double water pumps.

I haven't, partially due to cost, but if you do I suggest using a straight-thru type electric pump. Mezier makes a couple of this type- one of which fastens directly to a radiator inlet. Given the Pantera's battery placement, this seems like a good idea and I'd like to test one, but not at $300. So if you do, please advise how it works under around town and long distance high speed cruise conditions. Thanks.

Yes, I have run the two pump system. It lowered my overall water temp by about 10 degrees. It also gives you the ability to cool the motor with it off if it ever did overheat...

If your aim is assist with the whole slow motorway traffic jam scenario, I would opine that additional airflow through the rad will provide a superior result. Be it higher CFM pullers or a third large center mounted fan. WHile I champion that more coolant flow is always better than less, it may not resolve your issue at lower sppeds and more airflow will.

More than you may want to know at http://www.spacecitypanteras.c...Cooling-JTaphorn.pdf

Things I've learned along the way ...

there are two cooling system philosophies

The first (and older philosophy) is to circulate the coolant slow enough to give it time to thoroughly absorb heat in the engine block and thoroughly exchange heat with the air in the radiator. This is the philosophy espoused by Carroll Smith in his series of books about race car engineering.

The second is to circulate coolant as quickly as possible, this relies on the high differential temperature between the engine block and coolant to transfer heat quickly. The goal of this design to to eliminate the temperature gradient acros the motor; i.e. the cylinders are cooler at the bottom than they are at the top which creates a small difference in cylinder ID and therefore a small difference in ring performance. This is the same reason some race teams reverse the flow of coolant through their motors.

The Pantera cooling system was designed adhering to the first philosophy. For instance the purpose for using a two pass radiator is to slow down the coolant and increase the time it spends in the radiator. Also notice the small size of the under-car pipes running between the radiator and the engine.

To properly convert the Pantera cooling system to adhere to the second philosophy requires a lot of parts replacement and modification, as John Taphorn has done.

Evans cooling says a radiator the size of a Pantera radiator with a 3-1/2" core is good for a 500 bhp motor in racing conditions.

The popular belief is that its easier to pull air through a radiator than it is to push air through a radiator. Therefore the open core design of the Hall Pantera Phoenix radiator is the best choice for pusher fans, the other aftermarket Pantera radiators are better off using puller fans.

A shrowd definitely improves the performance of puller fans for stop & go driving, but it adds restriction to air flow at very high speeds (i.e. 120 mph+).

The crankshaft pulley found on the Pantera's 351C motor is the same size as the water pump pulley, providing the same pulley ratio as any other Ford product not equipped with A/C. But the tubing between the engine & radiator is smaller in diameter, longer, and has many more bends. This restricts the flow rate of the coolant. Some (including me) feel the coolant flow rate is insufficient for stop & go driving.

Several guys have installed the Flow Kooler coolant pump and have reported improved cooling system performance under stop & go driving conditions. The Flow Kooler pump is designed specifically to increase coolant flow at low engine speeds. Their model 1648 pump has two 5/8" ports, making a convenient way to connect the bottom connection of a header tank to the system.

The Edelbrock coolant pump also has two threaded ports which makes a convenient way to connect the bottom connection of a header tank to the system. The curved blade impellar of the Edelbrock pump raises the engine speed at which "cavitation" sets in, I conservatively estimate it will save 5 BHP at 6000 rpm. Good Ol' Vic.

Stewart Components stage 4 coolant pump for the 351W is rated at 160 gpm! It can be modified to fit the Cleveland. I believe Larry Stock sells them. I doubt it will flow 160 gpm in conjunction with the Pantera's restrictive coolant system, but it should raise the cooling system's flow rate significantly. I'd call that the quick and dirty way to achieve high coolant flow. The pump has a high-tech 8 vane impeller that only uses 3 bhp at 4500 rpm. I don't know if it has any heater hose connections, its a racing pump afterall. That may require some fabrication.

The tank that DeTomaso calls a "system tank" is obviously designed to be swirl tank. A swirl tank (or de-gas tank) is a tank that removes air from the coolant that is picked up in the engine, before it gets to the radiator. But the "system tank" cannot function as a swirl tank unless the radiator cap is removed and replaced by a simple bleed hose connection that can be plumbed to a header tank. More on header tanks later.

