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  • Cooling Concern

    Has anyone done any cooling system improvements or alterations to their engine? Have you had any success?

    Background Story: When offroading hard up in the mountains in the summer time my 2.8L was getting hot to the point I would have to pull over and let it cool off. The rad is new and built with larger dimpled tubes and more fins. Keep in mind I have no clue what the water passages in the block are like since I have not had the heads off the engine to look. However frequent coolant changes did not yield any sediment.

    So I am building my 3.2L (Still, got the wrong pistons waiting on new ones) and got to pondering the modifications mentioned in the Chevy power manual. One section mentions slightly enlarging the water passages in the head gaskets. However one paragraph above it mentions "for endurance racing engines" but does not specify if they are talking about this modification. So I am wondering if anyone has tried it on the street. The other modification involved enlarging the water pump inlet which I think I will try. For comparison can anyone measure 3400 head gasket water holes for me?

    One other thing I was looking at is 4 corner cooling. For example on the 4.3L is has coolant passages from the head to the thermostat which are cast into the intake manifold. However it also has passages, which are slightly smaller, coming from the back coolant ports of the cylinder head, that merger into the thermostat area aswell. On the 60 degree iron head RWD motors these ports are just blocked and water is forced through the front of the head. My modification would be to tap the manifold in the rear for tubes that lead to the front water passages. I have noticed on a lot of engine builds this type of modification is becoming more and more mainstream.

    So any thoughts?
    1993 EXT. CAB, 3.4L V6 TBI, 5spd manual. Sonoma
    1990 4Door, 3.2L V6 TBI, 5spd manual. 4X4. Trooper
    Because... I am, CANADIAN

  • #2
    Good ideas. I can't comment on them personally, but I do remember reading about a GM motor that had some type of external runner that went from head to head, bypassing running coolant through the LIM alltogether. Perhaps this is something else to look into. I wish I could remember more on the subject. Sorry

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    • #3
      Yea I know what your talking about. There is also the Smokey Yunick style outlet where you drill holes in the ends of the heads and attach the outlets there into a Y shaped pipe system and on to the rad. This system bypasses the coolant passages in the intake. I have also seen a Cadillac Big block with a coolant manifold block. Where 4 coolant hoses from each head fed into a manifold block on each side and then larger hoses carried that to a Y block and onto the rad.

      I think I will take the conservative approach on this. I have 2 spare manifolds and 2 spare water pumps that I will try the mods on and set them aside. If problems still arise with my new engine then I will consider installing them one at a time and observe the results. I would hate to throw everything on the motor now and find out it only works good a 4000RPM and up.
      1993 EXT. CAB, 3.4L V6 TBI, 5spd manual. Sonoma
      1990 4Door, 3.2L V6 TBI, 5spd manual. 4X4. Trooper
      Because... I am, CANADIAN

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      • #4
        edit, nevermind...
        Last edited by Honest Don; 03-27-2010, 06:09 PM.

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        • #5
          Hey betterthanyou, what kind of fan do you have? A mechanical one is always better then an electrical one. With a good fan shroud it'll pull more air through the rad. If it has a clutch make sure its working good, not free wheeling.
          I remember in the GM power manual(I can't remember the exact title) there is a mod done to the waterpump, at the lower rad hose inlet, a restriction that slows flow. Also some aftermarket WPs have those cheap impellars, the ones that are cast steel flow better.

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          • #6
            Well with the new engine I am not having any problems. The water passages in the block of the old motor were almost full of scale and debris on the back 2 cylinders. I do run an electric fan but it works just fine.

            I have contemplated adding an oil cooler and full shroud in the future.
            1993 EXT. CAB, 3.4L V6 TBI, 5spd manual. Sonoma
            1990 4Door, 3.2L V6 TBI, 5spd manual. 4X4. Trooper
            Because... I am, CANADIAN

            Comment


            • #7
              Gasket pics

              Originally posted by betterthanyou View Post
              For comparison can anyone measure 3400 head gasket water holes for me?

              Still looking for that? I'm thinking it wouldn't be that hard to put a gasket under a photocopier and send you a full size PDF to measure in metric joy.

              Comment


              • #8
                Na no worries.
                1993 EXT. CAB, 3.4L V6 TBI, 5spd manual. Sonoma
                1990 4Door, 3.2L V6 TBI, 5spd manual. 4X4. Trooper
                Because... I am, CANADIAN

                Comment


                • #9
                  Originally posted by ex-x-fire View Post
                  Hey betterthanyou, what kind of fan do you have? A mechanical one is always better then an electrical one.
                  3/4 of the guys on TRS will argue that point to no end, unless you go in some really deep water.
                  -60v6's 2nd Jon M.
                  91 Black Lumina Z34-5 speed
                  92 Black Lumina Z34 5 speed (getting there, slowly... follow the progress here)
                  94 Red Ford Ranger 2WD-5 speed
                  Originally posted by Jay Leno
                  Tires are cheap clutches...

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