440 6-pack overheating

[am3rican]

Hi all,

I have 68 roadrunner with a transplanted 440 6-pack. I've been struggling with overheating issues since i've purchased it this year. It's never actually overheated but comes close to it when idling or stuck in traffic. I have an after market B&M temp gauge that ticks up from 180 deg to 210 deg in traffic, before I shut it down. Tons of top end heat. When cruising, temp is just fine and is usually between 180-190 deg.

I'm working on a limited budget (baby coming this fall) so I'm trying to slowly replace parts until I find the magic bullet. I'm thinking I should just replace the single fan with a dual fan/shroud setup. I'm just not sure of CFM given I also have a 7 blade clutch fan. The northern brand dual fan setup is only 1600 cfm. Should I delete the clutch fan and go with a high CFM puller fan? I can't do both puller and clutch fan because of clearance issues.

What I've tried: Milodon high flow water pump, Milodon 180 high flow thermostat, new lower radiator hose with spring, coolant flush. System burped. Pretty sure no air pockets.

Here are some details on the car. Sorry about all the info but I like knowing all the variables when diagnosing:
-440 six pack bored 40 over. 4500 miles since rebuild.
-2 core 28" Northern Radiator (with 22" core)(replaced in 06) w/ new 16 lb cap. Never tested.
- single 14 inch be cool pusher electric fan. Not sure CFM. Mounted directly in front of Tranny cooler.
-7 blade clutch fan. No fan shroud.
-milodon high flow water pump with hi flow 180 thermo
-I have a vacuum gauge. Vacuum is good.
-I have headers (not ceramic coated). These generate A LOT of heat. I'd like to avoid replacing these.
-No coolant recovery tank.
-Not sure on timing, but def not running lean. If anything, runs little rich. I'm replacing carb base plate / throttle body gaskets next week. Center one is leaking. Carbs were last rebuilt when motor was rebuilt. Mechanic says they dont need to be re-jetted.

 

[HEMI-ITIS]

Where's your timing at??

 

[am3rican]

Not sure what it is now. was going to check it when the carb gaskets are replaced. I'm having my mechanic do the work. I don't have the know-how to time it properly. It has a mild cam.

What should the timing be?

 

[Dennis H]

Shroud and clutch fan needed. Green coolant. Ceramic headers run 100 degrees cooler. Brief 210 readings in traffic is not out of control. Get a laser temperature gun to be sure.

 

[am3rican]

Shroud and clutch fan needed. Green coolant. Ceramic headers run 100 degrees cooler. Brief 210 readings in traffic is not out of control. Get a laser temperature gun to be sure.

Without knowing the brand of the clutch fan, can I buy any shroud as long as it's the same length?

 

[HEMI-ITIS]

Start with 34 total and see how it runs and how the temp goes.What are you using for distributor and timing curve?

 

[am3rican]

Start with 34 total and see how it runs and how the temp goes.What are you using for distributor and timing curve?

Thanks for the tip. I'll be honest. I'm not sure if the distributor advanced or been dialed back. It runs and idles well so I didn't want to mess with the timing.

 

[bm02tj]

you answered your own question no fan Shroud will over heat when you are not driving at speed
so add that then look in to more if needed

 

[am3rican]

Just realized my radiator is 28 inches but it's a 22" core. 2 row, not 3 row but single pass with 1" tubes (Northern Part 209614). Now i'm wondering if it's undersized for the application.

The engine fan shroud for my radiator is $85. If this isnt enough, I can get an electric dual fan setup for $350 with the wiring harness. But, this will be all for nothing if my radiator is undersized for the application. I will have to repurchase the engine fan and electric fan setup if I upsize the radiator for a larger core.

This is my dilemma now.

 

[terzmo]

My timing is 35 advanced at 2500 rpm. I've had almost every 440 with heat issues in traffic and the only solution I have used is 7 blade steel fan with or without clutch..fan installed properly in a shroud(half in/half out,blades) and a 2 or 3 row aluminum radiator. The crossflows are ugly to me but they cool even better than a verticle. I also run a 160 stat to get the entire cooling system working properly and on hot muggy days in traffic, I "might" hit 190. Champion makes a great direct fit at a great price. All I use.

 

[WileE]

All else assumed acceptable as you say, I'd say your radiator is the culprit. I've encountered this myself & others many times. you need either a 4-row 0r a 3-row aluminum. With a clutch fan & shroud, a properly sized radiator should have no problem without using add-on fans, which I never had to use. Do not use more that 50-50 water/coolant, even less preferable.

 

[am3rican]

All else assumed acceptable as you say, I'd say your radiator is the culprit. I've encountered this myself & others many times. you need either a 4-row 0r a 3-row aluminum. With a clutch fan & shroud, a properly sized radiator should have no problem without using add-on fans, which I never had to use. Do not use more that 50-50 water/coolant, even less preferable.

Thanks. I'm going with the champion 3 or 4 row 26'' radiator. I'll most likely get the dual electric fans too. Do you run this setup? Any issues with depth?

