How do you like your scissor lift? I am considering one since my garage has limited space.

 

I love it. My wife bought it for my birthday some years ago, and it's been flawless since then. It has made my auto hobby life so much easier and has probably saved my back from injury more times than I care to imagine. Heaviest load I've had on it was with my Ford Flex, which at the time was about 5500 lbs:

https://www.fordflex.net/forums/sear...345&sf=msgonly

 

It appears you have some steel runners under the rollers. I am assuming this helps smooth it out on an old garage floor.

 

Actually the garage floor is smooth enough, the steel flat bars are there to ensure it stays smooth. I also put a length of rubber sheet cut to slightly wider than the flat bar to provide a bit of cushion too, and to prevent any rust stains from the unpainted flat bar from marring the floor. It's worked well for about nine years now.

 

There is a used Snap-on 6500 on FB Marketplace about an hour away from home for $1750. That is about 1/2 price of the better ones I have seen. Unfortunately, I have my military weekend so I can't go see it till Monday or Tuesday. At least this is a fun weekend, weapons qualification. Can't beat the deal, they buy the ammo, supply the weapons and pay you to do it. That is a win/win/win!

 

Single piston or double? I'd not be comfortable with the single piston lift. I have a whole collection of air tools that I rarely use anymore, just about every power tool I have now is electric - Milwaukee, Ryobi, EgoPower. Good stuff.

 

I was bummed. I had my long military weekend (Thursday through Sunday) checked this morning and the mid rise lift sold. Have the parts car up on cinder blocks and started taking parts off.

 

What follows can serve as a tutorial on how the Positive Crankcase Ventilation (PCV) System in the 2nd generation MINI works, and what can happen when it doesn't work. In an earlier post (https://www.northamericanmotoring.co...ml#post4672925) I detailed some significant work I had done rebuilding much of the cooling system in my Coupe. While I had much of top end of the engine apart, I decided to replace the valve cover with the spiffy new red aluminum valve cover that recently became available. I really liked the look of the new valve cover (see it here)) and was looking forward to getting the Coupe back on the road.

After putting about 300 miles on the car several serious issues became obvious. First issue was with puffy clouds of blue smoke appearing if the car idled for just a few minutes, like at a traffic light. Then some engine stutter at light throttle, that was new and unexpected, especially since I had just changed the plugs. Then a sooty buildup at the tailpipe, reappearing after driving 20-30 miles after cleaning the tip. And then, woah, I found almost no oil on the dipstick - this was a shock as I had just changed the oil while I was finishing the coolant system repair project. These were all red flags I couldn't ignore.

I pulled the plugs and was dismayed to see that my new plugs were fouled beyond belief with oily soot:


These plugs were new, this is how they looked after 300 miles.

So, it was time to look at what was going on back there. Pulling off the valve cover vent hose brought Surprise #1, as it took no effort to disconnect the hose from the valve cover, the snap ring connector was not holding the hose to the port on the new valve cover. After removing the vent hose, oil immediately started dripping from the port and the disconnected hose. That should have been dry; that hose connects to the positive crankcase ventilation (PCV) valve that is integrated inside the valve cover and is designed to maintain a slight vacuum above the valve camshafts. Any gases that leak past the valve stem seals are collected in the valve cover and then sucked back into the intake manifold to be returned in the engine, all part of the pollution control system. Again, little to no oil should be in that hose.


Oil dripping out of the valve cover vent port. Shouldn't be this much oil in this vacuum connection.

It was obvious that the valve cover vent hose was not sealing at the port on the valve cover, which would cause a significant vacuum leak between the intake manifold and the valve cover. I had to check the other end of the hose, which connects to the bottom end of intake manifold. The port connection there is just inboard of the throttle body. The only way to visually inspect that connection was to pull out the intake manifold, something I had to do when I replaced the thermostat and the crossover water pipe as part of cooling system rebuild project.

Unbolting the intake manifold after removing all the interferences was time consuming, there's precious little room to work behind the engine, and unbolting the bottom of the manifold from the engine block is not an easy task. Pulling the intake manifold loose gave me enough room to remove the throttle body and disconnect the intake flex hose from the manifold. Another surprise then (Surprise #2), as oil just poured out of the manifold and over the steering rack and then down over the floor of my garage.


Looking into the intake manifold, which was full of engine oil. The port in the lower right of the photo is the bottom end of the semi-rigid vent hose that connects to the vent port on the valve cover shown in the previous image.

I looked inside the manifold and saw that it was literally full of oil, with an actual puddle of engine oil inside the intake manifold. A mystery then - how was engine oil getting into the intake manifold? The only source had to be the hard vent pipe that connects the bottom end of the engine (the crank case above the oil pan, the space where the actual crankshaft is located) to the intake manifold. That vent pipe is the component in the PCV system where pressurized crankcase vapor is ventilated to the intake manifold via intake vacuum, and then burned in the engine as part of the combustion process.


