New Ford 351 with GT40 heads overheating at idle in water

Discussion in 'Mechanic's Corner' started by deshet, Jul 28, 2020.

  1. deshet

    deshet Active Member

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    New Ford 351 with GT40 heads

    The impellor is new and the pump is pumping water, (Sherwood pump G-21 or G21)
    The impellor has been installed twice to ensure that it was oriented correctly. I also disconnected pump outlet while running to verify the flow. The flow of a water was similar to that of a water hose at idle. Not sure how to check if the flow is enough.
    The cooling system has been primed.
    The exhaust system is new (risers, elbows, even hoses)
    Even installed spring in coolant hose to ensure that it wasn't bent or reducing flow,
    The heat exchanger has been cleaned and acid dipped, it is original but looks to be in good condition and doesn't leak
    The thermostat has been removed for testing only
    The strainer has been cleaned
    The risers are hot to touch
    The belt to the water pump is tight.
    The engine will start to run hot sitting in the water at the dock idling.
    I would think at idle in the water without a thermostat that it would be extremely difficult to overheat.
    The ignition coil is cool to touch

    The only thing that I can think of trying at this point is seeing if it overheats on the garden hose while in the water. The boat is at it slips and will have to be towed back to the trailer to remove from the water worse case.

    It did not seem to overheat on a garden hose before while on the trailer.

    7-28-2020 I have flushed water through the oil cooler in the opposite direction to ensure that I don't have any restrictions. Once the tide comes back in I will start it to see how it does.

    If someone can tell me how to check if the flow of the system is adequate that would be great.

    Please don't derail things over the thermostat it will be re-installed once I figure things out. (Fully understand the purpose of the thermostat)

    Is anyone running a stainless steel or titanium heat exchanger, I fairly certain that my heat exchanger isn't the issue but I would like to get a permanent solution as everything else on the motor is new?

    Thanks

    Thanks, for any and all help
     
  2. radioman

    radioman Well-Known Member

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    Is the riser to manifold gasket oriented correctly?
    When I got my new mani's & risers, there was a paper in the box that said incorrect orientation could restrict water flow and cause overheat.

    Are you sure the intake clamshell is free of critter growth? - IIRC there was another thread about overheating and it turned out to be clogged intake.
     
  3. Ship

    Ship Well-Known Member Supporting Captain

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    Also check timing again. And firing order.
     
  4. fluke37

    fluke37 Well-Known Member

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    Did u try running it from a bucket and check flow
     
  5. Gary S

    Gary S Well-Known Member

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    Looking down from above make sure your Sherwood is mounted like this- the screw that holds the cam in place needs to be toward the engine- which here can be seen on the right hand side of the pump. Also make sure you use a nut driver or socket on connections before the pump rather than using a screwdriver


    100_2320.JPG
     
  6. deshet

    deshet Active Member

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    I have included some pictures of the Sherwood pump with the top hose disconnected. it looks to be correct based on the picture above. The markings on the pump were not extremely clear but the bottom of it had an "1" which I assume is inlet. The top of the Sherwood pump had a weird looking stamp that I could not make out.

    https://drive.google.com/folderview?id=1Hpd6zrnQjeFtj-NF1UAE7-MZv8YoKs0Z

    at the above link you will see 4 videos of the engine running with clear hoses going into the heads. I had an air restriction until I rerouted the hose in the third 4 video. The pump is moving a decent amount of air, not sure if this is a problem.

    Thanks for any and all help
     

    Attached Files:

    Last edited: Jul 29, 2020
  7. deshet

    deshet Active Member

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    I will run it in a bucket and mark the bucket at 1" intervals. How long should it take to empty a 5 gallon bucket?


    Thanks
     
    Last edited: Jul 29, 2020
  8. deshet

    deshet Active Member

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    Here are some more pictures of the Sherwood pump before it was installed.
    I don't see the metal plate in some of the other pumps online not sure if this an older design

    Thanks
     

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  9. deshet

    deshet Active Member

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    It would not draw from a bucket sitting on the deck with a 50 foot water hose. I am not sure if the hose was too long.
     
    Last edited: Jul 29, 2020
  10. deshet

    deshet Active Member

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    The firing order was checked and matched up with a 1994 351w. This was done a few weeks back. I believe that the timing is off and will have that checked. I don't believe that the timing will cause an overheat at idle, but please correct me if I am wrong. I do believe that timing is the reason that the engine has no power above 1800 to 2000 rpm under load. I am trying to fix the little things correctly as they present themselves. I need to see if the timing is advancing above idle, I don't have the tools to check it and only have minimum experience adjusting the time on a fox body 302 but that has been many years ago.

    Thanks,
     

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