350 sbc heat soak

Built6spdMCSS

Royal Smart Person
Jun 15, 2012
1,799
113
Florida Beach
Asleep at the wheel I'd say haha

565bbchevy answered this already, like post 3 or 4. He needs a phenolic spacer much more than a fan or radiator imo. And he ought to confirm proper timing and spark as well.

I referenced fan selection because the conversation turned to fans.

And you're spot on, 200 isn't too hot.
Yea the phenolic spacer and what I think of maybe a bad Coil or ICM is what's going on here. Seen MANY over the years die when they are hot, start instantly when they are cold.

I'm not asleep just missed this one haha.

200 def isn't hot, my C5Z06 Fan low speed came on at like 220, I quickly fixed that in the tune, car is happier. :)

2022 made in Germany auto will run the fans on after shutting down for a time until the temp gets to the correct cooler temp.
So tell me where the temp sensor is, in the Radiator?
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,241
113
Galaxy far far away
Because one is a heat source and one is not. The engine can build and maintain heat. The ambient air flow is as close to having an infinite amount of energy to give away as there is for this example. If you were recirculating the air that has already cooled the radiator once, then your theory applies. But that's not the case.

I don't want to be argumentative, but your upside down here. The same principle applies for windchill. If the ambient air temp is 20 degrees and you have a jug of coolant on top of your car and you're traveling 60 mph the temp of the coolant in the jug will be a consistent 20 regardless of air flow because it's not a heat source and has nothing to gain or lose as long as it's at ambient temp. But if you put a heater in that jug and conduct the same test, then the jug will be cooler than the heater can heat it to because the ambient air is stealing it's energy.
You are the one who is upside down here.

The coolant is a closed loop vs the airflow which is a open system yes. However, heat doesn't stay in the coolant as its exchanged into the air passing through the rad. The heat flow isn't a closed loop as it convects into the air out of the liquid. The faster the coolant flows the better it scrubs the cylinder walls and radiator tubes to transfer heat from block to air. Basically its a Reynolds number thing. Higher velocity causes higher turbulance which increases convection coefficent at the boundary layer which increases heat transfer. In short the coolant doesn't maintain heat andvthe faster it circulates the faster it sheds heat into the environment. Don't forget air has a harder time absorbing heat than liquids. Its why you feel colder in water than in air even if both are the same temps.


Whats feels colder, still cold air, a slow cold wind, or a fast cold wind? Again this is related to Reynolds numbers. Your jug example does not make a whole lot of sense. If the air and jug are the same temp, then heat transfer won't happen due to zeroth law. However, if the air was even one degree warmer than the jug, then moving air would warm it faster than still air. And a fast wind would warm it faster than a slower wind. Similar thing if the jug was warmer than the air, a fast moving wind would cool it faster than a slow wind > still air. Of course turbulant moving air would transfer heat even faster than smooth moving air.

Here is some reading for those who disagree with what I have said.
https://www.stewartcomponents.com/index.php?route=information/information&information_id=11

https://www.stewartcomponents.com/index.php?route=information/information&information_id=13
 

Built6spdMCSS

Royal Smart Person
Jun 15, 2012
1,799
113
Florida Beach
Some of you guys are over here trying to explain the basis of thermodynamics and calculate the exact heat transfer here with the radiator...

And I'm over here reading the car running at 200゚at most, understanding the radiator is not the issue.

There is that common sense playing in. 🤣
 
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Rt Jam

Greasemonkey
Mar 30, 2020
234
43
Ontario Canada
Whether it is your problem or not. Install a thermostat. As for it was 190, now it's 200. That small spread of 10 deg does not mean anything. I did read it runs at 190, this is normal. Is this at during driving only, how about during idle and stopped?
It is normal for a coolant to rise in temp after being shut off as the water pump and fans are all not running anymore but that rise should not keep a good car from restarting.

If this problems is ONLY a hard start when hot. Ignore all chin spoiler, rear gear, spacers, radiator and fan ideas. None of this is going to make a difference after that car has been shut off for 15 min. At this moment, check for spark. If it's good then it's probably time to focus on the fuel. Why is it boiling. How is your fuel system plumbed in?
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,241
113
Galaxy far far away
Here is another good read for cooling system design basics for laymen. And its written by a LS swapper too so that will be double points for some of you.

http://billavista.com/tech/Articles/Cooling_Bible/index.html

Also not running a T stant delays warmup which increases engine wear. As I said betore 200 degrees is fine.
 
