160 vs 180 thermostat

New Hemi Engine Swaps

  1. CurtDawg510

    CurtDawg510 Well-Known Member

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    So i got my 6.4 in my 70 duster.... dam thing is a runner!
    Only thing i didnt like much was the temps with the 180 thermostat.... on a 95deg day it would run 192-194 deg on the highway.... fans turn on and 196, and i fell thats warm enough.... i know they can run hotter and do, but i dont like over 200 myself....
    Fans would turn on almost as soon as you stop, and would cycle on and off kinda quick (one min on, one min off or so) in city drivin....
    So now i am runnin a 160 thermostat, i like this alot better.... same 95deg day down the highway, im runnin 175.... and i can pull off the highway and do city drivin, pretty much all stop n go and the fans hardly turn on.... sometimes i can jump from highway to town, then back to highway and fans wont even turn on at all!... and when fans do turn on at 196, now it cools down to about 180-185 quick, then takes much longer before then turn on again.....where the 180 thermostat would keep temps right around 190-194, so the fans are almost always on....

    I also have a 180 oil thermostat, so oil temps are always around 175 cold days to 190 hot days

    just my experience

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    • RustyRatRod

      RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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      You have it now so that when the t-stat opens it never closes. They are supposed to cycle. Your mileage will likely suffer. Computerized engines are designed to run "whatever" thermostat they are listed to have. Differing from that can have poor driveability results. Lastly, if the engine does not get up to proper operating temp, you'll never get all of the contaminants out of the oil. Don't take my word for it. Look up something with a 6.4 in it and see what temp the fan kicks on. A lot of them kick on at 220 even 235. They are designed to run that hot.
       
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      • CurtDawg510

        CurtDawg510 Well-Known Member

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        But they pull timing when air intake temp reaches 117-120 deg, and or coolant temp hits 240.....im also tuning it with HP tuners, so its not really designed to run that hot anymore, i know they run them that hot to burn cleaner for emissions.....i drive in some heat, i dont want it runnin 20-40 deg hotter than thermostat rating when runnin down the highway....isnt that more when thermostat is stayin open?
        And for the oil, i runnin an oil thermostat, that keeps oil temps up....
        I get average 20mpg.... hot doggin included
         
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        • Tinmannz

          Tinmannz Well-Known Member

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          I agree with everything that RRR has to say, componets have a tendency to wear out sooner as well when they're not operating at the designed temps.

          That being said, you've got to be comfortable with the car as you're driving around town. I hate the feeling of having to keep one eye on the temp gauge and the other on the slow moving traffic ahead. I think part of the problem is that you may have poor air circulation within the engine compartment. Dropping in that behemoth has reduced some of the effective area that would allow for airflow and dump some of that engine heat.

          I once had a 30' 5 window coupe with a big ass engine in it that was tightly cowled and had the same problem as you. I tried a lower rated t-stat which helped, but eventually took the cowl side panels off and that solved my problem. Dump the engine heat in a tightly cowled engine will help the cause, especially in stop and go traffic. Hot rodders would cut louvers in the hood to help facilitate the problem, but I wouldn't expect you to do that.

          I'd run it as is, you can always swap in another t-stat if need be.

          Great looking project! I'd love to see the whole car.

          95* in Hayward? Eww!
           
          Last edited: Jul 11, 2020
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          • A56

            A56 MoParAffliction FABO Gold Member

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            Very nice project, but I would have to agree with Tinmannz about the motor being boxed in. It appears to be very snug in there. Are those scoops functional?
             
          • 67Dart273

            67Dart273 FABO Gold Member FABO Gold Member

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            You may have a bad thermostat, or something wrong with the cooling system OR a faulty gauge. But putting a colder stat in is not the answer
             
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            • Idaho

              Idaho FABO Gold Member FABO Gold Member

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              Sounds to me like you have it set up nicely.
              Great looking car.
               
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              • doug 371

                doug 371 Well-Known Member

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                Yep, glad it worked out well for you :)
                 
              • Dana67Dart

                Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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                Engines are designed to run in a specific temp range. As the engine heats up all the metal expands, the gaps designed in are there for that temp range, a lower temp range tightens up those gaps for better or worse.

                I agree that modern engines are designed to run hot for emission reasons, and that might be hotter than is good but the modern engines seem to last 2 to 3 times as long as our 60's engines so they must be doing something right. I would go with what the factory used.
                 
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                • MOPAROFFICIAL

                  MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                  If it's no longer tuned "stock" ....who cares.

                  They stat runs open, partially or full. They open before the rating as well, the rating means 'fully open by 160'
                  Run the temp where the tuner manual recommends ..because it's usually so the tune doesnt cause engine damage

                  Enjoy.
                   
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                  • /6 Matt

                    /6 Matt 30 Degrees Crooked

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                    Changing the tune doesn't change how the engine is machined. Youre going to wear things out much faster.
                     
