180 vs 195 Degree Thermostat [Archive] - Team Camaro Tech

: 180 vs 195 Degree Thermostat


Andrew69
May 10th, 12, 07:37 PM
I have been reading the discussions about thermostats and going without or drilling holes in them and it got me to thinking. (Yes, I know, that is dangerous) I have been running a 180 degree thermostat with the aluminum radiator and my temp gauge always reads around 170 degrees.

That 170 degree reading could be related to my temp sensor that is installed in the RH head under the header area. Even though the head is a heat point it is not at the top of the water jacket.

Might I benefit in performance with a 195 degree thermostat?

Steiner
May 10th, 12, 07:45 PM
You should be getting at hotter reading there than if you moved it to the intake. I get a little under 180 at the intake from the ECT sensor and over 190 in the head from the mechanical gauge. A thermostat just starts to open at the rated temperature, not fully open. That's why your newer cars with the 195 thermostat read about 210 degrees.

What brand thermostat are you running? I bought one of those Stewart Warner Stage III or something ones when I first dropped my engine in. It was actually for a blocked bypass setup so it flowed so much when closed that the car would never get up to temp with the aluminum three row radiator and high volume pump. Made it a pain to get the EFI setup since it doesn't start adjusting long term fuel trim until 145 degrees.

Grabbin2ndgear
May 11th, 12, 06:05 PM
I run 192's in my stuff, works out to be around 195 once it settles in. I don't think you can get the stock 192's anymore from GM , they sell you stant's now that are 195's. These motors were all designed to run at 195+. Smokey even liked to run his hotter, around 220 to get optimal performance.

Everett#2390
May 11th, 12, 06:12 PM
Robertshaw makes all the thermostats.
Try a 195F 'stat, heat makes horsepower.
Temperature stamped is opening temp, fully open 10F later.

Andrew69
May 11th, 12, 06:28 PM
Today I purchased a 180 degree t-stat from the NAPA store. Removed the current thermostat, which is also marked 180 degrees, and put both plus a thermometer in a pot of water on the stove. When the water was at 180 degrees the new one was just cracking open, while the old one was open ~ 3/16 inch. The photo below is at 180 degrees and you can see the old t-stat in the foreground with a pretty big gap.

Anyway, the new t-stat kept the engine right around the 180 degree mark and the engine seems to like the extra 10 degrees of heat.

Now you tell me I should use the 195 t-stat instead. Doggone it! :mad: (No offense to your Bassets Everette) ;) The guy behind the counter at NAPA did say their computer recommends the 195 for the 350 and 302 engines in '69. I guess I'll pick one up next week and give it a try.

Everett#2390
May 11th, 12, 06:36 PM
No offense taken, Andrew, it's only a science project.

Vegas69
May 11th, 12, 08:45 PM
Your carb will like 180, your engine will benefit from 195. :D

Steptoe
May 11th, 12, 10:56 PM
I have been running a 180 degree thermostat with the aluminum radiator and my temp gauge always reads around 170 degrees.
Well the most common issue ids the gauge not reading correct.
Take the sensor out groud the body and heat u with an accurate mercury themoeter in a jug of water connected to the guage...varify the gauge
Automotive temp gauges are not highly accrute and nor designed to be.
As to run 180 or 195?
well lets get into the real world....yes As smokey says more power devaloped at higher temps..BUT that also takes into considreation other stuff like machining tolerances matched to suit...are yours
Now lets take common sense further..
This more power is at a narrow max power rpm band width WoT....or in other words on the track.....Anywhere else ...well taking off from an interesction , hit the other side back off...hit the rpm range, and if did long enough diff between a 180 and 195 wouldnt make a scrap of difference
On a road trip open highway, not even close to rpm range and using maybe 20 hp.
So unless a full out track car looking for that tiny edge over the rest of the feild 180 against the 195 not a scape of difference
Real world.

DjD
May 11th, 12, 11:12 PM
Today I purchased a 180 degree t-stat from the NAPA store. Removed the current thermostat, which is also marked 180 degrees, and put both plus a thermometer in a pot of water on the stove. When the water was at 180 degrees the new one was just cracking open, while the old one was open ~ 3/16 inch. The photo below is at 180 degrees and you can see the old t-stat in the foreground with a pretty big gap.

Anyway, the new t-stat kept the engine right around the 180 degree mark and the engine seems to like the extra 10 degrees of heat.

Now you tell me I should use the 195 t-stat instead. Doggone it! :mad: (No offense to your Bassets Everette) ;) The guy behind the counter at NAPA did say their computer recommends the 195 for the 350 and 302 engines in '69. I guess I'll pick one up next week and give it a try.

