Technical What TEMP. thermostat to use

Using a Ford 302 engine, 4 barrel carb, roller cam, 300 HP, 3 row aluminum radiator, AC-- using either mechanical fan or electric -- what temperature thermostat suggest to use-- Thanks

 

160° in the summer and 180 er 190 in the winter....

 

I'm running a 180* in my car and the heat could be better. I'll let it ride but will change it to a 195* next fall.

 

I run 180's in my flatheads and Corvettes in the summer (they hibernate over the winter). This should be no problem if your cooling system is "up to snuff". In my opinion, running an engine too cool is not a good idea. I believe the practice of using different thermostats winter and summer came about a long time ago in the days of alcohol-based antifreeze. Modern coolants are much better and don't require a change. I would rather run my cars at 180-190 all of the time than at 160. The only use I can see for a 160 thermostat is to try to get by with a compromised cooling system until it can be fixed properly. In my opinion, they are in the same category as radical cams, 850 CFM carburetors, and high-volume oil pumps for regular street driven cars; not necessary and sometimes harmful.

 

Tubman is right on. The hotter an engine operates, the more efficient it is! Running 180-190 or higher is much better than 160. Too cool and the engine does NOT get hot enough too burn the moisture out of the system(this includes the oil also).The engine will run better and last longer with higher temps(within reason) versus lower temps.

 

I once saw a paper that was done by SAE if I remember correctly studying wear and engine temps. I remember it showed significantly higher wear around 160 and lower. 180 seemed ideal. Wish I had made a copy of it as this is just from memory. I run a 180 thermostat with a couple holes drilled to bleed any air that could be trapped.

 

Ran a 180 in my 5.0 powered Morris Minor with a Lincoln radiator and a electric fan on a temp sensor turned on at 140. No overheat issues in Florida in the summer in traffic. It ran around 185 all the time. Pro Comp aluminum heads , .512 Comp roller cam . flat top pistons.

 

I agree with the folks in the "warmer is better" camp. They don't run today's engines at 190/195 for no reason. Just make sure you have enough radiator/fan/water pump to keep it there and not let it get a lot higher.

 

The reason is lower emissions.

 

I always ran a 180 in my 48 and running down the highway it stayed right around 183/185 Temp went up in town because I didn't have enough fan to move the air.
I don't go into a panic if the temp rises for a minute in traffic and then drops back down though.
What ponders me is the guys on here that pull an engine out of a donor rig that came from the factory with a 195 thermostat and put it in their rod and then worry themselves to death because the engine runs over 190 with a 180 thermostat.

 

"Mr48Chev" - Don't get me wrong here, I'm just doing this because I enjoy these discussions. That being said, doesn't the thermostat control the temperature the engine will run at, rather than the engine itself? This is assuming the rest of the cooling system is of adequate size and in decent shape. Running an engine designed to use a 195 with a 180 or (even worse, a 160) may result in an engine that doesn't perform up to the standards that it normally would.

 

tubman is right, Engine oils need to be warm enough to dissipate moisture. Running your engines to cool is not good for performance or longevity of the oil. low temps are a major cause of sludge build up inside the engine. Especially when paraffin based oil is used..

 

Thermostat really controls how cold the engine runs, not how hot, if that makes any sense. It won't get any colder on average, than the rated temperature. It's up to the radiator to keep the high side temps within limits.

I believe any "modern" engine should run a 195 degree F thermostat. It will run better, and last longer, and keep sludge from forming. And the heater will work as it should too, something that is important, as a lot of people are rediscovering as of late.

 

180 in all my older vehicles.

 

^^^Same here^^^

 

The oil temperature is a primary concern. It needs to get above 212 (sea level) to get the water out. Oil usually runs about 30F hotter than the water in traditional (small block/big block domestic V8s prior to LS type engines) hot rod engines. 160 degree water temps require frequent (30-90 day) oil changes to stay sludge free. Modern engines may vary considerably in water to oil temp relationship. 215-220 sea level should be minimum oil temps. IMHO your mileage will vary.

 

When you're looking for absolute peak performance out of a race engine, you may like to run the engine fairly cold - it helps avoiding detonation just to mention one thing.
For a street driven car that sees full throttle for perhaps 2% of the time a higher engine temperature will help your engine burn the fuel cleanly, keep water and fuel out of the oil, and minimize wear. As long as the cooling system can hold that temperature stable under all conditions, ofcourse.

 

You have to decide at what temperature you want to run your engine. The more accessories, cooling capacity, type of cooling fan and horsepower all come into play. The cooling capability of your engine has to have the ability to lower the temperature below the desired running temperature in summer as well as winter. If you run a 160 degree thermostat it will open at 160 degrees and the temperature will continue to rise until the engine cooling system is able to stop the rise in temperature. This could come at 161 degrees or 220 degrees. Your thermostat will remain open until the temperature is reduces to 159 degrees approximately. In a properly designed cooling system, the temperature should remain within a few degrees of your thermostat setting, not just because of your thermostat but your cooling system.

 

We ran our dirt late model at 195-205 degrees for sometimes up to 100 laps. Never hurt a thing .

 

190-195 is all I’ve ever ran. Year round in anything

 

Bottom Line? Unless you have made significant modifications to the engine, use what the engine used from the factory. The longer I've been in this hobby, the more I find that the original designers really knew what they were doing. Even back in the early days, everything was designed as a system, and breaking any part of that system without a lot of thought is a big mistake.

 

I agree. Must remember the thermostat controls the min temp. I run a 190 in my Buick all the time.

Ben

 

Thanks for all your help and advise--