Hot Rods Thermostat modification

Sorry man, don't want to argue, but if you read the website and watch the video, they fail in the open position because of an over heating condition.

The only reason I bring this up is because I'm trying to understand the value of this thermostat design, and I just don't see it. I'm not looking to argue with anyone, just trying to understand the logic, because so far it's not making any sense.

 

Like a pot of water on the stove and a thermo meter?

I've read a bit in different automotive forums that a lot of the thermostats have been offshored for reasons of cost and are of very low quality. OEM only is the recommendation. In H.A.M.B friendly motors that means NOS. They don't go bad sitting on the shelf, i don't believe. Maybe, but I doubt it?

 

Debunk it as much as you want. When people tried to run dirt track cars without thermostats, they overheated. Installing the plate from a thermostat with the center pieces cut out cured it. It might have something to do with creating pressure inside the engine to force the water to go through the heads.

I drill a 1/16 hole in thermostats to bleed the air out and have ever since I worked at a Ford dealer and they advised to remove the thermostat, heat it and put hard candy in it. Who wants to do that every time the cooling system is drained? Mack had the low flow cooling system that was almost impossible to get filled without a hole in the thermostat. In later models they added small bypass lines. Thermostats seem to need to be immersed to work.

I've never had any problems with newer vehicles not heating fast enough. Air will go through a pretty small hole. A 1/16 hole will allow almost 2 cubic feet of air per minute to pass at 20 psi. A 1/16 orifice would flow .317 gallons per minute of coolant at 20 psi which is probably higher pressure than an automotive pump is capable of. In the winter, the coolant is flowing through the heater so the pressure is even lower.

An 1/8 inch hole flows 1.2 gpm at 20 psi. 3/16 is 2.8 gpm at 20 psi so they might be more of a problem. Some of the factory thermostats in newer forklifts have a hole and they're marked to put the hole toward the top as the thermostats sit vertically.

 

Great. Thank you. Now, can you tell us what happens to a t-stat with 3, 3/8" holes drilled through it? Both in open and closed mode? Thank you

 

Don't get this one at all .If the stat was stuck open , why would you need a fail-safe, who's design if meant to stick open?

 

I 'll buy into this one. A bit of a restrictor ...i.e, a gutted stat , might make the system work better.
I thought the poster was talking about a drag car and an electric pump. Normally you wouldn't put anything in the way of coolant flow. Most, if not all, of the cooling is done in the pits or staging lanes.

 

Blues Man , I'm like you . I still haven't thought of a scenario where a fail safe stat would be benificial.
Unless ,of course it's own primary valve were to stick closed. Then you might have a back up system, kinda like in airplanes..But ,it's gonna cost you extra

 

When I started this post I learned something which is 3/8" holes= no thermostat! From what others have said 1/8" is apparently right and what I'll do, but only on something old, pre computer.
I know they can fail shut at random. Many years ago while driving wife's 55 Belair temp gauge went up... I pulled it over, shut it off immediately. If I had not seen it I would not have believed it...the radiator all solder joints looked like liquid mercury. All melted. We let it cool down, eventually took cap off, removed t-stat, added some water and drove it home.
It has that same radiator in it, it never leaked. The motor was ok...didn't warp the head (235).
I still believe and always will a few holes like that is cheap insurance. The thermostat should still work as it should but give protection if it fails to open. The key is size and # holes.
Thanks!

Sent from my SM-S320VL using Tapatalk

 

Why don't you read my f**ken post properly instead of trying to twist the words.
Quoted below

When a car is imported it will sit for a while in transit [or on a car yard] I've had plenty of cars that overheated that a simple thermostat swap fixed the problem.

 

I don't believe that circle can be squared. Holes large enough to prevent overheating in the event of a thermostat failure, by definition mean the thermostat itself no longer operates anything even close to rated design.

A stuck thermostat is definitely a serious problem, overheating can be pretty much death to a motor. Piston rings lose their heat treatment and compression permanently. Seems to me a good quality temperature gauge and a sharp eye is important. The hard candy trick to prop open the valve during a coolant flush makes sense, and avoiding like the plague those el-cheapo imported thermostats. Also verifying temperature accuracy in a pot of water on the stove before installation.

