Cooling help needed??

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1967formulaS

1967formulaS

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Ok guys, so I have this overheating issue that is doing my head in.
First I'll go through the facts.
67 fastback barracuda.
440 motorhome engine that I done a quick freshen up on. Swapped the cast crank for a steel one, new rings, bearings, gaskets, etc.
383 early closed chamber heads, Victor 440 intake, 850 holley vac sec, msd6al ignition, hooker fenderwell headers.
Champion 4 core radiator with hiflow 160 Thermostat, shroud and twin Thermos. I've also made ducting behind the grille to direct the air, the fans pull hard and hold a rag on the rad when turned on.
Symptoms :
Start the car (fans off) it takes about 10 mins to get to 170F degrees. from there it will keep climbing to 212 at which point I put the fans on. I can cruise around with the fans on for a while (30 mins)
and then it climbs again to 230 degrees. At this point it's time to go home. :( :(
I've flushed the block, and radiator, the water pump is new, experimented with different thermostats, tried different timing and carb settings and spark plug gaps, I've got very good engine coolant in it, new 1.3 radiator cap, I've tried different engine oil grades,my oil pressure is good and I'm not loosing coolant.
I took some readings with my pyrometer and the radiator top tank reads 230 and the bottom tank is 176, so I know the fans are doing the job. Block at various spots is at 240 and heads at various spots are at 245.

I'm outta ideas except one.

My temp readings at the exhaust port where it bolts to the headers range from 700 to 800 deg F.


Is it possible the 383 closed chamber heads are the problem? I do have the open chamber 440 heads here.

Any ideas?
 
Try a different radiator.I had a cc375 champion and it sucked. Chased overheating on a new build for 6 months. Installed a griffin muscle car radiator and problem solved.
 
Sounds like the radiator is working. Bottom hose collapsing on itself? Driving at what speeds when temp climbs? Does it warm up sitting in traffic? Hood to radiator and cowl to hood seals installed? Has the system been burped of air? What are the timing specs? What water pump housing, some of the Mopar performance aluminum knock offs were known to be restricted internally. Just pulling more information.
 
What's with that ghey trendy 160 thermostat?

Engines always run better with 195. We all know this.

As mentioned before the radiator could be suspect.

Take the hood off like them boys on /Roadkill and see if it makes the Chevy difference.
 
Dubob said:
Sounds like the radiator is working. Bottom hose collapsing on itself? Driving at what speeds when temp climbs? Does it warm up sitting in traffic? Hood to radiator and cowl to hood seals installed? Has the system been burped of air? What are the timing specs? What water pump housing, some of the Mopar performance aluminum knock offs were known to be restricted internally. Just pulling more information.
Click to expand...

I disagree because temp steadily climbs and he never mentions it dropping. Exactly what mine did. Steadily crept till it was too hot.I tried different t stats no stat and hoses even tried timing to no avail.
 
daredevil, good info to know, I've got the same cc375 but not on the road. Was just trying to pull some more info and figured the 60 degree drop across radiator was good. Thanks.
 
Actually it looks like the rad and the fans are not doing a good enough job; 176 at the bottom of the tank with a 160 t'stat is not low enough. Either the overall flow is too low (pump or rad width or t'stat not opening right) or the fans or rad are not transferring enough heat it; the gradual heat build up most likely says that. I suspect the fans are not drawing enough since the temps does not go down when you turn them on; it sounds like the fan just slows the rate of climb. The 10 minutes from cold to 170 (10 degrees above t'stat temp) seems like a pretty reasonable warmup time.

How wide is the radiator?
What fan(s) do you have, and can you provide a pix of the shroud?
Is the system being properly cleansed of air when you fill it?

I would only suspect heads or block or gaskets if they leaked/had cracks. That can be checked by running a pressure test on the coolant system, and watching for pressure pulsations on the gauge as it heats up. The closed chambers I assume will give you higher compression ratio, which will cause more heat overall.

BTW, what are your temps down there now?
 
