Thread: What temperature?

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I was just wondering...
What temperature should a SBC run at? I use it for regular road use in a heavy vehicle (5000 lbs) and am currently running 160° thermostat. Is that maybe too cool? I have a quite high CR with Sealed Power flattops and 64cc iron heads, am running a roller cam and it runs OK, but maybe it would run a bit better still at a higher temp? I get over 60 PSI (35-40 at idle with the engine warm) oil pressure, which seems a bit high...
What good would a higher temp do? Maybe go 190 or 200? What do you think?
Thanks a lot,
Max

What temperature is the engine running at in normal operation going down the road?

Under normal conditions I get about 165°F. Doesn't go much higher if I race around a bit, I have a high flow thermostat and a good radiator core and cap. It reaches the temperature in about 2 minutes if I drive raound normally, faster if I race it. I guess it would go higher with a warmer thermostat... But do I want to go higher? That's the question...

Well, 165 seems a bit low to me to make the engine operate efficiently. I like my motors to run in the 185 to 195 range. This is where the make the best horsepower on the dyno, so that would indicate the engine is operating efficiently.... JMO

i have a similar problem, my engine barely reaches 160 after driving around 20mins. I havent taken to anybody yet but I think i have a problem as well.

Originally Posted by Dave Severson

Well, 165 seems a bit low to me to make the engine operate efficiently. I like my motors to run in the 185 to 195 range. This is where the make the best horsepower on the dyno, so that would indicate the engine is operating efficiently.... JMO

I agree with Dave. Runnin' 'em any colder than that increases internal wear dramatically.

I've been told that if the engine is running to cold (160 or below) and with today's gases the engine is not hot enough to burn all of the gas thereby potentially causing ring failure due to washing down the cylinder walls with excess fuel. Complete burn doesn't come until at least 180 degrees. Running 180 to 200 is best.


I'm no expert, but that's what the experts tell me.

OK, seems to be a bit more of an issue than I thought... Guess I'm going to put in a 190° or 200° thermostat. Got a very minor leak round the thermostat housing anyway, good time to yank it off
Thanks for the input, I may be a slow learner, but I'm getting there (I hope )
Greetings from across the lake
(where gas is $6,50 a gallon, so I do want complete burn )

My truck reaches 210 in traffic is that too hot? My '03 Tahoe normal operating temp is 210, why is that?, whats the difference?

Higher thermostat temperatures result in lower emissions and less cylinder wear for longer engine life. Your engine is too hot only once the cooling system starts to boil. Most cooling systems are at 12-16 psi and the boiling temperature of coolant at that pressure can be as high as 260 degrees. If the water flashes to steam, the engine will overheat because steam has poor heat conduction properties and wont be able to draw heat away from the cylinder fast enough. You can't just run your engine at 260 degrees to reduce liner wear, though. The 260 degrees you thermostat sees is kind of an average of the temperature of the coolant coming out of the enigne. Within the engine, there are going to be localized spots that are 20-50+ degrees hotter than the temperature the thermostat sees. In order to prevent localized boiling, a safety margin of thermostat temperature needs to exist. The GM engineers decided 195 for a small block chevy. The newer 210 degree engines run some fancy reverse flow direction cooling systems that make them more compatible with the higher temperatures. Though, the last of the 5.7L truck engines were standard flow and I believe they ran 210 degrees.

210 in traffic is good. Cars running r134 a/c run a little hotter than those running the old r12. I have one of each and have to keep reminding myself of this. But a/c aside, 200 -210 in traffic is average. Even 220 with the appropriate lcoolant mixture is okay. I have had a streetrod run as hot as 240 - 250 with no damage. The electric fan circuitry failed and the only cool air I could get was go fast air. Would not want to repeat that experience, and glad the engine was not of the aluminum variety.

As long as it doesn't boil, you're fine.

Just as important as the water temperature is the oil temperature. You don't want your engine oil running over ~240 F normally. So if you don't have an external oil cooler then you probably want to operate your engine around 200-210 F normally. Why? The babbit in bearings will flow plastically (permanently deform) somewhere around 280-300 F and you need some margin for higher loads (heavy throttle).

Kitz

Do you guys have any thoughts on useing water wetter or purple ice you know the additives that are made to help bring down temps?

On turbine engines, we get worried when the returning oil temperature exceeds 190 degrees. That's because the bearing itself could be much hotter.