When some guys pull the under-car tubes out of their Panteras they find them full of enough rust chips to restrict coolant flow, some bad enough that they are plugged solid; others find the tubes clean as if they were new with no rust chips at all.

Most Pantera cooling system woes are a result of the wrong thermostat being installed in the Cleveland motor.

The second biggest problem with the Pantera cooling system is the vent system as designed doesn't vent at all. Air accumulating in the radiator has no where to escape, as more air acumulates in the radiator it slowly detracts from the active surface area of the radiator. The fix for this is conversion of the expansion tank to a header tank and afterwards relocating the radiator vent to the new header tank.

When chasing problems related to the poor performance of the cooling system I recommend 4 things: (1) make sure the under-car tubes aren't plugged (2)install the Robertshaw 333 series thermostat (3) modify the vent system (4) install high air flow cooling fans appropriate for the type of radiator installed in your Pantera (or a radiator appropriate for the type of fans). The Phoenix radiator and Meriah fans are a natural pairing, as are the Fluidyne radiator and Flex-a-lite fan kit. The Ron Davis radiator includes puller fans.

My suggestion would be to do these things first if you haven't already done them ... before you do anything else ... because you may not need to do anything else.

-G

Since Chris specifically asked about a two pump system, the answer to his question is "it helps alot!"

It actually helped my car THE MOST, in stop and go traffic. BUT, I agree that the items George has posted should be checked and corrected first. The second pump will add to the efficiency of the cooling system IF the system doesn't have some other issue, as George pointed out. It wont solve a cooling system with pre-existing issues.

thanks, guys once again.
just to clarify.
i am in the end stages of a complete nuts and bolts restoration.
full engine rerebuild of a 4 bolt main quenched steel headed 351C. the engine builder has a rep as one of the best in our region.new ross racong pistons, SS one piece valves and roller rockers.
we have a new waterpump with bypass, the under car tube are brand new stainless, new fluridyne radiator from Bob Byres and sucker fans to match.
taking a vent tube from top of radator to back of car, the intenion is to the pressure tank, (new stainless pressure and expansion tanks) thoughts on the location of the vent tube running from front to rear. and who has done this.
since im going to a hugh amount of trouble with this build i dont think andother 2 or 3 dollars will killme to put the electric water pump in also if it is a good and worthwhile mod.

am just in need of the robershaw 333 thermostat so if there is a spare one out there or is there a Stant equivilant. Also has anyone heard of stewart components they do components for race cars and seem to do mode to robershaw thermostats.

Nice pic Chris!

No need to use substitutions!

Flow Kooler has the real deal oem 192F series 333 thermostats (333-190)

Flow Kooler

-G

Chris,
If it's any help the Stant part #'s are

13468 for the 180 degree
13469 for the 195 degree

and they are correct for the cleveland

Doug M

quote:

Originally posted by Cowboy from Hell:
Flow Kooler has the 192 degree F series 333 thermostats (333-190)

Flow Kooler

-G

Hi George Ive PM you andthanks for this

Thanks Doug.

quote:

Originally posted by INZOWHO:
Chris,
If it's any help the Stant part #'s are

13468 for the 180 degree
13469 for the 195 degree

and they are correct for the cleveland

Doug M

Chris, I have a Flowkooler pump on the front of the engine as well as a 55 gal per min electric pump in the system, (after the coolant has flowed through the engine & swirl bottle).
The electric pump switches on at higher tempreture to give the ststem a helping hand when it gets critical.
Theres an explanation of it here:
http://pantera.infopop.cc/eve/...0045562/m/1401059146

regards,
Tony.

Coolant speed needs to be fast enough to have a
turbulent boundary layer while staying under the cavitation
speed of the water pump. At slower speeds, flow is laminar. In laminar flow,
Newtonian fluids that come in contact with a surface exhibit a characteristic
velocity profile. The fluid layer that is in contact with surface has zero
velocity. The velocity increases from zero to freestream as you move away from
the surface. Laminar flowing or standing water is a poor thermal conductor
(actually it's a pretty decent insulator). Refer to:

http://www.engineeringtoolbox....ductivity-d_429.html

The thermal conductivity ( in units of k - W/(m.K) ) of a cast iron 351C block
is 55. The conductivity of carbon steel coolant pipes is 43 while an aluminum
radiator is 205 and a copper one is 401. Water is several orders of magnitude
lower at 0.58. Thermodynamics are driven by temperature differentials.
The greater the temperature differential, the more effective the cooling.
Increasing the speed of the coolant flow so that it has a turbulent boundary
layer introduces mixing which carries higher temperature coolant from the
center of the tube to contact the lower temperature surface, providing better
thermal transfer between the coolant and the tube surface.

