70 Still getting hot, what else to look for?

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Lars

Lars

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I have a pretty mild setup that still seems to be getting hot. Stockish 360, probably about 10:1 compression, mild cam (Comp XE 268 IIRC), J heads with stock valves and an old Edelbrock single plane. I have a home made shroud that covers the fan blades and will suck a shop towel up against the grill, a Summit 2 row aluminum rad, a flex-a-lite 18" fan and thermo clutch. Everything has about 2-300 miles on it. Yesterday with an ambient of about 80 degrees the car almost hit 210 (idling in front of my shop), which is way too hot considering the 180 stat I have in it. The intake seeps a little bit of coolant around the stat housing do to being warped, its not bad, but you can see the staining on the intake. I was wondering also if it would be a good idea to switch to a recirculating system over the puke can setup I have now, as the top few rows of the rad are never covered in coolant. I was afraid I had popped a head on my trip to the track cause the car hit about 240 in traffic, but I checked the oil and it looks brand new, no chocolate milk. Any ideas?
 
How old is the water pump and is it a high flow pump. Starting with the simple things first, pull the thermostat and make sure it's opening at 175-180 degF. Bowl of water on the stove with an accurate thermometer and it doesn't matter if its new or not, I had a brand new one fail last year and if it's not a high flow thermo. replace it with one that is.

Terry
 
demon seed said:
How old is the water pump and is it a high flow pump. Starting with the simple things first, pull the thermostat and make sure it's opening at 175-180 degF. Bowl of water on the stove with an accurate thermometer and it doesn't matter if its new or not, I had a brand new one fail last year and if it's not a high flow thermo. replace it with one that is.

Terry
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Standard pump, was installed in April of 07 when the engine was built, has 300 miles on it. I checked the stat with boiling water before I installed it in the engine and it functioned properly, I can't remember, but I think it is a standard replacement stat.
 
Did you use silicone gasket sealer? I had some excess get in a water jacket and plug some fins in my radiator.
 
shanson30 said:
Did you use silicone gasket sealer? I had some excess get in a water jacket and plug some fins in my radiator.
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Yeah, but I ran a stock replacement radiator up until about two months ago. that's when I went with the Aluminum rad cause it was getting too hot. It cools better, but still gets too hot.
 
did you say the engine was built 300 miles ago? if so it still might be tight depending on how tight it was set up during rebuild. The extra friction causes it to overheat until it loosens up. kim is right put a 195 stat in it it will let the coolant sit in the radiator longer in order to cool also what is the timing at idle??
 
I run a thermostat cap that has a temperature gauge built right into the cap. This way I can monitor the temperature at all times and also this will work as a safety so I never open up the cap when it is hot. I did get a brain cramp years ago with another Mopar I owned and opened the cap when the radiator was hot and I soon learned my lesson the hard way.
 
340dart.812 said:
did you say the engine was built 300 miles ago? if so it still might be tight depending on how tight it was set up during rebuild. The extra friction causes it to overheat until it loosens up. kim is right put a 195 stat in it it will let the coolant sit in the radiator longer in order to cool also what is the timing at idle??
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This had occurred to me, the engine only had about 100 miles on it until I made the 200 mile round trip trek to the track last month. The block has about 40K on it since it was punch out .030 a few years ago. I basically just freshened it up with new pistons etc in 07, so idk how tight it is. Timing is at 12 idle IIRC and 32 at full advance.
 
the main thing that could be tight are the pistons to the clyinder walls and or the ring gap. what is the piston to wall clearance? what is the ring gap? If you used standard rings they are high tension and it will run hot untill they seat in alt least that is what i came up with after tearing my engine apart after around 600 very light miles on it due to overheating and its real close to what your engine is except I rebuilt the bottom end too and I just wanted to check and make sure I didnt mess something up building it. Upon dissasembly I noticed the pistons seemed to have exsessive friction comming from them I checked the crank and it turned really free so I rechecked the piston clearances I have kb hyperneumatic pistons so I set the piston to wall a little tighter cuz they dont expand as much as forged and I set the ring gap to what I thought was the reccomended clearance at .010 and .012 and my machinist said that they may be binding but the cylinder walls wernt scuffed so we decided to set the ring gap alot looser and it acually ended up with more cranking compression and it still ran hot for only about 350 or so miles and it only got hot at idle then it went away I acually switched to a alum rad during this also before tearing it apart and it made it a little better but didnt fix it this is just a thought if you have covered all the regular cooling basics like you mentioned. good luck
 
Have you got the coil spring inside the lower rad hose. Being left out could cause overheating on the highway when engine is reving.

