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Yes, absolutely true Bob.
Decreasing oil pressure can certainly be an indicator of increasing
clearances.
M
On Tue, Oct 30, 2018 at 12:22 PM Bob Spidell <bspidell@comcast.net> wrote:
> re: "... delivery pressure itself is not that important and is really jus=
t
> an indicator that oil is being delivered to the bearings ..."
>
> Pressure is useful as a trend indicator.
>
> On 10/30/2018 8:54 AM, Michael Salter wrote:
>
> 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 hig=
h
> 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
>> 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 th=
is
>> type of pump put an excessive shear load on the bevel gears on the cam t=
hat
>> drive the pump, causing them to wear out. Later cars started getting th=
e
>> 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 ge=
ars
>> on the cams were re-engineered, IIRC they got an additional tooth to spr=
ead
>> 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--bu=
t
>> the 'high capacity' I believe refers to volume rather than pressure (whi=
ch,
>> of course, is mostly dictated by engine speed). The 'standard type' pu=
mp
>> 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 plent=
y
>> 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 o=
f
>> 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 th=
an
>> 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 removabl=
e
>> 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 usin=
g a
>> standard type crank up to 6000 rpm and the standard pump for race engine=
s,
>> steel cranks or anything over 6000 rpm. Both are precision machined and
>> assembled 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 cap=
acity=E2=80=9D
>> for road cars and =E2=80=9Cstandard=E2=80=9D for race engines? Surely th=
e highest 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 olde=
r 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? Di=
d the oil pressure
>> improve at all?
>>
>> 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 mine to my engine as part o=
f a small
>> winter project and hope I can squeeze a few more psi into the system.
>>
>> Thanks,
>>
>> Simon
>>
>>
>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/arc=
hive
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>>
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ll@comcast.net
>>
>>
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>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys
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>>
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>
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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">Yes, absolutely true Bob. <br></div><div =
class=3D"gmail_default" style=3D"font-family:comic sans ms,sans-serif;font-=
size:small">Decreasing oil pressure can certainly be an indicator of increa=
sing clearances.</div><div class=3D"gmail_default" style=3D"font-family:com=
ic sans ms,sans-serif;font-size:small"><br></div><div class=3D"gmail_defaul=
t" style=3D"font-family:comic sans ms,sans-serif;font-size:small">M<br></di=
v></div><br><div class=3D"gmail_quote"><div dir=3D"ltr">On Tue, Oct 30, 201=
8 at 12:22 PM Bob Spidell <<a href=3D"mailto:bspidell@comcast.net";>bspid=
ell@comcast.net</a>> wrote:<br></div><blockquote class=3D"gmail_quote" s=
tyle=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>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=3D"m_4764773932981263630moz-cite-prefix">On 10/30/2018 8:54 =
AM, Michael Salter
wrote:<br>
</div>
<blockquote type=3D"cite">
=20
<div dir=3D"ltr">
<div class=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-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,san=
s-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=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-serif;font-size:small">Of much greater importance is
"thin film pressure" which is generated by the engine f=
orces
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=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-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=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-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=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-serif;font-size:small"><br>
</div>
<div class=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-serif;font-size:small">M<br>
</div>
<div class=3D"gmail_default" style=3D"font-family:comic sans ms,san=
s-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"; target=3D"_blank">bspidell@comcast.n=
et</a>>
wrote:<br>
</div>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border=
-left:1px #ccc solid;padding-left:1ex">
<div text=3D"#000000" bgcolor=3D"#FFFFFF">
<p>I'll offer what I know/have heard*.=C2=A0 I have the =
9;high
capacity' 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 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.=C2=A0 Later ca=
rs
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 were 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 engi=
ne
rebuild and installed the DWR HC pump; I didn't notice an=
y
pressure change worth mentioning--I 'gained' 15 PSI a=
t
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).=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
suppose it allows inspection of the innards of the pump
without having to break the case.=C2=A0 I believe it's th=
readed
so not likely to pop out.=C2=A0 If you're getting a new p=
ump
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_4764773932981263630m_-555035641554905656moz-cit=
e-prefix">On
10/30/2018 5:12 AM, <a class=3D"m_4764773932981263630m_-55503=
5641554905656moz-txt-link-abbreviated" href=3D"mailto:simon.lachlan@alexare=
vel.plus.com" target=3D"_blank">simon.lachlan@alexarevel.plus.com</a>
wrote:<br>
</div>
<blockquote type=3D"cite">
<div class=3D"m_4764773932981263630m_-555035641554905656WordS=
ection1">
<p class=3D"MsoNormal">Hi,</p>
<p class=3D"MsoNormal">Has anyone got the Denis Welch oil
pump ENG672M? See:-</p>
<p class=3D"MsoNormal"><a href=3D"https://www.bighealey.co.=
uk/performance-parts/austin-healey/engines/3000-bottom-end?page=3D3" target=
=3D"_blank">https://www.bighealey.co.uk/performance-parts/austin-healey/eng=
ines/3000-bottom-end?page=3D3</a></p>
<h2 style=3D"margin-right:0cm;margin-bottom:6.0pt;margin-le=
ft:0cm;line-height:20.25pt">Their
text:- =E2=80=9C<span style=3D"font-size:9.0pt;font-famil=
y:"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",sans-serif;color:#555555">-
ENG672 is the standard type.</span><span style=3D"font-=
size:9.0pt;font-family:"Arial",sans-serif;color:#555555"><br>
- ENG672M is the high capacity pump.=E2=80=9D</span></h=
2>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-=
height:14.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial"=
,sans-serif;color:#555555">What
are =E2=80=9Cremovable gallery plugs=E2=80=9D?</span></=
p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-=
height:14.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial"=
,sans-serif;color:#555555">Is
it just me or is the above a bit counter-intuitive?
=E2=80=9CHigh 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? </span><=
/p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-=
height:14.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial"=
,sans-serif;color:#555555">And
don=E2=80=99t I remember that, with the standard BMC pu=
mps,
the older type is reckoned to be better than the
newer type? Is this something similar to Denis
Welch=E2=80=99s two pumps?</span></p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-=
height:14.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial"=
,sans-serif;color:#555555">Anyhow,
if anyone=E2=80=99s got one=E2=80=A6..what=E2=80=99s it=
like? Did the oil
pressure improve at all?</span></p>
<p class=3D"MsoNormal" style=3D"margin-bottom:12.75pt;line-=
height:14.4pt"><span style=3D"font-size:9.0pt;font-family:"Arial"=
,sans-serif;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 comp=
arisons. 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. </span></p>
<p class=3D"MsoNormal">Thanks,</p>
<p class=3D"MsoNormal">Simon</p>
</div>
<br>
<fieldset class=3D"m_4764773932981263630m_-555035641554905656=
mimeAttachmentHeader"></fieldset>
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