Coolant tubes under the car

1 1/2 can fit with a little patience.

Thanks all.

If you are willing to punch the holes larger with a chassis punch, and install larger grommets, then of course larger tubes can be installed.

I'm close to doing this for the "suction" side, I have all the parts to do it. I plan to ascertain that a local radiator shop can replace the 1-3/8 outlet elbow of the Hall radiator with a 1-3/4 outlet elbow ... once that is settled the holes shall be punched larger.

...Here's another one for debate.

IN MY OPINION:

Be advised, that if One is increasing the Diameter of the 'Tubes' to increase coolant Flow, the Definitive Restriction to the Cooling System Flow, is the Thermostat, Itself. As the 'High Flow' Robertshaw Stats 'Only' Open as far as:

180F = .260" (1/4")
195F = .130" (1/8")
'Curtain' Diameter 1.520"
Do the Multiplication and come up with the Maximum 'Curtain Area', to calculate the Flow Potential.

The Minimal Opening of the 195F, is the method of Raising the Operating Temperature of the Cooling System, Over the 180F.

We must keep in Mind, the 'Rating' of these Stats is NOT the Temp at which the Stat STARTS to OPEN!
The Rating IS the Temperature at which the Entire Cooling System is Brought-Up To, and Sustained At. And Then, there are All the Other Factors we know of, that effect the Efficiency of the Cooling System. We also know That List is Long!

Last, The 4.90" 'Over-Drive' Waterpump Pulley, WORKS! Yes, it Increases Flow, Within the Pump! Still, there is the Restriction at the Thermostat, by the Laws of Hydraulics, 'Restriction to Flow CREATES Pressure'.

quote:

Be advised, that if One is increasing the Diameter of the 'Tubes' to increase coolant Flow, the Definitive Restriction to the Cooling System Flow, is the Thermostat, Itself.

I would tend to agree with Marlin on this.
Increasing the diameter will increase capacity but not necessarily efficiency.
You will end up with more coolant the same temperature as before.

Doug M

the larger return would lower the pipe's friction/resistance and thus allow the returning coolant to be at a slightly HIGHER pressure.

higher pressure at pump suction reduces the possibility of impeller induced cavitation.

if the system's pressure setting of the radiator cap was on the suction, it would make little differance

the curtain area at full open (1/4") is the area of the original coolant tubes

The improvement to be realized by increasing the size of the plumbing, especially on the radiator outlet side, is based upon the principles of centrifugal pump operation. Coolant pumps are centrifugal pumps; such pumps do not have a linear output (i.e. flow) verses speed curve. The pump must rotate at a certain minimum speed in order to reach the point in which increases in speed result in increases in output. Below that speed the pump's output does not increase with increases in speed. The speed at which the pump's output begins increasing varies based upon the resistance to flow (i.e. head) at the pump's inlet and outlet. As the resistance to flow increases it requires a higher pump speed in order for the pump to enter that part of it's output verses speed curve in which increases in speed result in increases in flow. The Pump's maximum flow capacity shall also decrease as head increases.

Neither the OEM Ford coolant pump, nor ANY of its replacements, were designed to pump coolant over the distances it must be pumped in the Pantera's mid-engine application. The amount of head in the Pantera's cooling system caused the OEM coolant pump to drop lower in its output verses speed curve. The pump simply doesn't pump enough coolant at idle speed. Considering the nature of centrifugal pumps it should be no surprise that the lay-out of the Pantera's cooling system impinges upon the coolant pump's output.

Coolant pump output can be improved by 3 things:
• A pump with a different output verses speed curve (i.e. the Flow Kooler pump).
• Higher rotating speeds for the OEM pump (i.e. the SACC overdrive pulley).
• Less resistance to flow (i.e. larger diameter plumbing, fewer bends, bends with larger radius).

The rate of coolant flowing through the engine is restricted intentionally by Ford engineers by the singular square outlet hole in each cylinder head. Its been a long time since I measured one, but as I remember its more or less equivalent to a 3/8 inch diameter hole (or was that 5/8?). This is where the backpressure necessary to prevent boiling within the engine is created. These two small outlets are the reason I'm not too concerned about the diameter of the plumbing between the engine's outlet and the radiator inlet. I do not argue however that increasing the size of this plumbing would indeed decrease head.

Once the coolant flows through the radiator there should be as little resistance as possible for coolant flowing to the pump's suction. Why you ask? Simply because that is the parameters the pump was designed to operate within. The suction of the 351C coolant pump has a 1-3/4" OD hose connection. The radiator outlet of all Ford's V8 equipped vehicles was also 1-3/4" OD. In the Pantera the plumbing between the radiator outlet and the coolant pump inlet is 1-3/8" OD, which is obviously smaller than the designers intended. Considering the diameter and length of the radiator outlet plumbing it constitutes the most potentially severe "resistance to flow" in the cooling system's plumbing due to its impact upon the coolant pump's performance. Rubber hoses located on the radiator's outlet plumbing tend to collapse at idle due to the severity of the resistance to flow. Increasing the size of the radiator outlet plumbing to 1-3/4" OD is equivalent to a 62% increase in cross-sectional area. Its a simple and non-controversial improvement. The intention is to bring the parameters under which the Pantera's coolant pump operates closer to the parameters it was designed for.

