Over heating 66 Dart

[66 fish]

My 67 273 would do that after a coolant change. Get up to temp all ok. Turn off engine and you could hear boiling and if the rad was full it would dump a bit of fluid. I found that filling the rad with the upper rad hose off till the fluid came out the upper hose, fixed the problem. I also do not run an overflow so the coolant level in the rad is about 1 to 2 inches below the rad cap (like FSM says)

 

[66 fish]

The way I filled the radiator was to put about a gallon of pure coolant in the engine (cold) and a gallon of water. Then I would start the engine and begin to fill the radiator until it was about an inch above the rows in the radiator. I would keep the engine running until it came up to temperature and fill the radiator with 50/50 mix until it remains at about an inch above the rows then put on the cap. Thanks

 

[toolmanmike]

Was the engine ever boiled out when the engine work was done? Maybe some blockage in the passages possibly?

Yes, the engine was taken to a machine shop and it was put in acid, the deck was cut 5 thousand the heads were cut 5 thousand, the rods checked and the crank was polished. Plus when we got the block home we washed it out with soap and water, used brushed to clean out all the galleys and put in the new freeze plugs. My brother done the assembly of the enging and he is ASE certified master mechanic. But he is retired and lives in Florida, so I don't have his help in person. We talk on the phone, but so far we can't seem to narrow down the issue. Thank's

How hot does the engine get? Does it actually overheat and boil over? Yes it sounds like a fan/shroud issue. The original radiator would have been a 19" radiator and the HP273 radiator would have been a 22" AC radiator. The aluminum radiator you used should cool it fine with a good fan and/or a shroud.

 

[66 fish]

I probably need to change my name on here. I used to have a 66 Barracuda and that is when I used the 66fish name. I no longer have the Barracuda. But I have named my 66 Dart Clyde. So, I can get in my Dart named Clyde and ride!!

 

[66 fish]

How hot does the engine get? Does it actually overheat and boil over? Yes it sounds like a fan/shroud issue. The original radiator would have been a 19" radiator and the HP273 radiator would have been a 22" AC radiator. The aluminum radiator you used should cool it fine with a good fan and/or a shroud.

 

[toolmanmike]

I probably need to change my name on here. I used to have a 66 Barracuda and that is when I used the 66fish name. I no longer have the Barracuda. But I have named my 66 Dart Clyde. So, I can get in my Dart named Clyde and ride!!

66 Dart, same thing when it comes to radiators and cooling.

 

[toolmanmike]

I have overheating issues with my 70 Swinger. Yes it actually blow's coolant out all over the place. It has dealer installed A/C but they used the small 19" radiator. Bob at Glen Ray Radiators is going to build me a 22" so the issues should be gone.

 

[66 fish]

The radiator I now use is a 22" radiator. I can't seem to find my receipt so I don't remember the name of the radiator company I got it from. But it is an all aluminum welded radiator that has the exact appearance of the original radiator. It has the rounded tank on top and if it was painted black, unless you was looking for numbers or something it would look exactly like the original. I got the radiator off ebay. It is a 2 row radiator. My brother's 65 dart has the same set up I do and he has no shroud. But he has the original radiator. Although his is a 4 speed. I don't see how that can have anything to do with the overheating. However, I just remembered his has the dual point distributor, this is an ah ha moment for me. Maybe the timing is not right. We did set the total timing to 40 degrees. I wonder if the electronic ignition is not working with the engine properly? I don't know. I'm not a mechanic, my brother is. I was always the mechanic's helper! I understand how much of the mechanics work, but I am no mechanic!

 

[SSVDP]

The ignition timing could be part of your issues.
Otherwise it sounds like you need more air through the radiator when the car is not moving.
I just sold a seven blade fan from a ‘66 273 and it would be interesting to see if just that would have solved your problems.
And the auto trans cooler does put some additional heat into the cooling system that a manual trans does not.

 

[66 fish]

The ignition timing could be part of your issues.
Otherwise it sounds like you need more air through the radiator when the car is not moving.
I just sold a seven blade fan from a ‘66 273 and it would be interesting to see if just that would have solved your problems.
And the auto trans cooler does put some additional heat into the cooling system that a manual trans does not.

 

[66 fish]

I have installed a 7 blade direct drive fan. The air flow through the radiator is much greater now but the same issue is still occurring. The fan is still about an inch and a half away from the radiator. I will do more looking at the timing. I am just stumped!

 

[66fs]

273 HP auto never runs hot, 1.50 inch between radiator and fan. 300,000 miles

 

[1966DDart]

I have installed a 7 blade direct drive fan. The air flow through the radiator is much greater now but the same issue is still occurring. The fan is still about an inch and a half away from the radiator. I will do more looking at the timing. I am just stumped!

I'd be curious to know more about your timing as it can play a major roll in overheating. You mentioned before that you set it at 40 degrees total. Under a load it should be pinging like crazy. That just doesn't sound right...unless you have the vacuum advance hooked up. Disconnect the vacuum advance (be sure to plug the hose for now), get a timing reading at idle, and then run it up to say 3000rpms (or whenever the timing mark stops moving up) and get another reading. THAT reading is the "total" (base timing at idle + the mechanical advance in the distributor) and should be more in the 32-36 range. For a 273, I'd look more for closer to 32-34.

NOW hook the vacuum advance up and get another reading at idle. You probably measured around 8-14 before...and now, with no load (idle), it will probably read closer to 40+. If the vacuum advance is NOT working (or you have only a mechanical distributor...not overly recommended for street driving), your timing is staying low (say 10). This will cause the fuel to burn later and cause more heat to go into the heads and exhaust (think glowing manifolds in the dark)...thus making your engine harder to cool. With vac adv working, the timing goes higher than "total" and ignites the fuel sooner and burns more completely. So, the vacuum advance works only at idle or no-load cruising to create a efficient burn (think: better mpg) and runs cooler at idle.

 

[stroker402]

I'd be curious to know more about your timing as it can play a major roll in overheating. You mentioned before that you set it at 40 degrees total. Under a load it should be pinging like crazy. That just doesn't sound right...unless you have the vacuum advance hooked up. Disconnect the vacuum advance (be sure to plug the hose for now), get a timing reading at idle, and then run it up to say 3000rpms (or whenever the timing mark stops moving up) and get another reading. THAT reading is the "total" (base timing at idle + the mechanical advance in the distributor) and should be more in the 32-36 range. For a 273, I'd look more for closer to 32-34.

NOW hook the vacuum advance up and get another reading at idle. You probably measured around 8-14 before...and now, with no load (idle), it will probably read closer to 40+. If the vacuum advance is NOT working (or you have only a mechanical distributor...not overly recommended for street driving), your timing is staying low (say 10). This will cause the fuel to burn later and cause more heat to go into the heads and exhaust (think glowing manifolds in the dark)...thus making your engine harder to cool. With vac adv working, the timing goes higher than "total" and ignites the fuel sooner and burns more completely. So, the vacuum advance works only at idle or no-load cruising to create a efficient burn (think: better mpg) and runs cooler at idle.

too small a carb will make it run hot also.