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  #21  
Old 09-05-2018, 07:19 AM
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babywag babywag is offline
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Around here a recore job costs WAY more than a new radiator.
Last time I checked it was crazy $! Like $500 crazy.
Very few places even repair or recore radiators anymore, and the cost of a replacement core is ridiculous.
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'88 GW (aka Babywag) and '90 GW (aka JUNKbucket) both fuel injected
1994 Caprice wagon
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  #22  
Old 09-05-2018, 12:43 PM
EasTXJEEPER EasTXJEEPER is offline
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Location: Henderson,TX
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After Cleaning the original Brass & Copper Rad was beyond the cost of repair. I have a new one coming for less than $300 locally tomorrow at 10 am. Hope it direct fits like they say. I should be good to go easy for the Emory TX on the Square Car show on Sept 8 . Maybe I will See you There.
I had the only FSJ at this show last year. My kid may show his 89 GW and 82 Jambo if finds a driver this year.
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  #23  
Old 09-05-2018, 06:55 PM
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acct21 acct21 is offline
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I put one of the Chinese plastic radiators in 2+ years ago, and couldn't be happier. Keeps the rig about 10 degrees cooler than the OEM did. My OEM was clean, but developed a leak along one of the seams that was going to require a re-core. Last local shop in Austin that re-cores quoted me $600 + tax.

Plastic replacement cost me $160 from local box store, and has a lifetime warranty. Just had to buy adapters (off the shelf at Home Depot) for the tranny lines.
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  #24  
Old 09-06-2018, 12:13 PM
EasTXJEEPER EasTXJEEPER is offline
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I got a decent price for a alum and plastic direct fit replacement at $182. My junk Copper and Brass scrap price may surprise me. Old Tranny line fittings fit new bottom tank.
Back on the Road Again. I love cruising in this last of the big Cherokees
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  #25  
Old 09-06-2018, 01:50 PM
SJTD SJTD is offline
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Join Date: Apr 26, 2012
Location: Lompoc and Sunland, CA
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Quote:
Originally Posted by thumperjohn151
1st – I am no expert, but I been turning a wrench for 50 yrs. I am a troubleshooter by nature, and profession. I collect and restore classics from the 50’s & 60’s – So here’s my 2-bits – I rebuilt a FE block Ford (300+HP stock) – as you may, or may not know, rebuilt Fords are NOTORIOUS for running HOT after being rebuilt properly. So I started down the road to solving the problem – 4-core HiTine radiator (next step up was an Aluminum NASCAR), HP fan, fan clutch, HP fan clutch, no fan clutch, New T-stat, low temp T-Stat, no t-stat, custom built WP, custom pulley (smaller to turn the fan/pump faster), shroud. . . . After a year, and $1000+, there was no Joy in Mudville. . . One day while at my parts house, on an unrelated matter, while commiserating with my parts guy, a customer who overheard our conversation stepped forward and offered his $.02. . . He said “I know what’s wrong, and I know how to solve it…” “I’m listening…” He said what you need is a Robert Shaw High Performance Thermostat, and here’s why - He proceeded to explain the inherent design defect in the stock T-stats and how the system REALLY works (details if you request) – Short story is the stock T-stat isn’t keeping the coolant in the radiator long enough to draw off the heat!! OK, for $12 I’ll try one. . . PROBLEM SOLVED!! Idling in 100+ temps (Dallas TX) with the AC blowing 40degs. It might go up 5degs from the set temp. It also runs at set temp in 0degs. Going forward, I’ve installed these in all my cars/trucks as I go through them with success, including my ’87 GW 360 (which suffered the design defect of Vapor Lock – installed a 5psi electric FP all the way in the rear to “PUSH” the fuel). Robert Shaw was bought by Mr. Gasket. Your temp should not swing wildly – maybe go up a few degs. When pulling a long steep grade. Good Luck!!


I'm cornfused.

So you put in a thermostat that supposedly slows down flow so the water flowing through the radiator gets colder.

Doesn't that cause the water flowing through the motor side of the loop to get hotter at the same time?
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  #26  
Old 09-07-2018, 03:56 AM
wiley-moeracing wiley-moeracing is offline
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Its supposed to be a balance of the two. no thermostat will cause the coolant to flow to quick in block and radiator so low thermo transfer, slowing it down( like using a thermostat or a disc will slow the flow down inside the block and radiator so thermo transfer has time to happen.
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  #27  
Old 09-07-2018, 10:56 PM
yossarian19 yossarian19 is offline
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Join Date: Nov 13, 2016
Location: Grass Valley, CA
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I've heard of the restrictor tricks and never really bought it. Coolant isn't flowing any faster through the block than the radiator, so time coolant dwells in the radiator is time other coolant is also heating up in the block.
An engineer posted in another forum the basic formula for heat transfer. I can't find the post (ok, haven't tried) but here's what General Electric says

TLDR: The rate of heat transfer, Q, is determined from the equation: Q = WC Dt where W = flow rate of fluid (lb/hr) C = specific heat of fluid (Btu/lb/degrees F) Dt = temperature change of the fluid (degrees F)

So, you can see that reducing the flow rate of fluid is going to reduce the rate of heat transfer.

