mark 3 oil pump flow rate?

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Scottish888
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Location: Edinburgh, Scotland UK

mark 3 oil pump flow rate?

Postby Scottish888 » Tue Apr 09, 2019 12:08 pm

As I have my engine apart at the moment I thought I could check the oil pump flow rate by driving the pump with a drill and adaptor.
Does anyone know what flow rate to expect?

Regards

Jordan
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Re: mark 3 oil pump flow rate?

Postby Jordan » Tue Apr 09, 2019 9:52 pm

You could figure out the theoretical output if you knew the volume of the space between two of the pump's gear teeth and the portion of the cylindrical housing they move past. But it's a complex shape. Some calculation involving pump speed should provide the flow rate, but there would be some leakage due to inevitable clearances and possible wear.
I guess the volume could be obtained by dropping a pump gear into a known quantity of liquid, to see how much it displaced.
The housing data could be simply calculated, etc.

LaceyDucati
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Re: mark 3 oil pump flow rate?

Postby LaceyDucati » Wed Apr 10, 2019 8:43 am

I would just check the pump for condition and tolerance, paying special attention to bushing and gear end clearance. The pump will deliver enough oil, however check the end of the cam at the threaded end to ensure the cam is at minimum got a restrictor in it. This subject re oil flow to the cam lobes has been cover before somewhere. Obviously if the cam has an open end or there is "significant" wear at the crank end bushing, flow to the crank will be diminished. However it is my belief that you only need a steady trickle of oil to a roller bearing crank and I would not over think the reasoning for the rod failure. It is most likely the rod failed due to original component tolerance and quality issues. I would just do all the obvious checks and clean the engine thoroughly including the crank sludge trap and oil ways. For your reference below is the pump flow graph taken from the Condor A350 manual which has the same pump. I think it is turns per minute against volume.

oil flow graph.jpeg
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ranton_rambler
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Location: Stafford UK

Re: mark 3 oil pump flow rate?

Postby ranton_rambler » Thu Apr 11, 2019 5:23 am

Y axis is pump output.
X axes are pump speed and engine speed. Looks like pump is driven at 1/3 of engine speed.
I opened my pump up to check the inside looked OK and also measured up against the figures in the workshop manual.
Ian

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: mark 3 oil pump flow rate?

Postby Scottish888 » Thu Apr 11, 2019 10:24 am

All very helpful, thank you.
More info is always useful.

Regards

LaceyDucati
Posts: 521
Joined: Sun Sep 19, 2010 10:30 pm
Location: Wales UK
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Re: mark 3 oil pump flow rate?

Postby LaceyDucati » Thu Apr 11, 2019 5:32 pm

The Conor manual shows a jig for mounting the timing casing with an integral oil tank. So the test is done on the jig, and I assumed it was at pump speed. Then again it is only French and German text so maybe I missed something! Looking again I see the different scales for motor speed and pump speed.

Nigel


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