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I just so happen to measured mine the other day for just such
mine is roughly 4" X 14" which is about 175 in^3 (0.7 gallons)
the expected thermal expansion of 6.4 gallons of coolant from 70 to 195F will be 47 in^3 which is about 3.7" in the overflow tank.

the seams on my tank at 4 1/2" from the ends with a center 5" section.

So if you are using it as an overflow tank, the maximun cold level should be about at the top seam (down 4 1/2"). My opinion, as an overflow tank just having "something" in it is OK, as it will just be the catch and return for the swirl tank venting the coolant expansion.

Now if you plan to use the over flow as an expansion tank, that would be differernt....

My reply is based just on my expectations and I do not have any experaince (my concern is that the pressure relief cap is on the pump discharge and with the resistance of the long tube runs and the two pass radiator, the pump head may cause discharge with out being for expansion)
I come up with an expected 47 in^3 expansion which is 0.2 gallons. so one quart would go from empty to full, going 0.5 gallon would give some margin and still not be excessive. recall the existing is 0.7 gallons. If the car ever boils, then the extra catch volume would be nice ( I don't plan for boiling though)

remember, I am stating this from keyboard and don't have any hands on experance. so I don't mind being corrected if I have made an error
You have magic fingers. Why would I smash them? This is exactly the number that I need. My engineer is busy chasing Russian woman looking for US citizenship via marriage. I can't get his attention at the moment. I don't fit his criteria.

Of course I will need to re-read this all in the morning and then smash my own fingers for screwing around with this stuff, but a mans gotta do what a mans gotta do.

Relocated expansion tanks for me, Glassnose for him? This won't require a pre-nup agreement though.


So if I can't get an expansion tank with that capacity to fit and I need to go smaller than I need to reduce the fluid level in the main tank? I've got a 750ml can. That comes to 25 oz. I'm thinking I could rack two together though?

Still sketching this out. Needs to look right too

Thanks for the help. Big Grin
did I miss something, I see you are now calling it an expansion tank. the fill volume for an expansion tank would be different than overflow tank. Like I state on engineering forums, I need to see a drawing about what you are asking.

a TRUE expansion tank will not need a catch tank as it will maintain a pressurized air volume above the coolant.

IF the cold volume of air is twice the coolant expansion volume, when it is compress with expanding coolant it will have the pressure at 15 psig. thus I was looking at filling the converted overflow tank 7" low at cold.

If the cold air volume is between 2 and 1 the coolant expansion, the pressure will increase to 15 psig at a temp less than 195F AND some air will be blown out of a 15 PSIG relief cap.

I have also considered making the overflow tank into a pump suction header tank, then this tank would be filled, and with the least increase in temp, the "solid" cooolant's pressure will quickly go to 15 psig and a quart recovery tank is needed
JFB is right - most of the expansion is maintained in the expansion tank.

When I was stabilizing my cooling systtem, I had a catch tank that was connected to the radiator cap.

It would cycle about a coffeecup worth of fluid back and forth between a hot, and cold engine. See this thread, third post down.

http://pantera.infopop.cc/eve/...62/m/6401013256/p/11

Anyway - If your "catch tank" holds twice that much, it seems to me you would have margin, and if you put in 2 Quart sized tank, you would never have to worry about spillage.

Rocky
Rocky,
If I recall, you plumbed the overflow tank so that the bottom went to pump suction and then vented swirl (and radiator) into it.

so are you running with the converted overflow full cold with a recovery catch tank OR did you let it blow out the "coffee can" of hot fluid and now it has a little air in the converted overflow when cold and no longer relieves any coolant when hot
I have found that my operating temps are much more stable if I fill the the main, "surge tank" to the top, and the tall secondary tank, whatever we want to call it, about half way. Then once the operating temp is reached, the gauge doesn't bounce up and down.

It occurs to me though after what JFB posted about the expansion rate of the coolant, that if I reduce the level in the surge tank to allow for expansion there that the secondary tank becomes a "catch tank" rather than an "expansion tank".

