Cooling modifications - what worked for you?

[ShelbyDogg]

There is no reason a stock 360 should be running that hot with that set up.  Something isn't right.

360 huh?    I built a 360 for my 81 van to replace a tired 318 that I used to tow my race car and trailer. I had it bored .030 over and had stock everything else put in it. I had to start just towing at night time because it always ran HOT.  I'm guessing it was a core-shifted block and now had some thin cylinders. After a bad overheating problem when it finally blew a hose trying to go up some Ozark mountains, it never quite ran the same again, so we traded it in when my wife got a new car.

[miketyler]

I'd take a hard look at the tune and engine itself

Its actually a 340 but yes, did that. In fact I just got the car back from having Greg K. look at the engine for a second opinion and he found a few little things but nothing noteworthy. I too believed the problem was fundamental and once identifed, would be like flipping a switch and the car would probably run too cool. Unfortunately this has not been the case.

Worth mentioning though my hood sits up on the drivers side and probably leaks engine compartment air there. That would only help me though I would think.

I bought the SPAL pusher for it a year or two ago. Putting it on will move the fan closer to the core will see if that improves things.   



 
 

[quagmire]

It'd be hard to identify most any engine concerns like wall thickness or clearance problems without tearing it down or doing some surgery unfortunately.  If the electric fan helps, it is still only a crutch at best.  That engine shouldnt have a problem staying cool with your setup.  Does it get hot while cruising or only at idle?  If it is doing it over 30MPH, a fan won't help.  In fact, you don't need a fan at those speeds since the airflow from moving is more than the fan output.

[miketyler]

I agree. Cruising, it is pretty steady at 210, sitting idling at a light temps will increase to 230.   

I had always heard that about fans at speed. I had an opportunity to test that theory early on when I was running dual electric fans. I found that on my car, the engine did run slightly cooler with the fans running then without. This was tested on the same day on an extended run at 45 mph. Granted, they may not be doing much but they did add some additional cooling to my car.

I no longer run those dual electrics and found that the direct drive fan works the best. I'm not ready to tear this thing down yet.  If I had blockage or build up, should I able able to record these temp variations on the outside of the block with an IR gun?



     

[quagmire]

I doubt it, the heat is all generated in the cylinder and transfered to the wall.  The water jacket surrounds it, then the outside of the block.  By the time you are able to take readings it has already been absorbed and been distributed elsewhere so I don't think you'd be able to make any conclusions from the temps at that point. Maybe you could take oil temps at different coolant temps, that may or may not give you insight to friction or block issues.  The oil should take significantly longer to reach temp than the coolant.  And it shouldnt be too excessively hot either. 

[mrob]

Mike,
Since you already have a fixed fan, can you try installing a taller fan spacer? (instead of moving the rad. closer to the fan). On my Challenger, moving the fan 3/4" closer to the rad. made a noticeable improvement in airflow at idle.
Another idea (I don't think this will solve the problem, but every little bit helps) - put your hand below the rad. crossmember while the engine is idling. You'll probably feel some air flowing from the engine compartment to the area in front of the rad. That air is hotter than the ambient air, which does not help the situation.
I think you'll find that moving the fan 1" closer to the radiator will definitely help.

[ShelbyDogg]

I think the important thing here is having the fan in the opening of the fan shroud. Not how close it is to the radiator. I think my blades are 1/2 away from hitting the shroud all the way around. It can't get air from anywhere else.  When you tried the 7 blade fan and the clutch assembly, did you have the tight shroud around it?  I'm a believer in clutch fans. A good working one speeds up and slows down enough to hear the sound change.

[cudagirl4406pk]

Also you might make sure you dont have any air pockets in the cooling system i would drain it and refill with 50/50 pre mix anti freeze add purple ice and keep the sensor out for the temp gauge until the fluid pours out and then cap it and make sure rad is full this is the best way to make sure no air pockets in system according to my husband.

michele

[miketyler]

Thanks for the advice, will have to check outer edge clearance but I know its close. I was only considering the radiator relocation to accomodate the front pusher. I need another 1.5" clearance for it and it will place the front edge of the blades about 1/2" away from the  core and put it mostly INSIDE the shroud. This will be completely undo-able.

