Reply to "Cooling tube removal"

My observations re: the Pantera cooling system:

The 351C mounted in a '70 through '73 Mustang had no cooling problems what so ever. The problem with the Pantera's cooling system does not reside with the design of the motor. Just make sure you are running the Robertshaw 333-180 thermostat.

The Pantera cooling system has several inherent limitations in design due to the layout of the chassis, and it strays from the design of a Mustang cooling system significantly. It reflects an attempt to design a race car cooling system, but there are some strange deviations from that too. A race car cooling system is not practical for a street car anyway.

The Mustang has a 1 1/2" ID hose between the motor outlet & radiator. It has a 1 3/4" ID hose between the radiator and water pump inlet. The top hose is about 18" long, the bottom hose about 12" long.

The greater distance between radiator and motor compared to a Mustang reduces the flow capacity of the Pantera system. So does the extra restrictions such as the swirlpot, the many extra bends in the tubing, etc.

Race cars travel constantly at high speeds with the motors turning high rpms. Race teams often have to slow down the speed of the water pump, restrict the flow of water coming out of the motor (increasing back pressure in the engine reduces the likelyhood of boiling coolant in the heads) and use two pass radiators which again slow down the flow rate of the coolant.

But the Pantera is a street car, it doesn't travel constantly at high speeds, the motor doesn't turn high rpm constantly. What did the designers do? They installed a smaller pulley on the crank, slowing down the water pump. They used 1 3/8" OD tubing between motor and radiator (smaller and longer than the hose in a Mustang). They specified a two pass radiator. What we have here is a serious coolant flow problem. When the motor needed more flow, to return it to Mustang spec, the engineers gave it less.

Any retiree knows that if his RV has a cooling problem he needs either a larger radiator or more coolant flow. Apparently there were no retirees in Modena in 1970.

The small width & height of the Pantera radiator requires extra thickness to get adequate surface area, but as a radiator gets thicker, it impedes air flow through the radiator, this is mostly a concern for slow speed driving. The small width and height of the radiator also reduces the size of the fans that can be mated with the radiator, another detriment to adequate air flow at low speeds.

So the Pantera coolant system has reduced coolant flow, a thick radiator, and smallish electric fans, all these are conditions that will lead to improper cooling a low speeds.

A swirl pot is a device usually found on race cars. The Pantera's swirl pot has a radiator cap on it, this is not race car practice. Normally a swirl pot just has a top air bleed leading to the "surge" tank. The Pantera's overflow tank also has a radiator cap, as though it was planned to be a surge tank, but never connected to the system as a surge tank. So its just an overflow tank with a pressure cap, thats just plain bizzar.

The standard Ron Davis & Fluidyne replacement radiators have the same two pass design as the oem radiator, with the same 1 3/8" OD nipples. They did this so their radiators would be "drop in" replacements. Although they have an improved core design, they do nothing to resolve the inherent design flaw of the Pantera's cooling system, which restricts coolant flow.

Many owners install heavy duty electric fans and still experience cooling problems at slow speeds, this is because they have a voltage drop problem in the fan wiring, the fans are not getting a full 13.6 volts and therefore are not turning at full speed (not blowing air at rated capacity).

Some people are confused about the use of fan shrowds, logically a shrowd appears to be a restriction to air flow, so enthusiasts don't install them. This is true for a race car, which travels constantly at high speed. A shrowd DOES restrict the maximum possible flow of air through a radiator. However, a fan shrowd increases the efficiency of fans mounted behind the radiator, which are needed at slow speeds and at stops. The shrowd IMPROVES air flow at slow speeds. Which is why almost all road cars employ some sort of fan shrowd when the fans are mounted behind the radiator.

cowboy from hell