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Jun 14th, 2026
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Joined: Jun 2012
Posts: 2,242 Likes: 72
Talk Morgan Expert
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Talk Morgan Expert
Joined: Jun 2012
Posts: 2,242 Likes: 72 |
The K&N filter also has a hole in the end fitting so it can be wire locked on, handy if you do any competition where locking is usually required.
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Joined: Apr 2019
Posts: 488
Learner Plates Off!
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Learner Plates Off!
Joined: Apr 2019
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There isn't an anti drain-back valve in the pump as such, just the tight tolerance of the Gerotor gears.
I think the path of oil to the sump when the car is standing is through the pressure pump then to the inlet side of the filter so will either leak past the drain back valve or have enough pressure/head to push the ADBV open as flow will be in the same direction as when the pump is running, then through the filter, up the oil galleries and leak through the bearings into the sump so the ADBV will only stop wet sumping if it doesn't leak or is strong enough to hold back the head of oil.
Is it possible that another leak route is past the Gerotor gears and leak through the pump where it mounts on the pinion shaft and into the cam chest and then through the cam bearings into the sump not going through the filter?
Wonder if engines that wet sump have lower oil pressure than those that don't, was told by someone in the know that some X wedge motors have hot tick over pressure in single figures.
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Joined: Feb 2019
Posts: 3,857 Likes: 2
Talk Morgan Addict
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Talk Morgan Addict
Joined: Feb 2019
Posts: 3,857 Likes: 2 |
Mine wet sumps and hot idle is about 15 pounds pressure.
There is a small plate in the breather cavity, behind the triangular plate under the rear cylinder, with two bolts at the top of it. I believe that plate is designed to flex and open to allow oil to flow when pressure behind it pushes it open. When at rest it is closed, or should be. Mine sits on the part of the cade that is not a perfectly machined flat location and a wear mark can be seen on the side of the plate that contacts the case. If it were machined flat i bet the wet sumping would go away.
2019 M3W Sold and is now in Las Vegas enjoying the showgirls :-)
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Joined: Feb 2019
Posts: 3,857 Likes: 2
Talk Morgan Addict
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Talk Morgan Addict
Joined: Feb 2019
Posts: 3,857 Likes: 2 |
K&N have suitable filters (as shown in the Alternative Parts List):
▪ K&N Oil Filter p/n KN-171B (Black)
▪ K&N Oil Filter: p/n KN-171C (Chrome finish)
These are proven to work well on the M3W and have the benefit of a hex moulding on the end so you can use a spanner to easily undo them. That hex end is worth every penny.
2019 M3W Sold and is now in Las Vegas enjoying the showgirls :-)
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Joined: Apr 2019
Posts: 488
Learner Plates Off!
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Learner Plates Off!
Joined: Apr 2019
Posts: 488 |
Quote from the X Wedge Owners Manual
"Oil Pressure
Minimum hot (200° F) oil pressure is 8psi at idle and 40psi at 2800 rpm."
Lowest I have seen at idle is 14.5 psi and wet sumps.
Last edited by Obie; 07/08/21 11:46 AM.
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Joined: Apr 2019
Posts: 488
Learner Plates Off!
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Learner Plates Off!
Joined: Apr 2019
Posts: 488 |
There isn't an anti drain-back valve in the pump as such, just the tight tolerance of the Gerotor gears.
I think the path of oil to the sump when the car is standing is through the pressure pump then to the inlet side of the filter so will either leak past the drain back valve or have enough pressure/head to push the ADBV open as flow will be in the same direction as when the pump is running, then through the filter, up the oil galleries and leak through the bearings into the sump so the ADBV will only stop wet sumping if it doesn't leak or is strong enough to hold back the head of oil.
Is it possible that another leak route is past the Gerotor gears and leak through the pump where it mounts on the pinion shaft and into the cam chest and then through the cam bearings into the sump not going through the filter?
Wonder if engines that wet sump have lower oil pressure than those that don't, was told by someone in the know that some X wedge motors have hot tick over pressure in single figures. Not seen the inside of the crank case but the inner cam bearing housing look to be sealed from the crank area so not a leak source.🤔
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Joined: Nov 2017
Posts: 101
L - Learner Plates On
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L - Learner Plates On
Joined: Nov 2017
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Scott
2018 M3W
1995 Porsche 993
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Joined: Apr 2013
Posts: 1,370 Likes: 11
Has a lot to Say!
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Has a lot to Say!
Joined: Apr 2013
Posts: 1,370 Likes: 11 |
I've used the K&N filters as well as the H-D filters. They're good enough. After the first change having some debris on the sump drain magnet is expected. After that I would expect enough to possibly smear on the end of a finger. It's a good engine built to reasonably tight tolerances. Biggest problem is that it's air cooled and the oil takes a beating which is why synthetic is called for. The beast gets hot! Biggest thing is to change out the oil and filter religiously.
What's your mileage? Who cares. Is it practical? See #1. What happens when it rains? You get wet.
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