Sealing gaps around radiator

[gumby79]

The old wives tale of a thermostat removal resulting in a worsening overheating condition, is not a wives tale it is a fact when applied to carbureted small block Chevy ,Ford ,and Dodge V8 engines ( I do not have the experience/ exposure to say whether this carries forward into the injected era). At the loacal dirt 3/8mi track guys would pull a thermostat on an overheating car and then melt the engine down.
Ask me how I know, I told him it was a wives tale I didn't believe him, when the engine hit 260 the driver pulled off the track wiped out the entire valve train( Springs lost their tension alowing piston contact) , it was a expensive lesson.

The correct answer provided by the old head at the track ,was to cut the wax module and moving element out of the factory thermostat, creating a restrictor plate of a calibrated size ( off-the-shelf restrictor plates in varying sizes are available to fine-tune a cooling system for track use allowing the same cooling components[pump ,rad] to be capable in dissipating Heat from 150 horsepower to over 800 in SBC 350" without over/under cooling). it didn't matter what class you ran, or how much power / Waste Heat you made the restrictor-plate or specialized racing engineered thermostat was always required or overheating would result from excessive flow rate/ lack of dwell time to reject it's latent heat into the radiators metal.

It's about dwell time not exposure time as somebody stated.

OP How to apply my statement to your(or some one studying to to this mod) use case. Use an old thermostat modified in the manner I described as a restrictor to stimulate a stuck full open thermostat mode of operation. Then compair. It may be too late for the A/B test modified against unmodified is returning to stock would be painful.
Another way of validating the result is to disconnect the fan let the engine reach 10° above the onset point, reconnect and measure the amount of time it takes to reach the off point for the fan ( again a little late for you to get the data for " A"test) blicking the opening is a way to cheat and get it to warm up faster for testing.
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GAPS
Were they intentional?
Absolutely they serve the purpose of ease of assembly, nothing more nothing less.

They are a defect that , at that time, were not worth the expense of rectifying(added assimblely time , more labor, extra parts) due to law of diminishing returns. However the cost is more bearable for manufacturers in 2020, as they are chasing values 3-5 places past the decimal reductions in dragged because it all adds up to a smaller number in the end requiring less fuel making it easier to meet Cafe requirements.

Anything that reduces the pressure differential across the cooling core, AKA gaps, is a reduction in efficiency.

Well done project. I have been planing to do in the future for my vehicle but I have to finish modifying the cooling stack( A/C, trans, IC , and rad) to accommodate my increased heat load at lower than factory desined RPM 1150@55mph Vs there 1800. Rad is fine but a larger Intercooler is needed to keep IAT in check.



Dream Big Chisel Down To Reality

[cRiPpLe_rOoStEr]

The only way a thermostat removal would be likely to lead to an overheating is if a restrictor plate takes its place, or when it's resorted to some makeshift cover around the radiator. Well, even though overcooling would at some point become an issue with a thermostat removal even for some engines prone to an overheating such as Peugeot's TU5/EC5 and Ford's Zetec RoCam, resorting to an easily removable piece of cardboard in front of the radiator as it's quite usual among Argentinians doesn't sound so suicidal as assembling a restrictor plate at the usual location of the thermostat.

[EcoCivic]

Originally Posted by gumby79

The old wives tale of a thermostat removal resulting in a worsening overheating condition, is not a wives tale it is a fact when applied to carbureted small block Chevy ,Ford ,and Dodge V8 engines ( I do not have the experience/ exposure to say whether this carries forward into the injected era). At the loacal dirt 3/8mi track guys would pull a thermostat on an overheating car and then melt the engine down.
Ask me how I know, I told him it was a wives tale I didn't believe him, when the engine hit 260 the driver pulled off the track wiped out the entire valve train( Springs lost their tension alowing piston contact) , it was a expensive lesson.

The correct answer provided by the old head at the track ,was to cut the wax module and moving element out of the factory thermostat, creating a restrictor plate of a calibrated size ( off-the-shelf restrictor plates in varying sizes are available to fine-tune a cooling system for track use allowing the same cooling components[pump ,rad] to be capable in dissipating Heat from 150 horsepower to over 800 in SBC 350" without over/under cooling). it didn't matter what class you ran, or how much power / Waste Heat you made the restrictor-plate or specialized racing engineered thermostat was always required or overheating would result from excessive flow rate/ lack of dwell time to reject it's latent heat into the radiators metal.

It's about dwell time not exposure time as somebody stated.

OP How to apply my statement to your(or some one studying to to this mod) use case. Use an old thermostat modified in the manner I described as a restrictor to stimulate a stuck full open thermostat mode of operation. Then compair. It may be too late for the A/B test modified against unmodified is returning to stock would be painful.
Another way of validating the result is to disconnect the fan let the engine reach 10° above the onset point, reconnect and measure the amount of time it takes to reach the off point for the fan ( again a little late for you to get the data for " A"test) blicking the opening is a way to cheat and get it to warm up faster for testing.
---
GAPS
Were they intentional?
Absolutely they serve the purpose of ease of assembly, nothing more nothing less.

They are a defect that , at that time, were not worth the expense of rectifying(added assimblely time , more labor, extra parts) due to law of diminishing returns. However the cost is more bearable for manufacturers in 2020, as they are chasing values 3-5 places past the decimal reductions in dragged because it all adds up to a smaller number in the end requiring less fuel making it easier to meet Cafe requirements.

Anything that reduces the pressure differential across the cooling core, AKA gaps, is a reduction in efficiency.

Well done project. I have been planing to do in the future for my vehicle but I have to finish modifying the cooling stack( A/C, trans, IC , and rad) to accommodate my increased heat load at lower than factory desined RPM 1150@55mph Vs there 1800. Rad is fine but a larger Intercooler is needed to keep IAT in check.



Dream Big Chisel Down To Reality

Ugh here we go with the thermostat debate again. Reread post #12. Again- I never said removing a thermostat can not cause overheating, I said a higher flow rate will always equal more effective cooling as long as everything else is equal, which it may not be with no thermostat depending on the design of the engine and cooling system as I said in post #12. All 3 cars I have ran without a thermostat ran significantly cooler and did not exhibit any of the issues others have reported, but I don't doubt that some vehicles could for the reasons I mentioned.

I never thought about the gaps being there for ease of assembly at the factory, but that makes perfect sense. The easiest and quickest way to install the radiator into these cars at the factory would be to install the fans on the radiator and then install the radiator from the front before installing the AC condenser. The gaps on the side certainly do make assembly easier.

[EcoCivic]

Sealing those gaps seems to have made a big difference. Several weeks ago I
blocked the upper as well as most of the lower grill for winter and even
with all airflow blocked except that small rectangle at the bottom, the
coolant temp has not increased at all. It still runs at 182-186 degrees
while cruising like it always does even though we have been in the low 70's
the last couple days. Fans haven't come on once either although I don't sit
in much traffic. If I remember correctly, a similar grill block setup with
those large gaps present resulted in 210+ degree coolant temps at times
under similar conditions.

However, I can not definitively say that these mods are 100% responsible
for the improved cooling efficiency I'm seeing since I had an automatic
transmission with a cooler in front of the radiator last time I tried
blocking the grill so much for winter and I have since swapped to a 5 speed
so the different gearing and lack of a cooler could certainly affect temps
too.

I'm still experimenting to see how much I can block the grill while still
maintaining a decent safety margin and I need to come up with a better
grill block than cardboard and Gorilla tape too, but so far so good.