69Sting

I need to put a new thermostat in my 69, 350ci/350hp. Am I better off putting in the 195 degree or the 160 degree. 80% of my driving is just going for rides, 20% will be road course schools.
Right now I can't even hit around 150 degrees.

Stefan69

None of the above. Go for 180F that will give you a good compromise between performance and longevity.

Prost! :cheers:

Stefan

bence13_33

69Sting:
You say you can't even hit 150 degrees? So in town driving it never goes above 150 degrees?

Sounds like maybe your thermostat is stuck in the "open" position. This happened to me before (with my 350). My problem was I didn't have the thermostat lined up properly when I put it in so coolant was able to pass by the thermostat upon start up. My motor would never get up to temperature...the mis-aligned thermostat turned out to be the problem. Either that or your gauge is reading wrong.

I would think a 180 degree thermostat would be fine.

77Dream

Is it really hot where you live? I live in sandiego and most of my driving is done in 80 to 100 degree weather, I use a 160 thermostat to help make sure things stay cool. If it doesn't get that hot in your area then the I would go with 180.

:cheers:

69Sting

The didn't get driven a lot the 5 yrs before I got it, so I am sure the thermostat is just stuck open and at $3 for a new thermostat, I can afford to replace it.

Normally I take it out when it is betwen 50 and 80 outside. In WI we will peak in the 90's some times but then I hide in the air conditioned vehicles. Just too hot with a convertable and black leather. NO AC in this car.

I thought 180 as well. but the local Autozone only has 195 or 160. I will call around and try to find a 180. That seems to be the best route.

Thanks. :cheers:

69Sting

Found one. Going to break the bank though. $2.95 for the 195 or 160 temp. a 180 temp super thermo is 7.95. I think I am going to have to get a bank loan on this repair :rofl:

bence13_33

77Dream:
Actually the job of the thermostat is to keep your motor from running too cold. With a 160 thermostat, it will crack open right around 160 degrees letting coolant through the motor. Inevitably your motor is going to reach whatever it's operating temperature is. The 160 degree thermostat just opens up quicker pushing cool coolant through the motor sooner.

I run a 160 in my Corvette just because my big block runs hot and it gives me a few more minutes of enjoyment before the temperature starts to climb. A lot of a motor's wear occurs while it's cold, thus the need for a thermostat. Some people run without them. It seems to take forever for the motor to get up to temperature if you run without one. What you also find is that when you run without a thermostat or restrictor plate the motor will likely overheat once it reaches operating temperature. This is because the coolant is flowing straight through and doesn't spend much time in the radiator to cool off.

On hot days my motor runs right around 200-210 degrees around town. I help keep things running a little cooler by running straight water instead of anti-freeze during the summer. Just be sure to add rust inhibator. The water dissipates heat better.

Rockn-Roll

:nono: Even when I lived in WA with snow on the ground I would get up to 160 in about 5 minutes...it probably seems like forever while freezing those first 5 minutes, but yes...and I would have rather had it get up to 180 in 2 minutes with a thermostat at least cause at 160 the heater really doesn't work as well. During the winter I would prefer to run a 180 thermostat unless I plan on doing some auto sports...though I actually never have run any thermostat for like 20 years.

As for overheating because the coolant flow rate is too high...I've presented many engineering web sites, and background studies on heat flow that shows that increasing the rate of coolant flow will increase the heat transfer...it's something that engineers learn in their lower division thermodynamics class. Faster flows will result in faster, better cooling. Up to a point...at extremely high speeds (way beyond the capability of our water pumps) the coolant won't actually exist as a liquid...it will be turned into a gas and will hardly cool the engine at all (some gasses might work well in this event, but not H2O steam). This not only is true for the coolant flow through the engine, but also for the flow through the radiator...the faster you can get it to flow through the entire system then the better your cooling efficiency becomes. It is possible that the coolant gauge can read a bit higher, but this is because the heat will be more evenly distributed through the system; thus, the coolant temp in the engine block will actually be cooler in some of the spots where it otherwise would be hotter than at the coolant guage sending unit. A limiting factor here is the air flow through the radiator...we all know that even a broken air dam will cause our vettes to overheat. But, in general increasing the flow rate by removing the thermostat will increase the cooling rate of the system.