 

I'll try this one more time slowly. The thermostat was a factory installed fail-safe design, if it's good enough for GM, it's good enough for me. Thermostats fail, always have , always will and the thermostat failed this time on it's own ( parts fail ). The seal part of the thermostat looked bad and I'll assume the spring took a shit or wear on the pivot points from opening and closing thousands of times. Without this design, the thermostat would have failed in a closed position and over heated the engine and if driven long enough a possible head gasket problem. I don't really care what a video shows, this was real life and possibly saved my engine. Do what ever the heck you want to with your own, I'm done here.

 

So here's my thoughts.
Let's say the car is running hot and you're oblivious to the gauges. It's on the verge of creating steam in the system, and the TStat is wide open, on the failsafe it's stuck open on the catch.

A few moments later steam and air pockets hit the T stat and the temp sender. Well the gauge you are oblivious too just dropped and the normal T stat is closing because it's lost contact with the water. Making a bad situation worse.

You're still in for a world of shit because of being oblivious to the gauge. But the fail safe stays open and allows the cooling system /radiator to do something. Probably not much but it's not closed off from the system.

 

Why so sensitive? I asked the question because the purpose of the Fail-Safe thermostat, as claimed by the company that markets it, is that in the event of an overheating condition due to a deteriorating cooling component the Fail Safe thermostat will stick in the open position. I already know about thermostats sticking in the closed position from sitting around or due to poor manufacturing tolerances or materials, most of us have experience with that, that's not what the Fail Safe is designed to address. It's a simple question, you either don't get it, or you don't want to answer for some reason. That's OK, your non-answer will do.

 

I'll try this one more time, the thermostat DID NOT just stick in the open position for no reason at all, it only did BECAUSE YOUR CAR OVERHEATED!!! That is what it is designed to do. You are absolutely wrong with your understanding of how the part works, it doesn't just fail and stick open for no reason, it only does this for 1 reason and 1 reason alone IT OVERHEATED!!!!

 

Finally, a logical response from someone who understands how it works. Whew!

Now, what do you think about the claims that a standard thermostat will fail (stick closed) due to being exposed to an overheating condition? That's a new one on me, and I'm not calling bullshit on it quite yet, but I suspect it's marketing hype. In this case, if they are correct, than the Fail Safe will prevent the thermostat from sticking in the closed position, and causing more problems, but there's still something wrong with the cooling system that needs to be addressed, right?

 

Yes, something wrong because cooling system isn't supposed to overheat.

It's like a circuit breaker I guess,

No where in there claims or my post does it claim to solve a stuck closed T Stat. In order for it to work the coolant must be above the set point and then it sticks open. What happens during the over heat is coolant is replaced by steam and that loss of surface contact and heat transfer with the coolant will let a normal T stat close. Once that happens and you nuke the engine it's likely to find all sorts of seiezed up stuff including the thermostat.

I find them stuck closed because they sat. If it's stuck closed you'll see an overheat rather quickly, less than 10 mins. I've found them not closed sticking somewhat open too, that shows up as hours to reach operating temps.

Drilling a tiny itty bitty hole will extend warm up times. Enough that the computer knows you did it lol

 

I've turned a wrench for many a year. Sure, I've had plenty get lazy and/or stick open but I've never had one stick closed. I've heard the old wives tale about poking a hole in the thermostat (typically a single 1/16 or 1/8 hole), and I've seen evidence of it in thermostats I've replaced. I've always filed that away along with some of the other crazy "tips and tricks" like putting "cow magnets" on the fuel line to increase mileage.

I agree that if it actually helped to poke a hole in the thermostat then the factory would have been doing it for years now. But, to each his own. If it works for you and lets you have worry free driving then by all means, drill away.

Bobby

 

So by your reasoning, after I installed a new thermostat, the engine should have over heated again because the thermostat was not the root cause of the problem. I actually think I have a pretty good understanding of what happened in my case and with only replacing the thermostat 1) I have put on 20,000 miles 2) it's been 2 years since the repair 3) Never lost a drop of coolant before, during or after the repair and coolant level has never chaged. Why is it so hard for you to get it through your head that a thermostat can fail on it's own. It's a mechanical part, and they fail. Again do whatever you want on your own stuff.

 

Water pumps do not create any pressure. They are of the impeller (centrifugal) type. They will only circulate a fluid through an open circuit. When the path is blocked they just churn in place, which is why we can temporarily block the path with a closed thermostat. The pressure is created by the expansion of the coolant as is heated in the closed system and regulated by the relief valve in the cap. Every pound of pressure raises the boiling point 3 degrees. By raising the boiling point we are creating a greater temperature differential between the coolant and the ambient temperature. This allows the cooling system to exchange more heat for a given size.