Dual pass radiators double the path length so velocity is
also doubled. Smaller diameter pipes also increase velocity. This is done to
promote a turbulent boundary layer for increased cooling. Also, once a coolant
reaches a certain temperature (it's pressure corrected vapor point), it no
longer absorbs additional heat and, as it approaches that temperature, it
picks up heat at an increasingly slower rate. Slow coolant speed leads to
localized hot spots and boiling in places like cylinder head passages near
exhaust ports.

Dan Jones

quote:

laminar flow

Dan,

Thanks for the explanation. That makes allot of sense. I had to look up the term and I also found a cool video.

Check out: http://en.wikipedia.org/wiki/Laminar_flow

and

http://www.youtube.com/watch?v=p08_KlTKP50

Wouldn't it make sense to make the cooling tube in a radiator with impressions along the tubing to disrupt the laminar effect?

Scott

> Wouldn't it make sense to make the cooling tube in a radiator with impressions
> along the tubing to disrupt the laminar effect?

You could do that or put in vortex generators or trip strips but increasing
velocity has other benefits (reduction of localized hot spots).

Dan Jones

To clarify the point of my first post, additional slowing of the Pantera's water
flow to improve cooling (for instance further under-driving the water pump)
would likely only make things worse.

To increase the flow rate, there are several approaches that
might work. In addition to adding an auxiliary pump, you can increase the
pulley ratio but that may lower the cavitation RPM. You can also add a backing
plate or use a water pump with tighter tolerances or larger impeller or you
can use a water pump with a curved vane impeller. Properly executed, the
latter also has lessens the tendency for cavitation at higher RPM.

I intended to ask Forum member Mid-Engine Mike to share
his experience with installing a custom diameter pulley to
change his water pump speed and then follow up with why his approach
might work with one type of radiator (or pump) but not with another. It's
important to understand that mechanical automotive water pumps are not positive
displacement with a linear output. They are centrifugal pumps (like a
turbocharger) with a non-linear output. Also, multi-pass radiators present
a non-linear flow restriction. The restriction in going from a 2 pass design
to a 3 pass is much higher than going from a 1 pass to a 2 pass design. The
modern trend is to use a single pass radiator but there are times when the
increase in restriction of 2 pass design is beneficial (e.g. leads to higher
system pressure which eliminates boiling in localized hot spots).

Often a poster will be presented with multiple seemingly conflicting options
that he needs to choose between. One person says to increase the flow rate,
another says to decrease it, a third says to reduce restriction. All of these
may work in particular instances but, without understanding why and when they
work, it's little more than a guessing game. When you understand the basic
principles you can at least increase the odds that a particular solution
will work for you. For instance, it's easy to see why the stock Pantera
under-drive pulley which slows down coolant speed might work with the stock
dual pass radiator which offsets the effect by increasing coolant speed but
might present a problem if you switch to a a single pass radiator which does
not.

Dan Jones

A few years ago, while revisiting my Pantera's cooling system, I decided to consult with Stewart and Meziere, to see what they suggested. The people I spoke with at both firms were familiar with the Pantera and both had the same concerns and suggestions. They both felt the biggest problem with the Pantera's cooling system (once you replaced the OEM fans) was cavitation at mid to high RPM's, due to resistance to coolant flow. They went on to say that the largest contributor to this resistance was simply the length of the coolant lines due to the distance between the water pump and the radiator.

Both Stewart and Meziere had the same recommendations: remove as much restriction to flow as possible and install an electric "booster" water pump as close to the radiator's outlet as possible. The guy at Stewart told me they usually recommend two pass radiators but in the case of the Pantera, they'd go with a single pass rad, in order to reduce resistance to coolant flow and the chances of cavitation. I mentioned the remote thermostat mod. that some Pantera owners have had success with and both people liked the idea.

I did ultimately buy an electric "booster" water pump. I went with the Stewart as it presents zero restriction to coolant flow when it's turned off. The other thing I found interesting was that both company's representitives steered me away from using an electric water pump as the primary pump on a car that's mainly street driven.

