[HWYSTR455]

Originally Posted by 64speed

I do need to mention that GMB makes two separate pumps and it’s the nicer of the two but 40 dollars is ok. 130 not so much

I think Milodon buys the housing from GMB, uses their' own shafts and bearings. Believe there was a thread about this long ago, may even have had pics of the two taken apart.

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[Steve C.]

For interest only in my post number 43 above I linked the cooling improvements to the ’66 Tempest owned by Floyd Hand. This morning I finally found part 2 with the testing results.

Surprise, note this comment:

"Surprisingly, after upgrading the cooling system, its performance was surprisingly slightly inferior to that of the OEM-style system (see Test Results). This didn’t make sense, especially considering that the OEM-style system was getting long in the tooth and the quality of the new components are top-notch."

And this:

"..although the PRC custom shroud was very attractive, it limited the volume of air passing through the radiator so the Tempest ultimately ran cooler on the highway without it. "

But there was a good reason, read on with this link to part 2.....

https://www.hotrod.com/articles/hppp...ystem-upgrade/




.

[70GS455]

Originally Posted by Firebob

One thing I did notice last year. On my way home it was about mid 80s and I got stuck in a line of cars about 2 miles long getting through a stoplight. I was sure after overheating in Reno there was no way I was going to make it. When the temp started to creep up I got out and popped the hood about 6-8 inches. It let enough of the underhood heat out that the temp stayed under control. I was actually shocked that it worked because I was in traffic for quite some time moving now and then when the light changed and let a few cars through. Kind of makes me think that some sort of hot air evac system from the engine comp might go a long way to keeping things from getting ugly. They had air extractors on the original 69 Trans ams. I'm not sure how effective they were but those guys didn't usually do things for nothing.

Can also run the heater full blast. Won't be cold in the cockpit but will help cool the engine

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[RocktimusPryme]

Originally Posted by 70GS455

Can also run the heater full blast. Won't be cold in the cockpit but will help cool the engine

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You know that brings up another thought I had been considering. I have my heater core bypassed at the moment. The nipple on the water pump is plugged. Even with the heater off, how much will the extra volume of the heater core affect overall coolant temps?

Ive also wondered if a front air dam for my Firebird would significantly alter cooling at highway speed. I know I had overheating issues on my 3rd gen back in the day. Fiddled with fans and all. Finally someone asked me what the condition of my front air dam was. I checked and it was basically broken into non existence. Replaced that piece of plastic and my car ran cool again.

[70GS455]

Originally Posted by RocktimusPryme

You know that brings up another thought I had been considering. I have my heater core bypassed at the moment. The nipple on the water pump is plugged. Even with the heater off, how much will the extra volume of the heater core affect overall coolant temps?

Ive also wondered if a front air dam for my Firebird would significantly alter cooling at highway speed. I know I had overheating issues on my 3rd gen back in the day. Fiddled with fans and all. Finally someone asked me what the condition of my front air dam was. I checked and it was basically broken into non existence. Replaced that piece of plastic and my car ran cool again.

I did it years ago on a 57 chev that had poor cooling and in the summer it would help 5 or 10 deg.

I do know that in my car on very cold (<20 deg) winter days as long as the heater is full blast, the coolant takes forever to come up to temp until I turn it to low

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[dataway]

I would imagine on a later model cars (68 and later) heavily accessorized with AC, PS, PB that a 7 blade clutch fan can probably move more air than can escape from the engine compartment. It's basically got to push all that hot air down pass the engine and accessories and out the bottom of the engine compartment.

Opening the hood probably creates a definite improvement in air through the radiator. At highway speeds the draft created under the car probably evacuates the engine compartment pretty well.

I thought the vents on a TA were brake cooling vents .... if they led to the engine compartment then ... yes I'd guess they thought under hood air pressure was an issue.

[george kujanski]

From the HotRod article..."Coolant that flows too fast through the system will not allow sufficient time for cooling by the air that passes through the radiator core. Conversely, coolant that flows too slowly spends more time in the engine block where more heat transfers through the water jackets into it."

Physics reinvented again.

I guess if it's in a national magazine it must be true.

Interestingly, later on in the article, after the results, the author backs out of that statement.

George

[Grand73Am]

Originally Posted by dataway

I thought the vents on a TA were brake cooling vents .... if they led to the engine compartment then ... yes I'd guess they thought under hood air pressure was an issue.

The fender vents on a TA have nothing to do with the brakes. They are to the rear of the inner fender wells, open to the engine compartment. So, engine compartment air exits out of them.

[HWYSTR455]

Originally Posted by Grand73Am

The fender vents on a TA have nothing to do with the brakes. They are to the rear of the inner fender wells, open to the engine compartment. So, engine compartment air exits out of them.

Yeah, due to the large frontal area intake (grills), it needs to go somewhere. I think it was also to help prevent lift at higher speeds.

On the LeMans, when the fans came on and went full, if you stand next to the car, you can feel a ton of heat coming from under the car.

With the Flex-a-lite fans, I would sit in bumper to bumper DC traffic, on 100+ degree days, A/C on, and it stayed 5 degrees over the stat rating (180). Sometimes would sit for more than an hour, slinky-ing maybe 3 car lengths at a time. It worked. Very doubtful an engine driven fan could do as well in those conditions, with a similar built engine.

When you bypass the heater core, it's not really that the heater core provides much cooling capacity, it's more the coolant capacity that helps I would think.

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[dataway]

Originally Posted by george kujanski

From the HotRod article..."Coolant that flows too fast through the system will not allow sufficient time for cooling by the air that passes through the radiator core. Conversely, coolant that flows too slowly spends more time in the engine block where more heat transfers through the water jackets into it."