Then we hot rodders upset the engineers careful calculations by building high horsepower engines (a lot more heat generation) and put them in bodies with restricted radiator space and air flow (less heat dissipation capability). We engineer the best we can within the existing parameters of our projects, but sometimes go too far and have to start playing with crutches.

I've seen thermostats stuck both open and closed, probably closed more often. Man manufactures them and they can go bad 'just because'. All and all, in my experience, they're pretty trouble free.

 

Pumps do create pressure,
There's a low pressure side (suction) and high pressure (discharge) side. Some impeller designs more than others. Increase the flow rate thru the same size passage and the pressure goes up, has too. Increase the RPM and the flow rate goes up.

 

I always thought a thermostat was designed to hold water in RADIATOR to cool it not to heat it

 

It's purpose is to hold water/coolant in the BLOCK, until efficient operating temperature has been reached.

 

I'm trying to figure out why ,like myself,so many people where taught to drill a 1/8" hole in the flange. Was the original idea to allow steam to pass [during a overheating] to allow reintroduction of coolant onto the surface of the t stat?,allowing it to reopen?. Maybe it's not needed now with new designs?.

 

Correct and maximum temperature is determined by size and condition of the radiator, cooling fan, air available through the grill, among other things

 

The only thing that I know that it does is it allows air trapped under it to escape and allows the block to be filled all the way

 

Yep the drilled hole in thermostats was to aid in air bleeding. Ive never drilled my own thermostats and most thermostats you get now that are named brand has a check valve vent already made into the thermostat. Just install that at 12 o'clock and you can bleed the air out.

Another trick that I use at work without drilling the hole as its just extra work to do you aren't paid for is to hold the rpm up around 1,200 - 1,500 rpm with the heater on and keep it up till you get full heat from heater. Once there you can let the engine idle as air has most likely all gotten out by this point.

If you have a over heating problem or running warmer than it should problem it can be many things. Ive seen on fords too much total advance cause bad fuel economy as well as the engine run warmer than it should. Problem with my 292 Y8 is too much total advance at idle due to the cobbled together pieces that don't work together the old shop did back in the 80`s down here. My truck that 302 runs too cool so I am swapping the 180* thermostat out and putting a oem motorcraft 196* thermostat in on the new engine I put in.

 

I'm Not sure why that is so hard to understand. That's perfect gimpy!

Fast warm ups to operating temps is pretty crucial for quite a few matters. When the T STAT opens up AT THE SET POINT the hot coolant leaves the block past the T stat then into the radiator. The coolant entering the block from the radiator to replace the hot coolant that just left MUST be lower temperature than what just left.


A running engine
Coolant
Thermostat
Radiator
Air flow

A running engine
will do its job and heat the coolant.
Thermostat controls minimum temp from there...
Radiator needs to shed more heat and do it faster than the enginen can make it with the help of air flow. If the Heat shed rate is less then it will overheat shortly. If the heat shed rate is equal it will overheat when under stress.

 

When O'rielly bought out Checker / Kragens, the only thermostats they carried were the Fail Safe ones. "If it fails, it does in the open position" means that within a short time they will stick open. I tried 3 of them in 3 different vehicles, each one stuck open within 1 - 3 months of being installed. I went back to using Stant thermostats.

 

The factory, and many shops now, use a vacuum system to fill the coolant so they don't have any problem filling them. I happened to work at a Ford dealer in 1979-1980 and the coolant filling problem was often encountered and we didn't have the vacuum system. Ford's solution was the hard candy in the thermostat. Do you really want to remove the thermostat every time the coolant is changed which was every 2 years on the service schedule? Some people changed it every year. A 1/16 hole works great for that. Many cars don't have a shutoff valve for the heater. The coolant runs through it constantly and the air flow through it controlled.

Jeep used a restrictor in their heater cores.
Elastomeric Restrictor
Placed in outbound tube of heater to optimize coolant velocity and heat transfer.
https://www.rockauto.com/en/moreinfo.php?pk=529112

Apparently they haven't gotten the memo that flow speed doesn't matter.

 

Flow only results from a difference in pressure. Did you sleep through physics class? Here is a list of impeller pumps that provide pressures from 35 to 125 psi and their flow can be completely blocked.
https://www.grainger.com/category/s...pumps/centrifugal-pumps/pumps/ecatalog/N-1aco

As far as thermostats go, not closing is likely more common than not opening but when they don't close, it probably wasn't noticed until the weather gets cold. When they don't open, it is immediately evident.