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Paul69camaro
09-05-2006, 08:23 PM
After trying to decide which one to buy, I realized that I don't have a clue as to how these work.(I understand how a tank works but not the recirculating ones). What capacity should I get for a road race car and should I get a recirculating one? How does it work? Does it still just connect to the tube under the radiator cap or is there 2 hoses? Thanks again in advance for such a dumb question.

Paul

porschev8
09-06-2006, 12:13 PM
The Closed or Reservoir System vs. the "old style" Open System
One of the big disadvantages in the old open type pressurized system is that as the system cools, air is allowed back through the overflow tube. These systems are not totally filled with coolant because of the potential for coolant loss through the overflow tube when the coolant heats up and expands. As more coolant is lost through the overflow, less coolant is left to do it's job within the engine. Because of this, and that air can enter the system and reduce cooling system efficiency, overheating can occur. Closed reservoir systems were first used by car manufacturers in the early 1970's.
A closed or reservoir system has solved the problems listed above. This system is different in that a special radiator cap and overflow reservoir tank. Part of the radiator cap (http://www.centuryperformance.com/images/tech/radcapneck.jpg) is a second sealing gasket under the shell that contacts the upper sealing seat of the filler neck. What was the overflow hose is now the connection between the radiator and the "bottom" of the reservoir.
While the open pressurized system is filled to a point 2-3 inches below the top of the radiator, the closed pressurized system is filled completely with coolant and the reservoir is filled approximately half full. When the engine is started and begins to heat up, the coolant expands. As the coolant expands it is forced out out through the pressure valve of the radiator cap, through the overflow tube, and into the reservoir. When the engine is turned off and begins to cool, a partial vacuum is created in the radiator by the contracting coolant. The upper sealing gasket in the pressure cap will then allow the vacuum to draw the coolant back into the radiator and engine from the reservoir. As you may have noticed, the actual volume of coolant that displaces during heat-up and cool-down transfer is minimal in most all cases.
Because of the coolant going back and forth between the radiator and reservoir, practically all air is eliminated from the cooling system. This pretty much guarantees that the engine block, heater core, and radiator are full of coolant instead of air. This allows the most efficient operation of the cooling system. Generally, on closed systems, coolant is added only as required, and then it is added to the reservoir, not the radiator.


http://www.centuryperformance.com/coolingsys.asp

ProBell
09-06-2006, 01:37 PM
I agree with Paul on how this works. I have a closed system in my camaro with a LS1. I currently have a 1 quart overflow tank. I think it is just a little to small. The car has filled the tank and pushed fluid out 2 times on me in 4000 miles. I would go to 2 quarts,but this also depends on how much coolant is in you system to start.
As far as a recirculating system, I believe that is what is in a corvette. Their is no radiator cap on the radiator. The coolant goes through the over flow tank just like it does the heator core. The fill cap is located on the over flow tank.
This system is normally used when the radiator is mounted lower than the high coolant mark on the motor. The recirculating tank is mounted up higher to alow the system to be completely full.
I track my car with the standard system with no problums. Randy

Paul69camaro
09-07-2006, 09:56 AM
Guys, Thanks a bunch for the help. Tim thanks for explaining how the system works, now I can make an educated decision on the cooling system.

Paul

MonzaRacer
10-31-2006, 12:56 AM
The tank with the rad cap is not an "overflow tank,,, there is none if it gets hot it dumps to ground.
What they do is provide a high point in the cooling system so air is in the tank not the engine creating a hot spot or worse boiling points.
As for an over flow tank it should hold about a 1/2 qt to a qt with atleast 1 qt left for expansion.
A proper radiator cap is very much required for them to work properly.
First of all the hose has to go to within about a 1/2 in of bottom and be a tight seal at the nipple on the rad neck.
If you have electric fans you really need to understand how this set up works.
3 big compnenets are fan, thermostatic switch, and heavy duty relay(i prefer the oval ones from most 80's on up GM as they can take a 50-60 amp surge and not weld them selves together inside, my secong is the square Bosch type, and both have clamping diodes to protect other circuits).
You simply run about a 4 or 6 guage wire to a positive junction under hood, (I like using the ones for stereo work as they look good and are brass)then a fused wire of atleast 10 guage to power the relay. Now with a thermostatic switch you dont need to worry if its cool as it will run till engine gets to a set temp, so I just wire the contact side and pullin windings on same wire (you can hook pull in wire to a 12 KO source but if its hot when you park you have to leave key on to run fan) then you simply ground your fan and hook up the other pull in wire to your thermostatic switch(good ones for SBC are from Camaro era that are single wire and go in cylinder head, but i prefer to use it up in intake as it shuts down a little quicker) For my big block I used a 2 terminal for a Chysler that screwed right into the head.
Too simple and un complicated for some.
Oh and another thing I use uninsulated crimp terminals and the pin crimp (the u shaped crimp with the little pin that pushes in, it makes a u shaped crimp ) then solder it and shrink tube it. The best shrink tube is the sealing type put any will work. And I ususally in my salvage yard endevours stash lots of split tubing in my tool box as it usually just gets squished under the loader tires as they take the cars to the crusher.
A second choice would either be crimp and seal or the crimp/solder/seal terminal from Carquest (only place I have sean theos so far) but i only use then for temporary fixes or low load wires.
ANY HIGHLOAD WIRE SHOULD BE SOLDERED FOR MAXIMUM AMPERAGE FLOW.witho ut a properly designed set up that surge tank, overflow will get used a lot. And your system should run from cold with it full cap off til fan cycles and race engine few times. Then you raise the RPMS and top off and palce a proper preasure/Vacuum cap on it, top off your tank(see above for amount) then let car run and cycle several times and you will have a well cooled car.
Just figur it this way it works for the automakers to maintain proper heat so why wont it work for us.
Everyone makes it so hard to keep a car cool but I kept a BBC cool with a 3 row rad and a Grand am fan. And that 402 is still here today waiting on a new platform to power and its 12 yrs old.
Hope this helps and if anyone needs any help just pm me.
Lee