Need cooling help on Pro Street Big Block - Chevelle Tech
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post #1 of 16 (permalink) Old Mar 20th, 07, 5:05 PM Thread Starter
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Need cooling help on Pro Street Big Block

Any help would be appreciated! I have a 496 big block with a 8-71 supercharger, 5 lbs of boost, big Be Cool Radiator, 300 series Meizere electric water pump (rated at 55 GPH), Dual electric fans, and a 160 degree thermostat. When I went out cruising, I was fairly happy with my temp not going above 205 degrees for the first 50 miles. I stopped to get a bit to eat and resumed my trip about 30-40 minutes later. Upon my return trip, the temp hovered around 225 degrees and finally got to 230. WTF! I stopped for gas and there was a bit of boil over (not much). The coolant is fresh and the system clean and purged of air. I let it cool a bit and made it home, at about 225 degrees.

Are there any thoughts out there as to a solution for this over ehating problem. Am I too paranoid about 230 degrees? Would an extra circuit for the water pump when stopped help? An alternative to the water pump that I have? Any thoughts.

496 C.I. 4-bolt main
TH400 with Coan Converter
Dyers 8-71 Supercharger
Backhalved and Tubbed
4050 lbs with driver
9.66 sec in 1/4 mile
1.33 sixty foot
139 mph
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post #2 of 16 (permalink) Old Mar 20th, 07, 10:00 PM
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Re: Need cooling help on Pro Street Big Block

Is the torque converter in a constant state of slip on the street?The trans temp along with the higher engine rpm and reduced flow thru the rad core all add up to heat.It is a fine balance between street and strip.With that much motor..a tighter converter may be the solution.Food for thought only.
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post #3 of 16 (permalink) Old Mar 20th, 07, 11:05 PM Thread Starter
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Re: Need cooling help on Pro Street Big Block

I do not think that the torque converter is slipping at all in this aplication (3000 stall Coan set up for the blower), but I did not think about trans temp. No problems with it over the whole cruise.

Thanks for the thoughts.

496 C.I. 4-bolt main
TH400 with Coan Converter
Dyers 8-71 Supercharger
Backhalved and Tubbed
4050 lbs with driver
9.66 sec in 1/4 mile
1.33 sixty foot
139 mph
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post #4 of 16 (permalink) Old Mar 22nd, 07, 8:38 AM
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Re: Need cooling help on Pro Street Big Block

you may want to chang your timing ....the boost dosent seem to high ... as for the 160 t/stat its useless after 160 just stays open .. in effect this tells you your cooling system is not enough to modulate the t/stat .. put in a 180
this may help with the issue of time coolant cycles trough the rad ...to get cooled down before heading back to the block ...what cfm are your fans ? .
and lastly .. with electric w/p its a good idea to cycle the w/p and fans when you stop the engine to cool things down and avoid heat soak .

Don
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post #5 of 16 (permalink) Old Mar 22nd, 07, 11:31 AM Thread Starter
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Re: Need cooling help on Pro Street Big Block

Thanks for the thoughts Don. I have two 1200 CFM fans without a shroud that takes up most of the face of the radiator. I just ordered a dual set up that has a buit in shroud and flows 2800 cfm. I will be installing that this weekend. I will also try a 180 degree thermostat at the same time and see how this Sunday pans out.

How difficult would it be to cycle the water pump and fans after engine shut down? Is there a Kit or something available commercially?

496 C.I. 4-bolt main
TH400 with Coan Converter
Dyers 8-71 Supercharger
Backhalved and Tubbed
4050 lbs with driver
9.66 sec in 1/4 mile
1.33 sixty foot
139 mph
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post #6 of 16 (permalink) Old Mar 22nd, 07, 11:47 AM
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Re: Need cooling help on Pro Street Big Block

What is the pressure rating of your cooling system? Burping at 230 would indicate a low rating on the radiator cap. What kind of coolant are you using?
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post #7 of 16 (permalink) Old Mar 22nd, 07, 1:56 PM Thread Starter
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Re: Need cooling help on Pro Street Big Block

I am running a 21 PSI Moroso cap on the Be Cool Radiator. I am using the Prestone Green coolant and one bottle of Purple Ice in the system.

496 C.I. 4-bolt main
TH400 with Coan Converter
Dyers 8-71 Supercharger
Backhalved and Tubbed
4050 lbs with driver
9.66 sec in 1/4 mile
1.33 sixty foot
139 mph
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post #8 of 16 (permalink) Old Mar 22nd, 07, 6:38 PM
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Re: Need cooling help on Pro Street Big Block

Quote:
Originally Posted by Chas67 View Post
Thanks for the thoughts Don. I have two 1200 CFM fans without a shroud that takes up most of the face of the radiator. I just ordered a dual set up that has a buit in shroud and flows 2800 cfm. I will be installing that this weekend. I will also try a 180 degree thermostat at the same time and see how this Sunday pans out.