Terry
 
demon seed said:
Have you got the coil spring inside the lower rad hose. Being left out could cause overheating on the highway when engine is reving.

Terry
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Thats what I was thinking, maybe it is sucking it self shut. I had that happen on my old 73 scamp. Also have you "burped" the cooling system?
 
he said in his initial post that it was overheating sitting in front of his shop
 
Lars, you said you had a clutched fan, is it operating correctly? Do you have a fan shroud whick fits the fan correctly (far enough into the shroud and a correct diameter. Kev
 
340dart.812 said:
the main thing that could be tight are the pistons to the clyinder walls and or the ring gap. what is the piston to wall clearance? what is the ring gap? If you used standard rings they are high tension and it will run hot untill they seat in alt least that is what i came up with after tearing my engine apart after around 600 very light miles on it due to overheating and its real close to what your engine is except I rebuilt the bottom end too and I just wanted to check and make sure I didnt mess something up building it. Upon dissasembly I noticed the pistons seemed to have exsessive friction comming from them I checked the crank and it turned really free so I rechecked the piston clearances I have kb hyperneumatic pistons so I set the piston to wall a little tighter cuz they dont expand as much as forged and I set the ring gap to what I thought was the reccomended clearance at .010 and .012 and my machinist said that they may be binding but the cylinder walls wernt scuffed so we decided to set the ring gap alot looser and it acually ended up with more cranking compression and it still ran hot for only about 350 or so miles and it only got hot at idle then it went away I acually switched to a alum rad during this also before tearing it apart and it made it a little better but didnt fix it this is just a thought if you have covered all the regular cooling basics like you mentioned. good luck
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I honestly couldn't say, I could call the machinst, but its been so long I doubt he remembers. I am running KB hypers also, KB116CP IIRC. Maybe I just need to drive it more??

demon seed said:
Have you got the coil spring inside the lower rad hose. Being left out could cause overheating on the highway when engine is reving.

Terry
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360scamp said:
Thats what I was thinking, maybe it is sucking it self shut. I had that happen on my old 73 scamp. Also have you "burped" the cooling system?
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System is burped, they don't seem to make the springs anymore, so I cut down and coiled up a coat hanger.

70Duster440 said:
You might try bumping the timing up 3-4 degrees.
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Will do, I need to check it anyway cause I'm not %100 sure on what the timing is set at anyway.

demon seed said:
He also said it got up to 240 in traffic and I guess I should have asked how long it was idling in front of his shop to get up to 210 deg.

Terry
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Took about 10 minutes to hit that temp.

kanders said:
Lars, you said you had a clutched fan, is it operating correctly? Do you have a fan shroud whick fits the fan correctly (far enough into the shroud and a correct diameter. Kev
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I assume its working, I can't hear it working, it only has about 300 miles on it (like everything else). I had to fab the shroud, its pretty ugly, it has about 1/2 to 3/4 of an inch all the way around (I couldn't get it perfectly round).
 
Lars, to check the fan clutch get the engine to operating temperature(or slightly over to be sure) and shut the engine off then grab the fan and try to turn it. There should be a lot of resistance to turning if it's working correctly. Just like demonseed said, being new doesn't always mean it's good. Kev
 
have you psi.tested the cap.i hate problems like this there's so many things it could be and it is usually the simple ones that fixes it.
 
kanders said:
Lars, to check the fan clutch get the engine to operating temperature(or slightly over to be sure) and shut the engine off then grab the fan and try to turn it. There should be a lot of resistance to turning if it's working correctly. Just like demonseed said, being new doesn't always mean it's good. Kev
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will do, I'll check it and let everyone know what I find, probably will have to wait until next weekend though.
 
Are you using a factory electrical temperature gauge or a good mechanical gauge?
Are you confident your gauge is accurate?
 
I had a 360 509 cam worked heads i went with an aluminum radiator and electric fans ,i would overheat always , i put a new oem viscous fan and a stock fan shroud i could not get it over 185 same thing with my stroker viscous fan,stock shroud and aluminum radiator 185 all day long
 
73dart360 said:
I had a 360 509 cam worked heads i went with an aluminum radiator and electric fans ,i would overheat always , i put a new oem viscous fan and a stock fan shroud i could not get it over 185 same thing with my stroker viscous fan,stock shroud and aluminum radiator 185 all day long
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73dart360 i have seen this before

or check you timing and total timing, possible running lean, possible small vacuum leak running lean. car will run hot with these problem.
 
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