Over heating 66 Dart

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66 fish

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I have a 1966 Dart GT with a 273 4bbl engine. The engine has been refreshed with new rings, bearing and gaskets. Original pistons were used since there was very little wear in the cylinders. I did change the cam from original to a Comp Cam XE262. The engine has the LD4B intake and a Competition Series Carter 625CFM carb. I put on a new water pump, hoses and a new aluminum 2 row radiator. The radiator is from ebay and it is one that looks just like the original in appearance. I don't know how good it is, but it fit with no modifications. New thermostat 180 degree. I have a five blade direct drive fan. It was an original fan from a 1970 Dodge Dart with a 318. The engine cools fine going down the road but when I sit in traffic for more than about 5 minutes the temp gauge begins to climb. It does not jump up fast, but gradually will begin to climb. Oh, I do not have a fan shroud. The car did not originally come with one, so I figured that it would not need one. The engine is not a super high performance engine. It is not that much stronger than stock. Oh, one more thing. I used 302 cast heads to have hardened seats. Heads are stock, but the ports were gasket matched. the intake was also gasket matched. That is all the work done to the heads. They were of course rebuilt with new valves, springs (Comp Cam), and valve guides and seals. The fan is about an inch and a half from the radiator. If anyone can give me any advice I would appreciate it. Thank's.
 
Theyre expensive if you can find a factory early a body one, but you absolutely need a fan shroud.

Jake
 
the cheapest solution is a Shroud + a bigger 6 blade fan to move more air while sitting. Make sure the shroud is sealed around the entire perimeter and the fan should be approximately half in half out of the shroud.
That should help a lot.
 
Factory AC/HD Cooling optioned 65/66 V8’s used a 17 in 7 blade fan with a shroud. As noted shrouds are hard to find and generally expensive when you do, Slants used a 6 blade 16 inch fan and their own unique shroud.

An 18 inch 7 blade fan should fit without a shroud which would certainly help.
 
Don't need a shroud, Buy a flex fan and up it closer to the radiator, they sell the fan at oriellys 18inch or 20inch should do it. NEVER HAD A COOLING ISSUE EVER AGAIN IN ALL MY MOPARS
 
Theres no point in trying to get a shroud if if doesnt have the original radiator. Waste of effort and time.
 
Thank all of you for your replies. I will find another fan. Would one of the aftermarket "fit all" shrouds work? As you can tell I'm not looking for maximum performance. I jus want a car I can drive and enjoy. It is not going to be left in the garage and only taken out if the weather is just right. I want to drive and enjoy it. I like the friskiness of the little 273. It is just a simple fun to drive little car. No A/C, and only stock exhaust manifolds, but I did put dual exhaust. 1'7/8" each pipe. Thanks.
 
How can my 67 dart, 273, stock 7 blade fan, no shroud, blade is about 2 inches from the stock radiator idle all day with out ovetheating.

It must be pully diameters (IIRC are about the same), and fan pitch / diameter.
 
Dana67Dart said:
How can my 67 dart, 273, stock 7 blade fan, no shroud, blade is about 2 inches from the stock radiator idle all day with out ovetheating.

It must be pully diameters (IIRC are about the same), and fan pitch / diameter.
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Colorado. Not the south or southwest. Whats the hottest it gets there, 85?

Jake
 
xLURKxDOGx said:
Not the south or southwest. Whats the hottest it gets there, 85?
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90 but what's 5 deg.....:)
It's a so cal car, has only been in CO for two years, never overheated there either.

I just don't get it, not being sarcastic.
 
Its all in how much air you can pull thru your radiator, This means nice big fan, as close as possible to the radiator. You can have a nice 4 row radiator with the stock fan blade and it will overheat.
 
Not all that different in terms of Average high temp (Although none of this helps 66 Fish)
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@66 fish did it do this before the refresh?

Other than the work above did you change anything else?

Does the temp just climb till boil over or you does it level off, if so at what temp.

