[Squidward]

I don't subscribe to the "too much flow" theory. In a closed loop system you have 2 heat transfer devices at work: Engine to coolant, and coolant to radiator. Assuming air flow is constant, heat transfer is mC(Tin-Tout). If you slow the flow, the Tout of the engine goes up to balance the equation.

When I used to run a reactor plant, there were a few things we did when we "put the pedal to the floor": Reactor cooling pumps went to fast speed, and the cooling pumps for the main condensers went to fast speed. Flow is good for heat transfer.

My 67 FB runs the Champion 4 core, factory fan, Hayden 2797 clutch, and factory shroud. I used to fight with cooling at cruise speed when I ran an electric puller fan that I thought was plenty adequate. And I also thought I would have plenty of air on the highway. But it could idle all day in the driveway, running the ac in 117 degree weather.

I changed to shroud, clutch/fan, and went from 2 core aluminum to 4 core Champion. Issue solved. I just got back from a drive an hour ago in close to 100 degree weather, and the gauge never got off 180.

I think it is your fan setup blocking air flow. Because you are achieving significant variability in operating temps with changes in ambient air temp, I think you are in need of more air.

[Sirrotica]

Originally Posted by Jshiel50

Keep it simple..... had the same issue with a punched out 455 olds. I switched everything over to higher flow stuff and used different size water restrictors with electric fans. The problem was that water was flowing TOO FAST and was unable to cool. went to a stock pump, stock style 175 thermostat and a off the shelf flex a lite flex fan. Never had an issue again. Day temps in traffic never above 180 and night temps held between 165 and 175.

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Slowing coolant down to solve a heating problem is a myth, it never solves overheating problems. Heat transfers faster the more the differential is between the coolant and the radiator. That said, the more heat that is pulled from the radiator quickly will remove more BTUs from the engine into atmosphere.

Any time GM engineering was having an engine cooling problem, they went to higher output waterpumps, spun the waterpumps faster, and in one instance used dual thermostats in the water crossover to move a higher volume of water faster with more pressure to solve overheating problems. Any factory fix engineered by GM never involved slowing the volume of water down.

When running oval track Pontiac engines I have had heating problems more than once. Pontiacs have always had a tendency to run hot and require everything to be working properly and all the proper parts in the cooling system to run without overheating, especially in a racing situation. Solving them never included slowing down, or restricting flow through any part of the cooling system. The physics apply to any brand of cooling system, they don't change, they remain constant.

Question to the OP, is there a spring in the lower hose to prevent it from collapsing at cruise speed?

[Speargun]

Originally Posted by Sirrotica

...SNIP...
Question to the OP, is there a spring in the lower hose to prevent it from collapsing at cruise speed?

This is why I ask questions.
I didn't even think about that.

No. There is no spring in the lower hose. ....but there will be soon.

My pulleys are 8" on the crank & 6.2" on the water pump.
If I did the math right, that should be a 29% overdrive.

I don't have any bubbles in the water, no water in the oil, or oil in the water, & coolant levels are constant. Leakdown test was 4%-5% so a head gasket leak or cracked head is less likely.

AC condenser is at least 2" in front of radiator & there are no other obstructions other than the grill.

[Blued and Painted]

Originally Posted by Sirrotica

Solving them never included slowing down, or restricting flow through any part of the cooling system.

Then why does every race car using coolant run a a restrictor?

[Jshiel50]

Originally Posted by Blued and Painted

Then why does every race car using coolant run a a restrictor?

to slow down the coolant flow so it spends more time in the heat exchange process at the radiator!!!!!

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[Jshiel50]

its simple science for those who have chased their tails with this issue before....



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[ponyakr]

As with many other Pontiac subjects, opinions differ.

https://www.google.com/webhp?sourcei...iator+too+fast

[Sirrotica]

Originally Posted by Blued and Painted

Then why does every race car using coolant run a a restrictor?

They don't, I never did use any form of a restrictor. If I can run a Pontiac on an oval track with no restrictors and no overheating it proves the point.

Anyone using a restrictor is going to run cooler without it. Alcohol engines sometimes have trouble getting enough heat in the engines so a restrictor would cause one to run hotter. A restrictor will not make an engine run cooler.

Running any thing that inhibits flow impedes heat being dispersed.

And I'll ask you a question that will prove my point, Why after many years of OH problems so severe that the heads cracked from excessive heat did GM engineer a HO water pump and a new fan package as well as a dual thermostat water crossover for the 6.5 turbo diesel? No one thought slowing down water flow would cause overheating problems to disappear. Maximizing water flow cured the OH problems on that engine. Pontiac also drove the waterpump 30% faster on their A/C cars to deal with the extra load placed on the cooling system by the addition of A/C.

[Jshiel50]

Originally Posted by Sirrotica

They don't, I never did use any form of a restrictor. If I can run a Pontiac on an oval track with no restrictors and no overheating it proves the point.

Anyone using a restrictor is going to run cooler without it. Alcohol engines sometimes have trouble getting enough heat in the engines so a restrictor would cause one to run hotter. A restrictor will not make an engine run cooler.

