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Radiator shroud advise

Juan Veldez

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I just got a Cold Case aluminum radiator. They say I need to drill holes in the flange if I try and use an OEM shroud (which I need to buy). Cold Case has a dual electric fan/shroud that bolts up. I have the clutch fan and am going back and forth on which I should use. It's a 340 with 10.5 pistons, mild cam, single 4 barrel. I'm not worried about losing a few HP with the clutch fan, but I wonder HOW MUCH better the cooling would be with the two electric fans? Any advise would be appreciated.

20210727_081531.jpg
 

CCKen

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Juan,
What part is the radiator? I may be able to get you a part number for the factory shroud.
 

Juan Veldez

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Juan,
What part is the radiator? I may be able to get you a part number for the factory shroud.
MOP750A. Cold Case said I need P/N 2785435 for the shroud, but I will need to drill holes in their flanges to mount it. The weird thing is, the radiators are listed at 22" or 26" wide, but the actual core is a touch over 24". I assume the 22" wide radiators just have wider flanges to make up for the reduced width of the core, but I do see shrouds for a 22" or a 26". Nothing is easy on my first ground up restoration, geeze. I''l get the 26" shroud and keep my fingers crossed.
 
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70chall440

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The dual fans would probably cool faster and better than an OEM style fan but that doesn't necessarily mean you should do it. Dual fans will draw a lot of power when both are on so you need to have a very solid reliable (and powerful) electrical circuit. The fans will need to be on relays as well so there is more wiring involved (not that is a big deal per se).

I run electric fans in most of my rigs but when it comes to the aftermarket you are running a small risk in that they can burn up, relays go out, etc. which obviously you will not have with a standard fan/shroud arrangement. Not saying you shouldn't use the electric, just saying that it is not as simple as just doing it.

Personally I would probably try a conventional fan first and see what you get, if it keeps the engine cool then all good, if you are not happy with the cooling then go to the electric (JMHO)
 

Chryco Psycho

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The clutch fan is the better option , any power gained going electric will be lost turning the alt & you Will need a higher output alt + the cooling with the clutch fan & shroud is superior .
 

Juan Veldez

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The dual fans would probably cool faster and better than an OEM style fan but that doesn't necessarily mean you should do it. Dual fans will draw a lot of power when both are on so you need to have a very solid reliable (and powerful) electrical circuit. The fans will need to be on relays as well so there is more wiring involved (not that is a big deal per se).

I run electric fans in most of my rigs but when it comes to the aftermarket you are running a small risk in that they can burn up, relays go out, etc. which obviously you will not have with a standard fan/shroud arrangement. Not saying you shouldn't use the electric, just saying that it is not as simple as just doing it.

Personally I would probably try a conventional fan first and see what you get, if it keeps the engine cool then all good, if you are not happy with the cooling then go to the electric (JMHO)
That's my thought too. I'll buy an alternator that puts out a little more than stock just in case I switch down the road (literally and figuratively). Thanks for your input.
 

Juan Veldez

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The clutch fan is the better option , any power gained going electric will be lost turning the alt & you Will need a higher output alt + the cooling with the clutch fan & shroud is superior .
Clutch fan & shroud it is. I think the stock alternator pushes 90 or 95, I'll look for a 100-115. The prices, outputs, and styles are too numerous for my limited background. Any recommendations for the alternator?
 

Chryco Psycho

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Stock output is 45-60 amps my friend used a really good alt with higher output , I can get the brand , in my case a local rebuilder upgraded mine for higher output .
 

Chryco Psycho

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You are correct the 22 had side rails to support the shroud , the 26 should work but you may have to add a strip along 1 side to mount it correctly , .
FYI alum rads should be mounted with rubber isolators as they will not tolerate flexing .
 

Juan Veldez

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Stock output is 45-60 amps my friend used a really good alt with higher output , I can get the brand , in my case a local rebuilder upgraded mine for higher output .
And those numbers are misleading. It can be taken at idle or at higher rpm. I see a lot of 60 amp units, so a 95 amp one will do just fine. I see round and square back units listed. Does it matter if I am not too worried about trying to look stock?
 

Juan Veldez

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You are correct the 22 had side rails to support the shroud , the 26 should work but you may have to add a strip along 1 side to mount it correctly , .
FYI alum rads should be mounted with rubber isolators as they will not tolerate flexing .
I'll toss some rubber washers in there. Did not know that. Thanks!
 

Chryco Psycho

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Round or square back makes no difference as long as it has dual field connections .
If you go above 60 AMP the ammeter will not take it & the best advice is to disable the ammeter by connecting both wires to 1 terminal to prevent overheating / fire , the other thing needed is to run a bypass wire from the main terminal on the start relay to the alt output terminal using 10 Ga wire & a fusable link so the power doesn't even go through the firewall & other interior circuits .
 

CCKen

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MOP750A. Cold Case said I need P/N 2785435 for the shroud, but I will need to drill holes in their flanges to mount it. The weird thing is, the radiators are listed at 22" or 26" wide, but the actual core is a touch over 24". I assume the 22" wide radiators just have wider flanges to make up for the reduced width of the core, but I do see shrouds for a 22" or a 26". Nothing is easy on my first ground up restoration, geeze. I''l get the 26" shroud and keep my fingers crossed.
Yes the factory shroud is P/N 2785435. It is considered a 26" radiator by Chrysler. They go by the outside measurement.
 
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