This is strictly an engineering reality check...not intended to start a heated debate...again. If you disagree with what I'm saying then please call your State's University engineering department or check out an engineering Thermodynamics book from the library...even 20 year old books will have this info available. :conehead

Oh...and the egg came before the chicken. :jester

BSeery

oh -- the run a thermostat or not bit again.

I am just going to say this. GM put one in there for a reason. If it wasn't needed, then they wouldn't install them.

In fact most every water cooled car has one (couldn't say every one as I have not seen them all), and if they were not needed, after 100 years of automotive design someone would have removed the t-stat.

Plenty of smarter people than us and the engineers that post on the www have already figured out that at the least they were needed and at the worst they couldn't harm the motor (if working).

But the chance one may fail is not a good enough reason not to run one. In that same logic, why don't you remove your oil pump.

180 degree - high flow / super stat. :leaving:


[Modified by BSeery, 11:36 AM 4/15/2003]

AlwaysWave

check this out. http://performanceunlimited.com/illu...ermostats.html

69Sting

Good reading, the web site on thermostats is quite informational.
Considering my issue is not getting warm enough, I see I am hurting my motor not to mention putting raw fuel into the pistons because the fuel is not getting hot enough to eveaperate and mix with the air.

180F superflow, Well be put on this week. :jester
Hopefully it will get rid of the small dog in the motor.

77Dream

bence13_33
Well I guess it all depends. Like I said, I live where its very hot, If I had a 180 temp my engine temp would rise rapidly too that mark and keep rising untill the water is able too keep it cool. By the time this happens my car is very hot, close to overheating. with a 160 temp the cooling proccess starts sooner and the engine doesnt get quite as high.

The other reason I use a 160 temp is that my electric fans turn on at 195 and turn off at 175. If I had a 180 temp then my fans would almost never turn off. Right now they rarely turn on during the cooler days and nights, which is nice.

I agree that for most situations a 180 would be a better choice but if you lived here you might even run a t-stat. Your bigblock + 180 t-stat + 100 degrees = very hot:mad

OK... before I start WWIII, i'll shut up now. :D

Rockn-Roll

I've looked at that site before. There is no thorough explanaition of the test, nor how the results were obtained. Let's just say that the 50 hours of running was at freeway speeds of about 60 mph this would be about 3,000 miles. How much wear could there be? With a good oiled engine in good condition I believe it would be negligable as measured with a micrometer. Is the data collected while the engine is started with no oil on the cylinder walls? Do they prime the cylinder walls with oil? It is hard to believe that they could keep the cylinder walls of a running engine at 40 degrees for 50 hours...even if they did...how did they do it? Was the process used to keep it cool the actual reason for the wear? These questions need to be answered in order for the test to be valid. In my opinion tests were not even made...the graph could have just been created using ficticious data. From an engineering standpoint designs for machines which contain heat sources are placed as far away from the moving parts as possible to prevent the heat from increasing the wear in the parts. In some extreme cases coolant is used to prevent bearings and other high wear areas from getting hot. Although it does depend to some extent on the material in question, the general rule is that cooler parts will wear less. Something else to consider is the oil that was used...is it a light weight oil or heavy weight. If a heavy weight oil was used then the oil wasn't doing it's job at the cooler temp...thus the test did not evaluate the wear from heat, but actually the efficiency of the oil used to lubricate and protect the parts from wear at different temperatures.

Seriously, just because there's a graph does not mean that there was any test data...it's just an illustration of their marketing pitch...sales people do it all the time. Getting something hot to reduce wear goes against all the engineering data collected over decades of testing.

isosceles

According to the "How to build a High performance SBC" book, one way to get added HP is to get the oil temp higher than the water temp. I think they said optimal water temp at 170 and oil at 210?
I don't know if running a T-stat would help or hinder that, but it's something to consider.

As far as GM putting one in there for a reason? I think the main reason is for emission purposes. Seems like hotter motors burn more/emit less emissions, not to mention that the cat has to heat up to be able to work correctly.