340 running hot

-
RustyRatRod said:
It's very simple. IF the radiator is optimal for the vehicle and combination, it will cool the coolant faster than the engine can heat it. I'm not just arguing theory, I PROVED it through my own experiences. Once with my 75 Ford F250. With no other mods, I flushed the system and installed a high flow 160 thermostat. The temp gauge barely moves off the first line, and it's right. Coolant coming out of the engine is about 170* and goin into the engine is about 88*.

With Vixen, once I installed a high flow 160, her temp coming out of the engine is about 167* and going into the engine about 79*

The two radiators in those vehicles slap GET IT DONE and that's the the key. Having the most efficient radiator possible. The reason for the 160* thermostat is this. If you allow the engine to get to say, 190 or 195, there's not much "cushion" before it reaches what I call the point of no return. That's when the cooling system just gets maxed out and cannot shed heat anymore. It's a little different for each cooling system, but once reached, the engine just keeps heating up. So, if you open the thermostat earlier, you don't allow the engine to get to that point.

The reason for the high flow thermostat is exactly what we're discussing. Getting the coolant out as quickly as possible. If you find yourself having to allow the coolant to stay in the radiator longer, it's because the radiator is not doing its job for "whatever" reason. Not big enough, partially stopped up, or "whatever". A good optimized radiator that does its job efficiently will shed heat very quickly and allow that coolant to get back into the engine so as not to allow the engine to reach the point of no return.

Generally speaking, a stock to mild engine is not as "picky" when it comes to everything working in conjunction. But when you couple high compression, a big cam, lots of initial timing all in a small compact space with a small frontal area for air flow, you need to optimize each and every part of the cooling system, and leaving the coolant in the radiator too long does not achieve that. Hope all of that made sense.
Click to expand...
Well said Rob.
 
how much was the overbore on this engine when rebuilt ? and was it sonic checked ?
 
RustyRatRod said:
It's very simple. IF the radiator is optimal for the vehicle and combination, it will cool the coolant faster than the engine can heat it. I'm not just arguing theory, I PROVED it through my own experiences. Once with my 75 Ford F250. With no other mods, I flushed the system and installed a high flow 160 thermostat. The temp gauge barely moves off the first line, and it's right. Coolant coming out of the engine is about 170* and goin into the engine is about 88*.

With Vixen, once I installed a high flow 160, her temp coming out of the engine is about 167* and going into the engine about 79*

The two radiators in those vehicles slap GET IT DONE and that's the the key. Having the most efficient radiator possible. The reason for the 160* thermostat is this. If you allow the engine to get to say, 190 or 195, there's not much "cushion" before it reaches what I call the point of no return. That's when the cooling system just gets maxed out and cannot shed heat anymore. It's a little different for each cooling system, but once reached, the engine just keeps heating up. So, if you open the thermostat earlier, you don't allow the engine to get to that point.

The reason for the high flow thermostat is exactly what we're discussing. Getting the coolant out as quickly as possible. If you find yourself having to allow the coolant to stay in the radiator longer, it's because the radiator is not doing its job for "whatever" reason. Not big enough, partially stopped up, or "whatever". A good optimized radiator that does its job efficiently will shed heat very quickly and allow that coolant to get back into the engine so as not to allow the engine to reach the point of no return.

Generally speaking, a stock to mild engine is not as "picky" when it comes to everything working in conjunction. But when you couple high compression, a big cam, lots of initial timing all in a small compact space with a small frontal area for air flow, you need to optimize each and every part of the cooling system, and leaving the coolant in the radiator too long does not achieve that. Hope all of that made sense.
Click to expand...
Thanks for explaining it to me. I seen that the original post was back in 2017 and then just lately guy's started responding to it again, I sure hope that the OP found out the cause and got it taken care of. I would really like to know what the exact cause was for the overheating problem and what he did to correct the problem.
 
I once had this same issue with my HP 340 running close to 210. After cleaning out radiator, new 180 thermo stat, adjusted the timing and nothing really seemed to help so I added a fan shroud and my temp now was running between 195-200 on a hot and steamy day. I had an older fellow tell me to add a flex fan and move my fan back from the radiator. So I moved the fan back .500" , added the flex fan and now my temp runs any where from 175-190 with 190 being on a Hot and Steamy day sitting in traffic. Older guy told me that by moving my fan back from the radiator will allow the fan to pull more air thru more of the radiator. He also told me that many people thinking that moving their fan closer to the radiator will help cool it more which it does not... The move worked for me and I have never had any further heating issues...
 
Dan the man said:
But if it doesn't spend enough time in the radiator where air can be drawn through, the coolant can not get cooled down, known fact.
Click to expand...
And what happens to the coolant in the block while the coolant spends as you contend, enough time in the radiator? This link here (among plenty others) explains things and puts to bed the fallacy of slowing coolant through the radiator in order to draw out the heat:

Does fluid speed affect liquid cooling?
 
As 12many says, a fallacy.
And a bit of common sense shows this.....
The cooling system is a closed cct. If you leave the coolant in the rad longer, then that means the coolant is in the engine longer...picking up even more heat. When it arrives at the rad, the coolant is now hotter & the rad has more heat to dissipate.

Sometimes, trying to lower the temp of a hot running engine requires a systems approach. It may be that no one 'thing' on it's own is going to reduce temps by 15*.
But if you make 5 improvements that each knock off 3*, then you have your 15*.
Improvements can be sometimes obvious, others not so obvious. Obvious would be more efficient water pump, better fan, running pump faster.
Less obvious would be making sure the gaps around the shroud are sealed to the rad core so that all the air is pulled through the core. Less obvious are things like mating parts. Where coolant exits the heads to enter the intake [ some engines ], make sure the holes line up. Some Edel manifolds I have seen have smaller holes in the intake causing a mismatch. Result is turbulence & reduced flow.
 
Bewy said:
As 12many says, a fallacy.
And a bit of common sense shows this.....
The cooling system is a closed cct. If you leave the coolant in the rad longer, then that means the coolant is in the engine longer...picking up even more heat. When it arrives at the rad, the coolant is now hotter & the rad has more heat to dissipate.

Sometimes, trying to lower the temp of a hot running engine requires a systems approach. It may be that no one 'thing' on it's own is going to reduce temps by 15*.
But if you make 5 improvements that each knock off 3*, then you have your 15*.
Improvements can be sometimes obvious, others not so obvious. Obvious would be more efficient water pump, better fan, running pump faster.
Less obvious would be making sure the gaps around the shroud are sealed to the rad core so that all the air is pulled through the core. Less obvious are things like mating parts. Where coolant exits the heads to enter the intake [ some engines ], make sure the holes line up. Some Edel manifolds I have seen have smaller holes in the intake causing a mismatch. Result is turbulence & reduced flow.
Click to expand...
and our friend from down under knocks it outta the park again. Dammit Bewy, I'm thinkin more and more we might like to share some brews one of these days.
 
Mate,
There is one in the fridge for you next time you are in Sydney.....
 
Bewy said:
Mate,
There is one in the fridge for you next time you are in Sydney.....
Click to expand...
Funny that's where you are. I have an old high school friend who lived there for a while with the fellow she met and married from her Navy days. Sad story. He ended up getting cancer and died. She moved back home to Macon with her two daughters. They were HUGE FreeMantle Docker fans. I'm sure you know who they are. LOL Yup. If I ever get that way, count on it. lol
 
"Yeah, we're runnin' a little bit hot tonight
I can barely see the road from the heat comin' off..." David Lee Roth...:)
 
You must log in or register to reply here.
-

Back
Top