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    <p>re: "... delivery pressure itself is not that important and is
      really just an indicator that oil is being delivered to the
      bearings ..."</p>
    <p>Pressure is useful as a trend indicator.<br>
    </p>
    <br>
    <div class="moz-cite-prefix">On 10/30/2018 8:54 AM, Michael Salter
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAB3i7LK1diV=imAHBzxBj6tL06YDF9G7LOEd=JwRL3zT-eT21g@mail.gmail.com">
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        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small">I have a book "Repco Engine
          Service Manual" produced by Repco of Repco-Brabham fame that I
          use as my bible for engine building. <br>
        </div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small">On the subject of oil pressure
          it states that delivery pressure itself is not that important
          and is really just an indicator that oil is being delivered to
          the bearings. <br>
        </div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small">Of much greater importance is
          "thin film pressure" which is generated by the engine forces
          on a bearing which can be as high as 8000 p.s.i. at high RPM
          and is determined by the oil type and temperature, and the
          engine design.</div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small">Based upon this I believe that
          concentrating on having good oil pressure at idle is wasted
          effort. What is important is that the engine has some pressure
          at idle but good pressure in the normal operating range. <br>
        </div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small">A pump which puts out a huge
          volume uses excessive horsepower and can result in accelerated
          wear of the pump drive.</div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small"><br>
        </div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small">M<br>
        </div>
        <div class="gmail_default" style="font-family:comic sans
          ms,sans-serif;font-size:small"><br>
        </div>
      </div>
      <br>
      <div class="gmail_quote">
        <div dir="ltr">On Tue, Oct 30, 2018 at 11:30 AM Bob Spidell <<a
            href="mailto:bspidell@comcast.net" moz-do-not-send="true">bspidell@comcast.net</a>>
          wrote:<br>
        </div>
        <blockquote class="gmail_quote" style="margin:0 0 0
          .8ex;border-left:1px #ccc solid;padding-left:1ex">
          <div text="#000000" bgcolor="#FFFFFF">
            <p>I'll offer what I know/have heard*.  I have the 'high
              capacity' type in my BJ8, which is what the DWR
              techs/sales people recommended for a road car.  Older
              6-cyl cars had a rotor type pump.  They (the rotor type)
              are supposed to be more efficient--i.e. they pump more
              oil--at lower RPMs.  At some point it was discovered,
              probably from service bay repairs, that this type of pump
              put an excessive shear load on the bevel gears on the cam
              that drive the pump, causing them to wear out.  Later cars
              started getting the gear type pump, which is less
              efficient at lower RPMs but puts less of a load on the
              cam, and is probably less expensive to manufacture as well
              (esp. if the gears are the sintered iron variety).  I
              think the bevel gears on the cams were re-engineered, IIRC
              they got an additional tooth to spread the load.<br>
            </p>
            <p>The Welch HC pump is the rotor type.  I did a full engine
              rebuild and installed the DWR HC pump; I didn't notice any
              pressure change worth mentioning--I 'gained' 15 PSI at
              idle when I had my gauge overhauled--but the 'high
              capacity' I believe refers to volume rather than pressure
              (which, of course, is mostly dictated by engine speed).  
              The 'standard type' pump is a gear type, hence it's more
              appropriate for high-RPM race engines as pump flow is
              proportional to RPM, and at 6K RPM or more you'll get
              plenty of oil with less load from the gear type.</p>
            <p>I'm not positive, but if you look at the photos closely,
              you can see the 'gallery plug' on the top of the case.  I
              suppose it allows inspection of the innards of the pump
              without having to break the case.  I believe it's threaded
              so not likely to pop out.  If you're getting a new pump
              you'll likely need a new drive shaft and, surprisingly,
              DWR sells it cheaper than our (US) vendors sell it at (I
              think they might import the DWR shaft).<br>
            </p>
            * apply appropriate grains of salt<br>
            <br>
            Bob<br>
            <br>
            <div class="m_-555035641554905656moz-cite-prefix">On
              10/30/2018 5:12 AM, <a
                class="m_-555035641554905656moz-txt-link-abbreviated"
                href="mailto:simon.lachlan@alexarevel.plus.com"
                target="_blank" moz-do-not-send="true">simon.lachlan@alexarevel.plus.com</a>
              wrote:<br>
            </div>
            <blockquote type="cite">
              <div class="m_-555035641554905656WordSection1">
                <p class="MsoNormal">Hi,</p>
                <p class="MsoNormal">Has anyone got the Denis Welch oil
                  pump ENG672M? See:-</p>
                <p class="MsoNormal"><a
href="https://www.bighealey.co.uk/performance-parts/austin-healey/engines/3000-bottom-end?page=3"
                    target="_blank" moz-do-not-send="true">https://www.bighealey.co.uk/performance-parts/austin-healey/engines/3000-bottom-end?page=3</a></p>
                <h2
style="margin-right:0cm;margin-bottom:6.0pt;margin-left:0cm;line-height:20.25pt">Their
                  text:- “<span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555">Heat
                    treated castings for longer life and removable
                    gallery plugs to be sure it is clean are advantages
                    of both types of oil pumps we offer. We recommend
                    the high capacity for all road engines using a
                    standard type crank up to 6000 rpm and the standard
                    pump for race engines, steel cranks or anything over
                    6000 rpm. Both are precision machined and assembled
                    in-house to control the highest quality.<br>
                  </span><span
style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#555555">-
                    ENG672 is the standard type.</span><span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555"><br>
                    - ENG672M is the high capacity pump.”</span></h2>
                <p class="MsoNormal"
                  style="margin-bottom:12.75pt;line-height:14.4pt"><span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555">What
                    are “removable gallery plugs”?</span></p>
                <p class="MsoNormal"
                  style="margin-bottom:12.75pt;line-height:14.4pt"><span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555">Is
                    it just me or is the above a bit counter-intuitive?
                    “High capacity” for road cars and “standard” for
                    race engines? Surely the highest capacity is needed
                    where the engine is working hardest ie racing? </span></p>
                <p class="MsoNormal"
                  style="margin-bottom:12.75pt;line-height:14.4pt"><span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555">And
                    don’t I remember that, with the standard BMC pumps,
                    the older type is reckoned to be better than the
                    newer type? Is this something similar to Denis
                    Welch’s two pumps?</span></p>
                <p class="MsoNormal"
                  style="margin-bottom:12.75pt;line-height:14.4pt"><span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555">Anyhow,
                    if anyone’s got one…..what’s it like? Did the oil
                    pressure improve at all?</span></p>
                <p class="MsoNormal"
                  style="margin-bottom:12.75pt;line-height:14.4pt"><span
style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#555555">I’m
                    guessing that most people will have fitted one as
                    part of a big rebuild thus they won’t have
                    straightforward “before and after” comparisons. I’m
                    thinking of fitting mine to my engine as part of a
                    small winter project and hope I can squeeze a few
                    more psi into the system. </span></p>
                <p class="MsoNormal">Thanks,</p>
                <p class="MsoNormal">Simon</p>
              </div>
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