Cooling Issue

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800 in gear!?
Q1)What cam are you running then? That's a lotta Rs for a typical 270 ish cam. No matter, it's not too slow.
Q2)How about the TC; what kindof stall?
Q3)How hard is the tranny pulling at 800?
 
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Your crank pulley should be larger than the water pump / fan pulley. If it's not, that could be some of Your problem. -- A lot of little things can add up to create a cooling problem. -- Many of the items have been mentioned.
 
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AJ/FormS said:
800 in gear!?
Q1)What cam are you running then? That's a lotta Rs for a typical 270 ish cam. No matter, it's not too slow.
Q2)How about the TC; what kindof stall?
Q3)How hard is the tranny pulling at 800?
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1) I'm still tinkering with the tune. Right now, it idles at 800 in N and drops to 750 in gear. The cam is a single pattern 231@.050", .560" 108ICL in at 104.
2) It's a 9.5" Dynamic converter. It stalls around 3500
3) Not much (if at all).


RPMagoo said:
Your crank pulley should be larger than the water pump / fan pulley. If it's not that could be some of Your problem. -- A lot of little things can add up to create a cooling problem. -- Many of the items have been mentioned.
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I was thinking about this today. If I bring the revs up to 1200 or so, I can watch the temp come down very quickly. I bet a smaller puller would do the trick. I haven't measured them, but I will next time I mess with it. Where can I get a smaller diameter pulley?
 
While I was out messing with it today, I shot the trans cooler with my IR gun and it measure 135-140 after a drive, so I can't imagine that playing a role in this issue. Although I have the trans fluid going through the radiator first, then the large B&M stacked plate cooler in front of the radiator.
 
mopowers said:
1) I'm still tinkering with the tune. Right now, it idles at 800 in N and drops to 750 in gear. The cam is a single pattern 231@.050", .560" 108ICL in at 104.
2) It's a 9.5" Dynamic converter. It stalls around 3500
3) Not much (if at all).
I was thinking about this today. If I bring the revs up to 1200 or so, I can watch the temp come down very quickly. I bet a smaller puller would do the trick. I haven't measured them, but I will next time I mess with it. Where can I get a smaller diameter pulley?
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Well my cam is very similar, but I have a stick, so I idle mine down some.You're Ok there.And it looks like you have the rest sorted. So then it might be a good idea to speed up the pump.But I would do some of the other things first.I slowed mine down some and it still cools A-ok.
 
A couple other items that will help are -- (1) Go to 100% water, with something like Lucas Super Coolant, for lube purposes. -- This will probably bring out a lot of comments -- But -- I tried it, and it helped to bring the temperature down. (2) Seal between Your shroud and the radiator, in order to pull the maximum amount of air thru the radiator. ----- - I did the above, plus changed the pulleys, and added a 7 blade mechanical fan, to solve a over heating problem, with My 408. -- I got it to acceptable temps.
 
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Get your car up to the temp where you think it's hot at idle. Take a rolled up newspaper or magazine and see how easy it is to stop your fan.
 
His cooling is fine once he gets moving, from what I understand. Building heat at idle is almost always a lack of airflow through the radiator.
 
mopowers said:
What would be the point of this? If the clutch is operating correctly, won't this mess up the fan?
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No the steel fan will be fine. The point is to see how much the clutch is slipping, and it is a whole bunch kinder than to stick your fingers in there. I'm not a fan of that idea, but the point is made. I have tried other less violent methods, with non-thermostatic viscous couplings.You said yours was a thermostatic, so the little spring on the front has to be connected at both ends and then it has to get up to it's set point, and then it has to rotate the little valve to go from a viscous coupling to a direct drive. And Whoosh. roar, it comes to life. The roar is a sure sign that air is moving.
Another method to see how much air is moving thru the rad is simply to hang a piece of paper in front of the rad, and "measure" how hard the paper is being "sucked" onto the rad. This does not tell anything usefull if you have a condenser mounted in front.
 
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It may have a low % of engagement, no engagement at all or the thermostatic clutch may be engaging at the wrong temp.

Or it could not be fan related at all. Here is a video of how to do the test. You are just touching the tips of the blades. Don't jam the whole magazine in there.

 
I know someone mentioned this but I don't know if you responded. Do you have a seal between your hood and cowl? My car would act like yours. I have a fiberglass hood with no seal on it. I tried everything to cool my car. Aluminum rad, Brassworks water pump, transmission/oil cooler combo (transmission doesn't go through the rad), steel 7 blade fan with shroud and electric pusher fan. It would run 180 while driving but get into any traffic and it was instantly 200 to 230. I was troubleshooting this problem one day and thought that I had solved the problem. The car was idling in my driveway and the temperature was staying at about 170 degrees. Estatic that I thought I had solved the problem I put my hood back on, left the car running and went upstairs to clean up before I took the car for a test drive. When I came back down it was now running at 230 degrees. I was thinking what the heck is going on? I found that if I blocked the area under the lip of the hood with cardboard the cooling was a lot better. It seems that what happens is hot air is forced out from underneath the hood and then gets sucked back into the radiator where it gets warmed up. It again gets pushed back through from under the hood and then back through the radiator to be warmed up even further. You can see how this is going to work. Try putting a few rags between the car in the hood if you don't have a hood seal (I used air-conditioning foam rbber seal from Home Depot) This will at least allow you to test this Theory out in your driveway. Good luck
 
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1968FormulaS340 said:
No. You are not going to hold it stopped all day long. It's a fluid clutch. If it stops easy, you know it's bad.
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What's "easy?" Having never done it I have frame of reference. Can you describe how much pressure "should" stop it? If the thermostafic coupling is operational, I'd imagine it wouldn't be very easy to stop the running fan.

