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Discussion Starter #61
The water pump is currently a Weiand. I tried an Edelbrock and a stock pump. The Edelbrock water pump on my sbc used an impeller that resembles a turbo impeller, but the Edelbrock impeller for the BBC looked like a stock pump impeller. But, all 3 pumps performed the same on my car.
The timing was 26 initial and 36 total mechanical, with 10degrees in the vacuum can. It is currently locked out at 34. The rear gear is 3.73. You are correct on the radiator, the flow is side to side. The dual pullers are not shrouded, and I tried removing one to see if the fans were impeading air flow and did not change.
I put an air dam below the core support and the slowed it down, but temps still keep climbing.
Is it safe to assume your temperature reading is accurate?

3.73 is not a horrible rear gear ratio but it hurts on the highway compared to a car like mine with an OD. 2200 rpm at 75mph.

I definitely recommend you put the vacuum advance back on, the engine will run a little cooler on the highway at moderate cruise with closer to 48-50 deg advance. That might be all the difference you need if you're on the edge.

Check if the lower water hose is internally supported with a spring. With the car hot after a drive, hood open, bring the rpms up to 3000-4000 rpm. Watch the lower water hose to see if it collapses. I would try this even if you know it has a spring just to make sure it's doing it's job.

Do you have a thermostat and if so, what temperature and brand?
 

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I forget to say I have a turbo400.
Even with the distributor locked I run the vacuum can.
The thermostat is a Robert Shaw, it has the large opening. I have also run it without a thermostat and it was the same just took a bit longer to get to temp.
I have a spring in the lower hose,band it runs the whole length, never check it by reving but if you squeeze it it is solid.
I have March pullies and have tried both ratios they offer, I think one is called performance, and the other spins the accessories faster, and can't say I noticed any difference.
I trust the temp gauge. I can idle or drive slower than 30mph for as long as I want and temp will not go higher than thermostat setting.
My radiator looks new inside and out, and I had it to a radiator shop, to check the flow, he said it seems fine,but I think it is the problem.
I have had the motor apart and am sure of the way it is assembled. I used head gasket that AFR and GM performance recommend (it is a Bowtie Block), they both recommend the same exact Felpro gasket.
 

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Discussion Starter #63 (Edited)
I forget to say I have a turbo400.
Even with the distributor locked I run the vacuum can.
The thermostat is a Robert Shaw, it has the large opening. I have also run it without a thermostat and it was the same just took a bit longer to get to temp.
I have a spring in the lower hose,band it runs the whole length, never check it by reving but if you squeeze it it is solid.
I have March pullies and have tried both ratios they offer, I think one is called performance, and the other spins the accessories faster, and can't say I noticed any difference.
I trust the temp gauge. I can idle or drive slower than 30mph for as long as I want and temp will not go higher than thermostat setting.
My radiator looks new inside and out, and I had it to a radiator shop, to check the flow, he said it seems fine,but I think it is the problem.
I have had the motor apart and am sure of the way it is assembled. I used head gasket that AFR and GM performance recommend (it is a Bowtie Block), they both recommend the same exact Felpro gasket.
What temperature is the thermostat and when you're on the highway what temperature do the fans come on? Even though I'd expect the air flow at highway speeds to be sufficient, could be something about your car that impedes the natural amount of air flow thru the radiator.

Also, what temperature(s) do you see cruising steady state down the highway?

Water with anti-freeze and if so what percent anti-freeze? Or just a water wetter product?

Does your water system use an overflow tank? These are important because it allows the system to purge itself of air each time the engine heats up then cools.

Whose radiator brand is it? Some OEM replacement radiators are generic for that car and it's possible it doesn't have a high fins/inch number which would affect the overall efficiency of the radiator. In other words, you could be putting more heat thru the radiator than you can transfer out with the air fins and normal air flow.
 

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It is a 160 thermostat, fans set to come on at 180, I can adjust the setting to turn on.
I have tried straight water and 50/50 water antifreeze, never water wetter. I would like to get this BBC to work like the sbc use to with out water wetter.
It is a factory Harrison 4 core for an a 1970 a body.
I am using a recirculating expansion tank, put it on when I had the sbc.
Running on freeway at 65 temp will continue to climb, I slow down or get off highway and drive 55-45 and temps will drop, don't remember exactly to what.
Don't have a lot of time on this combo, and did not dive it at all last year, or this year yet for other reasons.
 