I will have to try the Prestone stuff or t least an all water mix to see what improvements that might make

[dodge freak 2]

Don't forgot the motor moves-lifts a bit-under hard acceleration, so a 1/2 inch of space is really chancing the fan striking the rad.

Did you check the engine timing, fuel ratio?

I hear the motors with too much overbore can run too hot.   

[Aussie Challenger]

  You have replaced and checked the water pump, thermostat, pulley ratios, the fan should be sitting at the 1/2 way point of the shroud entrance. As said above there are other issues, using anti boil additives can work but if you need them to solve this problem it is only masking the real problem. I wouldn't use the additives at this point as water should cool your engine, having said that when all is sorted out add the additives but don't use too much as it then works against you.
 A weeping head gasket, cam timing wrong, ignition timing wrong, wrong octane fuel. Does the radiator have a clear air flow from the front right on through the condensor and the radiator. I have found paper sitting between the condensor and radiator in a position hard to see, in dry climates grass can become lodged in the condensor and radiator fins, again hard to see.  Just another 

[ntstlgl1970]

This bothers me:

...Cruising, it is pretty steady at 210.....

 

It's really weird that the car won't cool more than that at speed. The most you could hope for is getting it to idle at 210 since that seems to be the system's cooling capacity.

Like other posters have said, a small block with a 26 inch radiator, good pump, good fan, tight belts, fan shroud etc, should have no problem keeping cool.

Once you are above the point when the fan/shroud etc. come into play (30 mph or so)the only thing controlling the temp from being too cold should be the thermostat in a propery sized and functioning system that doesn't have something blocking the radiator.

I know that your previous post on this issue was 6 or 7 pages long, and I think you have checked all the regular problem issues before, but have you ever checked for a head gasket or cracked head/block problem? With the engine off and cold, draw some coolant out of the radiator (until the level is about an inch low) and have a shop (or if you know someone who has one) use a 4 gas (smog) analyzer in the radiator neck (but not in the coolant of course) to eliminate faulty readings. You should have a pretty low amount (say less than 20ppm) of Hydrocarbons (HC) read in there. Then start the car and look for a change, it would be almost immediate and go up over 100ppm or so, and increase if you rev the motor up. Every once in a while we would get a car in where using the smog machine was the only way to tell there was a gasket or casting issue.
Alternate method - with the radiator full, cap on, car dead cold, start it up and have someone rev it up. Does the upper radiator hose pressurize immediately? That would also indicate a gasket or casting issue. Or if you pull the spark plugs, is there one that looks too clean? That would be a bad sign as well.

Didn't you also have a different belt/bracket/pulley setup than stock? Could you post those picture(s) again?

[miketyler]

yeah, it bothers me too. So much so that I rarely drive it and have at times considered selling or trading it for a different car altogether.

I agree, it sure seems like all the usual suspects have been covered at least twice now. I have not torn the engine back down since the the restoration. The engine compression is correct and leak down checked good. Coolant system pressure check was good as well. I think Greg put a sniffer on the radiator to check for exhaust gas but found nothing. I assume he followed a procedure or methd similar what you describe.

I do have a unique dual belt drive system. The belts do not contact the pulley surface as much as I would prefer but there are two of them contacting pulley surface. I did recently get a longer alt bracket and it has allowed me more adjustment and I have been able to get them very snug.

 

[dodge freak 2]

Wish there was a better picture but for what it looks like is the belts are just touching a 1/4 (if that) of the water pump pulley. With the drag of the water pump and fan it might very well be slipping at any rpms.

[IMNCARN82]

I just stumbled on this thread... hey I got a 340 +.030. It's always run hotter. I've asked around.ALOT!!!! I've compared it to standard bore temps with other 340 cars.Checked it with a lazer  all over.I'm running 2x12" JEGS 189.00 fans. They are awsome.Had a big change in hot starts with a carb/heat plate.The composite or wood ones. I'm waiting on a BC downflow rad. right now.I have the big factory now.It's old. Do not be alarmed by 340's+.030 running hotter than normal. I even have two different guages hooked up.One mech.,One elec.  I hear ya' bro! heat sucks.Best thing so far has been the cheap bubble wrap/foil insulation under the carpet. I cut the hood scoops open,Can see the heat dump out. Been fightin' this too... Cann ya' tell?  Right there with ya'    Rob