With an electric water pump it would be easy to flip a switch to flow the water to aid purging the system.

thanks guys, looks like a booster pump then. cheers all.
to all. not many of us are engineers and also i dont think any of us are interested in people trying to rubish other who are trying to help.
if you have a problem with someones post how about PM the person and having a private chat.
we are here because i enjoy our cars and like the brotherhood that they create.
enough said.

cj

Yes, I have found that running the backup electric pump in the system, filling with coolant is real easy, don’t even need the engine running.
Another bonus is you can leave the electric pump & fans running for a short period after engine shutdown, this sucks the heat out of the system rapidly.

When I purchased my car it was fitted with an aftermarket edlebrock pump.
It was useless at low RPM, such as traffic speeds, but OK when you got the revs up.
If I was sitting in traffic I could bring the revs up to 2,000 rpm & the car would start to cool down.
This only worked for a short period of time as the higher rpm eventually generated more heat & things became critical again.
I then tried an electric 45 gal per minute pump which replaced the edelbrock.
Much better at low rpm, no cooling issues in traffic.
But at high rpm the flow rate was not sufficient enough to keep the engine cool.
Which shows that high flow is king.
Since then I have made all sorts of changes to the cooling system, large alloy multi core PWR twin pass radiator, remote large capacity Thermostat, larger diameter stainless custom made coolant lines throughout, header tank feeding a Flow Kooler pump, vent lines from the heads & swirl bottle back to the header tank, back up electric pump that switches on at 95 degrees C.
In all the system is now much more efficient & copes better with our mega hot Australian summers & just on 400hp.
Only issue now is the Billet front hood vents are really inadequate to vent the volume of air that the two 14” sucker fans displace.
The paint on the hood was bubbling from the heat build up & I had to insulate the internal hood area surrounding the vents.
So, next thing, (along with other body work) is a larger radiator GT40 style hood vent.

regards,
Tony.

quote:

The paint on the hood was bubbling from the heat build up & I had to insulate the internal hood area surrounding the vents.

Paint bubbling from only radiator heat? Really?

quote:

So, next thing, (along with other body work) is a larger radiator GT40 style hood vent.

If you like the GT40 style hood treatment that’s reason enough to incorporate it but I don’t think it’s necessary for adequate cooling. If you are going to build an air dam/splitter and want to eliminate all under car air flow to the extent possible, this could be another reason. It will take more effort and modification than you might think to do it properly though. I believe Gary W (Comp2) has some pictures available on his work in this area. I’ve never had any cooling problems of any kind and I have 427 CI stroker in the low/mid 500HP range. Summer temps here are routinely mid 90sF. I do have the Ron Davis radiator Pantera Performance sells and it has twin suckers/pullers with plenum, and I believe the plenum is key. It has stainless transfer tubes but other than this is the ordinary Pantera cooling configuration with pressure and overflow tank. Ordinary Windsor (aftermarket block) cooling circuit and tstat.

Like all things cooling is a system and the parts of the system must work well together so ina ddition to the coolant flow considerations addressed in this thread, I think the best of all worlds at the point in the system wher the heat is rejected to the environment, with the standard Pantera radiator air flow scheme, is a well designed plenum with puller fans, and flaps on the shroud area that open at high speed but close at low speed to allow the plenum to work properly. I’ve never needed the extra capacity at speed so I dont have the flaps/trap door scheme. Maybe if I was open road racing at sustained speed it would be different. I think Johnny Woods posted a picture of how he had fashioned a plenum scheme as I describe above. You might search and a look.

Best,
K

I really tried not to make mine look like "Gt-40" hood but do the same thing. As Kelly said it was more to get the air out from under the car:

http://www.rc-tech.net/pantera1/hood/hood.htm

At the risk of sounding like no-value-add comments, the following is intended to be helping comments...

I have 600 HP and almost stock cooling system. And I have no cooling issues at all, not in France in the summer, not on the freeway, not in stop and go traffic, not even in stop and go traffic right after playing with a motorcycle in 2nd and 3rd gear for 10 minutes. My point is, that while I admire the craftsmanship, all these fancy solutions, they're not needed, electrical pumps, booster pump, not needed.

When I say my cooling system is almost stock, it's an aftermarket water pump, the Hall radiator is laid down and the fans are aftermarket puller fans. The latter hardly ever are needed. No extra dimension pipes, no extra pump, no electrical pump, no square holes in front lid.

