[Healeys] oil pump
WILLIAM B LAWRENCE
ynotink at msn.com
Wed Oct 31 22:53:37 MDT 2018
Oil pressure is not controlled by the oil pump, but by the pressure relief valve. A high capacity pump will provide more volume at lower engine speeds and so the pressure will stay higher at idle and lower speeds, but the relief valve will still set the higher limit of pressure.
You can mess around with shims and such to increase the relief pressure, but high pressure can also be detrimental since pressures above about 65 psi will tend to erode the bearing surfaces.
From: Healeys <healeys-bounces at autox.team.net> on behalf of Bob Spidell <bspidell at comcast.net>
Sent: Wednesday, October 31, 2018 6:16:44 AM
To: healeys at autox.team.net
Subject: Re: [Healeys] oil pump
It's kinda like blood pressure. Except, lower BP is better.
On 10/30/2018 6:55 PM, Engl wrote:
Indeed, oil pressure on your car (still think of it as your car!) is great as you indicate.
On Oct 30, 2018, at 2:01 PM, E.A. Driver <edriver at sasktel.net<mailto:edriver at sasktel.net>> wrote:
As with Bruce and Bob at rebuild of a BJ8 engine I added DWR hcpump in 2000, although I sold the car in 2016, I assume the current owner will verify that oil pressure during driving still ranges from 55 to 60 psi and at idle 20-25psi. As Michael has stated if the correct bearing clearances were met during rebuild there should be no issues.
Web master Saskatchewan British Car Club
On 30/10/2018 9:52 AM, Bruce Steele wrote:
I echo Bob’s comments. I’ve had the DWR high capacity pump for years.
From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Bob Spidell
Sent: Tuesday, October 30, 2018 7:17 AM
To: healeys at autox.team.net<mailto:healeys at autox.team.net>
Subject: Re: [Healeys] oil pump
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
On 10/30/2018 5:12 AM, simon.lachlan at alexarevel.plus.com<mailto:simon.lachlan at alexarevel.plus.com> wrote:
Has anyone got the Denis Welch oil pump ENG672M? See:-
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.
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