[Healeys] oil pump

Michael Salter michael.salter at gmail.com
Tue Oct 30 09:54:44 MDT 2018

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
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.


On Tue, Oct 30, 2018 at 11:30 AM Bob Spidell <bspidell at 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 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.
> 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.
> 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).
> * apply appropriate grains of salt
> Bob
> On 10/30/2018 5:12 AM, simon.lachlan at 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=3
> Their text:- “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.
> - ENG672 is the standard type.
> - ENG672M is the high capacity pump.”
> What are “removable gallery plugs”?
> 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?
> 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?
> Anyhow, if anyone’s got one…..what’s it like? Did the oil pressure improve
> at all?
> 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.
> Thanks,
> Simon
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