The vent hose and vent pipe are under vacuum during engine operation, each connect into the engine intake.

During the combustion process some gases leak past the piston rings and are forced into the crankcase - this is normal and how it is supposed to work. That blow-by of combustion gases does create significant positive pressure in the volume of the crankcase space, that pressure is relieved by the hard vent pipe connection between the crankcase and the bottom of the intake manifold. Engine manifold vacuum creates the path that allows the blowby gas pressure in the crankcase to be relieved into the intake manifold. If that vacuum is not present, blowby case pressure builds up in the crankcase to the point where the engine oil being splashed around by the crankshaft in the bottom end of the engine is forced out through the crankcase ventilation pipe and then into its connection point in the flex hose that is between the throttle body and the intake manifold. It sounds complicated, but it's a pretty simple path once you visualize how it is put together.

Maintaining engine vacuum is the key component in this system - now I saw where the failure point had to be, that being the ventilation hose snap ring connector at the valve cover. I removed the new red aluminum valve cover I had installed during the cooling system rebuild project and inspected the port where the ventilation hose connects the valve cover to the intake manifold. The intake manifold creates all the vacuum (negative) pressure to suck blowby gases created during combustion that build up in both the top end of the engine inside the valve cover, and in the bottom end of the engine. That means that the port connector on the valve cover has to be tight, with no leakage. Now with the new red aluminum valve cover off I was able to inspect the port connector around its full circumference. There I discovered something amazing - the aluminum casting on the new red aluminum valve cover that forms the actual port connector was incomplete. There was missing metal on the port connector to where the snap connector on the ventilation hose could never be completely secure. In other words, the flexible plastic ring on the vent hose fitting would never be able to be completely gripped in place on the valve cover connection port. This would result in a massive vacuum leak at that connection point, also allowing unmetered air to bypass the throttle body. That alone can cause all sorts of mayhem.


The cast aluminum port connector is incomplete, part of the ridge that holds the vent hose connector is missing.

That vacuum pressure leak would result in too much blowby exhaust gas pressure building up in the crankcase, where not enough vacuum is present to relieve that gas pressure in the crankcase. That gas pressure would increase to the point where engine oil churned up by the crankshaft would be pushed out through the vent pipe connecting the crankcase to intake manifold. Oil would then collect in the intake manifold; some of that oil would be sucked into the combustion chambers above each piston and be incompletely burned. That created puffy blue smoke and subsequently fouled my spark plugs. Oily vapor would also be pushed back up into the valve cover and through the PCV system integrated in the new red aluminum valve cover. This is the reverse of how that path is supposed to work.


OEM port on left, new on right. Just not enough metal on the new valve cover port to lock in the vent hose connector.

So, with the discovery of the incomplete casting for the valve cover ventilation port, I asked the vendor for a replacement valve cover, as this malformed valve cover would have eventually destroyed my engine if that failure was left uncorrected. Upon receiving the new valve cover I closely inspected the ventilation hose connection port and found it to be fully formed, the difference between the port from the first valve cover and the second was painfully obvious. I also test fitted the ventilation hose to the second valve cover and it snapped into place as intended; it was so tightly locked into the vent port that it took some doing to compress the snap ring hose connector enough to get it to come loose.

My curiosity was now piqued. After I learned more about how the BMW/MINI Positive Crankcase Ventilation (PCV) system is supposed to function, I decide to inspect the actual PCV mechanism. In the N16 engine, that portion of the PCV system is integrated into the valve cover, a design that is shared with many BMW engines. Both MINIs and BMWs utilize a flexible rubber diaphragm that regulates the balance between vacuum (negative pressure) and positive pressure inside the valve cover - that pressure changes between idle, wide-open throttle, and easy cruising. I decided to open the cover plate on the top of the valve cover and look at the internals of the integrated PCV valve. Now it was time for Big Surprise #3.

Removing the four screws over the PCV cover plate revealed the flexible diaphragm that regulates the pressure. What was immediately apparent was that the diaphragm was not seated in its recessed base ring; it was compressed and crushed partly outside of the recess that the diaphragm fits into. That was unexpected, obviously.


PCV diaphragm in the top of the first valve cover, with the cover plate removed. Note how the diaphragm is not seated inside the groove.

As I had not yet returned the first red aluminum valve cover to the vendor, I took the opportunity to look at the PCV diaphragm in that valve cover. Surprise #4 - that diaphragm (BMW also calls this a "membrane") was compressed and crushed partly outside its recessed ring, albeit in a different orientation. It was plainly obvious that the manufacturer that creates these beautiful red aluminum valve covers needs to work on their assembly processes and quality control. I would assume that the reseller receives these valve covers from the manufacturer fully assembled; there should be no reason for any reseller to disassemble the valve covers when received.