Don't waste your money, you will be fine with the 180... I'm not saying the 180 is better just that it is fine since that is what you have just bought...

DT
May 12th, 12, 09:44 AM
If there are NO overheating issues, I bet you would never realize a difference from 180 to 195. I happen to have a 160 in my BB. Works for me.

joesauer
May 12th, 12, 11:12 AM
180 should work fine...think that's what came with the car? If you want to get a little more flow (bypass) when the engine is cold try a 180 Robert Shaw Stage 2. It has 3 small holes drilled in it & is required when using some high flow water pumps (i.e Stewart).

Andrew69
May 12th, 12, 02:48 PM
Yep, it probably is just as well to leave the 180 in there. This car has no AC so keeping it at 180 vs 195 may make a difference to me, the passenger, during the upcoming summer months. At least now I have a 180 degree thermostat that is functioning correctly.

hhott71
May 14th, 12, 11:20 AM
It would be nice if someone would A-B some thermostats at the strip.
start with a 160 then a 180, then a 195 and last a 210 with a graph of ET and MPH
gains or losses as the temps varied.

DjD
May 14th, 12, 12:21 PM
It would be nice if someone would A-B some thermostats at the strip.
start with a 160 then a 180, then a 195 and last a 210 with a graph of ET and MPH
gains or losses as the temps varied.

That would probably be harder to do than just changing t-stats and making a pass. The efficency of the radiator core and water pump really come into play. If a cooling system can't drop the operating temp below the rating of the t-stat the stat will open and never close again. A lot of guys run a 160 t-stat and see 180 degs all day long, that t-stat never closes. My alum headed Nova runs this way, the sender is mounted in the intake manifold and the temp reads 170 degs and steady, I'm sure if the sender were in the head it would be 180.. On the other hand my iron headed Camaro has a 180 t-stat and the temp (sender in the head) gauge can read just over 180 and it will drop to just under. The hotter it is outside the more often it does this and maybe climbs to 190 tops.

The alum headed engine runs sharp and crisp from about 160 degs. The iron headed engine is cold blooded and needs to be at 180 before it really runs sharp and crisp. At one point in time I played around with the Camaros engine temps and found any temps above the 190-195 range seemed to create too much under hood heat and that caused it to seem anemic. Brought the engine temps down and the under hood temps dropped and the engine woke up!

I'm not trying to discredit that higher temps may make more power and burn off bad crankcase vapors. I just think there are trade offs like feeding the carb hot air from higher under hood temps. As well 170 degs maybe less will work to burn off the bad stuff in the crankcase, you may just need to run at operating temps a bit longer with the lower temps.

Steptoe
May 14th, 12, 02:27 PM
With a stock cooling system radiator no blocked cores or partly blocked the engine will run all day +/- 5 degree of the thermostat, be it a 140 160 180 or 210.
One can then trow a trailer on and tow a vintage car a 100 miles...on a hot day same
What will put temps up considerably is go from sea level to the snow line and then it will run hot.

The biggest issue with oil contanimation is short trips, regardless of thermostat temps...the therory of thermostat temps and oil temps has no real basis...there is more heat transfer thru oil than thru the water cooling system
This is why "Chrome for show black for track" Chrome /polished tappett covers, sumps etc are for show and black for track... stock tappet covers are tin, or if alloy have cooling fins and painted between.

It doesnt matter if one has a 140 or a 190, do a lot of short /round town stuff, then a good highway run and the oil levwel drops a little..it is the time the oil is hot giving enough time for the solvents/water etc to evaporate off.

And Denis mentions a trade off as to under hood temps and hight coolant temps for power.
Again spot on correct...yep engine dyno run show more power at higher temps....engine on a dyno, there is no under hood and induction air temps/source is controlled
A track car once againd ver similar situation..no inner gaurds etc.

Just because a engine does stuff on a dyno, on the track or street even chassis dyno very different results.

srode
May 14th, 12, 05:39 PM
When I was racing, I had no thermostat and I used to dump 10 gallons of water through the system before every race. Pushed it to just short of the bleach pits. Did my burnouts, dried them and staged quickly. That's the way the car ran the best times. If a car broke in front of me on the launch pad or there as a delay the engine was warmer than I wanted (not hot by any means) at the line and it ran slower, noticeably slower. I think it was because the intake was cooler that it ran better. I used a cool can for the fuel line too. Probably has a bit to do with how the car is tuned too.

For a street car, higher temps mean less moisture in the oil and that is a good thing.