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I have at least a 50/50 antifreeze in my car now...maybe even higher amount of antifreeze than that and my car is running noticably warmer this summer than it did last summer with just water and water wetter.
 

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I have at least a 50/50 antifreeze in my car now...maybe even higher amount of antifreeze than that and my car is running noticably warmer this summer than it did last summer with just water and water wetter.
Go here:

Then page down to "Specific Heat Capacity..." and read every word underneath the table. Your cooling system is performing to expectations when switching from water to 50/50 Ethylene Glycol and water.
 

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Discussion Starter #67 (Edited)
It is a 160 thermostat, fans set to come on at 180, I can adjust the setting to turn on.
I have tried straight water and 50/50 water antifreeze, never water wetter. I would like to get this BBC to work like the sbc use to with out water wetter.
It is a factory Harrison 4 core for an a 1970 a body.
I am using a recirculating expansion tank, put it on when I had the sbc.
Running on freeway at 65 temp will continue to climb, I slow down or get off highway and drive 55-45 and temps will drop, don't remember exactly to what.
Don't have a lot of time on this combo, and did not dive it at all last year, or this year yet for other reasons.
I'm not suggesting using water wetter, it's effectiveness to lower temperatures is barely measurable if at all.

What temperature does it get to? I wouldn't sweat 200-210 deg F if it stabilizes.

I wouldn't chose to use a 4 core radiator myself. Here's why they can be a problem. Theoretically the most effective radiator will always be the one with the largest frontal surface area. Since we are limited to the frontal area size of a radiator, we can add rows to increase the internal and external heat transfer areas. However, each row we add is exposed to progressively hotter "cooling" air and becomes less effective. As an example, we might expect the front row to see 100 deg air, the second row 135, third row 165 and the last row might be be trying to reject heat using with 190 deg air. The actual temperature gradient may vary from this but does represent what is happening in concept.

Now let's analyze what else happens with a 4 core radiator compared to a comparable 1 core radiator. Imagine you put both radiators on your garage flow each in front of a box fan. On the back of the radiator you put a 8" length of yarn then turn on the fan. I'm pretty sure we would see the yarn on the single core streaming straighter in the air flow than one on the 4 core fan. So it's obvious that with the same fan effort, MORE air volume will pass thru the single core than the 4 core. So even though we've added more surface area for heat transfer with the 4 core radiator, we've reduced the CFM (mass air flow) available for cooling.

So there are 3 effects when adding rows to a radiator. We add surface area, but reduce the average effectiveness of the overall surface area AND reduce the amount of air flow available to absorb the heat. At some point the advantage of adding rows is offset by reducing air flow - unless we do something to restore the air flow.

With this in mind, your 4 core radiator may be starving itself for air flow at higher highway speeds. Even though it would seem the problem is not air flow related, we might want to re-evaluate that. The faster you go the more heat you have to reject but the air flow you need might not get thru that radiator at higher speeds. The air would be more likely be flowing around the sides of the radiator and/or more of it is flowing around the car and not going thru the radiator.

If this is the case, you will see a noticeable difference with a 2 or 3 core radiator OR increase your fan capacity and add a shroud.

One more thought. I don't have any real data, but comparing an old school OEM factory mechanical fan with the OEM shroud to most electric fans, I'd say the OEM setup would be more effective moving air at highway speeds. Usually we expect not to need much help moving air at highway speeds but in a application where the radiator needs to have additional rows, the fan remains important even as speed increases. And a mechanical fan volume increases as engine speed increases so it's a natural solution for a thick OEM style radiator.

I haven't mentioned it yet but since we are discussing air flow volume, we should realize we are actually discussing MASS air flow. If a cooling system is limited by air flow capability while driving in higher density altitudes conditions, the car will run hotter since the CFM volume remains the same but with the lower air density drop the mass air flow also drops along with the cooling capacity. So a car that has just enough air to keep the cooling temperature right at 180 driving at sea level will run well past 200 degrees if driving thru the Rockies. I remember watching my fans run continually at 100% duty cycle trying to keep up doing that last year when normally they turn on for a short time and rarely go past 80% duty cycle. And my water temps were running as high as 210-215.
 

