why not run a 195F thermostat
 

been enjoying my car on the rare day we don't have rain lately. And noticed that when
I come off a highway run and the water temps are 190, that she idles smoother and feels
more responsive. Car never gets to 190 unless temps are 80 or better.
Usually around town she hangs at 183-185, so no big temp difference.
But I started thinking, why not run a 195?

Gerry

Why not. I assume that the original 180 F theromostat is an average solution for running in any climate from Arizona to Maine and it might run a bit colder than supposed to if you live in a colder area. Check your temp gauge so it reads correct though. ( its not overheating until the idiot lights comes on at 240 F;) )

195 is a safe temp for an engine. Many manufacturers use that thermostat in modern engines. Boiling is 212 degrees f and that is with no pressure in the cooling system.
As A.J. posted with a normal radiator cap (15 psi) the boiling number is closer to 240 degrees and you are asking about a 195 degree engine coolant temp. No worries and if the engine likes it , listen to the engine.

Told a Big Boss at my old job one time, "The Engine is TRYING to tell you something, are YOU willing to listen?" Dead quiet in the room for about a minute and the Big Boss said, "Yes I Am" and we had a successful engine program. Never got fired for telling the truth in 39 years but not everyone was as smart as that guy was.

Tom V.

Hum?
 

If 5°~7°F makes the engine run that much better....Need to be checking the tune-up. Hotter combustion chamber temps and the fuel mix lights off better/easier.

So might need a little more initial timing or idle mix leaned out just a tad.

Clay

T-stats are kind of counter-intuitive. The higher the T-stat temp, the longer before it opens letting the coolant in the radiator stay in there longer, letting it cool more. Running a 160° stat will usually increase your temps because it will be open most of the time not letting the radiator do it's job. Try a lower temp stat to raise your temp a little. As stated above, you need heat to get proper combustion efficiency.

The whole purpose for running the lower (180°F) thermostat for most guys is that they are pushing the limits on static compression and can't run warmer temps. Then some guy reads that lower temps are better and the next thing you know the entire Pontiac Community thinks their car will self destruct at any temperature above 180°F..........Just like the self destruct feature at 5600rpm and 9.6:1 static compression ratio.
The '72 Pontiac Service Manual specifies a 195°F Thermostat.

It's the other way around. It allows the water to stay in the engine longer to get warmer.

Stat temp
 

Well I feel carb is set right. Same plugs look great for
A few years now. Timing is conservative at 12 initial and 20 mechanical
All in around 3200 rpm. Ported vacuum gives another 12.
Runs great as is and just thinking aloud on this one
My engine just seems happier and smoother with 180 rather
Then a 160. Maybe the fuel
Atomizes better. My crossover is open and even after a highway run
She cools back down to 182-3 after a few miles in the heat.
Just thinking aloud.

Do what?
 

If a cooling system is functioning properly, a cooler thermostat will not make an engine run hotter. Thermostat sets minimum engine operating temperature. Doesn't matter what radiator temps are as long as everything else is working right. Working right the water exiting the radiator will be cooler than what goes in. Then the thermostat will open or close to keep minimum engine temp where it's suppose to be.

The OP's car heating up at highway speeds...tells me something in the cooling system needs a little TLC.

Clay

Different temps
 

When I ran a 160 my temps were 165-170 on highway.
With a 180 my temps have been 182-190. 190 was max on long highway
Run in the heat. So I feel cooling is adequate. Heck that is why I wanted
To see if anyone else runs a 195.
Gerry

:huh:

Maybe..But
 

Might be worth a try if the engine likes the 190° temp.
But, my biggest fear would be gaining the additional 10° (on the highway), with the 195, that you had with the other two thermostats mentioned.

Don't know what compression you're running, but 205° temps might get you to the point of detonation.

I'ld have to try bumping initial timing up some and see if it runs better. Depending on your highway cruise RPM vs. centrifical advance...the engine may even run cooler.

I'ld have fun with it tweaking all the same.

Clay

The 400 in my car is out of a '69 Firebird (for comparison to the OP's setup.)

I run a 195 thermostat, (what it left the factory with), and find that my motor runs better at 200.

Old wives tale. Simply not true

This. If your engine runs hotter when you put a colder T-stat in, something is wrong.

For max power you want a cold intake. Colder/denser charge = more power. However, we're not driving around at full throttle all the time. As this is the street section, drivability is important. A warmer intake helps keep fuel in suspension giving a more homogeneous air/fuel mix that will burn better at lower RPMS/intake port velocities and hotter cylinders promote more complete/efficient combustion.

I run a 180 stat in my street cars. Good compromise between keeping things a little cooler for more power yet warm enough for good drivability.

My Formula never ran above 190-ish with a 180 T-stat in it (Needled hovered either side of 190 depending on air temps and how I was driving the car). The only time the gauge went above 195 was when there were problems.

To the OP - if I was you I'd try dialing in a couple more degrees of advance just to see what happens. Could be the engine will run cooler on the freeway. If it runs a little cooler and you don't get any pinging, try another couple of degrees. I wouldn't go over 36 total, but you might see a difference going more than 32. Or, you might not. Only way to tell is to try it. If you find it runs cooler on the freeway but you get pinging driving around town you could also try finding a vac can that gives more advance.

I'd also install a 180 thermostat. IMO, 160 is just too cold for daily driving/around town.

Thermostat
 

Currently running a 180 superstat. And after reading about it will leave well enough alone.

There should not be really any difference between 180 and 195 but for full throttle power!

I would say the better running you have with higher motor temps are due to your cruse air to fuel ratio being too fat, and or your spark plugs you are running are too cold!

Another possibility since you did not post up if the motor has been rebuilt or not is that the higher motor temps on a high mileage motor will close up the ring gaps and make for more even and higher cylinder pressure and in turn even more engine vacuum!

Temp?
 

Well the motor is the original 68 400 with 16's large valve.
Factory iron intake and long branch manifolds.
The cooling system is an aluminum rad with 2 rows of 1" tubes.
AC pulleys, severe duty fan clutch with 7 blade AC fan.
Water pump is 11 bolt, cast impeller with tight clearance to divider plate.
All filler panels and seals in place.
Plugs are R45S and same set are clean for years.
Motor was rebuilt 12 years ago. All stock except for TRW forged
Pistons. Running the 068 cam. Non AC car.
Gerry
She is just a cruiser and mostly does shorter trips.
That why I thought of higher temp. Once it gets to
September it barely even touches 180!!
Again thanks for the replies

Make sure the idle speed screw returns firmly against the stop with choke off hot. It may need more return spring
Make sure the mechanical advance is coming back to zero at idle in and out of gear. The mechanical advance may be sticking or have weakened aftermarket springs giving erratic idle.
Hot fuel pump pressure would be another check. Be careful off fire.
Confirm the above then adjust mixture screws and throttle stop @ off the highway temp.
And leave the 180 as is.

An engine is thermally more efficient at higher temps, if it can stand it. Cars from the 1980's to present are set to run at about 220 degrees coolant temp for greater fuel economy and lower emissions. Our old dinosaurs are more prone to detonation at that temp, so 195-ish would be ideal. All things being equal, an engine running at 195 will be more efficient than one running at 160-180. I also agree that what was said earlier about installing a lower temp T-stat to raise operation temps is simply not true. Just the opposite.