312 temperature gauge

[miker98038]

Best I can recall, I came across that on Kirk F White’s site, when he owned the “clone” of Spencer’s 55 bird. Built by Spencer when he redid his original. But Mr. White passed on, and all that info seems to have disappeared.

Over at yblocksforever I’ve seen comments that the water enters the head thru the block, then flows forward to the manifold crossover at the front. Consequently the oem sender location reads a bit lower than one added at the front crossover near the tstat. I’ve no personal knowledge. My stroker motors, supercharged, or high compression have always cooled fine if the radiator/fan shroud combination is well engineered. Even in the bird, where getting air out of the engine compartment is the final item.

 

[KULTULZ]

Just to be concise, the FYB WP introduces cooled coolant to the front of the cylinder barrels (L&R). The coolant then travels through the block cylinder barrels water jackets cooling those. It then enters the heads at the rear of the engine and then travels through cyl head passages rear to front and then both head passages join at the intake manifold coolant crossover.

Where engineering placed the sensor only reads the coolant temp as it exits the left side block water jackets. If there is a problem(s) in the right cyl cooling jackets, it isn't going to report that. The hot coolant then will cool somewhat (if no head problems) and when it reaches the thermostat (and WP by-pass) will be somewhat cooled and not alert that there is a problem(s) somewhere in the cooling system.

This is one reason the engines overheat so badly (other than improper service). The coolant will reach boiling points and the sediment(s) (from using tap or well water - rust from not using the proper coolant) will fall out of suspension causing hot spots, cyl head rising, WP vane erosion and blown head gaskets.

Once the engine passages get plugged with debris/rust the overheating really begins.

The BIRD is much more susceptible due to poor engine compartment air flow and hot soak.

The coolant sensor has to be in that crossover behind the thermostat (IMO) to alert the driver there may be a problem somewhere in the system.

 

[EricCJ]

Just to be concise, the FYB WP introduces cooled coolant to the front of the cylinder barrels (L&R). The coolant then travels through the block cylinder barrels water jackets cooling those. It then enters the heads at the rear of the engine and then travels through cyl head passages rear to front and then both head passages join at the intake manifold coolant crossover.

Where engineering placed the sensor only reads the coolant temp as it exits the left side block water jackets. If there is a problem(s) in the right cyl cooling jackets, it isn't going to report that. The hot coolant then will cool somewhat (if no head problems) and when it reaches the thermostat (and WP by-pass) will be somewhat cooled and not alert that there is a problem(s) somewhere in the cooling system.

This is one reason the engines overheat so badly (other than improper service). The coolant will reach boiling points and the sediment(s) (from using tap or well water - rust from not using the proper coolant) will fall out of suspension causing hot spots, cyl head rising, WP vane erosion and blown head gaskets.

Once the engine passages get plugged with debris/rust the overheating really begins.

The BIRD is much more susceptible due to poor engine compartment air flow and hot soak.

The coolant sensor has to be in that crossover behind the thermostat (IMO) to alert the driver there may be a problem somewhere in the system.

Just to add a bit, the Birds also have a 1" extension on the rear of the water pump, I have no idea why, but it does cause them to run very hot at low speeds, simply removing the 1" spacer solves that issue. I discovered that for myself many years ago when a friends wife had one she liked to run in parades, I owned my radiator shop at the time and tried a number of things without success until I had the Bird in one stall and my '46 pickup in the other that had a 312 in it. And noticed mine did not have the spacer., Pulled it out of the Bird and solved the problem. You do have to space behind the WP pulley to align the belt, and maybe the Gen adjusting arm don''t really remember.

 

[rotorwrench]

Flatheads had the King Seeley temperature sender in the right bank cylinder head which gave the system indication of cold to hot with no actual temperature scale but at least it was a temperatue sensitive unit. The switch unit in the left bank head was just a switch where the bi-metallic switch was set to the temperature that was considered an over temp, If the coolant temp rose to that temperature level then the switch would open the whole circuit and the indicator would go to full hot. It was a short term insurance that if the left bank did quickly overheat then the indicator would quickly indicate that. Even though the engine had two separate bank cooling systems that included two thermostats on most cars, they both met with a common upper radiator tank so if one side did overheat then it did eventually overheat the whole system but it took a longer period to react if there was only one sending unit. This is why they elected to have two sending units even though only one of the units reflected temperature changes.

I would have no problem with a sending unit placed after the thermostat in the system. This would tell the operator exactly when the thermostat opens fully. Most thermostats have a way to bypass a small amount of coolant until it opens but it is limited or the thermostat wouldn't be able to do it's job. At least the Y-blocks had a shared cooling system. The factory indicator system should be repairable but good quality reproductions may not be what was originally used. The early Y-blocks still used the King Seeley system and none of the reproduction parts function as well or as reliably as the originals. A person has to scour the country to find functional components for them but there are likely some still out there from places like Southside Obsolete up in Minnesota. I miss Stacy Brown from up in the Dallas Fort Worth area. That guy always had stuff like that.

 

[Gene F]

Just to add a bit, the Birds also have a 1" extension on the rear of the water pump, I have no idea why, but it does cause them to run very hot at low speeds, simply removing the 1" spacer solves that issue. I discovered that for myself many years ago when a friends wife had one she liked to run in parades, I owned my radiator shop at the time and tried a number of things without success until I had the Bird in one stall and my '46 pickup in the other that had a 312 in it. And noticed mine did not have the spacer., Pulled it out of the Bird and solved the problem. You do have to space behind the WP pulley to align the belt, and maybe the Gen adjusting arm don''t really remember.

Wait a minute what spacer? How do you correct that for the alternator belt? What if my car has the optional bigger gear in the back....sustained freeway speeds?

 

[miker98038]

I believe the tbird spacer came about because to the engine to chassis layout. The front harmonic dampener is different, to clear the front crossmember. This moved the crank pulley forward. Rather than use an extension of some sort on the pump drive, the whole pump moves forward 1” from the spacer. Removing the existing spacer and adding a 1” spacer to the pump shaft (common enough on other vehicles)/pulley/fan does the same thing. Maybe more load on the pump bearing? Either way, guys do it, and often fit a smaller w/p pulley to increase the drive speed at idle. Pick your poison.

 

[KULTULZ]

The BIRD specific WP spacer (8A510) moved the WP forward 1in so as to keep the WP drive belt(s) in alignment with the damper pulley(s) due to the damper pulley being moved forward due to the unique front engine mount on the BIRD (as mentioned).

FORD did not modify or release a special pump for the BIRD and it resulted in the WP impeller not being fully extended into the timing cover boss resulting in loss of coolant flow into the timing cover volute.

There are now modification(s) available to correct this.

 

[KULTULZ]

Correct placement (IMO) would have been in the front intake coolant crossover as to read both banks/heads.

See if these help -

 

[Gene F]

I see thanks. My Fairlane does not have that, so I guess I am good to go.