 

[coloradodave]

Another opinion: Before you pull the trigger on that new set-up you might want to remove your current electric fan set-up to open up the area directly in front of the radiator. Then pick-up a fan shroud that fits your car. The brand of clutch fan doesn't matter. What does matter is the diameter of the fan and placement front to rear, as someone already said. Give that a try first. Maybe you'll save some money. Please remember that these cars ran and cooled fine before anyone used an electric fan. 180-190* running temperature is fine. Occassional rises to 210-220* won't hurt your motor. A properly pressurized cooling system with 50/50 mix won't boil until 265*. If it's not puking water out in traffic, I think the above will fix your 'problem'. BTW, what is the opening dimension of your radiator core support, 22" or 26"? Generally, if the radiator cools OK going down the road, but not in traffic, the fan air movement is the thing to concentrate on.

 

[am3rican]

Another opinion: Before you pull the trigger on that new set-up you might want to remove your current electric fan set-up to open up the area directly in front of the radiator. Then pick-up a fan shroud that fits your car. The brand of clutch fan doesn't matter. What does matter is the diameter of the fan and placement front to rear, as someone already said. Give that a try first. Maybe you'll save some money. Please remember that these cars ran and cooled fine before anyone used an electric fan. 180-190* running temperature is fine. Occassional rises to 210-220* won't hurt your motor. A properly pressurized cooling system with 50/50 mix won't boil until 265*. If it's not puking water out in traffic, I think the above will fix your 'problem'. BTW, what is the opening dimension of your radiator core support, 22" or 26"? Generally, if the radiator cools OK going down the road, but not in traffic, the fan air movement is the thing to concentrate on.

Core measures 22". I have to admit it does cool the motor while going down the road just fine. After doing more research i'm not sure I want to abandon this radiator just yet. EVen though it's 2 row, the tubes do measure 1". I'll get the shroud and move the electric fan to allow unobstructed air flow into the engine fan.

I'll take a picture of the engine bay when I get a chance.

 

[brasil]

have the same "problem" ... my 440 runs great on the "Autobahn" ( highway... ) about 185 °F with a 180 thermostat... FlowcoolerPump, 180 highflow thermostat... New aluminum radiator... Fan shroud ... 7 blade Flex a lite... timing @ idle 10 deg btdc all in @ 38 deg ..
normaly everything should be o.k......... until I slow down...like in city traffic "She " goes up to 210 °F
Tomorrow I will recive a 6 Blade 19 inch race fan with steel blades.... hope this one will cure the problem...

Greetings Juergen

 

[62MAX]

have the same "problem" ... my 440 runs great on the "Autobahn" ( highway... ) about 185 °F with a 180 thermostat... FlowcoolerPump, 180 highflow thermostat... New aluminum radiator... Fan shroud ... 7 blade Flex a lite... timing @ idle 10 deg btdc all in @ 38 deg ..
normaly everything should be o.k......... until I slow down...like in city traffic "She " goes up to 210 °F
Tomorrow I will recive a 6 Blade 19 inch race fan with steel blades.... hope this one will cure the problem...

Greetings Juergen

You may be surprised,flex fan's were not made for cooling !!

And as to what Dave posted before this,the 440 in my 62 wagon is .030 over,Isky cam,4 core 22" radiator,6 blade A/c pump,fixed 7 blade fan,shroud,180* thermostat,has never seen anything above 195* ever regardless of ambient temp,will idle as long as I let it and never goes above 185* at the thermostat housing checked with a gun,and it has A/C.My 6pk Superbird is equipped the same other than 26" radiator and it runs the same and this is the only air intake on it ! Sometimes we are our own worst enemy by trying to re engineer things that work !




" AND THERE IS NO ELECTRIC FAN " !!

 

[brasil]

Recieved a 6 Blade 19 " race fan ( solid steel...) today.... crusing around on the country roads... the water temp. does not go higher than
190 F° ... but if I have to stop...( at a stop sign...or red light ) the temp. climbs up.... till 210 °F... That is to much in my opinion...because I use a 180 °F thermostat...

@ 62 MAX .... I know that those flex a lite Fans are only good for racing.... but I did not have another fan when I switched from electrical fans to the "old school FAN "

 

[WileE]

Thanks. I'm going with the champion 3 or 4 row 26'' radiator. I'll most likely get the dual electric fans too. Do you run this setup? Any issues with depth?

In 40 years on my own street cars, I've NEVER used, or had to use, an electric fan.

- - - Updated - - -

You may be surprised,flex fan's were not made for cooling !!

And as to what Dave posted before this,the 440 in my 62 wagon is .030 over,Isky cam,4 core 22" radiator,6 blade A/c pump,fixed 7 blade fan,shroud,180* thermostat,has never seen anything above 195* ever regardless of ambient temp,will idle as long as I let it and never goes above 185* at the thermostat housing checked with a gun,and it has A/C.My 6pk Superbird is equipped the same other than 26" radiator and it runs the same and this is the only air intake on it ! Sometimes we are our own worst enemy by trying to re engineer things that work !




" AND THERE IS NO ELECTRIC FAN " !!

Bingo... what Colorado & max says ! and I've never used flex fans for street cars, either.

 

[am3rican]

In 40 years on my own street cars, I've NEVER used, or had to use, an electric fan.

- - - Updated - - -

Bingo... what Colorado & max says ! and I've never used flex fans for street cars, either.

I have the shroud purchased but will replace the flexalite fan too. Do you know where I can source the fixed blade fan and part number?

 

[brasil]

bought my fixed fan blade at summit... Part No. FLX- 5719 it´s a huge 19 " fan.. with 6 blades

Greetings Juergen