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Discussion Starter · #1 ·
OK I know that the 4bt runs cool. But how cool? I will be using it in my
'48 CJ3A (GVW approx 2200), slow speed offorading, max highway speed of 65mph, 35" tires, 4spd T-19 tranny.

The stock radiator needs to go for clearance issues (too thick). There are really no performance (i.e. thinner) replacement radiators available, and I DO NOT want to pay for a custom job.

So junkyard, here I come! On initial investigation, it appears as if a Honda Civic/del sol (1992-2000) radiator may be the right size, and as a bonus, the inlet/outlets are in the approx. correct locations. bounce

So the hundred dollar question: is this enough cooling, or am I getting myself into trouble?

BTW, I am not sure of the thermostat rating (suggestions?), and I will be running electric fan(s), and possibly a Volvo intercooler.

Also, I just wanna wish everyone here a very blessed, prosperouse, happy, and smokey new year!
 

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I don't think the Volvo intercooler will work for you. From the research I've done it will not stand the higher pres. that we all run the 4bts at. They are made for 12 to about 16 lb boost and much less vibration. The plastic tanks on the side are what will give out on you.
 

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On my Power Wagon/M37 Conversions, I use the stock radiator that handled a 230 cu in flat head 6 Gas'er. I dont know the specs but that work great with 4BTA's. I have them recored, a pressure neck added and change the in/out to match the hose size on the 4BTA's. I use an electric fan which hardly ever runs.

Paul
 

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My 4BT is in a '67 Dodge fullsize truck and uses the stock V8 radiator. It's far more than enough. Never needed the fan once, and I live in the high desert and most of my driving is in the mountains, running it pretty hard, in temps to about 110*.

I know a lot of Jeeps were converted to Chevy smallblocks. Wahtever radiator is used for that should be fine for a 4BT as they simply run cool, as most diesels do.
 

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Discussion Starter · #6 ·
Sounds great! Thanks for all of the replys!
 

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I used a radiator from a '70's dodge pickup with a 225 six cylinder in my scout. It is pretty small in dimensions and has both inlet and outlet on the passenger side to match the 4bt.
 

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Get a Del Sol VTEC rad, it's double core and should keep things cool.
 

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A rad from a 4.0 ranger is pretty small.....But works well.
It is what I used when I did the 5.0 transplant into my '93.
It'll keep the truck cool while pulling a 5000 lb Lincoln Mk VIII on the car trailer
at 80 MPH in the summer!
 

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I realize this is a very old thread now but I wanted to see if anyone has any more recent feedback on the radiator issue. I am putting a 4BT in a Jeep TJ and would like to use a smaller radiator to allow room for intercooler piping. I am thinking about the Honda Civic radiator with an electric fan and the intercooler in front. Any experience or feedback on that setup? Thanks.
 

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Give it a try, can't hurt.

Still no fan on my 4BT and has never overheated.

I hardly ever run the fans on the 5.0 Ranger.
 

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I don't think the Volvo intercooler will work for you. From the research I've done it will not stand the higher pres. that we all run the 4bts at. They are made for 12 to about 16 lb boost and much less vibration. The plastic tanks on the side are what will give out on you.
I´ve run a volvo intercooler with my 4BT for 4 years, seeing 25+PSI all the time. No problems yet.

Isuzu NPR intercoolers are externally almost identical dimensionwise and are all aluminum...


You will be surprised how little radiator a 4BT needs... But CT is not as hot as NM.
 

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I seem to remember back in the day we put mustang 65-66 radiators in jeep v8 swaps. In my own swap I just used the stock wrangler radiator and have never had a problem. I was concerned about cooling and bought a fancy electric fan that never even comes on.
 

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I'm looking into swaping a 4bt into my '78 Bronco. It's a Trailer Special with one of the largest radiators Ford made then. I know this is overkill, but it won't over cool will it?
 

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As long as your thermostat does its job then it shouldn't. But the 4bts run very cool anyway so its possible.

Sent from my Droid using Tapatalk 2
 

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I never understood how, with a functioning thermostat, a radiator could be "too big". Maybe too much cold airflow around an engine that barely stays warm with a thermostat that barely opens?
 

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It seems to me that a better design for a coolant system would be for the hot coolant be split. One leg going to the radiator for cooling, and a second leg that is routed back to the cool coolant side of the engine where, instead of a "thermostat", a mixer valve is placed, to mix the recirculated hot coolant with the cooled coolant such that the correct temperature fluid is returned to the engine. I had a 94 buick and here's how it worked: the engine would finally heat up, the thermostat would open and dump hot coolant to the radiator while the cold coolant was flushed into the other side of the engine. In the winter, when that cold coolant finally made its way back to the thermostat, the thermostat would slam shut and engine temp would go off scale to the cold side. Then the cycle would repeat itself. Imagine living up north and the coolant is 0 degrees. The block goes from 180 to 0 in seconds! That can't be good. These days, it shouldn't be that hard to design a mixer valve that's cheap enough. I understand that in some engines there is already have a recirculate path within the block...
 

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Most thermostats have a bypass to bleed air when its closed. If you have enough core area the bypass flow rejects quite a large portion of heat. Couple that with the hysterisis of the thermostat... leads to a engine that is running too cold,"over cooled".
 

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It seems to me that a better design for a coolant system would be for the hot coolant be split. One leg going to the radiator for cooling, and a second leg that is routed back to the cool coolant side of the engine where, instead of a "thermostat", a mixer valve is placed, to mix the recirculated hot coolant with the cooled coolant such that the correct temperature fluid is returned to the engine. I had a 94 buick and here's how it worked: the engine would finally heat up, the thermostat would open and dump hot coolant to the radiator while the cold coolant was flushed into the other side of the engine. In the winter, when that cold coolant finally made its way back to the thermostat, the thermostat would slam shut and engine temp would go off scale to the cold side. Then the cycle would repeat itself. Imagine living up north and the coolant is 0 degrees. The block goes from 180 to 0 in seconds! That can't be good. These days, it shouldn't be that hard to design a mixer valve that's cheap enough. I understand that in some engines there is already have a recirculate path within the block...
It takes quite a bit of time for cold coolant to cool down a hot engine. Even in frigid connecticut, the jumps in temperature you mention don't happen. But yes, not an ideal system.
 
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