I can't speak to why some folks get results with a restrictor. I suspect that any time a fancy thermostat fixes the problem, it's because the other one wasn't opening properly.
Remember - these things worked just fine with OEM style stuff when they left the factory.

Edit: Further Reading from Stewart Components (they own the Robert Shaw brand)

Last edited by yossarian19 : 09-07-2018 at 11:03 PM.
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  #28  
Old 09-07-2018, 11:11 PM
440sixpack 440sixpack is offline
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Join Date: Jul 21, 2016
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Exactly. when your thermostat sticks open you over cool you don't heat up.
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  #29  
Old 09-08-2018, 01:08 AM
SJTD SJTD is offline
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Join Date: Apr 26, 2012
Location: Lompoc and Sunland, CA
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That's what I was tactfully trying to say.

The point is to remove heat from the engine, not to cool the water. The faster the coolant flows the higher the heat transfer. Both from the walls of the engine to the coolant and from the coolant to the radiator.
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  #30  
Old 09-08-2018, 10:22 AM
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rang-a-stang rang-a-stang is offline
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I have no personal experience running w/o a TStat and both sides of this discussion make perfect sense. So I spent the last 20 or 30 minutes asking the smartest cooling expert in the whole world (google) the same question. Here's what I found in those 25 minutes'ish:
1) there must be 20 different forum threads on this exact topic that basically mirror ours here: same 2 perspectives, no personal experience, just go back and forth with theory
2) This discussion is universal, I read from owners asking about Nissan 240SX, Ford Focus, SBC, etc.
3) I saw articles written by "experts" that quoted the same 2 perspectives, no universal answer or even majority answer. The closest thing I can find to a universal conclusion is like this "There is no reason to run w/o a TStat. If you can't cool with the correct TStat, you have other issues."

I have about 6 TStat gaskets in my garage and will offer to ship 4 of them (I'll pay for the shipping) to anyone with a rig that runs great, cools well, lives in a warm'ish climate, that is willing to pull their TStat, drive it for a few days, and let us know what happens (we know it will take FOREVER to warm up, but does it keep going or does it NEVER warm up?). If my truck was on the road, I would be doing it instead of writing this post...
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  #31  
Old 09-08-2018, 10:32 AM
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rang-a-stang rang-a-stang is offline
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I also just submitted the following to Stant:


Quote:
Originally Posted by rang-a-stang
Hello Stant,

I own a 1979 Jeep Cherokee Chief with an 1978 AMC 401 in it. It is bone stock. There is a debate on my full size Jeep forum discussing if a rig will overheat or never heat up if a the engine is run without a thermostat. The two sides of the debate say:
1) No TStat and the rig will overheat because coolant flows through the radiator too quickly to exchange enough heat with the air.
2) No TStat and too much coolant goes through the radiator and it will over cool and never reach operating temperature.
Is there truth to either or both of these statements? If so, which one/how? No one is saying an owner should run w/o a TStat, we are just debating what the results would be if we did. We are not looking for a specific Jeep/AMC/V8/Carb answer, we are just hoping for a general answer. Something like:
"Generally speaking, most water cooled, gasoline engines will __________ if operated with no TStat is installed when one was originally designed to be installed. This is because __________."

Anything you guys can offer to us? We are on the International Full Size Jeep Association Forum. Let me know if you want the link and I can send it to you.
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  #32  
Old 09-08-2018, 11:10 AM
SJTD SJTD is offline
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The problem with this equation:

Q = WC Dt where W = flow rate of fluid (lb/hr) C = specific heat of fluid (Btu/lb/degrees F) Dt = temperature change of the fluid (degrees F)

Is that there are two unknowns. Delta T and Q. The conclusion stated assumes dT remains the same between the two conditions. If it does and flow increases then yes, the heat transfer increases.

But if you increase flow the dt will change. This is the argument made above, that decreasing flow causes the water leaving the radiator to be cooler. True but only half of what goes on.

Have to go deeper and look at what's happening inside the engine and radiator at the metal/water interfaces. It involves more complicated equations involving the Reynolds number which is basically a measure of turbulence. Higher flow increases the Re giving better heat transfer at the metal/water interface.

I suppose I'll have to get out my old Heat Transfer book. Haven't used this stuff in years.

Seems to me I wrote up something on this including equations a few years ago but I don't know if/where I posted it.