Running any thing that inhibits flow impedes heat being dispersed.

And I'll ask you a question that will prove my point, Why after many years of OH problems so severe that the heads cracked from excessive heat did GM engineer a HO water pump and a new fan package as well as a dual thermostat water crossover for the 6.5 turbo diesel? No one thought slowing down water flow would cause overheating problems to disappear. Maximizing water flow cured the OH problems on that engine. Pontiac also drove the waterpump 30% faster on their A/C cars to deal with the extra load placed on the cooling system by the addition of A/C.

cuz they 6.5 diesel is junk

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[Sirrotica]

Originally Posted by Jshiel50

its simple science for those who have chased their tails with this issue before....



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Correct physics remain the same in any OH problem, slowing down flow only impedes an already deficient system. There are hundreds of aftermarket waterpumps available for high performance use and none impede the water flow to cure OH, they all add pressure and flow.

[Jshiel50]

Originally Posted by Sirrotica

Correct physics remain the same in any OH problem, slowing down flow only impedes an already deficient system. There are hundreds of aftermarket waterpumps available for high performance use and none impede the water flow to cure OH, they all add pressure and flow.

If it were a deficient system that's why the stock design remained sufficient enough for decades upon decades until someone screws with it.... agree to disagree. I'm out.....

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[Sirrotica]

Originally Posted by Jshiel50

cuz they 6.5 diesel is junk

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I guess so, mine has 260,000 miles on it and still going stong. BTW no OH problems either. So much for your opinions.

If you have any statistics to back anything you say, post them up so all here can learn from your vast knowledge.

From the Flow Kooler site;

Cooling FAQ
1. Doesn't coolant need more time in the radiator to cool?
No. But a lot of people still think so. We have come up with some explanations for the Doubting Thomas.

Debunking the I Can Have It Both Ways Theory

The water has to have "time to cool" argument is most common one we hear. In a closed loop system if you keep the fluid in the heat exchanger you are simultaneously keeping it in the block longer. Unfortunately, the block is the part that is generating the heat. Sending hot coolant from your source (engine) through the heat exchanger (radiator) to the sink (air) will transfer heat as long as there is a temperature difference between the source and sink. The engine is still generating heat the whole time so why keep the coolant there any longer than you have to.

Debunking The Conscientious Electron Theory

We hear that the coolant has to stay in the system longer to cool but what is heat transfer really but conduction, convection and radiation of electrons. The fluid in your system transfers those electrons based principally on the source-sink differential and the exchange material's transfer rate. An electron moves at varying speeds - Bohr's model has it moving at 2 million meter/second and with a mere 11 million eV boost you can get an electron to 99.9% of the speed of light. Though they move at varying speeds physicists accept that electrons move fast - really really fast. Far faster than the flow rate of the water pump. Your engine coolant's electrons do not know (or care) how fast you send them through the system - they just knows that the source is hotter than the sink and off they go.

Debunking Grandpa's Flathead Theory

"But wait a minute, I know Grandpa used to put washers in his flathead to slow the flow and cool his engine." We know people did this too. They still do it but the cooling benefit is not from the slower flow but the increase in dynamic pressure in the block that builds from the restriction. Consider that Grandpa had two flathead water pumps sending twice the volume through the same size radiator core as the Model B 4 cylinder. Too much flow in this no pressure system results in fluid loss. Slowing flow rate helps prevent that. At some point Grandpa maxed out the throughput and began building pressure in his block. Increasing block pressure helps reduce the onset of hot spots on his cylinder walls and formation of steam pockets in his block. This is a real benefit and does help cooling but is only realized when throughput nears capacity or is at capacity. While these restrictions may make sense when your rpm is excessive or your flow rate exceeds your heat exchanger throughput, they do not make sense for most applications. If you doubt this thinking then try this simple Ask Dr. Science experiment; clamp off the lower hose while you watch your temp gauge. Hopefully, you will debunk Grandpa's theory yourself before you experience vapor lock and melt your engine.

Flow restriction is not all bad if it serves to prevent cavitation. Cavitation occurs when a pump turns so fast that you generate lower pressure and air bubbles or vapor forms. These bubbles eventually implode and damage the engine block wall and impeller. Rapidly spinning the impeller can literally rip the air from water but may not actually move the fluid, it's tantamount to turning an eggbeater in a paint bucket. Restricting the fluid flow to raise system pressure in the block may help prevent cavitation at higher RPM but is it necessary for most vehicles? Probably not.

Most vehicles do not need to restrict flow because they do not reach or sustain high RPM. Additionally, thin aluminum radiators already restrict by design e.g. fewer rows of thinner tubes. Restrict it further and you may as well hose clamp the lower radiator hose and we know how that works out. When you face Grandpa on the track you may want your washers, otherwise, keep them in the toolkit.
Simply put, you have a far better chance of keeping your cool with greater flow rate through your heat exchanger and exiting the system than holding it in your heat exchanger while generating heat in your engine block.