If you have a clean, tight, no air bubbles, working as designed cooling system, it'll work just fine. Again, hoping this comment is taken in a positive spirit, spend your money and effort on something more fun...

quote:

If you have a clean, tight, no air bubbles, working as designed cooling system, it'll work just fine. Again, hoping this comment is taken in a positive spirit, spend your money and effort on something more fun...

Amen, brother!

I feel badly for people who feel they HAVE to go to great lengths to try to improve the Pantera's cooling system, cutting this and hacking that and plumbing in this other thing. If the system is maintained properly, it's just not necessary.

Having said that, the stock fans are junk. And a stock radiator is 40 years old and well past its prime. But I've got a Dan Jones-designed 408 stroker, which put out 539 hp and 509 ft/lbs. Where I live, it routinely gets over 100 degrees F in the summertime. I have a standard (not "Phoenix") Hall Pantera stock replacement radiator, Hall Meriah pusher fans, and an Edelbrock water pump. That's it. No magic, no gadgets or swirl-inducers or anything like that. Oh, and no Hibachi-grille vents or anything else in the hood--the sheetmetal is stock. The original ducting plates which forced air into the front of the stock radiator are still present (one on each side, one on top).

My car resolutely refuses to overheat. Running down the freeway, with a Robertshaw 333-180 thermostat, it will run right at 180 degrees. If I let it get good and hot and then idle in traffic on a 100-degree day, it MIGHT get up to 200 degrees, and then just sit there, all day long. My idle speed is 1000 rpm (setting your idle speed too low can induce overheating, I suspect, but don't know that for a fact).

I've achieved this simply by bleeding the system properly (in fact I use a vacuum bleeder which works even better than the normal technique) and powering the fans directly from an aux fuseblock, and grounding them locally through diodes.

Lori's '71 Pantera has a high-mileage stock engine, and the same cooling components as mine. It, too, absolutely refuses to overheat under any circumstances.

So all this multiple-pump, bloody-great-vent-holes everywhere stuff is something to do just for the sake of doing it, not something to do because it's even remotely necessary. Having said that, if you LIKE doing stuff like that and don't mind spending money that way, then more power to ya!

P.S. I forgot to mention, I use about 40/60 antifreeze/water with Redline Water Wetter. The Redline product knocked about 10 degrees off....

thanks and certainly no offence taken, sometimes maybe we over think things.

cheers Cj

quote:

Originally posted by No Quarter:
At the risk of sounding like no-value-add comments, the following is intended to be helping comments...

I have 600 HP and almost stock cooling system. And I have no cooling issues at all, not in France in the summer, not on the freeway, not in stop and go traffic, not even in stop and go traffic right after playing with a motorcycle in 2nd and 3rd gear for 10 minutes. My point is, that while I admire the craftsmanship, all these fancy solutions, they're not needed, electrical pumps, booster pump, not needed.

When I say my cooling system is almost stock, it's an aftermarket water pump, the Hall radiator is laid down and the fans are aftermarket puller fans. The latter hardly ever are needed. No extra dimension pipes, no extra pump, no electrical pump, no square holes in front lid.

If you have a clean, tight, no air bubbles, working as designed cooling system, it'll work just fine. Again, hoping this comment is taken in a positive spirit, spend your money and effort on something more fun...

I appreciate everyone’s comments & also find them all very valid.
Let me say that when I'm talking Perth summers I mean 38 to 45 degrees C, that’s 100 to 116 degrees F ambient air & very dry.
That’s the temperature in the shade !
That ambient air temperature is fairly useless at cooling.
The stock cooling system simply did not work in the summer, in the winter it was adequate.
Which for us a Perth winter is 16 to 24 degrees C, (around 65 to 75 F).
Unless I drive on a winters night which sometimes drops to zero.

And yes, most of what I have done is for the sake of doing it.
Its my job, (I design race buggies for a living) & I love to modify & improve.
99% of what I have done has been a vast improvement over the stock equipment & has vastly increased reliability & performance.
My car is a running experiment & I would not have it any other way, but thats just me.

Regards,
Tony

quote:

I use about 40/60 antifreeze/water with Redline Water Wetter

I use the local cheapo anitfreeze approx 50/50. Change at least every other year.