PCV diaphragm in the second valve cover, also not seated and deformed, in a different direction. Note that the diaphragm also appears to be dirty - valve cover #2 had not yet been installed, still new in the box.

After some negotiation with the vendor, along with detailed explanations with photos, the vendor did authorize the return of the two failed valve covers, and both have been shipped back and I've been refunded for the cost of the two valve covers. I did end up paying for new gaskets, spark plugs, and a repeat oil change, to say nothing of the time and labor I put into this adventure. An expensive learning experience, to be sure.

I ended up reinstalling the OEM valve cover. I've now driven over two thousand miles with the original valve cover in place, with no issues. Oil consumption is essentially none, and the tailpipe is clean, no soot. Plugs still look almost new. No blue smoke, engine performance is as good as it ever was, as both God and Sir Alec Issigonis intended.

I would recommend that owners of a MINI with the N16 engine take a moment to inspect the PCV system in the valve cover and check that the vent hose connection is intact and not leaking. It is easy to do and would only take a few minutes.

 

Kind of a bummer with the aluminum valve cover. I like the looks of it. If mine went bad (N18) I was considering it prior to this.

I do know that the PCV makes a huge difference on oil consumption. When I bought mine, it was using 1/4 quart per fill-up (approx. 400 miles). After doing some research here, I replaced the PCV valve and now if I use a Qt. in 5000 miles it is a lot.

 

Good to know on that. My dad mentioned that my R57 used some oil when he was driving it, but in the 2,300 miles I've put on it so far, it's still in the middle of the dipstick

 

Thanks for the PSA concerning those aluminum valve covers. I had one of those on my shopping list, and had planned on taking it apart when received just to see what it looked like inside. Sounds like that might be a good idea for anyone that buys one just to make sure the PCV diaphragm is seated correctly.

 

I had known that as well, which is why I zeroed in on the PCV as soon as I saw that the dipstick had almost no oil on it within just a few hundred miles after changing the oil. I had that issue with my Passat some years ago; the VW TSI motor also uses a diaphragm in the PCV valve body to govern the vacuum pressure. Diagnosing and replacing a failing VW PCV is pretty straightforward, the biggest difference between the VW and MINI as that in the VW, the crankcase pressure will build up to the point to where it'll blow out the main seal on the crankshaft first. What I've learned here is that in my situation, the PCV system was inoperable because there was little to no vacuum (negative) pressure from the vent hose connecting the intake manifold to the valve cover. There was no reliable seal on the vent hose connection to the valve cover, simply because the cast aluminum valve cover was not fully formed at that port connector. In my engine, crankcase pressure was being relieved by spitting engine oil directly out through the crankcase vent pipe and into the flex connector just outboard of the throttle body. Flip a coin at to which, MINI or VW, would have been the less expensive repair if not corrected before catastrophic failure. Regardless, I do expect that all of this engine oil being blown out through the engine has probably shortened the life of my catalytic converter considerably.

 

Issues with the PCV diaphragm is a manufacturing error, it is not something that one would expect when buying a new valve cover. Understanding that my experience here is with the N16 engine (and by extension the N12 engine), probably the more common issues rest with the PCV vent hose, which has two weak points. The first weakness is with the two connectors on the vent hose - the seal on each connector is maintained by the o-ring that fits inside each port the hose fits into. The connector at the port at the bottom of the intake manifold is essentially impossible to check without removing the intake manifold itself, which can be a real bear of a task. The most one can do with the intake manifold in its installed location is to check to make sure that it is actually fully seated in the port, and that there's no discernable movement when reaching up past the steering rack and subframe. The connector on the other end of the PCV vent hose fits into the port on the passenger side of the valve cover, which also should be snugly seated in the port and that the pinch-style connector is intact in its full circumference. If you find the connector almost impossible to squeeze to break its death grip on the vent port, then you've got a tight connection that'll maintain a vacuum seal.

The second weak point is with the vent hose itself - it looks like it is a flexible hose, but it isn't. It's actually fairly brittle and easy to crack, and once it is cracked, you've lost the ability to pull a vacuum on the valve cover. I've seen a video of a tech with mad skills who was able to worm a replacement vent hose into the twisty path from the valve cover down to the bottom of the intake manifold, but I sure as heck wouldn't have the patience to do that. Take a look:

 

In my previous posting, I described some of the issues discovered after changing out the OEM valve cover for the shiny new red aluminum valve cover. While it looked great, that new valve cover created a near disaster itself, all because of a malformed aluminum casting on the PCV vent hose connection, and because of an mis-installed Positive Crankcase Ventilation (PCV) valve that is built into the valve cover. So after re-installing the original valve cover I did some more research on the MINI's internal PCV valve assembly. After learning more about how the system works, and how it can fail, I decided that I’d give it a go and replace the hidden PCV valve apparatus that is internal to the valve cover.