[Jshiel50]

Originally Posted by Sirrotica

I guess so, mine has 260,000 miles on it and still going stong. BTW no OH problems either. So much for your opinions.

If you have any statistics to back anything you say, post them up so all here can learn from your vast knowledge.

sorry.... not trying to be a troll on here.... When it comes to diesels I'm partial to Cummins. It's all good bro... your the expert here

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[Lee]

Originally Posted by Speargun

I currently have the timing set just below where I get spark knock.

You get spark knock with Edelbrock heads and only 10.25:1 compression? You must have over 40 degrees total - BACK IT OFF!

Also buy/borrow a wideband and check your AFR.

Personally, I'd put it on a chassis dyno with a wide band hooked up, and see how far off the tune is. Just getting the timing and jetting corrected could cure your cooling issues.

A 3000 cfm Black Magic shrouded fan and a BeCool 2-row were enough to keep my old iron head 469" (see signature) running 180 most of the time, in Houston heat.

[Speargun]

Originally Posted by Lee

You get spark knock with Edelbrock heads and only 10.25:1 compression? You must have over 40 degrees total - BACK IT OFF!

Also buy/borrow a wideband and check your AFR.

Personally, I'd put it on a chassis dyno with a wide band hooked up, and see how far off the tune is. Just getting the timing and jetting corrected could cure your cooling issues.

A 3000 cfm Black Magic shrouded fan and a BeCool 2-row were enough to keep my old iron head 469" (see signature) running 180 most of the time, in Houston heat.

I have a wideband on it & can set my AFR at whatever I want. Right now it's set at 14.2 or 14.5 at cruise, 13.8 @ mid throttle, & 12.8 @ W.O.T. (iirc) I would have to look at what is programmed to be sure.

[george kujanski]

Attached is a graph I copied a while ago for a radiator from a manufacturer's site, (I don't remember who). It can be clearly seen that the heat transfer rate in BTU's/min INCREASES as the airflow and/or coolant flow rate increases.

Not only that, if slower is better, reducing coolant flow rate to zero should be the best.........unless there is some happy spot where it's the best. Problem here would be to find that happy spot and use a constant speed pump which the automotive engineers did not design in.......

Can't argue with Physics.

George

[TheSilverBuick]

Maybe I missed it, but is there any kind of air dam under the radiator to help create a low pressure spot behind the radiator? In conjunction with a proper fan shroud air flow shouldn't be an issue.

[ponyakr]

"....unless there is some happy spot where it's the best. Problem here would be to find that happy spot..."



https://www.summitracing.com/parts/m...nmKhoCURzw_wcB

http://www.speedwaymotors.com/Water-...r-Kit,605.html

https://www.summitracing.com/parts/a...TciRoCD3vw_wcB

http://www.jegs.com/i/Canton-Racing-..._O9hoCdlLw_wcB

https://www.summitracing.com/parts/m...ul-hoCjJ_w_wcB


" just make certain that there is a restrictor with an inside diameter about 11/16
inch in the single tube thats feeds into the radiator. This is important because there is no thermostat in the system, and overall flow volume will be controlled by the size of this orifice.If it is too large,the water will flow through the system too quickly ,and if it is too small,the water will flow too slowly!"
said by THE SMOKEY YUNICK!..."

Apparently this is a subject that has been hotly debated for many years.

https://www.trifive.com/forums/archi...p/t-60820.html

http://www.yellowbullet.com/forum/sh...ad.php?t=69033

http://www.chevytalk.org/fusionbb/sh...d/174080/pid//

My opinion is that there can probably be slight variations in coolant flow which will be OK, IF & ONLY IF there is enuff air flow thru the radiator. And, as mentioned, some radiators will remove more heat from the coolant than others, with the same flow rate & air flow cfm. I suppose the only way to know which parts will cool your particular engine better, would be to try all possible combination of parts, in your car, the way you drive. Not everybody has the $$ to try many combos. But, many do. It would be nice if some of you guys who have plenty to spend would do some extensive cooling equipment testing. Overheating is a VERY common problem, brought up occasionally on all Pontiac forums.

It would be nice to know, for sure, exactly which type & brands of radiators cool best, which fans actually cool best, which pumps actually cool best, etc, etc.

[Sirrotica]

For the people that choose to ignore physics there are restrictor washers. As long as the radiator has plenty of airflow and area, you cannot pump water too fast through a cooling system.

If you don't have enough radiator area or airflow through it, your fighting a losing battle from the beginning. Restrictor washers won't fix it either. Restrictor washers will raise the pressure of the coolant on the high pressure side of the pump possibly reducing cavitation from a poor impeller design, a band aid for another problem which should be addressed and repaired.

[Lee]

Originally Posted by Speargun

I have a wideband on it & can set my AFR at whatever I want. Right now it's set at 14.2 or 14.5 at cruise, 13.8 @ mid throttle, & 12.8 @ W.O.T. (iirc) I would have to look at what is programmed to be sure.

Good! Only concern there is the accuracy of the unit. I recently saw an AEM that was WAY off.

Now pull the timing down, and see how it runs.