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I have a book "Repco Engine Service Manual" produced by Repco of
Repco-Brabham fame that I use as my bible for engine building.
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.
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.
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.
A pump which puts out a huge volume uses excessive horsepower and can
result in accelerated wear of the pump drive.
M
On Tue, Oct 30, 2018 at 11:30 AM Bob Spidell <bspidell@comcast.net> wrote:
> I'll offer what I know/have heard*. I have the 'high capacity' type in m=
y
> 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 suppos=
ed
> 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 typ=
e
> 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 gea=
rs
> on the cams were re-engineered, IIRC they got an additional tooth to spre=
ad
> the load.
>
> 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 (whic=
h,
> of course, is mostly dictated by engine speed). The 'standard type' pum=
p
> 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.
>
> 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 tha=
n
> our (US) vendors sell it at (I think they might import the DWR shaft).
> * apply appropriate grains of salt
>
> Bob
>
> On 10/30/2018 5:12 AM, simon.lachlan@alexarevel.plus.com wrote:
>
> Hi,
>
> Has anyone got the Denis Welch oil pump ENG672M? See:-
>
>
> https://www.bighealey.co.uk/performance-parts/austin-healey/engines/3000-=
bottom-end?page=3D3
> Their text:- =E2=80=9CHeat 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 standa=
rd
> 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 assembl=
ed
> in-house to control the highest quality.
> - ENG672 is the standard type.
> - ENG672M is the high capacity pump.=E2=80=9D
>
> What are =E2=80=9Cremovable gallery plugs=E2=80=9D?
>
> Is it just me or is the above a bit counter-intuitive? =E2=80=9CHigh capa=
city=E2=80=9D for
> road cars and =E2=80=9Cstandard=E2=80=9D for race engines? Surely the hig=
hest capacity is
> needed where the engine is working hardest ie racing?
>
> And don=E2=80=99t 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=E2=80=99s two pumps?
>
> Anyhow, if anyone=E2=80=99s got one=E2=80=A6..what=E2=80=99s it like? Did=
the oil pressure improve
> at all?
>
> I=E2=80=99m guessing that most people will have fitted one as part of a b=
ig
> rebuild thus they won=E2=80=99t have straightforward =E2=80=9Cbefore and =
after=E2=80=9D
> comparisons. I=E2=80=99m 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.
>
> Thanks,
>
> Simon
>
>
> _______________________________________________
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>
> Archive: http://www.team.net/pipermail/healeys
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--00000000000000e2fd057974353a
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr"><div class=3D"gmail_default" style=3D"font-family:comic sa=
ns 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=3D"gmail_default" style=3D"font-=
family:comic sans ms,sans-serif;font-size:small">On the subject of oil pres=
sure it states that delivery pressure itself is not that important and is r=
eally just an indicator that oil is being delivered to the bearings. <br></=
div><div class=3D"gmail_default" style=3D"font-family:comic sans ms,sans-se=
rif;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 temp=
erature, and the engine design.</div><div class=3D"gmail_default" style=3D"=
font-family:comic sans ms,sans-serif;font-size:small">Based upon this I bel=
ieve that concentrating on having good oil pressure at idle is wasted effor=
t. What is important is that the engine has some pressure at idle but good =
pressure in the normal operating range. <br></div><div class=3D"gmail_defau=
lt" style=3D"font-family:comic sans ms,sans-serif;font-size:small">A pump w=
hich puts out a huge volume uses excessive horsepower and can result in acc=
elerated wear of the pump drive.</div><div class=3D"gmail_default" style=3D=
"font-family:comic sans ms,sans-serif;font-size:small"><br></div><div class=
=3D"gmail_default" style=3D"font-family:comic sans ms,sans-serif;font-size:=
small">M<br></div><div class=3D"gmail_default" style=3D"font-family:comic s=
ans ms,sans-serif;font-size:small"><br></div></div><br><div class=3D"gmail_=
quote"><div dir=3D"ltr">On Tue, Oct 30, 2018 at 11:30 AM Bob Spidell <<a=
