[Healeys] oil pump

[Bob Spidell]

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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