The "book" says the entire system is 26 quarts. Who am I to argue? How much room do I need to leave in the surge tank for the expansion of that coolant if the secondary tank is only used as a "catch" can?



What I do not know now, is that if I do reduce the coolant level in the surge tank, will I be running hotter and the temps cycling up and down more? I don't like to see that in a coolant system. It gets me very nervous and makes me worry that there is a component failing or a hose is expanding and contracting and getting ready to pop?

I need to get the tall, 4" x 14" tank to a place where I can access it easily. The problem is is won't fit anywhere else. I need to substitute another tank for it in a location that is easily accessible when the engine is hot.

I have two possible candidates for that substitution.

This Moroso unit which is 1.4 quarts and fits the space

http://www.ebay.com/itm/151522...e=STRK%3AMEBIDX%3AIT

And this one that is 750ML (25 oz) but could be racked into a double or triple tank unit.

http://www.ebay.com/itm/161369...e=STRK%3AMEBIDX%3AIT

(I posted the links here simply because it is easier than posting pictures of them here with the 200 mega bite picture limits.)


So again, as far as I understand it, and I'm wrong or confused often, depending on how I fill the "surge" tank determines on whether or not the secondary tank is an "expansion" tank or a "catch" tank. Am I incorrect?


I have all of those tanks here now. I don't need to buy them.
Hi Doug,
Good discussion topic, as this seems to be a relevant topic for many with mid engine config.

My experience makes me first ask the question.. Do you have an air bleed line coming from your radiator back to the swirl tank? When I built my GT40 (basically the same car as we know), I had a major issue with the temp at first. Big swings in temp and simply not stable. First, I ran two lines from the top corners of the radiator into a "T" then to the swirl tank. Significantly improved. Then I tapped into the intake manifold (note: weber induction) on both bank water jackets and ran lines into a "T" and then forward and "T'd" into the line going into the swirl tank. Then, I ran the engine at idle with the swirl tank cap off. Set the coolant level so that running at idle with cooling fans running the tank was full. My logic was that this was a stable "norm", and the expansion tank would be used whenever I got into "hot" running conditions. I can honestly say...I did not have to revisit it even once.

coolant bleeds pic

Hope this helps.....
quote:
Originally posted by Rob Borruso:

Do you have an air bleed line coming from your radiator back to the swirl tank?



Yes. a -4 line runs from both corners of the radiator to a t in the front then to the vacant water temp sender boss in the swirl tank.

I did this 20 some odd years ago. It was the Ford remedy to bleeding air from the system and is in one of the Tech Bulletins issued when the Pantera was still being warrantied by Ford.

I think it works well while others claim it fixed nothing.

The other thing I did as far as the gauge goes is the original Veglia gauges were changed out in favor of VDO as well as the senders. Now at least the senders match the gauges. At least VDO agrees what the water temperature actually is at that spot.
terminolgy gets confussing...
this is what I have recently gathered from reading postings on this site

IF you have the original configuration;
tank A would be surge or swirl tank. it has the radiator cap so that when pressure exceeds 15 psig the expanded coolant is vented into tank B
Tank B would the the recovery. the hot coolant that enters will be sucked back into the swirl tank as the system cools. the cap on the recovery should allow air to easily come in and out of the tank.

You DO NOT want any air in the circulating coolant. entrained air reduces the thermal conductivity and promotes corrosion. the purpose of the swirl is to spin out bubbles, let them collect under the radiator cap and when it relieves, the air will be vented to the recovery tank

the top configuration is the original.

the second configuration has converted tank B into an expansion tank. the pressure relieving cap is removed from swirl and placed on top of expainsion. the top of the swirl (and shown, the top of radiator reversing tank) are vented into the expansion tank. the bottom of the expansion tank is connected to the water pump suction. the air that enters mixed with the vented coolant will accumulate above the coolant under the relieving cap. this arrangement now has the radiator cap relieving pressure that of pump suction, not of pump discharge like original configuration.

for an expansion tank, the amount of air when cold changes the temperture pressure relationship. if the volume is greater than 2 expansion volumes, the pressure when hot will be less than 15 psig.

the bottom configuration converts the expansion tank into a header tank. the differance is NO AIR within the pressurized coolant system. a resevior tank would be need so that when the cap relieves the expained coolant, it can be sucked back in when cooling. with no air in the pressurized system, as soon as the coolant begins to expand, the pressure quickly reaches 15 psig of the cap relief.