...The WaterPump Cannot 'Take-In' MORE Liquid, Than It can Pump Out Through the Thermostat.
Hence, the Restriction to Flow, Regardless of the Pressure (At the Thermostat), The Coolant would just 'Back-Up' on the SUCTION side of the Pump, and the Pressure would be Lowered. The LOWERING of Pressure is what Causes Cavitation. Cavitation....The Release of Gas 'Bubbles', gas that was previously 'Held' within the Liquid because it was under pressure. I have seen The Erosion of Hardened Steel caused by Cavitation. Erosion similar to a Water Jet Cutter. Yes! Unbelievable!! And in That regard, JFB is absolutely Correct!

Your Correct about the 'Head', though.

One more thing, Pumps Do Not 'SUCK'. They just provide a 'Void' and create Flow. And Pumps do Not Create Pressure. Pressure is created when there is a Restriction to Flow, the creation of a 'Head'.

I'm using 1.5 inch tubes for a simple reason having nothing to do with performance or cooling; they cost less than 1 3/8. With appropriately sized grommets, they fit with no enlargement of the chassis holes needed.

do you have a link to 1 1/2 grommets you used?

Try McMaster-Carr but make sure you get high temperature grommets.

Thanks to all for the feedback.

5715 will be powered by an all aluminum 400 CI Clevor engine so the Cleveland specific cooling parts, specifically the thermostat, are different. The Clevor will have considerably more output than the stock engine so I want to optimize the cooling system. A remote thermostat will be used. My understanding of an automotive cooling system’s dynamics parallel George’s that’s why the larger coolant tubes. I'm planning on using 1.5" tube to the radiator and 1.75" return. A high flow water pump will be used. I plan on using the car as much as possible so idle and low speed cooling (flow) are important to me. Am occasional track day is likely (system thermal capacity).

George, Do you mind sharing the metal punch size and grommet part number or source? Thanks!

Mike

Pantera's overheat at slow speeds or idle when there is a combination of low air flow over the radiator (compensated somewhat by electric fans) and low flow from a belt driven mechanical pump. Consider addressing the latter with an electric booster pump, which can also be set to run off to avoid heat sink when the engine is turned off.

Julian

quote:

Originally posted by Racecar Mike:
Thanks to all for the feedback.

5715 will be powered by an all aluminum 400 CI Clevor engine so the Cleveland specific cooling parts, specifically the thermostat, are different. The Clevor will have considerably more output than the stock engine so I want to optimize the cooling system. A remote thermostat will be used. My understanding of an automotive cooling system’s dynamics parallel George’s that’s why the larger coolant tubes. I'm planning on using 1.5" tube to the radiator and 1.75" return. A high flow water pump will be used. I plan on using the car as much as possible so idle and low speed cooling (flow) are important to me. Am occasional track day is likely (system thermal capacity).

George, Do you mind sharing the metal punch size and grommet part number or source? Thanks!

Mike

I didn't change the coolant flow tubing size on my all aluminum Fontana/Clevor engine, but I did eliminate the surge tank from the high pressure side of the system. A good aftermarket high volume water pump, like a Flow Kool will give you great flow and the smaller water pump pulley that Scott Bell sells is a good idea and actually does lower low speed water temperatures by a few degrees. You still need a good radiator and sucker fans, which I assume you already have. If you are going to make a lot of power and also track the car, you should consider an oil cooler. Just make sure that your oil pump can handle the extra load it will have to by having to pump through the cooler. I am using two oil coolers on my car and I have reduced my track oil temperatures quite a bit.

If you need to enlarge the coolant pipe holes, McMaster-Carr has the appropriate stud driven hole punches. They have the grommets too.

Further to Julian's comment, I spoke with an engineer at Stewart Components years ago, who felt that an electric booster pump, placed as close to the output of the rad as possible, would be a huge improvement.

Stewart also has some awesome 351W belt driven water pumps.

quote:

Originally posted by Racecar Mike:

... George, Do you mind sharing the metal punch size and grommet part number or source ...

Hi Mike, I'm always glad to share info. I had to special order the grommets, in quantity! I forget who I ordered them from, it may have been via Newark Electronics. But I'll be glad to mail you a few of mine if you want them. The chassis punch, as David suggested, was purchased from McMaster. I live in a condo, no garage. My car & tools are kept in a public storage unit. I should be there within the next day or so, I'll get the specific information regarding sizes for you then.

Hi George, Thank you very much. I will gladly pay something for a few grommets and pay the shipping. Please no rush. I'm a few months away from installing new tubes.

I did consider using a Stewart electric booster pump but don't really know if it's needed. One could be added later if needed. I have looked into Stewart, Flow Kooler and Meziere water pumps. Nice stuff, many choices.

Slightly different topic. Has anyone used a serpentine belt pulley system on a Windsor block in a Pantera?

Thanks.
Mike

SN 4280 had a serpentine belt system.

If you search here or on PROVAMO you will probably find a few pictures. It was set up for a Cleveland motor, though.

Rocky

Mike

the chassis punch I purchased is 1-7/8" diameter. Greenlee #5004248

the grommets are obviously 1-3/4 ID

the inner OD matches the punch, 1-7/8"

the overall OD is about 2-1/4"

they are made of a fairly tough durometer material.

I think my plan was to punch the larger hole so that the bottom of the hole aligns with the bottom of the original hole. As in the picture below.

PM me with your address and I'll mail you some grommets.

Note that all known serpentine belt systems rotate the water pump backwards from what was used as-stock, so such systems take a specific water pump to pump water properly.