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DC motor sizing help

  1. Sep 27, 2012 #1
    I am new here and don't know if this is appropriate so let me know. I am not an engineer and no formal training other than a few Physics classes in college many years ago. I do however have a high mechanical aptitude and have always done some personalization of machines. Eg. I put a lawn mower engine on my bicycle at age 10. etc.

    I am now attempting to modify a 1958 Corvette Rochester Ramjet fuel injection to run on a different engine. The item I need help with is the means of powering the high pressure pump. Originally it it mechanically driven via a flex cable attached to a special distributor.

    Since the engine is not going to exceed 6000 RPM and the cam speed is 1/2 the speed of the crankshaft, I will need to find a suitable 12VDC motor that is capable of up to 3000 RPM.

    I do not know how much torque/power it will take to turn the gear pump that it will attach to but a greater concern it that it will operate in an environment that consistently exceeds 200° F. It does not need to be variable speed as the flow is controlled by a mechanical bypass value in the fuel reservoir.

    I would appreciate any help on pointing me in the right direction, who I might talk to etc.
    Thanks for your time.

  2. jcsd
  3. Sep 27, 2012 #2
  4. Sep 28, 2012 #3

    I wish I could just use an electric pump but the existing gear pump sits inside a reservoir of fuel and the output channel is cast into the reservoir then to a flow control valve and then "spilled" back into the reservoir of fuel.

    Thanks for the other ideas. I have spoken to several "experts" and they sent me here!
  5. Sep 28, 2012 #4

    jim hardy

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    Gold Member

    you might look into modern fuel pumps.

    Not long ago I disassembled a Ford in-the-tank pump and found it to be a remarkably small electric motor similar to those in electric RC cars, driving a simple impeller type pump that's more tangential than centrifugal. It's surrounded by filters and structure, but the heart of it is size of a computer mouse..

    Clearances are necessarily small to create required pressure in absence of positive displacement mechanism, so an input strainer is a MUST.

    but it's a possible approach for you.

    myself i'd look into the inline pumps from hot-rod sites like Summit Racing.
  6. Oct 1, 2012 #5

    Thanks for the reply. I do not know how much pressure the in the tank pump can generate. I have been told by the experts that the original gear pump can generate up to 200 PSI although it generally would need at least 100PSI to operate correctly.

    The Summit inline pumps have good volume but generally less than 60 PSI.

    I need to focus on a motor that can drive the existing pump as I mentioned to Pantaz earlier. Thanks for the good thoughts!
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