alistairolsen
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| posted on 22/4/09 at 12:20 AM |
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How much power to run an oil pump?
Say one wanted an electric oil pump, and had a unit such as that off a ford crossflow with a shaft drive and an integral filter head. How large a
motor would be required to turn this sort of unit on appropriate gearing?
Any other ideas for small, cheap oil pumps? I may be looking for one that can create normal levels of oil pressure and one which can flow oil with no
pressure differential required.
Cheers
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ReMan
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| posted on 22/4/09 at 05:44 AM |
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In theory at lest the power that it takes to run it would now be transferred as an equal load on the alternator
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Mr Whippy
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| posted on 22/4/09 at 06:34 AM |
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Why would you want and electric one? At normal running speed a standard one is an overkill and dumping a lot of its oil through the by-pass valve
for starting you can use a pressurized oil reservoir (Accusump) that are available on the web to prime the engine for around 20 seconds at full
pressure before and as you start the engine -
linky to details
[Edited on 22/4/09 by Mr Whippy]
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sickbag
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| posted on 22/4/09 at 06:40 AM |
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Just a guess this so please take it as such.
I would imagine the pump would need less than 1 horsepower to drive it. Although the pressure is usually around 40 - 60PSI, the volume is relatively
low.
As a xflow pump has a max working speed of @ 3000RPM, but attains full flow/pressure way before that, you would need a motor that delivers low speed
rather than high speed torque. One of those motors used more and more for power steering should be more than adaquate, but I wouldn't want to
comment on their long term reliability.
I can see the major benefits of this - full oil pressure before you even start the motor. You could leave the pump running after switching off to cool
internal components, etc.
Good idea ReMan.
Finally back on the job!
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liam.mccaffrey
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| posted on 22/4/09 at 07:05 AM |
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i have a little side project going to manufacture an external electric oil pump assembly for the sprint car. So I guess i will find out what it takes
in time
I am using multiple old pumps for the preesure and scavenge stages and machining an ali housing to hold the pressure gears and obviously an external
oil res too.
MASH dry sumping
or
"Build a dry sump system for £250 and race it too!"
if you will
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nitram38
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| posted on 22/4/09 at 07:45 AM |
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Why not the original mechanical pump or a high volume or high pressure pump?
If your electric one burns out or blows a fuse..............so will your engine. 
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sickbag
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| posted on 22/4/09 at 07:59 AM |
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quote:
Originally posted by nitram38
Why not the original mechanical pump or a high volume or high pressure pump?
If your electric one burns out or blows a fuse..............so will your engine.
It could be wired so if the fuse or motor blows then it kills the sparks straight away.
This would be a more reliable way of detecting failure than waiting for the oil warning light to come on on a normally lubed car.
Plus you could alter the pressure manually to compansate for tempurature conditions, etc.
It would negate the need to keep the engine ticking over waiting for the turbo to cool down if fitted.
Doesn't some ABS systems use an electric motor to generate the line pressure? I'm sure my Dads old Granada did.
Unfortunately I can't see any downsides, but that has always been one of my downfalls. 
[Edited on 22/4/09 by sickbag]
Finally back on the job!
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alistairolsen
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| posted on 22/4/09 at 08:31 AM |
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The non pressurised one is for rear diff cooling and the pressurised one is for rear mounred turbo experiment. Sound like a wiper motor wont be big
enough?
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BenB
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| posted on 22/4/09 at 08:33 AM |
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You could actually be quite trick and use PWM to control the speed of the oil pump so that ther was always just a little bit more pressure than needed
(ie only a little oil coming out of the pressure valve). That way you could use less amps when you didn't need huge oodles of pressure (just to
pee it out of the pressure control valve). Not sure if this is done usually though, never did fancy the idea of relying on an electrical pump alone
for my engine safety but using the same fuse for ignition or having a low oil pressure activated kill switch would sort that out....
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richardlee237
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| posted on 22/4/09 at 11:49 AM |
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A couple of points
1) The engine bearings do not require high pressure to be lubricated. In a plain bearing the pressure in the bearing is generated by the wedge formed
between the journal and the bearing. This pressure can be 100,000 psi but over a very small area. For lubrication, the oil pump only has to deliver
the oil in quite small quantities to the bearing.
2) To cool the bearings and mainly the piston the engine requires high oil flows
3) The engine oil pressure is related to the resistance to flow and oil viscosity. It is quite possible that the oil flow is less at higher pressure
than at lower prssure as the lower pressure is due to the viscosity reducing.