Physics reinvented again.

I guess if it's in a national magazine it must be true.

Interestingly, later on in the article, after the results, the author backs out of that statement.

George

Yep ... written by someone that has never seen a heat transfer formula

Whether you cool 1 gallon by 10 degrees, or 2 gallons by 5 degrees, you still remove the same amount of heat from the coolant.

Although, an often over looked aspect of heat transfer is the "Delta T" in the formula. The higher the differential between air temp and coolant temp the faster heat will be removed at a fixed flow rate. People understand it very well when it comes to high air temps .... 100 degree air doesn't cool as well as 50 degree air. But it applies to coolant temps also, 160 degree coolant doesn't transfer heat to 100 degree air as quickly as 180 degree coolant does. It's all about the difference in temps between the coolant and air, the greater the difference, the greater the heat transfer (assuming fixed flow rate of coolant and air).

However the problem with most cars when it comes to the cooling system is insufficient coolant flow, or insufficient air flow (assuming parts adequate to the task are installed). The system should have enough overhead to handle less than optimum Delta T.

[Tom Vaught]

Originally Posted by dataway

Yep ... written by someone that has never seen a heat transfer formula

Whether you cool 1 gallon by 10 degrees, or 2 gallons by 5 degrees, you still remove the same amount of heat from the coolant.

Although, an often over looked aspect of heat transfer is the "Delta T" in the formula. The higher the differential between air temp and coolant temp the faster heat will be removed at a fixed flow rate. People understand it very well when it comes to high air temps .... 100 degree air doesn't cool as well as 50 degree air. But it applies to coolant temps also, 160 degree coolant doesn't transfer heat to 100 degree air as quickly as 180 degree coolant does. It's all about the difference in temps between the coolant and air, the greater the difference, the greater the heat transfer (assuming fixed flow rate of coolant and air).

However the problem with most cars when it comes to the cooling system is insufficient coolant flow, or insufficient air flow (assuming parts adequate to the task are installed). The system should have enough overhead to handle less than optimum Delta T.

Very Good Post! Many can learn from Info like that.

TV

[Formulajones]

Went for another ride today. Temps outside are 95 degrees.

Could not get the car over 165 degrees. Slowed down on the back roads and it cooled to 160 pretty quick and after a few minutes actually dropped to 152 degrees and stayed there.

Sitting still idling for about 10 minutes and it only crept to 160.

Runs super cool for a big motor. I think I have it licked. Not worried about the 100+ temps we'll have here in a couple weeks.

[torqhead]

Originally Posted by Formulajones

Went for another ride today. Temps outside are 95 degrees.

Could not get the car over 165 degrees. Slowed down on the back roads and it cooled to 160 pretty quick and after a few minutes actually dropped to 152 degrees and stayed there.

Sitting still idling for about 10 minutes and it only crept to 160.

Runs super cool for a big motor. I think I have it licked. Not worried about the 100+ temps we'll have here in a couple weeks.

Hey Larry, was at a little local car show this weekend and a guy with a 70 Mustang was complaining about car overheating... Guess what he had... lol Told him if he got rid of that fancy chrome radiator shield he may be surprised what happens. His was a single fan model, ridiculous.

[Formulajones]

Originally Posted by torqhead

Hey Larry, was at a little local car show this weekend and a guy with a 70 Mustang was complaining about car overheating... Guess what he had... lol Told him if he got rid of that fancy chrome radiator shield he may be surprised what happens. His was a single fan model, ridiculous.

LOL, Yep. My 69 SCJ mustang had all it's original stuff (unrestored survivor). With 3.91 gears it would buzz a bit on the highway. All 50 year old parts, never ran hot. They don't have much radiator in them to begin with, and not much of a shroud either, but the mechanical fan did a good enough job to keep things in check. Here's a pic after a 35 year hibernation before I brought it back to life.
Seems the stock stuff works if everything is in good working order. People start to monkey around with things and problems arise.

[GTO JONES]

(2) 12" fans and shroud for sale fits 69 GTO ! ! !

[dataway]

Formula .... if it's cooling that good now ... actually might want to consider going to a 180 thermostat. Probably gain some engine efficiency ... and I bet with the increased heat transfer of 180 degree coolant it would be rock steady at 175-180 in the worst of conditions.

I see the secret to that SCJ cooling system right away. That no clutch mechanical fan looks like it's about 1/2" away from the radiator core, that's going to create a seriously powerful draw through the radiator.

[Steve C.]

Larry,
It would very interesting to know how it would of worked with the same radiator but with a better designed fan shroud with dual Spal electric fans.


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[torqhead]

Originally Posted by GTO JONES

(2) 12" fans and shroud for sale fits 69 GTO ! ! !

Hilarious!!!

[GTO JONES]

Originally Posted by Steve C.

Larry,
It would very interesting to know how it would of worked with the same radiator but with a better designed fan shroud with dual Spal electric fans.


.

I may at some point but for now I'll stay with the stock shroud and clutch fan, it cools way to good to mess with. I will say the cold case radiator with 1 1/4" tubes does a hell of a job keeping the 571 cool. Shout out to cold case.

[Formulajones]

Originally Posted by Steve C.

Larry,
It would very interesting to know how it would of worked with the same radiator but with a better designed fan shroud with dual Spal electric fans.


.

I'd be curious Steve, but don't think dad is at this point right now. This engine is running the coolest it's ever run now, and doing it in the hottest climate it's ever been in. I put the stock shroud and clutch fan back on as an experiment not expecting it to stay there, and didn't expect it to make as much difference as it did. I think dad is so happy with it now it may stay this way.

I have no doubt a better designed Spal setup would also do the trick, but the stock stuff right now is kicking butt.