I suspect the electric fans are inadequate. I dont like aluminum Radiators. JMO
 
It's pretty hot down here over summer around 100 most days. The 190 is not suitable down here in summer and 160 is the norm for big block mopars down here. I had a normal 190 in it, with no improvement, so went with a hiflow 160 one with slight improvement.
Hoses are working fine, heats up at cruising speeds around 40-50 mph, heats up alot quicker when I'm having some fun :)
Timing was set at 12 deg, now at 18deg but no improvement.
Burped all the air out which is easy as I don't run a heater.
I've got an alloy water pump on it but will try the original one and see if it helps, if all else fails I'll try a new radiator. If it is the radiator, I will be disappointed. Why make a big alloy rad that doesn't work?
I don't have the hood seals in, but in saying that I have massive holes where my fenderwell headers go, so I'm not sure if the seals would ever work now.
 
That fan shroud is way too close to the radiator. You're asking the air during free flow to make an extremely abrupt turn once it passes through the rad. I'm betting you're getting "stacking" and no air is flowing.

I'm not sure what fans those are, but a lot of the aftermarket ones are crap. I use a V6 Ford Contour fan on a 26" radiator and it's great with a 470hp 340. It looks like you have a 22" radiator through.
 
1967formulaS said:
It's pretty hot down here over summer around 100 most days. The 190 is not suitable down here in summer and 160 is the norm for big block mopars down here. I had a normal 190 in it, with no improvement, so went with a hiflow 160 one with slight improvement.
Hoses are working fine, heats up at cruising speeds around 40-50 mph, heats up alot quicker when I'm having some fun :)
Timing was set at 12 deg, now at 18deg but no improvement.
Burped all the air out which is easy as I don't run a heater.
I've got an alloy water pump on it but will try the original one and see if it helps, if all else fails I'll try a new radiator. If it is the radiator, I will be disappointed. Why make a big alloy rad that doesn't work?
I don't have the hood seals in, but in saying that I have massive holes where my fenderwell headers go, so I'm not sure if the seals would ever work now.
Click to expand...

The lower temp tstat does not allow the radiator to work efficiently. The coolant needs some time in the radiator to cool. I am not saying that is the only issue but a 160 is not going to work for you. I suggest a high flow 180-85, seal the hood as well. My car in Florida used to get to 220 in traffic but always dropped when moving. That was with a thin flex fan and 1 pusher electric. I think that is fairly normal for a BB A-Body. It never boiled over. I run a 033 from glenray now with a stock factory correct monster fan and it runs cooler than it ever has. Its not quite as hot here in North Georgia but plenty hot enough in summer.
 
Good point about the stacking. The problem I have though is space. My fan pully is already very close to the fans.
I'll try a 180 hiflow and see how it goes.
I have a massive 7 blade steel fan, but I'll need to cut the shroud off and remove the elec fans.
Maybe I should do that.
I'll get a pic of it.
 
That fan looks to have been modded. What is the Part#?
 
Stock correct 69 BB fan.
 

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I am just gonna add.........ANOTHER overheating problem involving electric fans.........
 
1). You have a LOT of radiator space blocked off from incoming air.

2). Throw the stupid 160* thermostat in the ditch and use either a 180* or a 195*.

A Thermostat has ZERO ZERO ZERO ZERO to do with maximum operating temperature. ZERO. It only controls the minimum operating temperature. PERIOD.

3). What's the specs on those fans? You need about 4K CFM of air flow give or take for a warmed up or hot engine.

4). Get your timing sorted out. Didn't you say in your other thread that your timing is at 12* BTDC? That sounds a little low and low initial timing can and WILL cause one to overheat.

5). There have been enough threads on here about bad luck with Champion radiators, that I will never, ever buy one. Were they the last radiator on earth, I would walk.

6). Does it ever cool off? When it comes to a stop? When it goes down the road? Over heating going down the road is generally water flow, while over heating at low speeds or a stop is air flow.

This isn't rocket science. It's not hard to figure out. You have so many things wrong or fighting against you, I am actually surprised you are getting around the block.
 
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