I know this topic has been discussed before, but I wanted to bring up a specific question. Is there such a thing as max power operating temp? I ask because my engine builder says that my new 355 makes the most power at 210 degrees. I know my modern LS2 engine runs at 210, but that is with modern components etc. I have always thought that the cooler the better for older V8's etc, but I am no expert. What do you guys think?
I've been running a .030 over 350 for the last 12 years and it runs right at 180 degrees. I don't know how much more power I could get by running 30 degrees hotter but I don't think I'd be too comfortable doing it.
I know this topic has been discussed before, but I wanted to bring up a specific question. Is there such a thing as max power operating temp? I ask because my engine builder says that my new 355 makes the most power at 210 degrees. I know my modern LS2 engine runs at 210, but that is with modern components etc. I have always thought that the cooler the better for older V8's etc, but I am no expert. What do you guys think?
Look at the temp gauge in new cars they all run over the old 180 standby.Heat equals horsepower and more complete burning of fuel causing better mileage.
I just learned the hard way that not having enough heat is as bad as overheating. I was always so happy my T only ran at 150 going down the road, but I just had to tear the heads off to clean off the built up carbon that I feel was caused by too cold of an engine and too rich of a fuel mixture. It was so bad I actually had NO compression in one cylinder.
I have now replaced the thermostat with a 180 instead of the 160 I had, and have also put a fuel pressure regulator set at 3.5 pounds. The plugs are now burning a nice whitish color and the carbon seems to be going away due to a system cleaner I am running in the fuel tank.
Now it runs down the road at 170 or so and seems much better.
I always liked 180 thermostats. My 04hemi is suppose to run at 210, but on a dyno it made more power at 190 and the air fuel ratio was better at the lower temp, I'm sure the computer had everthing to do with that though..but I still run a 190degree thermostat in it..
With a 350/355 I've always ran 180degree thermostats.. I think 210 would be way to high, just if your running 210 and something happens, you'll have more time to react at 180 than you would at 210..plus your tuning tghe engine, not a computer doing the tuning..
They say hotter does make more power and it should, bores open up when heat is introduced to them and bearing fits get a tad bigger also, effectively loosening the engine up..also oil viscosity breaks down with heat, basicly thinning the oil, making less resistance on internal parts.
I agree, plus living in Florida it doesn't take long for the temp gauge to go from ok to too hot before you notice it. My Jeep truck had a 5.0 Ford I swapped in it and I could never get it below 190-200 going down the road, but it was fine for 5 or 6 years that I owned it.
They tell me some new cars have electric fans that don't even come on until 220.
I thought the warer the fuel, the easier it atomized, causeing more of it to burn, giving better gas mileage. Way back when we where running at the strip, we used to plug the heat passages in the intake so the colder fuel would give more fuel in the cylinders because it was denser. Of course we weren't worried about mileage then. More fuel and hotter plugs.
As for best operating temp, you need to concider air flow over and around your engine. Some cars will benefit from having a hood actually causing a tunnel effect. A engine with no hood can run hotter than one with a hood.
This is mostly hair splitting to my thinking. On the street the only thing i worry about is that the dang thing don't overheat. I do like to see between 180 and 210 on the guage tho.
RPM and DonsRods are correct.................as your engine builder likes 210..................hey, its what works for the individual involved.......but let me elaborate a little furthur...............
Certain things are 'designed' to run a certain way..............certain ring and piston combo's if not run at a certain temp...........can cause undue wear, block and ring wear, that is..............
Its like the trans cooler thing....................most cars had to trans coolers built into the radiators...........it was more for warming the fluid up than it really was for cooling..........but it aslo did the cooling effect.............thats why any really heavy duty units had like aftermarket coolerson them, AFTER, the radiator trans cooler..........or they had a seperate thermostat for opening at a predetermined temp..................
But in your case with the 355.................as long as you got a cromemolytop and a cast iron 2nd ring.................180 would be fine.............
If you got chromemoly on both top and 2nd rings...........yes..............it'd be best to run it at 210...........or you run the risk of alot of undue block wear.............
I don't know if there is a strict relationship between temp and HP, but internal combustion engines in general work more efficiently the hotter they are. But of course we don't want it so hot that we degrade the oil, or cause the engine to boilover. I've been running my SBC for 15 years at 230F max. But I know where my boilover point is (250F) by experimenting, and so it's OK. If you don't know where your engine will boilover, then you would want more cushion. But 180F is not the holy grail, and don't spend time and money chasing it.
Look at the temp gauge in new cars they all run over the old 180 standby.Heat equals horsepower and more complete burning of fuel causing better mileage.
The higher temperature that today's engines run at has more to due with achieving specific emission levels than higher power. Combustion chamber temperatures must be kept within a certain temperature window to minimize NOX. That wasn't a concern in the past, and as long as an engine ran hot enough (usually 180º) to boil of any condensed water in the oil, that's all that was needed.
The higher temperature that today's engines run at has more to due with achieving specific emission levels than higher power. Combustion chamber temperatures must be kept within a certain temperature window to minimize NOX. That wasn't a concern in the past, and as long as an engine ran hot enough (usually 180º) to boil of any condensed water in the oil, that's all that was needed.