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ASharpShark

Not-quite-so-new-guy
Thread starter
Jun 14, 2020
11
3
Holy Jesus how did I miss this clusterfk....


Tell me what that will do besides just cool the coolant in the Radiator and drain the battery..

I'm going to do my best to apply what I know of thermodynamics, physics, and common sense to un-potato this mess. Sheesh..


Hi Jaden.
My question on this is how are you seeing this quick of a temp rise? Turning the key on and seeing the temp gauge spiked that high within a minute? If it's dumping that much gas before firing there is an ignition issue so it may be a bad coil or ICM. You have the gas, you lack the spark.

That is not hot, at all. You get into the 215 range then worry.

Heat soak and over heating are two very different things. If the car runs at 200 at most, it's not over heating.

Parked sitting still with no air moving through the engine bay, hottest part is anything exhaust so that heat will dissipate all over the engine bay until it all cools off. That is heat soak.

Higher RPM will generate more heat, yes. That much heat in the engine bay seems to be a lot and you are getting vapor lock if it's boiling gas off in the lines. Others can chime in here to help remedy that with some tricks, my stuff is all EFI.

Just trying to help with the above, the Radiator is not the issue here...
Sorry for the late replies all, I work long shifts in the heat every day and fall asleep almost as soon as i get home so i can mostly work on my car during the weekend. I also spend any time during the week to work on a seperate project car, a 1985 cutlass supreme 442. If i havent answered or replied to you yet i may have misread and not seen it or havent been able but i will asap!

Hi! I am seeing the temp rise through the gauge with the key turned yes, all of the ignition system is all good and brand new but i will double check my spark plugs tommorow, and i have tested a fan delay timer and it works really well for keeping the cars temp down while i go into the store and it starts up pretty quick with no raw gas smoke or smell! (Havent wired it up yet will do soon)

However after driving the car today (still no thermostat, also will be doing tommorow so that may contribute) after sitting at a stoplight for about 1 minute and giving about 3/4 throttle, it died on me and i had to coast through the intersection. I am assuming this is called vapor lock? The car was running 195~ and was doing good until i tried to gun it.
Also its good to know 215 is a fine temperature!

I have "3.73" gears but they feel more like in the range of 4.56 gears since the car doesnt even wanna go past 55 mph. Could having such high rear gears contribute to high rpms constantly leading to running the car hotter? I would think so and thats what i understand from your last paragraph i just am not sure how much of a difference heat wise it would make
 

ASharpShark

Not-quite-so-new-guy
Thread starter
Jun 14, 2020
11
3
I have ordered the spacer, its on the way and yes, my radiator set up is really good, i dont think its the issue, i am more concerned if my rear end can cause a lot of excess heat in which case ill swap it to lower gears asap which i need to do already.
 

ASharpShark

Not-quite-so-new-guy
Thread starter
Jun 14, 2020
11
3
Whether it is your problem or not. Install a thermostat. As for it was 190, now it's 200. That small spread of 10 deg does not mean anything. I did read it runs at 190, this is normal. Is this at during driving only, how about during idle and stopped?
It is normal for a coolant to rise in temp after being shut off as the water pump and fans are all not running anymore but that rise should not keep a good car from restarting.

If this problems is ONLY a hard start when hot. Ignore all chin spoiler, rear gear, spacers, radiator and fan ideas. None of this is going to make a difference after that car has been shut off for 15 min. At this moment, check for spark. If it's good then it's probably time to focus on the fuel. Why is it boiling. How is your fuel system plumbed in?
Well the only problem was a hard start and it wanted to dump fuel, however i gave it about 3/4 throttle as i said in another reply after sitting at a stoplight for about 1 minute and it vapor locked on me in the intersection and shut off (i think im using vapor locked correctly) this is making me think what you all have been saying about the coolant flowing too much and maybe causing it to get hot although the temperature gauage does not change sitting at the stop light. My fuel system is all stock mostly, everything from to the pump to the tank is all original/new but ran like stock. After the pump it goes to a metal line and goes into a rubber line that connects to the fuel filter and back into a rubber line to the carb.
 

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