Overheating -- Corrective measure questions.

Heating / Cooling / AC

  1. Kent mosby

    Kent mosby FABO Gold Member FABO Gold Member

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    I have just read the rather lengthy and well detailed thread on overheating and yet I still have some questions and did not want to hijack that thread.
    I have a 1973 plymouth scamp with a 512 that always ran under 200* while moving. This past weekend I went to a car show Car d'Lane and during the Friday cruise it was 90*. The cruise was more of a crawl. In about 30 minutes I travelled maybe a mile. My temp steadily climbed to 251* according to the sniper readout. Nothing blew and I pulled off the route. As soon as I got it on the road at about 35 mph it dropped to 205 within a couple miles. I obviously need to correct this issue asap.
    My cooling specs are.
    180* Mr. Gasket 4367 high flow, high performance thermostat
    Mopar 7 blade fan. crank to fan pulley ratio,, .95:1
    Griffin performance 8-00038 26.5x18 2 row with 1.25 inch tubes
    3871088 mopar 8 blade water pump.
    7 psi radiator cap
    Shroud, Homemade by me but looks appropriate,,, let me know
    There is a 10x12 inch trans cooler in front of the radiator.

    Since the radiator cools appropriately when the car is moving and at the race track, I assume that I have enough radiator but not enough coolant and/or air flow at low speed or idle. Correct???
    Now for the corrective measures. Our race track closed so I do not need a cooling system for that purpose. I am now making the car a street/show driver. Slow speed cooling is a must.

    My thoughts to improve things are that I could overdrive the water pump by changing pulleys?? And/or get a different one but this one is supposed to be good.

    I could switch to electric fans controlled by the sniper efi but that would require that I change the alternator to a 90 amp from 60 and I would have to change the radiator as this one is 3 inches thick and it sticks out from the core support by an inch leaving only 2 inches from the water pump pulley to core.

    I could get an electric water pump that may save some space. In AndyF's book he states that the electric pumps are ok for racing but will not keep up for street use. Any experience on this? Good or bad idea?

    I could change the thermostat to a 160 milodon high flow model.

    Anyone use a pusher fan in addition to this setup for street use??

    I tried to gather as much info as possible before posting but I may have missed something. What would you do to correct the slow speed cooling issue? IMG-0730.jpg IMG-0731.jpg IMG-0883.jpg IMG-1251.jpg IMG-0838 (1).jpg
     
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    • RustyRatRod

      RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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      One thing I see that kinda jumps out is, you've introduced too much fan into the shroud. Generally, you're supposed to have about half the fan out of the shroud, maybe a little more. Yours is the opposite. Most of the fan is in the shroud. I would try a shorter spacer. You have the room from what it looks like to back the fan out some.

      The second thing I'd recommend is a Stewart high flow 160 thermostat. Getting as much flow as early as possible will help the engine from ever getting to "that point".

      I like that fan. Although it's not the five blade staggered fan, it is staggered. The MP engine book "says" the five blade staggered fan moves more air, but I don't know if it moves more than THAT fan. If it does, it's splittin hairs. I think backing the fan off some and the cooler high flow thermostat will get it. Make sire it's a Stewart. They ain't cheap, but they're worth the extra money.
       
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      • RustyRatRod

        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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        • d1970

          d1970 TODAY IS A GOOD DAY TO HAVE A GOOD DAY

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          if the fan is too deep into the shroud it can cause turbulence affecting airflow and cooling ability.
           
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          • RustyRatRod

            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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            Gettin rid of that GAWD AWFUL accordion upper hose will sure make it look better AND it will increase flow as well. 86 the bottom one too if you have one there. They look stupid anyway. Chevy stuff. lol No offense.
             
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            • Kent mosby

              Kent mosby FABO Gold Member FABO Gold Member

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              The only way to move the fan out of the shroud is to move the radiator forward. For some reason it has a 1" offset flange that sets it back from the core support by an inch. Would that be enough?


              Yea, that upper hose was a bandaid that stayed there. I have been meaning to replace it but have not found the correct one. There was not a 440 in a 73 scamp. Maybe I can look for one out of another model. Lower one is correct.
               
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              • RustyRatRod

                RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                Use a thinner fan spacer and shorter bolts. Simple. For the hose, go to whatever local parts store you use and ask to go behind the counter and look for a molded hose that matches what you have. They'll let you do it unless they don't want your business anymore. lol
                 
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                • 12many

                  12many Well-Known Member

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                  An electric pump would likely (depending on model/gph rating etc) move the water faster at idle up to an rpm point better than the mechanical but then as your rpm’s increase the mechanical will move it faster as they all have higher gph ratings which you just can’t match with an electric. So you might have cooler running down low in stop and go traffic but as speeds and rpm’s increase you’d likely have hotter running temps. I saw about a 10-15 degree increase going from an 8 vane w/plate mechanical to a moroso electric. I put the mechanical back on, and am looking into an inline electrical pump for the lower hose to run at the track for between runs cooling.
                   
                • AAndrews

                  AAndrews MOPAR .. Move Over, Plymouth Approaching Rapidly!

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                  A lot of good suggestions here..

                  One thing I noticed. You have a 10 x 12 inch aftermarket trans cooler mounted in front of the radiator? That's 120 square inches of air flow being partially blocked. If its a 26 " rad then almost half of it has an obstruction to airflow in front of it.

