big Grin My caps have bad rubber. In fact Im very amazed that stock 71 engine is running quite properly and not showing overheating problems in +25c. (regular driving) But I quess adding few horses and bigger carburator the soup is ready and boiling.
Cheers. Peter
alasorsaalasorsaMember
George I just found this thread of yours on the cooling system tank modifications and I had a couple of questions.

1. Does the header tank (formally the overflow tank) have a pressurized cap or not?

2. Could one not just remove the pressure valve or use a non-pressurized cap on the swirl tank and use the existing neck nipple to connect to the header tank?

Thanks Tony
George PGeorge PAdmin.
quote:
Originally posted by alasorsa:

1. Does the header tank (formally the overflow tank) have a pressurized cap or not?



Yes a 13 psi (or less) pressurized cap.


quote:
Originally posted by alasorsa:

2. Could one not just remove the pressure valve or use a non-pressurized cap on the swirl tank and use the existing neck nipple to connect to the header tank?



As long as the air can flow to the swirl tank's nipple un-impeded, it might work.


-G
George PGeorge PAdmin.
quote:
Originally posted by Rocky:

Is there no longer a "check valve" at the radiator? It looks like the radiator vent is just a straight hose to the header tank.



No check valve.

quote:
Originally posted by Rocky:

Did you use rubber hose, or a hard line of some type?



There was a factory 1/4" OD steel tube under the car for this purpose. I replaced mine with some new 1/4" OD stainless steel tube. I prefer to keep the sections of rubber hose as short as possible.

-G
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