I am considering a fourth configration not shown. besides using the swirl tank to spin out air bubbles, I am thinking about using heater core flow into header tank to deaerate the warmup sweeping of the block and heads.

EDIT...reply to the two post while I was composing.
the pressure in the swirl tank will be higher than the pressure at the radiator so venting the radiator does not seem to be possible Confused

in my illustrationa, the expansion tank would be at the lowest pressure in the system (pump suction) so the reversing tank on the radiator will have a higher pressure to assist venting

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First off, I was a bit surprised to see Doug asking for our wisdom. He always seems to do pretty good all by himself; his advice is always accurate and well thought out.

As for our two coolant system tanks.

I"d really like for us to all agree on proper terms for the two tanks. It is often hard for me, an owner for 12 years, to follow some threads as the tank "names" vary from one thread to another, and sometimes even in one owner's posting.

If you study the orange Ford Masters Parts Catalog the tanks are labeled like this:

The shorter tank, with the 13 (OEM) pound pressure cap, is known as a -

Radiator pressure tank

The taller tank, with the zero pressure cap -

Radiator reservoir tank

Sadly, other Ford publications confuse the nomenclature.

Reservoir tank = expansion tank

pressure tank = supply tank

And we seem to add yet other terms -

pressure tank = surge tank = swirl tank

The radiator air bleed hose, mentioned by Rob, running to the pressure/supply/surge/swirl tank was outlined in Ford TSB #8, article #61. It superseded an earlier TSB that called for that air bleed to leave the radiator and attach to a revised metal under-car coolant tube located at the radiator.

I have a TSB #61 'stock' piping system, with the radiator air bleed line running into the pressure/supply/surge/swirl tank. No other tank modifications, such as is done with the systems outlined by George and John Taphorn.

In practice on 2511, I use a Lisle no spill radiator funnel.

http://tinyurl.com/ovnye9w

It allows the newly-filled system, while the car is idling, to easily take additional coolant as the coolant system stabilizes and purges trapped air.

Once the system is no longer accepting coolant from the Lisle funnel, it is removed, pressure cap installed and engine shut down.

Pressure/supply/surge/swirl tank is now filled to the top. Upon shut down, some coolant will likely expand through the pressure/supply/surge/swirl tank into the reservoir/expansion tank.

When all has cooled, I then fill the reservoir/expansion tank about half way to allow some coolant to remain in reserve.

NOTE: While the TSB #61 article says to "fill" the pressure AND reservoir tanks, I've found that is just asking for a coolant spill from the reservoir tank when a hot engine is parked and expanding coolant will usually exit out the reservoir bleed-to-the-ground hose.

Not sure all this applies to Doug's task, but thought it was germane to the thread.

Larry

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I don't know everything Larry. What I do know, I probably had to do about 100 times before I got it right? MAYBE MORE! Roll Eyes

No one would answer me on THIS so I posed the question here. Someone else must have screwed it up and eventually got it right? Wink

Before I posted the question, I presumed that 1) the "swirl tank" needs to be filled to capacity all the time. 2) the "overflow tank" needs to NORMALLY be somewhere about 1/2 full cold. That gives it expansion room and refill capacity both equally at 1/2 of it's volume.

I would think that both were calculated to be correct for the Panteras system based upon the entire system capacity AND the maximum expansion at maximum hot or whatever value the engineer presumed for that.

So my assumption here is that I need to substitute the same capacity "overflow" tank for the existing one?

@JFB. I am running the stock configuration. Pressure cap on the "swirl tank". Atmosphere cap on the "overflow". It's been running fine for quite some time now. I see no reason to re-engineer the entire system at all.



