Wondering what you guys are running to keep them big block A-bodies cool.

The car in a 1971 Dodge Demon. It hasn't been driven much in the last 5 years but it always ran hot. I couldn't keep it under 210.It has a mild 383 built years ago but always ran hot. It has a cast passengers side drop water pump housing, 26" E-body radiator and a belt driven flex fan.

Now that I have an itch to drive it every day I want to get it right. I have since moved south to Texas where I'm going to need all the cooling I can get with hot ambient temps.

Doing some research I noticed there were two different water pump housings. We had to run the passengers side drop to get a timing mark tab. That is my first idea if the coolant is even flowing correctly. My lower hose feeds the bottom tank and upper to the t-stat neck. I still have heater core connected but not against removing if it helps with cooling.

Another "if" I have is we never opened the radiator core up for the 26" e-body radiator. I did have it steam cleaned twice with no change.

I know this thing can and should run cooler. timing had no effect and honestly cant nor think the carbs we ran did anything for the issue. T-stat is a 180 also.

I'm prepared to upgrade to aluminum radiator and electric fan but hate to have same results and it just being a issue with flow. I've tried several different gauges too.

If you have any input on the matter I appreciate it. Also what setup you're running to keep it under 200.

Flex fans are usually a bad idea. For a street car the trick is to copy what the factory did on the cars with max cooling.

Big radiator, shroud, big clutch fan, over drive water pump, 8 vane water pump, etc.

Flip thru a master parts book sometime and look at the cooling parts used for taxi, cop cars and station wagons. That will show you what you need to do.

What Andy said...


And, a good 4 core copper/brass with a proper shroud and fan clutch setup should cool it well. No need to disconnect your heater either.

Not having the core support opened up to the size of the radiator is a bit of a waste though, should take advantage of the radiator size I would say.

Electric fans are nice in cases, but you need a charging system upgraded to go with it. And a good fan clutch and shroud package on a large radiator should work great anyways..

That's what I did. If you look through my build, the part numbers are listed somewhere. IIRC I used a Polara rad, Roadrunner fan shroud and a Jag fan clutch.
I hope this helps. I haven't finnished the build to see if it works.
Copper

More info needed: that eng always ran hot in that car or in the car it came out of also. any idea if the rad is partly plugged. not usually critical is pulley ratio/# of vanes but post what you have. shroud or no shroud. fan distance from rad. fan type (did you say flex which ain't good). #1 #1 does it run hot stoplight to stoplight or out on the highway (or both). I'm assuming mixture is OK (no vac leaks) & hopefully no combustion leaks and you said timing is OK. stat opening all the way. pump nipple side does not matter. Holler when you can

Thanks for the replies everyone.

Car ran hot all the time. No vacuum leaks. Again its been a while since we messed with it really trying to get a good direction to go. I have a shroud and fan is spaced up close. I had radiator flushed processionally twice. Doesnt mean its not restricted but it came out of a running e-body. Thats why i was think of replacing it the unknown... Deffinitly going to lose the flex and open the core... as far as pulley size. I remember we had to hunt for a pulley, weather its over or under driven not sure. Ill measure them later.

Get a laser heat gun, aim at the bottom, middle and top of rad. Check hoses waterpump, just about everywhere water flows. Bottom of rad. should be cooler than the other spots. 210 is not bad but should be around 170-90. A buddy has a 65 Hemi(472 iron) with no shroud,4 blade fan and it never goes over 170, sounds like you have some issues in the engine, maybe cam retarded a lot, not a clean combustion, timing off, what do the plugs look like?
One thing I foggot to add, the engine will not run cooler than what the temp. is at bottom of rad. So if your rad says 190 at the bottom, it is circulating to fast or stopped up.

You might also want to check the waterpump vanes to back of waterpumphousing distance.
Ideally you want the vanes to 'just' touch the housing if mocked up without a gasket in place.
Also, more vanes means more water pumping action.

Quote:

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I had radiator flushed processionally twice. Doesnt mean its not restricted but it came out of a running e-body.

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I have never had good results with flushes or ultrasonic cleanings. I prefer to have the radiator's core rodded out that way you know each tube will flow. So start with a good radiator and follow what the others have said.

The factory big block A-Body's had a 22" 3-core radiator with the drivers side lower hose and worked just fine. No reason to use a 26" radiator, cutting the core support will just make it ugly when you can just use the right parts to begin with.

Great input guys! I got some things to do on my end but have a better idea what to look for. Thanks!

Normally the WP housing does not seem to matter too much as long as it bolts up and the WP clearance is close. I don't "think" shrouding of the original 22" opening and 26" radiator is a big issue either.

The condition of the radiator matters, shroud and good fan matters and drive ratio/WP type matters. An original spec 3 or 4 core radiator can be good as can a 2"+ thick aluminum radiator.

Is it hot while rolling down the road? Hot a idle/slow speed? or both? Hot rolling usually means the radiator is not effective or water flow/water pump is not enough. Hot only at idle/low speed usually means fan/airflow is not adequate.

This will either fix it or give us the info to help you fix it.

https://board.moparts.org/ubbthreads/ubbt...re-posting.html

Great info, thanks! I going to go ahead and get a new pump and radiator. Was looking at the 440 source housing but find nothing but bad news on them, have they fixed this issue yet? Would really like to take as much weight as possible off the front end.

Yes, stay away from the 440 source aluminum housing as it has a much smaller opening than the early style housings. My buddy John bought showed me the difference last year, you can't even put a finger in the opening while the early housings you can put a couple fingers in there!

X2 on a laser gun. reportedly HF has one for cheap which works well for what it is. This'll tell you if the rad is the prob WO having to mess with it. flushing can sometimes not be enough and rodding is good but can weaken the tubes in a rad that is already weakened & make it leak on down the line & alot depends on the skill of the guy at the rad shop. If you have an emissions testing station they can stick the probe into the airspace above the coolant level & tell you in seconds if it shows hydrocarbons (combustion leak) while running & a rad shop can pump it up to 15 lbs & see if it holds psi & best is to borrow a gauge & let it set overnight (do it when it is hot). A car down south may have been run WO antifreeze & may have extensive rust inside & pulling a core plug & visual & blasting it with the car wash wand might help with that. You said it runs hot all the time right? even out on the highway?. Holler back with any news. What Rhino said I would not butcher the car by opening up the supports on the side.

We switched vendors and stopped selling those housings several years ago.

Get the laser temp gun.

Get real world temperatures from the different parts of the system as suggested above.

Report back with numbers.

That is the proper way to diagnose the issue.

Without actual numbers the only thing ANYONE can do is guess. Some guesses will be right. Some will be wrong. You are nearly guaranteed to waste time chasing your tail.

http://www.amazon.com/Etekcity-Lasergrip-Temperature-Non-contact-Thermometer/dp/B00837ZGRY

Aside from a HF one, these are cheap too..and not much more than the price of buying lunch.

Good to know!