Can we talk about back pressure helping low end power now?
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Last edited by SJTD : 09-08-2018 at 01:13 PM.
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  #33  
Old 09-08-2018, 01:25 PM
440sixpack 440sixpack is offline
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Location: oregon
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More flow = more cooling. there is a point where more flow won't gain you anything but there is no point where more flow reduces cooling.

The only thing running with no thermostat gains is if you start with a lower temperature it takes longer to heat up. sort of like a loaded truck hitting a long hill with a run, it takes longer to slow down but you're still going to top the hill at the same speed.
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  #34  
Old 09-08-2018, 11:28 PM
SJTD SJTD is offline
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Join Date: Apr 26, 2012
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For doubters I will sell them a new water pump I've designed. Pumps less water.

I call it the Slo-Cooler.
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  #35  
Old 09-10-2018, 08:44 PM
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Herk Herk is offline
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If I remember right from Thermodynamics, the way a system pretty much dependent on surface area getting hot compared to surface area of heat rejection, and the velocity of the liquid (water) coolant really doesn't matter unless it's going way to slow (has to be moving fast enough that it doesn't boil and form air bubbles on the hot side). So long as the radiator flows coolant well, and air can move over it, a stock FSJ cooling system should work just fine.


Some new thermostats have pretty small holes in them. Small enough to be a restriction on a large engine. I've had good luck with this thermostat in any engine I've put it in: https://www.rockauto.com/en/moreinfo...179514&jsn=395
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  #36  
Old 09-11-2018, 02:24 PM
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rang-a-stang rang-a-stang is offline
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From Stant:
Quote:
Originally Posted by Stant Tech
From my experience this will not over heat. If it is a cold day you will not build any heat in the cab of the vehicle. I use to pull the thermostats out when I was in my trail rig to avoid overheating. Not having a thermostat in will not allow the system to recirculate like it is designed. I hope this helps some. I also like running an 160 degree thermostat in my street/ strip trucks and cars. It would be just fine in a trail rig also especially if you are riding in the cold.
My thoughts on the response: He has personal experience running around w/o a TStat and did not overheat. In fact, he mentions running cold. hhhmmm....
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  #37  
Old 09-11-2018, 02:24 PM
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rang-a-stang rang-a-stang is offline
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From Stant:
Quote:
Originally Posted by Stant Tech
From my experience this will not over heat. If it is a cold day you will not build any heat in the cab of the vehicle. I use to pull the thermostats out when I was in my trail rig to avoid overheating. Not having a thermostat in will not allow the system to recirculate like it is designed. I hope this helps some. I also like running an 160 degree thermostat in my street/ strip trucks and cars. It would be just fine in a trail rig also especially if you are riding in the cold.
My thoughts on the response: He has personal experience running around w/o a TStat and did not overheat. In fact, he mentions running cold. hhhmmm....
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  #38  
Old 09-11-2018, 10:50 PM
SJTD SJTD is offline
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160 Degree?

If and I do mean IF, a 160 degree thermostat would make the engine run cooler in hot weather it would keep the engine from properly warming up which is not a good thing.

All it would really do is open a little sooner. Wouldn't have any effect on steady state engine temp.

Amazing that you got that response from a thermostat manufacturer.
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  #39  
Old 09-12-2018, 05:57 AM
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Heavy_Metal_Thunder_81 Heavy_Metal_Thunder_81 is offline
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Just my .02¢

I've been running a 195° stat with a 100% stock cooling system in my Cherokee since I bought it over 10 years ago. Since then I've lived in Illinois, Florida, Virginia, Washington state, and the vast deserts of California. My rig has seen temps well below 0° and well above 110°, on highway, in city traffic, and flogged off-road...never once have I had an issue with the cooling/heating system. If your engine is mostly stock-ish and your stock cooling system can't keep up, then something is wrong with your system. Any type of trick or bandaid, is just that. There is no reason the factory system shouldn't be able to keep up. The factory didn't build vehicles designed to overheat. Just a thought.
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  #40  
Old 09-12-2018, 08:08 AM
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babywag babywag is offline
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x2 John, never had an issue either...

Far as this...
From Stant:
Quote:
Originally Posted by Stant Tech
From my experience this will not over heat. If it is a cold day you will not build any heat in the cab of the vehicle. I use to pull the thermostats out when I was in my trail rig to avoid overheating. Not having a thermostat in will not allow the system to recirculate like it is designed. I hope this helps some. I also like running an 160 degree thermostat in my street/ strip trucks and cars. It would be just fine in a trail rig also especially if you are riding in the cold.

The way it is worded implies a reply from avg. Joe tech support and not an engineer. No different than some opinions I’ve read online.
There is really very little benefit in running a cooler tstat in a driver.
In a track only or race car that gets pushed hard and see lots of WOT it has been shown to help.
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