1968FormulaS340 said:
His cooling is fine once he gets moving, from what I understand. Building heat at idle is almost always a lack of airflow through the radiator.
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It fine when it's moving, but more importantly, it's fine at about 1200 rpm even standing still.

AJ/FormS said:
No the steel fan will be fine. The point is to see how much the clutch is slipping, and it is a whole bunch kinder than to stick your fingers in there. I'm not a fan of that idea, but the point is made. I have tried other less violent methods, with non-thermostatic viscous couplings.You said yours was a thermostatic, so the little spring on the front has to be connected at both ends and then it has to get up to it's set point, and then it has to rotate the little valve to go from a viscous coupling to a direct drive. And Whoosh. roar, it comes to life. The roar is a sure sign that air is moving.
Another method to see how much air is moving thru the rad is simply to hang a piece of paper in front of the rad, and "measure" how hard the paper is being "sucked" onto the rad. This does not tell anything usefull if you have a condenser mounted in front.
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How do you "measure" how hard a piece of paper is sucked into the radiator? I'd imagine the difference in pressure between 800 rpms at idle and 1200rpm would be pretty subtle.

superchargeddrt said:
I know someone mentioned this but I don't know if you responded. Do you have a seal between your hood and cowl? My car would act like yours. I have a fiberglass hood with no seal on it. I tried everything to cool my car. Aluminum rad, Brassworks water pump, transmission/oil cooler combo (transmission doesn't go through the rad), steel 7 blade fan with shroud and electric pusher fan. It would run 180 while driving but get into any traffic and it was instantly 200 to 230. I was troubleshooting this problem one day and thought that I had solved the problem. The car was idling in my driveway and the temperature was staying at about 170 degrees. Estatic that I thought I had solved the problem I put my hood back on, left the car running and went upstairs to clean up before I took the car for a test drive. When I came back down it was now running at 230 degrees. I was thinking what the heck is going on? I found that if I blocked the area under the lip of the hood with cardboard the cooling was a lot better. It seems that what happens is hot air is forced out from underneath the hood and then gets sucked back into the radiator where it gets warmed up. It again gets pushed back through from under the hood and then back through the radiator to be warmed up even further. You can see how this is going to work. Try putting a few rags between the car in the hood if you don't have a hood seal (I used air-conditioning foam rbber seal from Home Depot) This will at least allow you to test this Theory out in your driveway. Good luck
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The hood as both, a front radiator core support seal and a rear cowl seal.
 
Post #22 is indeed a excellent “rule of thumb” , thanks Rx3. The hood seals have very little to do with over heating problem at low or idle speeds. The seals are usually a “C” shaped long strip of rubber, they are engineered to capture the rush of air to expand to cover the gap between the hood and radiator support and cowl area. This only happens at highway speeds and not sitting idling or at low speeds. Thermostatic fan clutch, is not really a clutch like a flywheel-clutch for a manual transmission. So the device never completely locks up, unless its bad. Ideally at idle and low speeds the fan clutch should cycle in and out, like an earlier post mentioned, you should hear the roar of air the fan is making while the thermostatic part of the fluid clutch is working properly. I would check this by spinning the fan blade while the car is cold, and then again while the car is hot, you should feel a measurable difference. Buying new car parts from the local parts stores don't always match up to except-able standards, we need for yesterdays cars. I have done what others suggested by holding the fan blade while the car gets into the hot zone, which indeed does a better test, but it is half hazard way of doing it, use caution. Drilling a hole in the thermostat, if you thinks it helps...it does. I have read an earlier post about having an issue much like yours, his pump vane was slipping on the shaft, I have never seen this but I guess it happens....Me I would try the fan blade without the fan clutch and if it works will, I would invest in a “world-class” fan clutch then.....
 
Went out and took some measurements yesterday. My WP pulley is about 6-7/8 OD and my cranks pulley is 6-1/2" OD, so obviously my WP pulley is larger than my crank pulley.

Dicer said:
I would check this by spinning the fan blade while the car is cold, and then again while the car is hot, you should feel a measurable difference.
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Tried this yesterday and the clutch is relatively harder to spin once the car is up to temp. I don't think there is anything wrong with the clutch.


Dicer said:
Me I would try the fan blade without the fan clutch and if it works will, I would invest in a “world-class” fan clutch then.....
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I will be trying this soon if everything else checks out.

fan.jpg


fan2.jpg
 
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AJ/FormS said:
Under steady state conditions you shouldn't be seeing the water temp going up and down.The stat just does not work that fast! What I would do is grab an old stat and cut everything off it so that you are left with just the restrictor. Install that and roadtest it.
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This test is next on the list. While driving it yesterday, I noticed the temperature swings even after 30 mins of driving. It would climb to 220, then drop down to 190 very quickly and stay there for a while before climbing quickly to 210-220-ish and back down. I'm suspecting an issue with the thermostat.
 
skep419 said:
It could be that your heater hoses are backwards :poke:
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2 different size heater hose, if they were backwards you would have a hose to tight for the fitting and one to big for the fitting to fit on
 
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