[z/27 camaro]

Hi Guys
i just changed the T-stat in my 69 350 SB. i put a 195* T- stat in. i took out a 160* out and i didnt look at it till i put the other in.
whats the proper temp T-stat for my motor?

this new one looks like it might be acting a little wierd too on the temp gauge. the temp goes up to about 3/4 on the gauge before the T-stat opens and then comes down to 1/4 or between a 1/4 and 1/2 on the gauge.
i havent been able to run it on the road yet, as the insure doesnt kick in till April.
whats do you guys think?
thanks

 

[DjD]

Run a 180 deg stat, no reason for anything else... The temp has to climb to what ever the stat is rated for or above before the stat opens. So if you are running a 195 figure the temp will reach 200 before the liquid can flow through the block and core and your cooling system does it's job. Then it's going to cool down some and if it drops below 195 the stat will close and the cycle begins all over again. Your guage may not be calibrated but it's registering the heat rise and drop so that's a good thing. Some stats open slower and the temp will go up a bit more. With a 180 you'll see a bit less movement on the gauge. The 165 stat probably would never close once it opened. It would only be doing half it's job that way...

 

[z/27 camaro]

thanks for the info Dennis........i meet you and the white wonder in Seattle a few years ago at the camaro show at the college and we all went up to Kevin Sadams car collection. [ i still get goose bumps when i look at the pics i took there.] you making any road trips to vancouver BC this year?

 

[DjD]

Mike that was a great trip and Kevin's place was icing on the cake... I wish I could find the time to make another adventure north but it's not in the cards this year. I do have a long weekend planned where we are going about 200 miles south to Pismo Beach for 4 days but that's really it so far...

Hey you should hook up with Dan and Mark for their trip south, we are all meeting up on Aug 18th in the bay area. I'm sure they would love the company...

 

[wiskeesour]

My engines, above 400 cubes gets a 195*. below that is a 180* just my opinion tho...

 

[Fred Ficarra]

Like Dennis said, no reason for anything else except a 180*. Mine came with a 195 originally but that was for emissions. Hey, the lifters were spec'd to .004 more clearance than the year before because of emissions. (yeah, right!)
One exception to Dennis' rule: I just went to my Chevy dealer last week and bought a 160* Delco. With aluminum heads and 12.5:1 compression, ya gotta run cold. I had tested my old (no name) 160* stat and it was only half way open at 190*. It even had the two Smokey Yunick vent holes.
The new Delco tested and works perfectly.

 

[onovakind67]

If you're using Smokey's vent holes you should read what he has to say about engine operating temperature:
Running an engine at 180° will drop the overall horsepower by 2-3%. For max power the coolant should be at least 200°, and you should have at least 25 pounds of pressure in the system. Actually a racing engine like the smallblock Chevy will produce more horsepower as the operating temperature is increased, all the way to a maximum limit of about 220°.

Power Secrets - Pg. 121

 

[DjD]

If you're using Smokey's vent holes you should read what he has to say about engine operating temperature:
Running an engine at 180° will drop the overall horsepower by 2-3%. For max power the coolant should be at least 200°, and you should have at least 25 pounds of pressure in the system. Actually a racing engine like the smallblock Chevy will produce more horsepower as the operating temperature is increased, all the way to a maximum limit of about 220°.

Power Secrets - Pg. 121

I'm not questioning Smokey, I believe what he says. I just don't think 2-3% hp loss is an issue in city traffic, the freeway or even out on a country road. I believe 160degs is the bottom edge of a properly warmed up engine with respect to longivety. That and most factory and replacement cooling systems will work well enough that running a 195 stat will only result in temps bouncing between maybe 180 and 200 as the stat opens and closes. What does that do for power and engine longivity? My experiences have been that the 180 deg stat seems to be the most stable, less fluctuation.

I put about 75 - 100 miles on my ragtop yesterday in about 68 - 70deg weather and my temps only hit 180 sitting at a light. The rest of the time the needle sat just below 180. Stock water pump, stock style fan and clutch and a modine core in the stock 3 core tanks along with a Robert Shaw 180 stat and a 16lb radiator cap... Safe operating temps, no excess heat buildup causing too warm of air feeding the intake and power to spare for the useage...

Now if I were building a car for the track I'd be inclined to utilize a lot of Smokeys tips and tricks, more pressure in the system allows it to heat more without boil over and as long as you can get a cool intake charge run 200+ and make every ounce of power you can...

