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Topic Review (Newest First)
11-18-2005 10:03 AM
cliff tate
Quote:
Originally Posted by Tech @ BG
Dirt Car 18,

Actually the water temp was up about 35 degrees, as was the block temp (via infared after a run) and oil temp up almost 25 degrees if I remember correctly I'll have to double check my notes. As soon as I put it back in everything went back to normal. In my mind that's telling me I was hotter.
with no restriction even withe pressure the rapid flow would likely act as a syphen and creat spots of air or steam in the engine causing hot spots and many other problems down the lake.with raw watter cooling ther ar many differences than a radiator, the angle of the engine .watercooled exaust versus dry. in versus out of watter flowetce. cliff
11-18-2005 09:07 AM
montea i read on here before that it was better to run without a thermostat (gutted one) because it runs cooler and wont over heat.. i tried it on my SBC and yeah it does run cooler and takes forever to reach operating temp. never over heated, just wasnt able to get warmed up. cold engine = more wear. i dont see the point, so i installed a 180-190 stat and it stays constantly at 190 degrees after its warm wich doesnt take to long.

i will always run a thermostat now.

If you are going to run without one and have your car run cold and create more wear, the same time why not use some real cheap low grade no name motor oil
11-18-2005 08:41 AM
Tech @ BG Dirt Car 18,

Actually the water temp was up about 35 degrees, as was the block temp (via infared after a run) and oil temp up almost 25 degrees if I remember correctly I'll have to double check my notes. As soon as I put it back in everything went back to normal. In my mind that's telling me I was hotter.
11-18-2005 08:36 AM
Dirt Car 18
Quote:
Originally Posted by Tech @ BG
Since this has been brought back up I've got a question for those that may know. Since they're saying it's totally based on pressure not time, I'm confused since I've seen a difference. On one of my boats it has an open cooling system (picks water up from the lake goes strait through the engine, and back out into the lake) at idle it runs about 15 PSI water pressure. Normally about 155 degrees water temp once it finally warms up with a 160 thermostat with four 3/16" holes in it. At high speed I can get over 40 PSI in the engine. I would think this should be enough to get to all of the "hot spots" in the engine. I can control the top end water pressure with a relief valve. I took the thermostat out completely, and the engine ran hotter. Still the same 40 PSI in the engine. Now to me this would probe that the water needs to stay in the engine a little longer to transmit hit. Now I realize this test was not empirical, because I didn't measure the GPM water flow before and after, but am I missing something?

You said the water temp is 155*with a thermostat and that engine ran hotter without the thermostat. I'm assuming we are talking about water temps being hotter, not metal temps? By my way of thinking, the cooling system must be more efficient without the stat. The more heat that is transferred from the engine to the coolant the HIGHER the water temps should be. Assuming that the amount of heat that the engine produces is a constant value, the only way the water can be hotter is for the engine (metal) to be cooler, thus greater efficiency. I would think this to be especially true in an open system as long as the lake temps are constant.
11-18-2005 08:08 AM
Tech @ BG
Quote:
Originally Posted by red65mustang
love his logic, remove the cat's= more HP,

so remove the thermostat=more hp?

"if ain't broke don't fix it!"

Na, I actually wanted to try it to verify what was going on within this thread when it first came up. I put the thermostat back in after the second run, the engine temp was getting hotter than I felt comfortable with.
11-18-2005 08:05 AM
red65mustang love his logic, remove the cat's= more HP,

so remove the thermostat=more hp?

"if ain't broke don't fix it(by removing it)!"
11-18-2005 07:31 AM
Tech @ BG Since this has been brought back up I've got a question for those that may know. Since they're saying it's totally based on pressure not time, I'm confused since I've seen a difference. On one of my boats it has an open cooling system (picks water up from the lake goes strait through the engine, and back out into the lake) at idle it runs about 15 PSI water pressure. Normally about 155 degrees water temp once it finally warms up with a 160 thermostat with four 3/16" holes in it. At high speed I can get over 40 PSI in the engine. I would think this should be enough to get to all of the "hot spots" in the engine. I can control the top end water pressure with a relief valve. I took the thermostat out completely, and the engine ran hotter. Still the same 40 PSI in the engine. Now to me this would probe that the water needs to stay in the engine a little longer to transmit hit. Now I realize this test was not empirical, because I didn't measure the GPM water flow before and after, but am I missing something?
11-18-2005 07:07 AM
Bob C
Quote:
Originally Posted by Dirt Car 18
About the only facts in this whole thread can be found at this link provided by xntrk
I agree 100%. That's what I've always believed to be true.
There are a lot of myths floating around, like the one about hot water freezing before cold water. oops, I probably shouldn't have said that
11-17-2005 08:21 PM
Dirt Car 18
Quote:
Originally Posted by xntrik
About the only facts in this whole thread can be found at this link provided by xntrk
11-17-2005 06:55 PM
black66
Quote:
Originally Posted by Tech @ BG
No myth here! No thermostat, and you will run hotter than running say a 160.