All things considered I'm still listening to everyone here. I am NOT the expert on this at all. In fact there is little that I am the expert on. I'm not highly intelligent, just highly experienced. "Are you experienced?" -Jimi Hendrix.

There has been much discussion about modifying the stock existing system with an attitude by some that presume the people who designed it were mentally defective and knew nothing. Interesting position? Smiler

PROBABLY what I will do, probably, leave both tanks where they are and just attach a hose line to the hose nipple on the overflow on the "overflow" tank and just run it to a catch can were it is accessible and be done with it? A definite maybe or maybe a probable probability? Wink
quote:
1) the "swirl tank" needs to be filled to capacity all the time. 2) the "overflow tank" needs to NORMALLY be somewhere about 1/2 full cold. That gives it expansion room and refill capacity both equally at 1/2 of it's volume.

PROBABLY what I will do, probably, leave both tanks where they are and just attach a hose line to the hose nipple on the overflow on the "overflow" tank and just run it to a catch can were it is accessible and be done with it? A definite maybe or maybe a probable probability?



Doug -

My only comment - if you use one of the catch tanks that feeds from the bottom, and you plumb it up to your radiator cap on what I called the "expansion tank", then it will suck and blow in and out of your "closed circuit" system, and you won't squirt coolant on the ground.

It may be a little fluid , or it may be a lot.

If your 3rd "catch tank" feeds in/out of the top of the thrid (catch) tank, then you will have to manually pour the fluid back (somewhere) - either into the system or into the toilet.

Regards -

Rocky

My system is a hybrid of pictures #2 and #3 - the basic difference is that the "expansion tank" in the middle paicture is only half full, and the "overflow tank" in #3 catches what very little fluid is ejected during regular operatations.
some more of my thoughts...

with the 14" tank plumbed like picture #2, and the tops of the expansion and swirl at the same elevation, when the pump stops there will be a path so that the water level in a partially filled expansion will equalize with the swirl, thus the level in the swirl will go down and the expansion go up.

If I should go with partially filled configuration, I would try to raise the top of the expansion about 7" above the top of the swirl. thus if I filled the swirl, it will fill the expansion to the same elevation.

the reason for the swirl tank is to remove air from the circulating coolant. taking the seperation of coolant and air farther would be to eleminate any pressurized air and coolant boundary by completely filling the expansion tank like picture #3. with this configuration, the elevation between the swirl and expansion can have both tops the same.

another consideration between the partial filled or the full filled expansion tank would be the rate of pressurizing the coolant as tempertue increases. with a full tank, the pressure quickly goes to the cap rating (15psig shown). If the expansion tank is not filled exactly to the correct level the coolant pressure will not reach cap rating.

I am thinking picture #3 will be my choice

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quote:
Originally posted by JFB #05177:
some more of my thoughts...

with the 14" tank plumbed like picture #2, and the tops of the expansion and swirl at the same elevation, when the pump stops there will be a path so that the water level in a partially filled expansion will equalize with the swirl, thus the level in the swirl will go down and the expansion go up.

If I should go with partially filled configuration, I would try to raise the top of the expansion about 7" above the top of the swirl. thus if I filled the swirl, it will fill the expansion to the same elevation.

the reason for the swirl tank is to remove air from the circulating coolant. taking the seperation of coolant and air farther would be to eleminate any pressurized air and coolant boundary by completely filling the expansion tank like picture #3. with this configuration, the elevation between the swirl and expansion can have both tops the same.

another consideration between the partial filled or the full filled expansion tank would be the rate of pressurizing the coolant as tempertue increases. with a full tank, the pressure quickly goes to the cap rating (15psig shown). If the expansion tank is not filled exactly to the correct level the coolant pressure will not reach cap rating.