How difficult would it be to cycle the water pump and fans after engine shut down? Is there a Kit or something available commercially?
Sounds like you bought a Spal twin 11 inch fan set up ... the thermal switch
is set to kick the fans on at 195 degress and off at 175 .. this is a open closed ground switch thus.. run another wire from the top of the sensor to a toggle switch under the dash to ground the relays this way ....any time you want to run the fans you can .. along with tripping the electric water pump and run in combo while the motor is off ... a strip track trick to cool things down between runs .
Another tip .. mix your coolant 70 % distilled water 30% anti freeze
while im at it ...presure cap ratings ...each lbs of cap pressure increases puke point 6 degrees 10 bls = 60 added degrees = puke point 271 degrees ... high cap presures do nothing to keep motors cool
a efficient rad ... good flow ...and high cfm will cool alot of HP's
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post #9 of 16 (permalink) Old Mar 23rd, 07, 5:06 PM Thread Starter
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Re: Need cooling help on Pro Street Big Block

I bout the adjustable temp switch for the Be Cool Set up as well. I trust that I will be able to report success after this weekend!

496 C.I. 4-bolt main
TH400 with Coan Converter
Dyers 8-71 Supercharger
Backhalved and Tubbed
4050 lbs with driver
9.66 sec in 1/4 mile
1.33 sixty foot
139 mph
Chas67 is offline  
post #10 of 16 (permalink) Old Mar 23rd, 07, 5:58 PM
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Re: Need cooling help on Pro Street Big Block

Quote:
Originally Posted by ALUMITECH REPRODUCTIONS View Post
while im at it ...presure cap ratings ...each lbs of cap pressure increases puke point 6 degrees 10 bls = 60 added degrees = puke point 271 degrees ... high cap presures do nothing to keep motors cool
a efficient rad ... good flow ...and high cfm will cool alot of HP's
You can't keep it cool if you can't keep the coolant in the system. If you increase the boiling point, you increase the ability of the system to absorb heat at higher temperatures. Once the coolant boils, it won't absorb more heat.

I was under the impression that the boiling point was raised about 3/lb, so a 10# cap would raise the boiling point to about 242. If the pressure cap is on the high pressure side of the radiator, it could be even less.
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post #11 of 16 (permalink) Old Mar 30th, 07, 12:54 PM
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Re: Need cooling help on Pro Street Big Block

I was under the impression that the boiling point was raised about 3/lb, so a 10# cap would raise the boiling point to about 242. If the pressure cap is on the high pressure side of the radiator, it could be even less.

You would be correct
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post #12 of 16 (permalink) Old Apr 1st, 07, 12:51 PM
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Re: Need cooling help on Pro Street Big Block

chas, don is giving some good advise. I have a 402 BB dyers setup ,be cool rad ,stock waterpump , when i added the dual spal fans = end of overheatng whoas . if i turn my fans on and leave them on i can run at 160 all day long. let us know what happens lets see some pictures of your car. Dave
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post #13 of 16 (permalink) Old Apr 1st, 07, 9:50 PM
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Re: Need cooling help on Pro Street Big Block

I see a second issue here -

If you're running that hot while cruising, that means you're running that hot with airflow through the radiator. So the new fans will help while stopped or slow, you still have a problem when cruising at speed.

I'd take a look instead/in addition at your electric waterpump, it may not be up to the task. Are you getting full voltage at the pump while the fans are also on?

Mark

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post #14 of 16 (permalink) Old Apr 2nd, 07, 10:32 AM Thread Starter
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Re: Need cooling help on Pro Street Big Block

Update to all.

While the Spal fans fit the radiator, they will not clear the belt of the blower! I would have to move the radiator back at least 2.5 inches. I have already recessed it to clear the long blower drive and do not have any more room options. I did install the 180 degree thermostat in place of the 160. But all is not lost.

I will be building a custom aluminum shroud for the two fans that I have (Permacool flat hi-perf 12 inchers). Also, I will install a Spal adjustable temp switch so that the fans will come on at a set point and run until the temp reaches another established point. I will also wire the water pump to continue to run with the fans. I will also add a manual override option to keep them on longer if needed. My hope is that the lost radiator area formerlly not shrouded, along with cycling the cooling system, will give me lower temps.

You can see some pics at

http://members11.clubphoto.com/charl.../guest-1.phtml

I will be updating them later.

496 C.I. 4-bolt main
TH400 with Coan Converter
Dyers 8-71 Supercharger
Backhalved and Tubbed
4050 lbs with driver
9.66 sec in 1/4 mile
1.33 sixty foot
139 mph

Last edited by Chas67; Apr 2nd, 07 at 11:26 AM.
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post #15 of 16 (permalink) Old Apr 2nd, 07, 12:04 PM
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Re: Need cooling help on Pro Street Big Block

i have in the past run diff size restrictors in place of the thermostat, sometimes you have to hit that fine line of keeping water in the rad. long enough to cool as opposed to keeping it too long in the block.
usually with a 3" belt, it kills room for a fan, which i think is some of the overheating problem versus the blower causing it
then i have seen the fans wired wrong, blowing in rev dir
good luck with it, one of the hardest things to fix is overheating problems

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