href=3D"mailto:bspidell@comcast.net";>bspidell@comcast.net</a>> wrote:<b=
r></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border=
-left:1px #ccc solid;padding-left:1ex">
=20
=20
=20
<div text=3D"#000000" bgcolor=3D"#FFFFFF">
<p>I'll offer what I know/have heard*.=C2=A0 I have the 'high c=
apacity'
type in my BJ8, which is what the DWR techs/sales people
recommended for a road car.=C2=A0 Older 6-cyl cars had a rotor type
pump.=C2=A0 They (the rotor type) are supposed to be more
efficient--i.e. they pump more oil--at lower RPMs.=C2=A0 At some poin=
t
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.=C2=A0 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).=C2=A0 I think the bevel gears on the cams wer=
e
re-engineered, IIRC they got an additional tooth to spread the
load.<br>
</p>
<p>The Welch HC pump is the rotor type.=C2=A0 I did a full engine rebui=
ld
and installed the DWR HC pump; I didn't notice any pressure chang=
e
worth mentioning--I 'gained' 15 PSI at idle when I had my gau=
ge
overhauled--but the 'high capacity' I believe refers to volum=
e
rather than pressure (which, of course, is mostly dictated by
engine speed).=C2=A0=C2=A0 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.=C2=A0 I suppos=
e it
allows inspection of the innards of the pump without having to
break the case.=C2=A0 I believe it's threaded so not likely to po=
p
out.=C2=A0 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=3D"m_-555035641554905656moz-cite-prefix">On 10/30/2018 5:12 =
AM,
<a class=3D"m_-555035641554905656moz-txt-link-abbreviated" href=3D"ma=
ilto:simon.lachlan@alexarevel.plus.com" target=3D"_blank">simon.lachlan@ale=
xarevel.plus.com</a> wrote:<br>
</div>
<blockquote type=3D"cite">
=20
=20
=20
<div class=3D"m_-555035641554905656WordSection1">
<p class=3D"MsoNormal">Hi,<u></u><u></u></p>
<p class=3D"MsoNormal">Has anyone got the Denis Welch oil pump
ENG672M? See:-<u></u><u></u></p>
<p class=3D"MsoNormal"><a href=3D"https://www.bighealey.co.uk/perfo=
rmance-parts/austin-healey/engines/3000-bottom-end?page=3D3" target=3D"_bla=
nk">https://www.bighealey.co.uk/performance-parts/austin-healey/engines/300=
0-bottom-end?page=3D3</a><u></u><u></u></p>
<h2 style=3D"margin-right:0cm;margin-bottom:6.0pt;margin-left:0cm;l=
ine-height:20.25pt">Their
text:- =E2=80=9C<span style=3D"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=3D"font-size:10.0pt;font-family:"Arial&qu=
ot;,sans-serif;color:#555555">-
ENG672 is the standard type.</span><span style=3D"font-size:9.0=
pt;font-family:"Arial",sans-serif;color:#555555"><br>
- ENG672M is the high capacity pump.=E2=80=9D<u></u><u></u></sp=
an></h2>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-height:1=
4.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial",sans-se=
rif;color:#555555">What
are =E2=80=9Cremovable gallery plugs=E2=80=9D?<u></u><u></u></s=
pan></p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-height:1=
4.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial",sans-se=
rif;color:#555555">Is
it just me or is the above a bit counter-intuitive? =E2=80=9CHi=
gh
capacity=E2=80=9D for road cars and =E2=80=9Cstandard=E2=80=9D =
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=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-height:1=
4.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial",sans-se=
rif;color:#555555">And
don=E2=80=99t 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=E2=80=99s two pumps?<u></=
u><u></u></span></p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-height:1=
4.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial",sans-se=
rif;color:#555555">Anyhow,
if anyone=E2=80=99s got one=E2=80=A6..what=E2=80=99s it like? D=
id the oil pressure
improve at all?<u></u><u></u></span></p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-height:1=
4.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial",sans-se=
rif;color:#555555">I=E2=80=99m
guessing that most people will have fitted one as part of a
big rebuild thus they won=E2=80=99t have straightforward =E2=80=
=9Cbefore and
after=E2=80=9D comparisons. I=E2=80=99m thinking of fitting min=
e 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=3D"MsoNormal">Thanks,<u></u><u></u></p>
<p class=3D"MsoNormal">Simon<u></u><u></u></p>
</div>
<br>
<fieldset class=3D"m_-555035641554905656mimeAttachmentHeader"></field=
set>
<br>
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