I am thinking picture #3 will be my choice


What is the original location of the factory "expansion tank" in the car? Is the cap 7" higher than the cap on the "swirl tank"?
quote:
Originally posted by LF - TP 2511:..I"d really like for us to all agree on proper terms for the two tanks....
The radiator air bleed hose...running to the...swirl tank was outlined in Ford TSB #8, article #61. It superseded an earlier TSB that called for that air bleed to leave the radiator and attach to a revised metal under-car coolant tube located at the radiator....Larry


I completely understand the annoyance of not using the proper terms to describe devices. I probably am the most aggressive corrector of others at work. The problem for me is when the OEM's published term does not agree with the actual function of the device and general used terms for the industry. Thus I am at fault for using descriptive terms instead of published names. As for the general used terms for the industry, I am not automotive, but the same devices used in a car cooling system are used in other industrail systems that I am more familair with and adding more confussion when I use those discriptive terms.

My car 5177 did not have TSB #8 article #61. However it did have the earlier superseded air bleed. I was also curious about the effectivness and inspected my tubes and surpressid to find the small tube stabin to the 1 1/4" radiator outlet tube was just flush with the outer diameter (and just upstream of an elbow) making it questionable as being able to provide any ability to vent the upper section of the radiator tank.

I have not read any of the TSB (I guess I need to find a copy of them somewhere). Do you recall which radiator side tank was stated in TSB #8 ariticle #61 to be used for bleed? I have question George P about his cooling drawing (that I plagurized for mine) and he confirmed that the reversing side tank was chosen for a reason versus the outlet/inlet tank. And that reason would be the flow induced head would be greater and thus assist venting/bleed flow.

quote:
Originally posted by PanteraDoug:,
What is the original location of the factory "expansion tank" in the car? Is the cap 7" higher than the cap on the "swirl tank"?

I don't remember for 5177. I have noticed that in photos that some engine cover pannels have a hole cut above the tank and others do not. I have not checked my engine cover yet
I can't find any original photos that show that 7" relationship. They all appear to be even at the top of the tanks.
I'm not doubting you, just can't find anything that agrees with that.
My car, as I recall, did have a small tube welded to one of the pipes near the engine and it had been capped off with a hose and clamp.

The water temp sender was not in the swirl tank. That port in the tank was plugged. The sender was in the engine block.

I added the hose from the radiator to the swirl tank.
I may need to build a new tank out of brass sheet metal and solder it together to get it to fit where I want it to go.
One of the reasons I am at loss to answer some of these questions is because where the overflow tank is located.
It needs to come out from under the screen so I can monitor it properly.
My 180 headers are what caused the relocation of the tanks further back under the screen.
One of the discussions I had with Gary Hall about this was "you don't need the overflow tank". That was his comment.
I didn't know anything at that point so I didn't even question the comment.
A few notes: the two OEM tanks -at least in the late '72s & newer, were nickel-plated both inside & out under that flat black paint . Careful paint removal produces a nice bling at zero cost. They may still corrode, though.

The small-tank clamp was welded to the rt. inner fender panel, and was lined with some type of foam. It rots & falls apart, leaving the tank not well retained. I've seen those tanks fall thru the stock clamp and literally drag on the ground- visible from behind the car! Check yours and use some type of rubber glued in (hi-temp glue) if necessary.

Replacing the big recovery tank with a plastic tank from a generic auto parts store should be done carefully. I did this a while back, and within a month, it started leaking. Because heat off the right header MELTED IT!

The connection from the rad cap overflow is 1/4" while the connection to the base of the big recovery tank is 1-3/8" and I've seen the most gawdawful conglomeration of amateur hose adapters down there to hook this up. Most of which leak air so the vacuum produced by a cooling engine will not pull water back into the main cooling system. Thus the engine "uses & loses water"....

The hose routing at the rad in the early Blue Owners Manual (and the TSBs) may not be how your car is plumbed. I tried it both ways and it made zero difference in stable operating temp on a 500 mile run whether colder water went into the top or in the bottom of a stock rad, regardless of theory.

'Vented' thermostats with two little air bleed holes drilled in them probably make the 8 extra feet of bleed hose from rad to tank superfluous. It may take a LONG time on the road to purge all the air either way. Quite a bit gets caught inside the cylinder heads.