                  The factory did not do it this way, even for Hemi Cars! The rad had internal provisions for trans fluid cooling.

                  I'll be the first to say I'm speculating here but this stood out to me as a possible problem.
                   
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                  • Tooljunkie

                    Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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                    If its like my parts store, they have 2 hoses. For some reason rad hoses dont fail like they used to.
                     
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                    • ir3333

                      ir3333 Well-Known Member

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                      if you have a 7 psi rad cap you would have boiled over at ( 7x3 ) 21 plus 212 or 233 degrees so you weren't at 251 degrees. If you were at 251 i think it might have expanded and locked until cool.
                      I'd be suspicious at that that much change when it has been fine...try a new gauge
                       
                      Last edited: Jun 21, 2021
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                      • Kent mosby

                        Kent mosby FABO Gold Member FABO Gold Member

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                        I do not have any fan spacer at all on the pulley. The fan is touching the pulley.
                         
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                        • Dana67Dart

                          Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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                          I don't know if this is even posable but back in the day when SB Ford's went from v belts to serp belts they did not change how the water pump bolted to the front of the engine they just changed the direction the impeller should rotate and the internal pathways for the coolant to travel.

                          Everything else would just bolt up, fan, pulley etc

                          If one bought a serp pump and put it on a v belt engine the pump would be run backwards. That would cause all kinds of issues
                           
                          Last edited: Jun 21, 2021
                        • yellow rose

                          yellow rose Overnight Sensation FABO Gold Member

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                          You can NOT underdrive the pump that far. You have a kick ass radiator. As RRR said, you NEED a Flowkooler pump and some overdriven pulleys. And a Stewart Components thermostat. There is nothing like it on the market. These are the old Robert Shaw thermostats.

                          You’ve got most of what you need with the radiator. Now you need a couple of little thangs and you’ll be pooping in the tall cotton.

                          EDIT: I forgot to mention you need to throw the shroud away and use a spacer to get the fan about an inch away from the radiator. If you get it that close, you want need a shroud. It will be close enough to the radiator to pull plenty of air at idle (if you get the pump speed, and by mechanical connecting the fan speed up where it should be) to keep it cool at at high speeds the shroud won’t be packing air.
                           
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                          • yellow rose

                            yellow rose Overnight Sensation FABO Gold Member

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                            Like the Davies-Craig pump? Man those are way cool. I will get me one of those pumps with the controller and all of it. Then I won’t need the water pump.
                             
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                            • RustyRatRod

                              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                              I can just about 100% promise you there's a spacer there. Once they've been on a while, they kinda become "married".
                               
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                              • Kent mosby

                                Kent mosby FABO Gold Member FABO Gold Member

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                                new water pump and thermostat are on the way. I will remove the shroud and check out the pulleys tonight. Thank you for all the guidance.
                                 
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                                • Dubob

                                  Dubob Well-Known Member

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                                  I use a 20630 gates for upper hose on my Demon.
                                   
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                                  • superchargeddrt

                                    superchargeddrt Well-Known Member

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                                    I have an electric fan (from a Chevy HHR) cooling my radiator. The radiator does not have a transmission cooler in it so I have combo trans/oil cooler sitting flat(no blocking the rad) with its own electric fan. I run about 190 degrees on my 418 stroker.

                                    Edited: Should have been 190° not 290°
                                     
                                    Last edited: Jun 22, 2021
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                                    • furyus2

                                      furyus2 Well-Known Member

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                                      What I noticed, was you don't have a hood seal. That keeps the air from going around the radiator, instead of through it. Also, if the radiator is too far from the core support, have the rad mounts cut off, and welded on in the proper place. This might put the rad where the shroud will work.
                                       
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                                      • 12many

                                        12many Well-Known Member

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                                        Before I settled on the Moroso I looked at those and there were two other versions that were mounted right off the bottom outlet but can’t recall the brands or exactly what the mounting setup was
                                         
                                      • Mike69cuda

                                        Mike69cuda 66 is the new 17 FABO Gold Member

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                                        I just made the mistake of having the fan too far in the shroud. It really hurt my cooling. When I went 1/2 in 1/2 out it really made a difference.

                                        I have concluded that the fan and the shroud must be matched. I had an old fan that was designed for the 1/2 shroud. Didn’t work with a full shroud.

                                        I believe that if you have a fan designed for a full shroud, it would also help solve your problem. Most cars & trucks have the fan “all in” in the last 30 years. The fans are different shapes, but I am not smart enough to understand the difference.
                                         
                                      • RustyRatRod

                                        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                                        Make sure you look at that fan REAL close. I have never in my life seen a fan spacer MADE onto a fan. First time for everything, but I just BET they are separate.
                                         
                                        Last edited: Jun 21, 2021
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                                        • RustyRatRod

                                          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                                          I think his shroud will be fine if he can get that fan back out of it some.
                                           
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                                          • Garrett Ellison

                                            Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

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                                            Looks like a factory 17 inch fixed fan. Those move a lot of air. I've seen them cool a lot worse than that. Like mentioned, new water temp sensor for the sniper, smooth hoses off the radiator, Flow Kooler or PRW pump, and overdrive pulley set. What diameter is your bottom pulley?
                                             
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