 

[Fred Ficarra]

Well onova, ya know, as an OLD fan of Smokey, I can't think of a thing he wrote that didn't refer to a RACE CAR.
Sure, small blocks need to run hot. But during a race on a circle-track, controlling temperature is a little easier than in stop-and-go traffic on a hot summer day with the hotrod. And I'll bet he had race fuel, not pump gas. Ten bucks? Hell, I'll go fifty.:yes:
Another trick of his is to pour that egg preservative (I can't think what it's called) into the back of the combustion chambers of aluminum heads. It hardens and therefore insulates the heat in the combustion chamber to make as much power as a iron head. Bet he didn't have to pull heat out of the chamber to avoid pinging on pump gas ether. Hundred bucks?
And did we talk about how heat utterly destroys the stuff in the engine compartment of our classics?

 

[z/27 camaro]

hey Fred......
i was looking at the pics of your camaro.......nice......how do you like the gear vender OD?
you've had it in there for 23 years??? wow.
i have 1 too..........put it in 3 years ago........love it!
did you know Baldwin Motion had a similar OD unit as a dealer option in 1969 called a Hono drive. bit of classic trivia.

what are you using as a switch for the GV OD? a foot switch?

thanks for the T-stat info guys!

 

[Fred Ficarra]

hey Fred......
i was looking at the pics of your camaro.......nice......how do you like the gear vender OD?
you've had it in there for 23 years??? wow.
i have 1 too..........put it in 3 years ago........love it!
did you know Baldwin Motion had a similar OD unit as a dealer option in 1969 called a Hono drive. bit of classic trivia.

what are you using as a switch for the GV OD? a foot switch?

thanks for the T-stat info guys!

Back in '72 I bought a Hone-O-Drive. It was a 30% OD. At 60 MPH my RPM dropped about 1000rpm. But because it used a U joint between it and the tail shaft of the primary transmission, IT VIBRATED LIKE HELL in direct drive. When it blew up one day, I found that the company had gone out of business. Lucky me. The GearVenders is a much better product except the RPM's only drop about 600 at 60MPH.
My unit has the foot switch like the headlight dimmer switch. I mounted it on the floor just above the headlight dimmer. It's OK, but confusing, even after all these years. But I have the option of leaving the dash mounted rocker selector switch in 'Auto' mode. Then it would shift into OD at 45MPH no matter what the throttle setting, and back to direct drive at about 20MPH. I haven't used that position since it was new, when I found out how boring it is.:noway:
And thank you for the nice comment!

 

[onovakind67]

Well onova, ya know, as an OLD fan of Smokey, I can't think of a thing he wrote that didn't refer to a RACE CAR.
Sure, small blocks need to run hot. But during a race on a circle-track, controlling temperature is a little easier than in stop-and-go traffic on a hot summer day with the hotrod. And I'll bet he had race fuel, not pump gas. Ten bucks? Hell, I'll go fifty.:yes:
Another trick of his is to pour that egg preservative (I can't think what it's called) into the back of the combustion chambers of aluminum heads. It hardens and therefore insulates the heat in the combustion chamber to make as much power as a iron head. Bet he didn't have to pull heat out of the chamber to avoid pinging on pump gas ether. Hundred bucks?
And did we talk about how heat utterly destroys the stuff in the engine compartment of our classics?

Why would controlling the temperature in a street car be more difficult than that of a circle track car? More mud gets in the radiator? All you have to do is keep the water and air flow going and your hot rod will stay cool all the time. Modern 500 hp cars run 200+ all the time and I don't see them pulling over with cooling problems.
You'll bet he didn't have to pull heat out of the combustion chamber to avoid pinging on pump gas? Where else would you pull heat out of to prevent pinging with any gas? Running WOT on race gas with whatever modifications he made will produce far more heat than a street driven hot rod.
My measurements on our road racing car show that under hood temperatures are generally about 70 degrees less than the engine temperature. I don't see that raising the temperature from 110 to 130 is going to considerable shorten the life of your engine compartment. The average radiated heat from the exhaust system should remain fairly constant regardless of the operating temperature. Your timing and fuel control will greatly affect this temperature.

 

[Fred Ficarra]

We obviously live in different parts of the country. Ours is often gridlocked. In the summer is when construction happens. (If we voted for the last gas tax increase) That means more slow downs.
And you're forgetting that for each doubling of speed results in 4 times the air movement. I can't recall a hotrod ever overheating while moving at highway speed. (but I'm sure somebody must have blown a hose)
An example of my point is the way Hotrod Magazine tortures the competitors in such events as the pump gas drags (among others). They are forced to drive in city traffic. Many cars overheat and drop out.
One more thing; Do you run a restrictor instead of a thermostat in your race car? That's all you need at RACE SPEED.
Your mud analogy isn't applicable. Mud stops air flow. You're back to a hotrod stuck in traffic.
But maybe my reference is skewed. I've been running BBC's in my rides since the mid '60s.
And your race car engine temp readings is EXACTLY my point.