Be sure you've replaced the swirl (small tank) radiator cap neck with a U.S-made one if you're using a U.S made cap. They are shorter than Euro caps and will not develop their rated pressure in an OEM tank neck made for longer Euro caps. A 16 lb U.S cap opens at maybe 12 psi. FWIW, a stock Euro cap was rated at 0.9 bar or 13.2 psi. The base of stock soldered cap-necks were often rough and won't seal except temporarily with a brand new cap; replacing the neck fixes both problems.

Do not try fixing boil-overs with an 18-22 lb NASCAR radiator cap. A 43-yr-old stock rad (and some aftermarket aluminum ones) was only tested to about 16 psi when new. First the rad tubes swell, then rupture at higher pressures and even good (not stock) hose clamps won't hold.

When upgrading the hoses and clamps, don't forget the 3" long section of heater hose under the dash. Often neglected, this one may rupture and scald your (or your passenger's) ankle while fogging up the windshield at high speed! This is the reason for manual cut-off valves in the heater lines.
quote:
Originally posted by Bosswrench:
....
The connection from the rad cap overflow is 1/4" while the connection to the base of the big recovery tank is 1-3/8"...

'Vented' thermostats with two little air bleed holes drilled in them probably make the 8 extra feet of bleed hose from rad to tank superfluous...


is that an extra 1" on that tank connection?

I see the problem with getting air out of the radiator is a problem like an upside down glass under water. the stock radiator has the outlet near the center of the tank so the tank area (and finned tubes) above the outlet have air trapped.

I don't have actual elevations, The below illustration is an attempt to visulize the venting problem.

I also do not know the head with coolant flow. the numbers beside the sections are represenitive of the flow induced head pressures.

Comparing the two configurations, which one would actually allow the air trapped in the upper radiator to escape and allow coolant to fill. the lower tries to show both of the TSB modifications.

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quote:
Originally posted by PanteraDoug:
..I may need to build a new tank ....to fit where I want it to go.
... because where the overflow tank is located.
It needs to come out from under the screen so I can monitor it properly...

Back to your query Doug;
is the problem not being able to add coolant to the tank alone with routinely checking the level.

If just verifing coolant is in the tank. would you want to add a level switch and warning lamp?
Or could you see a sight glass installed at the low level

Now IF it is also needing the ability to add coolant reguraly, how about using a windscreen washer bottle and pump with a feed line installed at tank low level and an overflow at tank high level. then occasionaly fille the windscreen bottle and run the pump till coolant drains back
quote:
Originally posted by JFB #05177:
quote:
Originally posted by PanteraDoug:
..I may need to build a new tank ....to fit where I want it to go.
... because where the overflow tank is located.
It needs to come out from under the screen so I can monitor it properly...

Back to your query Doug;
is the problem not being able to add coolant to the tank alone with routinely checking the level.

If just verifing coolant is in the tank. would you want to add a level switch and warning lamp?
Or could you see a sight glass installed at the low level

Now IF it is also needing the ability to add coolant reguraly, how about using a windscreen washer bottle and pump with a feed line installed at tank low level and an overflow at tank high level. then occasionaly fille the windscreen bottle and run the pump till coolant drains back


I don't have a problem. I am looking to relocate the "overflow tank" and investigating the volume that the substitute needs to be.

where it is now is under the screen in the corner behind the firewall and under the window. It is not accessible there.
Thankyou GP, I know about that one, but it don't fit where it has to go.

I'm just going to get some copper or brass sheet metal and build it to the exact dimension and have it silver powder coated. It will look like mill stainless steel.

This way it can be the complex shape of the inner fender, made for the car, not a universal or something else from another vehicle that seems similar.

You gentlemen have given me the information that I need and I thank all for that.

I'm a little busy building things and this has just has to go on the list and wait it's turn.

Maybe a few weeks. IF it turns out presentable, I'll post pictures. 50/50 on that? Wink

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