mini2
Junior Member
Posts: 8
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Post by mini2 on Feb 13, 2021 11:14:03 GMT
Hi,
Is anyone aware of a bad batch of oil filters out there?
If I leave my Mini for more than a couple of hours the oil seems to drain from the filter back into the sump. Meaning that every time I start it up the filter has to refill, which is going to cause wear on the engine.
I have tried two filters now, both the same. The housing is nice and tight so I don't know what else to do
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Post by notamini on Feb 13, 2021 23:44:49 GMT
I think you have the filter assembly together incorrectly. Seems to me there is a part in there that acts like a one way valve or stops the oil from bypassing the filter. Martin can confirm this.
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Post by jockduck on Feb 14, 2021 10:07:27 GMT
Hi, How long does it take for the oil light to go out when starting? Jock
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mini2
Junior Member
Posts: 8
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Post by mini2 on Feb 14, 2021 17:50:37 GMT
Hi, How long does it take for the oil light to go out when starting? Jock About 7 seconds. If the car has been run within a day it will go out within a second. I.e. if I drove it in the morning, and then parked it up all day it would go out instantly if I started it that night.
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Post by jockduck on Feb 15, 2021 10:09:27 GMT
Hi, That does not sound too bad, I am not familiar with the later automatics, what kind of oil filter type has your car got? horizontal or vertical spin on??. cartridge type filters don't have an anti drain valve, I wish designers would mount filters vertically down so they would stay full. I guess you could have an internal leak that allows the the oil system to drain down and take a few seconds to refill on starting. I once knew a manual Mini that would take 30 seconds to turn off the oil light but that had a worn oil pump, autos don't have that issue. Jock
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mini2
Junior Member
Posts: 8
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Post by mini2 on Feb 15, 2021 10:37:46 GMT
Hi, That does not sound too bad, I am not familiar with the later automatics, what kind of oil filter type has your car got? horizontal or vertical spin on??. cartridge type filters don't have an anti drain valve, I wish designers would mount filters vertically down so they would stay full. I guess you could have an internal leak that allows the the oil system to drain down and take a few seconds to refill on starting. I once knew a manual Mini that would take 30 seconds to turn off the oil light but that had a worn oil pump, autos don't have that issue. Jock Its a horizontal filter, sits just under the alternator. It is a cartridge type filter that sits within a metal housing
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Post by notamini on Feb 15, 2021 20:38:00 GMT
Jock Never seen a spin on automatic. I was told the pressure is too high. I have seen a modified version for a spin on for an 1100. I have pics if you want to see.
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Post by jockduck on Feb 16, 2021 10:04:49 GMT
Hi that was why I asked, I had heard suggestions of spin ons with some people having problems with cartridge filters but yes the pressure in reverse is too high. unfortunately I don't have a spare filter head to examine at the moment to verify the drain down theory, I just had a thought I think the oil pump has a non return valve to stop it draining back, I have a couple to look at tomorrow if I remember. Jock
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Post by notamini on Feb 16, 2021 23:06:02 GMT
Great. I'd like to know too. My car has a habit of raising the oil level the longer it sits. Never used to do that. And if left too long the filter case leaks for a few seconds at startup.
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Post by simonwri on Feb 16, 2021 23:31:09 GMT
Out of interest what oil pressures are you running?
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mini2
Junior Member
Posts: 8
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Post by mini2 on Feb 17, 2021 8:12:59 GMT
Great. I'd like to know too. My car has a habit of raising the oil level the longer it sits. Never used to do that. And if left too long the filter case leaks for a few seconds at startup. Yes the level on mine raises too when its been left. That's what made me first start looking into the filter!