My impression is, it's the lube oil thats the limiting thing with running higher engine temperatures. Viscosity is a temperature thing but it doesn't decrease linearly, most multigrades drop viscosity off quite markedly in the high 100's. It is quite common to run circle track engines up in the 210-230 range but the lube oil needs to be down in the 170 range to avoid excessive viscosity (hence film strength) loss.
Don't forget the heat loss of the coolant in the radiator is a function of the temp. difference between the cooling air and the coolant - the greater the difference ("delta T") the greater the loss.
The higher temperature that today's engines run at has more to due with achieving specific emission levels than higher power. Combustion chamber temperatures must be kept within a certain temperature window to minimize NOX. That wasn't a concern in the past, and as long as an engine ran hot enough (usually 180º) to boil of any condensed water in the oil, that's all that was needed.
I believe this is correct. There are many variables that affect water temperature. The 210 thermostats are part of compliance with emissions standards. 210-230 is around the maximum for a part water cooled engine. The computers and fuel injection also play a part as well as compression ratio and cam and ignition timing. Engine builders that like 210 degrees may be in a state that has emissions requirements for street engines.
Something to think about is the fact that 60s engines like my 396 were never designed to be run over 180 deg. Even with hardened valve seats for unleaded gas the cylinder head configuration allows very high combustion temps that frequently result in detonation. One size fits all kind of answers don't work well in this case.
Well, to be totally simple.....the cooler the engine the better as far as lube is concerned, and the cooler your air density on your intakecharge...the more horses.....detonation is a direct byproduct of too much heat in most cases as far as performance engines are concerned caused by ignition timing being out....too low a octane rating and various other causes....under engine load.
Some engine designes are designed to run better with more heat. Before Smokey Yunick died he designed a lean burn engine in a Fiero that got MUCHO miles per gallon and ran really well to boot! The government don't like to hear all that though....so they keep getting the car engineers to bandade the problem.
The Diesel industry....Cummins ran their engines super hot and injected air into the exhaust system to clean up some emissions and try to keep decent horsepower ratings...
Its all a shell game though...if it ain't broke..don't try to fix it. Hotter enginetemps are harder on engines, the cooling systems and the electronics that operate them. Horses in racing isn't done with a cold engine....just a engine thats operated in a cooler range to take advantage of a cool dense fuel/air mixture. If rou try to race a 'cold' engine....you gotta run a engine that 'worn out', clearance wise. Cold oil doen't lubricate as well as warm oil.
Now....you actually make morehorses running just a touch on the lean side that does create more heat. A little food for thought...
Well, to be totally simple.....the cooler the engine the better as far as lube is concerned, and the cooler your air density on your intakecharge...the more horses.....detonation is a direct byproduct of too much heat in most cases as far as performance engines are concerned caused by ignition timing being out....too low a octane rating and various other causes....under engine load.
Some engine designes are designed to run better with more heat. Before Smokey Yunick died he designed a lean burn engine in a Fiero that got MUCHO miles per gallon and ran really well to boot! The government don't like to hear all that though....so they keep getting the car engineers to bandade the problem.
The Diesel industry....Cummins ran their engines super hot and injected air into the exhaust system to clean up some emissions and try to keep decent horsepower ratings...
Its all a shell game though...if it ain't broke..don't try to fix it. Hotter enginetemps are harder on engines, the cooling systems and the electronics that operate them. Horses in racing isn't done with a cold engine....just a engine thats operated in a cooler range to take advantage of a cool dense fuel/air mixture. If rou try to race a 'cold' engine....you gotta run a engine that 'worn out', clearance wise. Cold oil doen't lubricate as well as warm oil.
Now....you actually make morehorses running just a touch on the lean side that does create more heat. A little food for thought...
The higher temperature that today's engines run at has more to due with achieving specific emission levels than higher power. Combustion chamber temperatures must be kept within a certain temperature window to minimize NOX. That wasn't a concern in the past, and as long as an engine ran hot enough (usually 180º) to boil of any condensed water in the oil, that's all that was needed.
I have been told by several lube engineers that automotive oils have 180F as a design working temperature, and that additives such as Zinc (ZDDP) really only work at that temperature. Some engine designs cool oil better than others, IMH experience the SBC is not very good at it and an oil/air cooler with a 165F thermostat bypass is a good addition that also gets you another quart or so of oil capacity. That way, if you want to run the engine mass at 210F and get a tad more efficiency, the oil is still delivered at its design temperature. Don't forget iffen you going to run the water that hot, better use a coolant additive and a cap with decent pressure rating, like 10lb or even a bit more if you live a distance above sea level to prevent steam pockets forming in the hot spots. In an SBC getting the hot water out of the back of the heads as well is always a very good thing (like in a Victor Jnr)for an even temperatured engine.
IMHO even though he is gone, Smokey Yunick is still a man ahead of his time in lots of ways. The engine temperature thing is just one.
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I was always so happy my T only ran at 150 going down the road, but I just had to tear the heads off to clean off the built up carbon that I feel was caused by too cold of an engine and too rich of a fuel mixture. It was so bad I actually had NO compression in one cylinder. 