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Monte Carlo guy has a big block with headers stuffed into a spot where a small block lived, IIRC. One thing the BBC with headers does is block airflow through the engine compartment where it once could flow freely. The low pressure area a the base of the firewall between the body and the ground is a designed flow path for cooling system air. Block it off and the pressure gradient from in front of the radiator to the bottom rear of the engine compartment gets reduced and the result is less flow through the radiator. Big cowl hoods also exacerbate this by letting in "high" pressure underneath the hood and the flow potential decreases even more. This is also why when the chin spoiler/radiator air dam was installed, the system worked incrementally better - taking air that was piling up under the engine/floor and sending it into the radiator helps change the pressure gradient a little.
When I worked on UTV's even the inner fender shape and size mattered for airflow through the radiator. If I remember right, a Monte used to have a pretty long shroud to enable the fan to pull air properly. (It's also why they made great demo cars as they could take a lot of front hits without the fan eating the radiator.)

For the fan flow thing, it may be interesting to measure the fan speed with the fan installed on the radiator and then mounted safely to just work without pulling through the radiator. If it turns several hundred rpm more in "free flow" then Randy's thick radiator hypothesis has credence.

Changing from brass to aluminum would go along ways to transfer more heat, along with removing a paint layer to make the brass rad look pretty.

On OHV equipment, I have to make rads thicker, add more fan and create proper shaped fan shrouds to keep 'em cool at WOT when it's 42C outside. You'd have to use at least 5 of them little 3000cfm Spal's to match the needs of a 400hp engine at 2Bar boost.
 

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I do not remember seeing where the temp sensor was located. IIRC the sensor in the head will have a slightly higher reading than on the intake manifold.
 

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My temp has climbed as high as 235, (forgot to say that last post) and I got off the freeway, I believe it would have kept climbing since it didn't seem to start slowing down it's rate of climb.
I understand what your saying about the 4 row radiators, makes sense.
I have a Griffin 2 row, I am going to install. The tube size is 1 1/4 and has a few more rows than the Harrison.
One of the things I thought of/noticed recently is this motor sits higher than the sbc. My thermostat housing might be a bit higher than my radiator cap. It made me wonder if I could have air stuck in the system.
I have a thermostat housing that has a radiator cap on it I can try, it will be the highest point and I can fill it there. I recently got the car ready to go so I can try to fix this again.
 

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Discussion Starter #71
Monte Carlo guy has a big block with headers stuffed into a spot where a small block lived, IIRC. One thing the BBC with headers does is block airflow through the engine compartment where it once could flow freely. The low pressure area a the base of the firewall between the body and the ground is a designed flow path for cooling system air. Block it off and the pressure gradient from in front of the radiator to the bottom rear of the engine compartment gets reduced and the result is less flow through the radiator. Big cowl hoods also exacerbate this by letting in "high" pressure underneath the hood and the flow potential decreases even more. This is also why when the chin spoiler/radiator air dam was installed, the system worked incrementally better - taking air that was piling up under the engine/floor and sending it into the radiator helps change the pressure gradient a little.
When I worked on UTV's even the inner fender shape and size mattered for airflow through the radiator. If I remember right, a Monte used to have a pretty long shroud to enable the fan to pull air properly. (It's also why they made great demo cars as they could take a lot of front hits without the fan eating the radiator.)

For the fan flow thing, it may be interesting to measure the fan speed with the fan installed on the radiator and then mounted safely to just work without pulling through the radiator. If it turns several hundred rpm more in "free flow" then Randy's thick radiator hypothesis has credence.

Changing from brass to aluminum would go along ways to transfer more heat, along with removing a paint layer to make the brass rad look pretty.

On OHV equipment, I have to make rads thicker, add more fan and create proper shaped fan shrouds to keep 'em cool at WOT when it's 42C outside. You'd have to use at least 5 of them little 3000cfm Spal's to match the needs of a 400hp engine at 2Bar boost.
I have a thin core Ebay radiator on the car now. The thicker core Griffin radiator I took off is in my storage shed and I have another new radiator that might have a core thickness between those 2. When I get back to Orlando from New Zealand, I will be taking out the Ebay radiator and putting the new one in. Perhaps I can do some testing using each of the cores while I have everything available. Besides a box fan that I have, I can also try the testing using the pusher and puller fans that I use on my radiator. I can try a few different things including the yarn test and perhaps can rig up a manometer to measure some pressure drops. If I could get my hands on an adjustable strobe light I could use that to measure RPM change.

Everything you wrote about different body styles, engine configurations and chin spoilers are correct. If there is no where for the air to leave the engine compartment, that will hinder total air flow. I have turbo headers that go up and forward, then twin turbos with 3" exhaust blocking the air flow. Plus I have an intercooler laying horizontal sandwiched between the lower radiator support and the front of the oil pan partially blocking the remaining opening in the front of the engine compartment. I compensate by having a 14" pusher fan in front of the radiator along with the dual Ford Contour fans.

