<div dir="ltr"><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">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">
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<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">simon.lachlan@alexarevel.plus.com</a> wrote:<br>
</div>
<blockquote type="cite">
<div class="m_-555035641554905656WordSection1">
<p class="MsoNormal">Hi,<u></u><u></u></p>
<p class="MsoNormal">Has anyone got the Denis Welch oil pump
ENG672M? See:-<u></u><u></u></p>
<p class="MsoNormal"><a href="https://www.bighealey.co.uk/performance-parts/austin-healey/engines/3000-bottom-end?page=3" target="_blank">https://www.bighealey.co.uk/performance-parts/austin-healey/engines/3000-bottom-end?page=3</a><u></u><u></u></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.”<u></u><u></u></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”?<u></u><u></u></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? <u></u><u></u></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?<u></u><u></u></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?<u></u><u></u></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. <u></u><u></u></span></p>
<p class="MsoNormal">Thanks,<u></u><u></u></p>
<p class="MsoNormal">Simon<u></u><u></u></p>
</div>
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