The 4EFTE engine has two breather ports in the valve cover where in the factory configuration, one port is connected to the recirculation valve (not a blow off valve), and the other port is a PCV (Positive Crankcase Ventilation) valve which is connected to the intake manifold. The PCV valve is a one-way valve which allows airflow from the valve cover into the intake manifold when the manifold is under vacuum/off boost. I removed the PCV valve and tested it and found it to be faulty, as it allowed airflow in both directions.
Open breather port circled on left, PCV valve circled on right :
In light of the faulty PCV, and factory recirc valve being replaced by an aftermarket Turbosmart recirc valve, I chose to delete the factory PCV setup and install an oil catch can. I use a good quality Provent filter (made by Mann+Hummel) in my diesel 4WD and it does a very good job of filtering out oil from the crankcase/blowby vapour so for the Mini I chose to use their smallest model, the Provent 100 which is ~150mm high & 100mm diameter.
To join both valve cover ports to the Provent filter, I needed some fittings and to join the two different size valve cover ports (male 12mm & female 14mm) to the Provent (19mm) it was going to a mess of off-the-shelf hose adapters and pieces to join all the sizes so I made some custom adapters myself. With some HDPE stock (commercially available plastic rod, not the recycled material I made myself) on the lathe, I machined a series of pieces for the custom adapters. HDPE is resistant to oil as well the low temperatures of the vapour so is suitable for this use.
I made all the pieces on the lathe, then cut/beveled/notched the pieces for the tee and 90 degree fitting. They were glued together using Loctite All Plastic Superglue. This Loctite glue has a "surface activator" component, specifically for low surface energy plastics such as Polyethylene, which can be hard to get a good bond using standard superglue (aka cyanoacrylate). The two custom hose adapters allowed me to run 1/2" hose from the valve cover ports.
Another custom adapter connects the 1/2" valve cover hose to the 19mm hose on the Provent filter.
The filter has been mounted on the inner guard above the drivers side engine mount, in the position that was freed up after the remote oil filter was previously moved into the wheel arch. Two rivnuts were fitted in the guard for mounting the filter. The result is a clean looking series of connections between hoses that doesn't look like it has just been hacked together. All of the custom fittings were made with small tolerances to give a tight fit for both the hose & the valve cover ports so that there is no need for any hose clamps, giving a clean look. As long as the filter is not blocked, the PCV system is not under pressure and clamps shouldn't be necessary, but the filter has a pressure bypass valve built into it anyway.
The outlet hose from the filter is routed to a piece of 1/2" steel tube which I machined and welded into the intake piping (pre-turbo). This completes a closed crankcase ventilation system where no air or vapour is vented to the atmosphere.
The Provent filter has an internal reservoir to hold any oil condensed out of the air stream. To allow me to drain any oil from the filter I fitted a short length of clear fuel hose that leads to a valve mounted in the wheel arch. Since I have to access the wheel arch to change the oil filter, the position of the drain valve and clear hose will serve as a visual reminder to check/drain the Provent when I do an oil filter change.
I used a spare Fumoto oil valve I had on hand (normally screwed into an oil sump for draining oil) and made some brass adapter pieces for the drain line.
I haven't decided on the exact placement of the drain valve in the wheel arch but it will likely be bolted onto one of the subframe tubes.
Open breather port circled on left, PCV valve circled on right :
In light of the faulty PCV, and factory recirc valve being replaced by an aftermarket Turbosmart recirc valve, I chose to delete the factory PCV setup and install an oil catch can. I use a good quality Provent filter (made by Mann+Hummel) in my diesel 4WD and it does a very good job of filtering out oil from the crankcase/blowby vapour so for the Mini I chose to use their smallest model, the Provent 100 which is ~150mm high & 100mm diameter.
To join both valve cover ports to the Provent filter, I needed some fittings and to join the two different size valve cover ports (male 12mm & female 14mm) to the Provent (19mm) it was going to a mess of off-the-shelf hose adapters and pieces to join all the sizes so I made some custom adapters myself. With some HDPE stock (commercially available plastic rod, not the recycled material I made myself) on the lathe, I machined a series of pieces for the custom adapters. HDPE is resistant to oil as well the low temperatures of the vapour so is suitable for this use.
I made all the pieces on the lathe, then cut/beveled/notched the pieces for the tee and 90 degree fitting. They were glued together using Loctite All Plastic Superglue. This Loctite glue has a "surface activator" component, specifically for low surface energy plastics such as Polyethylene, which can be hard to get a good bond using standard superglue (aka cyanoacrylate). The two custom hose adapters allowed me to run 1/2" hose from the valve cover ports.
Another custom adapter connects the 1/2" valve cover hose to the 19mm hose on the Provent filter.
The filter has been mounted on the inner guard above the drivers side engine mount, in the position that was freed up after the remote oil filter was previously moved into the wheel arch. Two rivnuts were fitted in the guard for mounting the filter. The result is a clean looking series of connections between hoses that doesn't look like it has just been hacked together. All of the custom fittings were made with small tolerances to give a tight fit for both the hose & the valve cover ports so that there is no need for any hose clamps, giving a clean look. As long as the filter is not blocked, the PCV system is not under pressure and clamps shouldn't be necessary, but the filter has a pressure bypass valve built into it anyway.
The outlet hose from the filter is routed to a piece of 1/2" steel tube which I machined and welded into the intake piping (pre-turbo). This completes a closed crankcase ventilation system where no air or vapour is vented to the atmosphere.
The Provent filter has an internal reservoir to hold any oil condensed out of the air stream. To allow me to drain any oil from the filter I fitted a short length of clear fuel hose that leads to a valve mounted in the wheel arch. Since I have to access the wheel arch to change the oil filter, the position of the drain valve and clear hose will serve as a visual reminder to check/drain the Provent when I do an oil filter change.
I used a spare Fumoto oil valve I had on hand (normally screwed into an oil sump for draining oil) and made some brass adapter pieces for the drain line.
I haven't decided on the exact placement of the drain valve in the wheel arch but it will likely be bolted onto one of the subframe tubes.
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