And yes, I agree the aluminum radiator is a much better option than a painted brass unit.
 

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Discussion Starter #72
My temp has climbed as high as 235, (forgot to say that last post) and I got off the freeway, I believe it would have kept climbing since it didn't seem to start slowing down it's rate of climb.
I understand what your saying about the 4 row radiators, makes sense.
I have a Griffin 2 row, I am going to install. The tube size is 1 1/4 and has a few more rows than the Harrison.
One of the things I thought of/noticed recently is this motor sits higher than the sbc. My thermostat housing might be a bit higher than my radiator cap. It made me wonder if I could have air stuck in the system.
I have a thermostat housing that has a radiator cap on it I can try, it will be the highest point and I can fill it there. I recently got the car ready to go so I can try to fix this again.
235 and climbing is too hot.

If you are getting reasonable flow, I really doubt you have an air bubble problem.

Every engine has air pockets in it after draining then replacing the coolant until it goes thru a few heat cycles. But the air in the system gets carried to the radiator by the water then get pushed out the overflow at the system pressure builds up. This eventually purges all of the air. That's why the overflow needs to be repeatedly refilled until after a few heat cycles.
 

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Old Mopar guy posted a situation I believe happened to me. He claims old radiators can suffer over the years from thermal cycling and CRACK LOOSE THE FINS from the tubes. Rad can be clean and leak free, flow like an SOB but not radiate much heat. This might be a difficult nut to crack, sometimes.
 

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Discussion Starter #74
I have a spring in the lower hose,band it runs the whole length, never check it by reving but if you squeeze it it is solid.
I wanted to visit this one more time. Next time the engine is hot, check the hose by revving the engine. Those hoses get very soft when hot and collapse easily. It doesn't take but a minute and even if the hose is only necking down in one small section, it could be enough to hurt the water flow. This may not be the case but it's worth verifying.
 

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Air going through the radiator is something I can work on. This car has nothing to force the air through the radiator after it goes through the grill, it can deflect and go over, under or around. Maybe not down as much since I put a air deflector below core support, and as I said it seemed to help.
My friend has a 91Camaro that was running hot, hefixed it by putting the plastic shield back on that fit over the top of the core support and the front header panel. His air must have been going in and up over the radiator into engine compartment.
Since I never had a problem with any of my sbc, and the fact my car never came with anything to direct sir, never gave much thought.
I will say, on a test stand i have, to run engine's on prior to install, the BBC got warm A LOT faster than my 434 sbc. In fact I had to shut it off because temps were getting hot. The radiator and electric fan used could not keep up with the BBC, but always did for the sbc. These big engine's make a lot oh heat.
 

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Discussion Starter #76
Post later when you see how it turns out.

Good luck. ;)
 

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Discussion Starter #78
My radiator cap sits lower than my intake manifold how do I purge the air out?
Systems designed like this are difficult to deal with and filling the system can be a pain. I would try this:

Put a small petcock type fitting at a high point on the intake. Keep it open until you get the radiator filled 100%. Close the petcock, put the cap on the radiator, coolant reservoir should also be connected and full of water/coolant. Start the engine. Then after the engine heats up some, crack the petcock and let air bleed out. After air stops bleeding out, close it and let the engine continue to heat.

Keep an eye on the temperature gauge while doing this. Once you see a temperature above your thermostat, shut the engine off. Slightly open the petcock and let any residual pressure release. At this point you will have to put your hand on the radiator to see if it's hot which indicates flow of hot water from the engine. You CAN'T open the radiator to check the flow after you start this process. As the engine cools, it will draw coolant into the radiator from the reservoir.

Let it cool 40-60 degrees. and watch to see if it draws in coolant during the cool down process. Then restart the engine and repeat the process - when the engine is operating temperature again, open the petcock slightly and bleed the air. Let the engine cool and watch the reservoir. If water/coolant escapes anytime during this process you've gotten enough air out of the system to stop.

Basically what you are trying to do at this point is let pressurized air out every time you heat the engine. Then when it cools it will naturally draw water from the reservoir. Once you bleed enough air out, it will circulate normally. So once you have circulation (radiator hot), you can stop bleeding the air from the petcock. At this point most of the remaining air will be carried over in small pockets and should end up collecting at the top of the radiator.