How long has the refreshed eng been used since refresh?
 
65 Dartman said:
Factory AC/HD Cooling optioned 65/66 V8’s used a 17 in 7 blade fan with a shroud. As noted shrouds are hard to find and generally expensive when you do, Slants used a 6 blade 16 inch fan and their own unique shroud.

An 18 inch 7 blade fan should fit without a shroud which would certainly help.
Click to expand...

I know plenty of people that run fine without a shroud but I know plenty that don't. He could try without the shroud first and try and save some $$ but if a 17" with a 7 blade fan is available, that's the best option by far.
 
I chased this problem years ago. Not the radiator, it cools fine on the highway. Had a shroud, still overheated at idle. Tried clutch fan, still overheated at idle . Tried a factory flex fan, never overheated. Removed shroud, never overheated. Now I run 3 row cores in original radiators, flex fans, no shroud, never overheats. Yeah I know, overkill. Summer is hot everywhere, lame argument. I have lived from SD to SC and FL. Cooling is the same.
 
The original engine for this car was a 225 slant 6. It never ran hot. The 225 had began to use oil and it needed to be rebuilt. I had another 66 Dart GT with this 273 4bbl engine. That one was wrecked. I took all the V-8 stuff out and put the engine in the current 66. The 273 4bbl in the original body did have some overheating issues when it sat at idle for a long time, but the radiator in that one was leaking and destroyed in the wreck. This car has all the V-8 brackets motor mounts and so forth to put this engine in this car with no aftermarket parts. The only things I have changed from the original 4bbl engine is the 302 heads, new aluminum radiator, and I forgot, I did add electronic ignition. I bought the distributor, coil, and ignition box for a 1984 Dodge D150 318 engine. I got the wiring from an old dodge that found at a salvage yard. It was easy to change from points to electronic ignition. It's weird, my brother has a '65 Dart GT. But it is an all original car with the 273 4bbl and a 4 speed. I tried to pretty much make it the same as his. My car has an automatic where his is manual. Otherwise they are the same and his never gives any overheating issues. The engine only has about 1000 miles on it even though it has been refreshed about 3 years. The temp will rise to a little more than half the gauge while in traffic. But, as soon as I begin moving it will begin to come down. It comes down quickly. After I drive it when I park it will push coolant out the overflow. If I am in traffic for a long period of time, or say in a drive through at a fast food, it will push coolant out the overflow.
 
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66 fish said:
The original engine for this car was a 225 slant 6. It never ran hot. The 225 had began to use oil and it needed to be rebuilt. I had another 66 Dart GT with this 273 4bbl engine. That one was wrecked. I took all the V-8 stuff out and put the engine in the current 66. The 273 4bbl in the original body did have some overheating issues when it sat at idle for a long time, but the radiator in that one was leaking and destroyed in the wreck. This car has all the V-8 brackets motor mounts and so forth to put this engine in this car with no aftermarket parts. The only things I have changed from the original 4bbl engine is the 302 heads, new aluminum radiator, and I forgot, I did add electronic ignition. I bought the distributor, coil, and ignition box for a 1984 Dodge D150 318 engine. I got the wiring from an old dodge that found at a salvage yard. It was easy to change from points to electronic ignition. It's weird, my brother has a '65 Dart GT. But it is an all original car with the 273 4bbl and a 4 speed. I tried to pretty much make it the same as his. My car has an automatic where his is manual. Otherwise they are the same and his never gives any overheating issues. The engine only has about 1000 miles on it even though it has been refreshed about 3 years. The temp will rise to a little more than half the gauge while in traffic. But, as soon as I begin moving it will begin to come down. It comes down quickly. After I drive it when I park it will push coolant out the overflow. If I am in traffic for a long period of time, or say in a drive through at a fast food, it will push coolant out the overflow.
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Was the engine ever boiled out when the engine work was done? Maybe some blockage in the passages possibly?
 
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)
 
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
 
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