4) The main damage to engine bearings is done at start up because the journal has settled onto the bearing and lubrication does not re-occur until the
shaft has turned and the bearing lubrication wedge has re-formed.
5) Pre lubrication with an electric pump is an effective way of ensuring there is oil at the bearings to form the wedge at start up. Pressure can be
quite low just so long as oil comes out of all the lubrication holes. The same effect can be achieved with a simple hand pump.
6) I have worked with diesel engines with both mechanical and electric oil pumps and can honestly say that an electric pump is a disaster waiting to
happen on a small high speed engine.
7) The only power saving is if you modulate the speed of the pump to achieve the desired pressure rather than a constant speed pump with pressure
regulator.
Quote Lord Kelvin
“Large increases in cost with questionable increases in performance can be tolerated only in race horses and women.”
Quote Richard Lee
"and cars"
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liam.mccaffrey
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| posted on 22/4/09 at 12:02 PM |
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my proposed electric system will be wired to cut the engine in the case of failure as well as having an oil pressure light.
it also provides pre start pressure and protection against surge
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Dingz
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| posted on 22/4/09 at 12:22 PM |
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What is the flow rate, any ideas? I have some formulae somewhere for oil pumps.
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britishtrident
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| posted on 22/4/09 at 12:34 PM |
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quote:
Originally posted by richardlee237
A couple of points
1) The engine bearings do not require high pressure to be lubricated. In a plain bearing the pressure in the bearing is generated by the wedge formed
between the journal and the bearing. This pressure can be 100,000 psi but over a very small area. For lubrication, the oil pump only has to deliver
the oil in quite small quantities to the bearing.
2) To cool the bearings and mainly the piston the engine requires high oil flows
3) The engine oil pressure is related to the resistance to flow and oil viscosity. It is quite possible that the oil flow is less at higher pressure
than at lower prssure as the lower pressure is due to the viscosity reducing.
4) The main damage to engine bearings is done at start up because the journal has settled onto the bearing and lubrication does not re-occur until the
shaft has turned and the bearing lubrication wedge has re-formed.
5) Pre lubrication with an electric pump is an effective way of ensuring there is oil at the bearings to form the wedge at start up. Pressure can be
quite low just so long as oil comes out of all the lubrication holes. The same effect can be achieved with a simple hand pump.
6) I have worked with diesel engines with both mechanical and electric oil pumps and can honestly say that an electric pump is a disaster waiting to
happen on a small high speed engine.
7) The only power saving is if you modulate the speed of the pump to achieve the desired pressure rather than a constant speed pump with pressure
regulator.
Nicely put
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02GF74
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| posted on 22/4/09 at 12:47 PM |
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quote:
Originally posted by richardlee237
6) I have worked with diesel engines with both mechanical and electric oil pumps and can honestly say that an electric pump is a disaster waiting to
happen on a small high speed engine.
that is quite a compelling argument.
if electric oil pumps had huge advantages, then production cars wold have them fitted.
as for the bearings wearing out, most mordern engines, if mainained propeerly, and in some cases not so properly, will do in excess of £ 100,000 quite
easily without a rebuild.
BTW interesting project though so don't be put off.
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alistairolsen
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| posted on 22/4/09 at 01:01 PM |
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quote:
Originally posted by richardlee237
A couple of points
1) The engine bearings do not require high pressure to be lubricated. In a plain bearing the pressure in the bearing is generated by the wedge formed
between the journal and the bearing. This pressure can be 100,000 psi but over a very small area. For lubrication, the oil pump only has to deliver
the oil in quite small quantities to the bearing.
2) To cool the bearings and mainly the piston the engine requires high oil flows
3) The engine oil pressure is related to the resistance to flow and oil viscosity. It is quite possible that the oil flow is less at higher pressure
than at lower prssure as the lower pressure is due to the viscosity reducing.
4) The main damage to engine bearings is done at start up because the journal has settled onto the bearing and lubrication does not re-occur until the
shaft has turned and the bearing lubrication wedge has re-formed.
5) Pre lubrication with an electric pump is an effective way of ensuring there is oil at the bearings to form the wedge at start up. Pressure can be
quite low just so long as oil comes out of all the lubrication holes. The same effect can be achieved with a simple hand pump.
6) I have worked with diesel engines with both mechanical and electric oil pumps and can honestly say that an electric pump is a disaster waiting to
happen on a small high speed engine.
7) The only power saving is if you modulate the speed of the pump to achieve the desired pressure rather than a constant speed pump with pressure
regulator.
wonderfully accurate post! The information contained is only beaten by its irrelevance.