Now every time you heat cycle the engine it will continue to purge air normally out of the radiator overflow. But you will have to watch the reservoir and keep filling it until it stops drawing coolant back in. This may take several heat/cool cycles.

Note - This may not work well if you system is not sealed tight. Don't open the petcock unless the engine is hot enough to pressurize the system.
 

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My radiator cap sits lower than my intake manifold how do I purge the air out?
For situations like this, heres an out of the box solution... If its possible to mount an expansion tank from a late model car (or aftermarket aluminium one) in the engine compartment somewhere higher than the engine and rad then that can solve this issue. It can be back towards the firewall for example.

It has to be a proper expansion tank with its own radiator cap, not just an aftermarket reservoir etc.

But its a bit of messing about to get it right, you have to set it up like a later model oem car in a sense, but if you do it will likely bleed itself.

The large lower fitting of the expansion tanks (suction side of expansion tank, usually 5/8 to 1" ) needs to be tee'd into the lower hose (or suction side of heater hose)

Can use one of these to into the lower rad hose....



https://www.ebay.com/itm/38mm-1-50-OD-Polished-Alloy-T-Piece-TPiece-BOV-Dump-Valve-Adapter-Aluminium/272792308281

Then the upper small nipple on the expansion tanks (typically 3/8" approx) needs to go to the top of the radiator. Many aftermarket radiators wont have a 3/8" nipple though. Another work around is one of these temp sensor adapters in the top hose with a 1/8npt to 3/8 hose tail fitting inserted.

https://www.ebay.com/itm/Water-Temp-Temperature-Gauge-Radiator-1-8-NPT-sensor-Hose-T-ADAPTER-BLACK-38mm/312229672214

https://www.ebay.com/itm/SPEEDFLOW-1-8-NPT-TO-3-8-HOSE-TAIL-SF421-02-06-BLK/361073765165

Some expansion tanks have 2 small upper 3/8 fittings , in this case, one can go to the top of the radiator and one to the top hose or tee into the heater outlet.

Once this is done, a higher pressure cap needs to be put on the radiator than what you have on the expansion tank.. to effectively seal off the radiator, and let the expansion tank to the breathing if needed. For example a 20psi on the radiator and a 15 or 12 psi on the expansion tank.

Some oem expansion tanks even have a coolant level switch in them that you can actually wire to a light inside the cabin... so if you have a water leak you'll know about it sooner.

This isnt a theory ive actually done it to vehicles and just bought the gear to do my mullet mobile because it gets air in the top of the radiator sometimes, gets hot and pisses me off.

It also means you can drive cross country if needed and not have to check or top up the radiator level, the expansion tank has more reserve plus you can simply see into it it if its clear plastic or has a fluid level tube built in like some do.

It can add a bit of new school convenience to old school.
 

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Air going through the radiator is something I can work on. This car has nothing to force the air through the radiator after it goes through the grill, it can deflect and go over, under or around. Maybe not down as much since I put a air deflector below core support, and as I said it seemed to help.
My friend has a 91Camaro that was running hot, hefixed it by putting the plastic shield back on that fit over the top of the core support and the front header panel. His air must have been going in and up over the radiator into engine compartment.
Since I never had a problem with any of my sbc, and the fact my car never came with anything to direct sir, never gave much thought.
I will say, on a test stand i have, to run engine's on prior to install, the BBC got warm A LOT faster than my 434 sbc. In fact I had to shut it off because temps were getting hot. The radiator and electric fan used could not keep up with the BBC, but always did for the sbc. These big engine's make a lot oh heat.

Is the radiator sealed to the core support?
Is the rubber seal between the hood and the core support missing?
These are two fundamentals you can apply that will promote air going through the radiator.
Pix would go a long way here to see what ya got under the hood.

The other item you mentioned is you have tried a few water pumps without much affect. The only pump out there I have found flow numbers on and comparisons to stock and competitors is Stewart. Like Randy has stated before, two of the three fundamentals (and tuning knobs) that affect cooling are coolant flow (volume or mass) and air flow. Just changing a water pump does not necessarily rule it out as a root cause.


Lastly, the best cooling system can be brought to its knees by simple little things, like the vacuum valve in the cap not working to allow the radiator to suck in coolant during cool down. Have it tested or just pick up a new cap since they are inexpensive.


Lastly, this part of Randy's cooling thread should maybe be made into a new thread for 70mc. Randy's original basics of cooling systems should be made into a sticky as it should be the first stop for folks having cooling issues.
 
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