You need something to keep the water in the engine long enough to pull the heat out of the engine. This is why the thermostat opens when it gets to temp, and flows back into the radiator to cool off. It doesn't have to be a thermostat, you can put a restrictor in place to control water flow. This is done on most race engines.

Regardless of how you do it, you want to control engine temp weather your computer controlled this will give you your best power, and life out of your engine.
BG Tech is correct. I run a 160 in the summer. Car never get past 195 even in the hottest days or worst bumber to bumber cruises. And I am running a 530 HP small block.


I tried a 195 thermostat this summer and I was running 205-210 on really hot days or crusing...

Quote:
I'm moving to an electric motor-driven water pump
Electric water pumps are good for racing. But will not compete with a good mechanical high flow pump. Been there done that.....
11-17-2005 06:25 PM
pepi
thermostate

yes.............. hell yes...................a thousand times YES
11-17-2005 06:15 PM
matt167 yes a thermostat is needed, in a street vehicle, especially in new vehicles because of emissions. The thermostat stays closed until operating temp, when it opens, it closes off the link to the radiator when closed, but there is always a bypass to the water pump to keep water circulating in the engine itself, keeping temps uniform with no hot spots, once open ( a small block chevy 180 will be fully open at 190-195 degrees, a 195 ( new car ) would be fully open around 212 degrees ). The thermostat allows the coolant in the radiator to cool off, and the coolant in the engine to absorb the heat from combustion, until the thermostat rating when it all starts over again, a thermostat keeps the engine in a operating temp range, to run efficently. a engine running too cold will produce HC's and Co's and would fail a emmisions test, and will be inneficent, a engine at the proper operating temp will be efficent and won't produce as many HC's and Co's.
11-17-2005 11:45 AM
itsnotbutter! up untill recently i didnt know how i stood on this matter... but yea you can run with out a T-stat and yeah when its cold its cold then finally when it heats up and your going 65 mph for some time its gets hot and when its hot danm is it hot... so ill be putting a t-stat back in soon. Too fast of a flow with out it ?? who knows but i hope one day some one can engineer a more effiecinet way of cooling other than water jackets , rubber hoses, t-stats, iron propeller belt driven pumps, blocked Rads by comfortable A/C condersors and hi psi rad caps.... Im just saying tho
10-24-2005 06:59 AM
thenige I've actually just read up on this subject myself since I'm moving to an electric motor-driven water pump and was wondering if I needed a thermostat since I can control the water pump operation via a switch.

Some history..

Back in the 55-57 Chevys if the thermostat was removed from these cars the engine would actually overheat.

Original thoughts were that the coolant was moving through the engine too quickly to provide proper cooling.

The actual problem was that when you remove the thermostat from a cooling system with a vertical radiator, the point of highest pressure moves to the radiator. That said, the excess pressure was higher than the capacity of the radiator cap spring, and coolant would escape.

So in my view, if you must run without a thermostat, make sure you have a cap rated at higher than stock psi.

Now if your more serious about cooling, you can modify the water pump housing which has a bypass to avoid pressure buildup when the thermostat is closed (assuming you have one).

What you do is plug the bypass and drill 4 holes (.200 for 160F thermostat or .080 for a 180F thermostat). This will improve block filling since air in the waterjackets has a place to escape. The four holes and plugging the bypass usually results in a measurable drop in coolant temp. This depends on your heads and water pump (racing heads and pumps often change the flow).

Regards,
Nigel
10-23-2005 04:05 PM
coldknock Don't forget about cavitation. With little to no pressure differential before and after the impeller the water, sometimes, will spin in a circle with the impeller and not cool a cotton pickin' thing. One more reason to have a thermostat in place.

Larry
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