Once and for all people Im not using this to lube an engine, at all, ever!
I need a pump to pump oil. One to provide flow through an oil cooler so that my diff doesnt melt and another for a seperate project to provide
lubrication for a turbo which will be nowhere near an engine or oil system so needs its own.
Cheers
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sickbag
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| posted on 22/4/09 at 01:23 PM |
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quote:
Originally posted by alistairolsen
quote:
Originally posted by richardlee237
A couple of points
1) The engine bearings do not require high pressure to be lubricated. In a plain bearing the pressure in the bearing is generated by the wedge formed
between the journal and the bearing. This pressure can be 100,000 psi but over a very small area. For lubrication, the oil pump only has to deliver
the oil in quite small quantities to the bearing.
2) To cool the bearings and mainly the piston the engine requires high oil flows
3) The engine oil pressure is related to the resistance to flow and oil viscosity. It is quite possible that the oil flow is less at higher pressure
than at lower prssure as the lower pressure is due to the viscosity reducing.
4) The main damage to engine bearings is done at start up because the journal has settled onto the bearing and lubrication does not re-occur until the
shaft has turned and the bearing lubrication wedge has re-formed.
5) Pre lubrication with an electric pump is an effective way of ensuring there is oil at the bearings to form the wedge at start up. Pressure can be
quite low just so long as oil comes out of all the lubrication holes. The same effect can be achieved with a simple hand pump.
6) I have worked with diesel engines with both mechanical and electric oil pumps and can honestly say that an electric pump is a disaster waiting to
happen on a small high speed engine.
7) The only power saving is if you modulate the speed of the pump to achieve the desired pressure rather than a constant speed pump with pressure
regulator.
wonderfully accurate post! The information contained is only beaten by its irrelevance.
Once and for all people Im not using this to lube an engine, at all, ever!
I need a pump to pump oil. One to provide flow through an oil cooler so that my diff doesnt melt and another for a seperate project to provide
lubrication for a turbo which will be nowhere near an engine or oil system so needs its own.
Cheers
You building a jet engine then? A friend of mine did this years ago with a small turbo - what a laugh! If not, then explain yourself!
Finally back on the job!
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alistairolsen
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| posted on 22/4/09 at 01:39 PM |
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Right, first of all I need to sort some way of flowing oil with bugger all pressure so I can add a pump and cooler to my diff.
Second one is for a potential remote turbo project, siting the turbo where the backbox is. In order to do that I intend to use a t3, bail on the water
cooling as you dont need it and run a seperate oil system.
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richardlee237
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| posted on 22/4/09 at 01:48 PM |
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quote:
wonderfully accurate post! The information contained is only beaten by its irrelevance.
Yes I know, your right, but I had this overwhelming desire to write it as it is so often misunderstood.
I'll now pack up my soapbox and go !!
Quote Lord Kelvin
“Large increases in cost with questionable increases in performance can be tolerated only in race horses and women.”
Quote Richard Lee
"and cars"
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alistairolsen
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| posted on 22/4/09 at 01:57 PM |
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lol, cheers for the post,certainly interesting reading! Justhavinga bad day on forums and wondering if folk can read 
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richardlee237
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| posted on 22/4/09 at 02:33 PM |
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Getting back on subject.
1) Re the diff cooling
The very fact that the diff is churning the oil means you'll have pressure variations in the diff casing. If you have an old diff you can drill
holes in you could do a simple experiment with the car jacked up and the wheels turning and take pressure measurements using a simple water
manometer.
Once you know where the high and low pressure points connect up a cooler and see if it works.
PIA yes but interesting.
Locost ? oh yes!
2) Re the turbo
Use a small hydraulic pump (£100 or so ) driven from the prop shaft, or elec motor. Use a finned ally tank in the airflow and you could be OK
Flows and power readily available on pump makers websites.
Just thought, drilling a lot of pressure tappings in the diff could weaken it and cause it to explode. but hey it would be exciting. !!
Quote Lord Kelvin
“Large increases in cost with questionable increases in performance can be tolerated only in race horses and women.”
Quote Richard Lee
"and cars"
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alistairolsen
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| posted on 22/4/09 at 02:47 PM |
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Thats a very interesting idea that I hadnt thought of! Saves weight and money!
Lowest pressure has to be in the air above the oil I guess as the diff is vented so that would make sense for the return, and just above, so that the
oil doesnt have to climb.
For the high pressure... I guess the bottom of the nose where the front of the crownwheel is heading down through the oil althought testing would be
required.
I wonder if sufficient differential exists for it to work on any length of pipe....
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