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                    • AJ/FormS

                      AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                      A good stat sets the minimum operating temp.
                      The efficiency of the rest of the system sets the maximum. The efficiency is always changing, with airflow thru the rad as the principal player, followed hotly, by the waterflow.
                      It's nice to have a system that is able to overcool, so the stat can do it's job.
                       
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                      • j par

                        j par Well-hung Member

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                        Take a 60's engine rebuild it to factory specifications with roller lifters and put a computer-controlled fuel injection and computer-controlled timing on it and see if it doesn't last just as long...
                         
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                        • j par

                          j par Well-hung Member

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                          I think the op's doing fine...
                          Nice project and keep it cool..
                           
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                          • pishta

                            pishta I know I'm right....

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                            Id run it as is. Maybe wrap the headers/manifolds to keep bay temps down? Manifolds are cheap, wrap aint gonna break them down.
                             
                          • 318willrun

                            318willrun Utube channel 318willrun

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                            Awesome project. Gotta be just a killer ride!
                             
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                            • gtokid1

                              gtokid1 Well-Known Member

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                              Stat starts to open at that rating fully opened 6 to 8 degrees higher.
                               
                            • famous bob

                              famous bob mopar misfit

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                              I think most of lasting longer has to do with overdriven transmissions , it is like not putting as many miles on the engine -----------less rpm.
                               
                            • famous bob

                              famous bob mopar misfit

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                              ^^^^I hope , I`ve done just that .
                               
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                              • j par

                                j par Well-hung Member

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                                Here's my theory on why they last longer..
                                think about being able to turn off the fuel injection and the ignition gets to burn those last bits of fuel before it shuts off. Then think of a carbureted car that shuts off the ignition and the Pistons are still going up and down sucking down the fuel and air on top of the cylinders which now at startup has washed the oil off..
                                 
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                                • MOPAROFFICIAL

                                  MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                                  Machined...? NO.
                                  180-220 is fine. Expansion factor is what speaking of. 150 or less would be a problem.
                                  With more power comes more heat, tune is changed from stock, not within stock parameter. If his motor is shrouded by a tight compartment ..whos to say there aren't hot spots the gauge doesnt show in the back near the firewall...
                                  ...get a heat gun and zap some readings, then see. Your 360 say 0 intial timing too, you gonna run it that way..?
                                  Shit has expanded by 180, even if it didnt..its not blowing up over it.


                                  Yep and fuel injection. New engines dont get the fat or lean spells our carburetor engines do..and they auto adjust for optimal timing on the fly...the overhead cams outlive the old stuff mostly as well...the ring packages are better...the machining process is light years ahead of say what a 440 was carved on.
                                  Its definitely NOT because of running temps like some in this thread are overstressing.
                                   
                                  Last edited: Jul 12, 2020
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                                  • MOPAROFFICIAL

                                    MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                                    Did you take auto shop as a kid?
                                    Go toss a 180 thermostat in a pot of water with a temp reading of 150 or so and watch it start opening.
                                    Im old enough...unless something changed...by design, they are supposed to be fully open by the advertised rating .
                                     
                                  • 318willrun

                                    318willrun Utube channel 318willrun

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                                    True!
                                    1. Overdrives. A engine turning 2200 rpm's vs 1600 rpm's @ 60 mph. That's 36,000 more revolutions in 1 hr. Think of all the hours to get to 100,000 miles.
                                    2. Oils. Todays off the shelf oils are superior to yesterday oils (except for our flat tappet cams)
                                    3. As J par mentioned, FI vs Carbs. FI runs the car so much cleaner.
                                    4. Progression in the machining process. You didn't find Auto Gauges at the end of a CNC process 100% gauging every critical dimension of a machined part and feeding offsets back to the lathes.

                                    .
                                     
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                                    • Dana67Dart

                                      Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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                                      From the horses mouth...
                                      Stant


                                      THERMOSTAT TEMPERATURES
                                      • Thermostats have a “rated” temperature such as 180F or 195F
                                      • This is the temperature the thermostat will start to open, give or take 3 degrees
                                      • The thermostat fully open about 15-20 degrees above its rated temperature
                                       
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                                      • MOPAROFFICIAL

                                        MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                                        To be a smart-ass , nil point...I use mr. Gasket high-flow thermostat. Lol
                                        learned this a long time ago they start opening before the rating and they're fully open by/if not 90% .
                                        Our shop teacher was the shit, we had cut down race motors and he drove a cherry 40's plymouth special every day.
                                        He set up the hot plate...filled it...setup a thermometer in it and dropped a 180 thermostat in.... it started popping open at 150-155 slowly...he showed us the difference between design and actual function. They dont smoothly open either...they pop in increments is what it visually looks like.
                                        I'm not gonna argue it. I know what I've seen ..and you know what you've read.
                                        All good. It's not gonna help going back n forth over a thermostat
                                         
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