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mini2
Junior Member
Posts: 8
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Post by mini2 on Feb 17, 2021 8:13:52 GMT
Out of interest what oil pressures are you running? Not sure as I only have the oil light. But once the filter has been refilled the light goes out and stays out
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Post by jockduck on Feb 17, 2021 9:56:59 GMT
Hi guys, I always thought it was the torque converter draining down to the half way point that raised the sump level, it is my experience that all automatics have this feature hence the correct procedure required to check the oil level. Even my spare engine/box with zero miles since rebuild does this. Jock
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Post by notamini on Feb 17, 2021 12:55:42 GMT
When cold oil psi is about 75 on the engine side. I was also told it was the TC draining but this question made me wonder.
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Post by jockduck on Feb 18, 2021 10:03:18 GMT
Hi, I checked the oil pump today and there is no non return valve, there is a pressure valve that dumps oil from the discharge back to the suction to control the maximum pressure (140 psi ?) so no anti drain down valve. Jock
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Post by mra-minis on Feb 18, 2021 19:27:29 GMT
I can be contacted on martin@kmprecisionengineering.com
7 seconds is a bit too long, but if you have a bit of wear and tear then it will take longer for the light to go out, the light would go out at about 7psi, I would advise getting a pressure gauge on your engine and a 200psi gauge on your transmission as this will tell you a lot about the health of you unit.
The spin on oil filter type will work just look at a JCB for instance thousands of psi of oil pressure and they use a spin on, just a stronger one, the problem is finding one that does all that an engine requires, ie filters down to sub micron level and flows a high enough rate to keep up with demand etc...
the later type AP2 variants will go as high as about 260psi however most are about the 180 to 200psi I have no confirmed data just empirical from my own tests as the design manual has a lot of assumptions on pressure, some of the 998's had 85psi.
The torque converter does drain and yes it is exactly why you have to check the oil in a very specific manner
The reason for the canister leaking at start up only is due to various combinations of effects within the oil / hydraulic system.
All of the AP1 & 2 range uses a horizontal filter, they are all very similar, with the exception of the 1100/1300/America which has a shorter but fatter filter unit and noticeably stronger case, never heard of one failing due to overtightening.
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Post by mra-minis on Feb 19, 2021 0:43:28 GMT
I can be contacted on martin@kmprecisionengineering.com
And to answer the original question...
The filter would allow oil to move in either direction so cannot be at fault, unless it was fitted incorrectly of course then it would be faulty but not with the issue you are asking about.
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Post by notamini on Feb 19, 2021 1:30:39 GMT
Martin. Can you confirm if there are actually pieces in the filter assembly that prevent oil from bypassing the filter? I always thought there was and it would only bypass oil if the filter is too blocked.
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Post by mra-minis on Feb 19, 2021 1:39:20 GMT
Martin. Can you confirm if there are actually pieces in the filter assembly that prevent oil from bypassing the filter? I always thought there was and it would only bypass oil if the filter is too blocked. I can be contacted on martin@kmprecisionengineering.com That's correct, there is a platform that is spring loaded, as the pressure behind the spring is overcome by the oil pressure inside the filter then it will lift off the seat and bypass unfiltered oil to the system ! The old adage is "dirty oil is better than no oil"
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Post by limby2000 on Feb 19, 2021 21:13:07 GMT
Dont worry guys, my newly rebuilt engine takes a good 3 seconds when cold to move the needle on the oil pressure gauge, very annoying indeed.
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Post by mra-minis on Feb 19, 2021 21:49:08 GMT
I can be contacted on martin@kmprecisionengineering.com
I was looking at an electric hydraulic pump the other day for one of my machines, interestingly plumbing it in would be simple enough, turn on wait for pressure then start problem gone, should be able to remove the existing pump/s ?!
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Post by jockduck on Feb 20, 2021 10:08:02 GMT
Hi again, I don't know if it helps, I unbolted Ottos oil filter bowl today for a filter change and I got less than a cupful out of it, The car had not run for a couple of days and I had the car jacked up on the LHS so that I could change the rear hydrolastic displacer. So it seems that the oil filter can drain down over some days especially if the LHS is higher than the right. Jock
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