I had replaced the PCV in my Passat’s 2.0 turbo engine a few years ago after having the intake valves cleaned by walnut blasting. I had found heavy coking over the valves and the intake plenum while doing some engine mods; it’s a common problem with all direct-injected gas engines. Walnut shell blasting is the best way to clear away that gunk. Replacing the PCV valve in the Passat took about fifteen minutes, it’s externally mounted on the engine and is designed for easy maintenance.

Many European-designed vehicles use a PCV valve design where a flexible diaphragm (also called a "membrane") is used to regulate vacuum pressure. As part of an emissions control system (a good thing), engine vacuum is used to suck out blow-by combustion gases that accumulate in the crankcase of the engine. The flexible diaphragm has a central disk that maintains a seal against a vent channel where blow-by combustion gas (exhaust vapor that forces its way past the piston rings and down into the crankcase) is sucked out of the bottom end of the engine and routed back into the intake manifold. If not vented, crankcase pressure can build up to the point where it can force oil out through the valve cover gasket, sensor seals, and vent pipe connections. This crankcase gas pressure can even build up to a point where the pressure can blow out the crankshaft main seals - not a pretty picture.

Crankcase ventilation as part of an emissions control system has been around for decades, it is not a new thing. There are different types of PCV valves that are used in gasoline engines; European vehicles have long used a flexible diaphragm design to regulate how much engine vacuum is needed to balance out positive vapor pressure that builds up below the pistons and in the crankcase. Regulating how much vacuum (negative) pressure is crucial, vacuum will change depending upon throttle opening and engine power. How the diaphragm system works to manage these opposing pressures is well described in this image from the Audi TT forum at https://www.ttforum.co.uk/:



https://www.ttforum.co.uk/cdn-cgi/im...01-jpg.455687/

The weak link in this kind of PCV system is with the flexible diaphragm. The blow-by combustion gases that pass by the diaphragm can eat away at the flexible diaphragm material; over time this can weaken the diaphragm to the point where pinholes and cracks can develop, compromising the regulatory effect on engine vacuum produced by the diaphragm.

It turns out that the type of flexible diaphragm PCV hardware used by MINI, as well as across the BMW line, is NOT considered to be a user-serviceable component. That's unfortunate. This is in spite of the need for periodic replacement of PCV components. Servicing the PCV system is a routine maintenance task in BMWs and MINIs. What is very unfortunate is that “routine maintenance” of the PCV system in older BMWs and MINIs is accomplished by simply replacing the entire valve cover, as the PCV "Valve" is incorporated internally in the valve cover. Simple, but expensive.

Replacing a MINI’s entire valve cover in the N12 through N16 engines to fix a failing PCV system is still the standard remedy recommended by the factory. Most MINI owners would resign themselves to having to buy an entire valve cover to fix a PCV vacuum leak. But there is a simpler and far less expensive alternative – that being to replace the flexible diaphragm inside the PCV system in situ, without having to replace the valve cover. Only simple tools are required, along with a new $20 PCV diaphragm cap. The photos below show what is required to do this repair on the normally-aspirated (non-turbo, non-S) N16 motor. What is involved to do this repair on the N12, N14, and N18 motors is similar.



PCV valve cap/cover. PCV Breather Hose connection to the intake manifold is in the upper left. Mass Air Flow sensor is at the top of the image.

First thing to do is to remove the plastic cover over the spark plugs - two screws at the top, then remove the oil fill cap. The cover then lifts off easily by rocking it forward a bit to release the tabs in the front edge of the plastic cover. Reinstall the oil fill cap to prevent anything from falling into engine. Then use a pry tool to pop the PCV cover off the valve cover. Note the PCV valve breather hose is just outboard of the cover. It is not necessary to remove that hose, or any other components, from the engine.

Using a suitable pry tool, work the PCV cover cap loose. Be careful not to damage the coil pack connector just forward of the cap. The PCV cap has four sacrificial plastic clips holding the cover in place, these clips will most likely break away when prying up the PCV cap. Use steady force to pry up the cap off the valve cover.

Once you remove the cap, the flexible diaphragm will become visible, either in its well in the valve cover, or stuck up in the PCV cover you just pried loose. Either way you will want to inspect the flexible diaphragm. If your PCV system is failing, you will likely find some cracks or pinholes in the diaphragm material, causing a vacuum leak situation.


PCV Diaphragm. Note the broken tabs from the sacrificial PCV cap, remove these before installing the new cap.

Common symptoms of a failed PCV diaphragm include excessive oil consumption, a smoking exhaust, rough idle, oil-fouled spark plugs, and loss of power. You may see any, or all, of these symptoms, as the causes are all dependent upon how much vapor pressure leakage is passing through the flexible diaphragm. Odds are that you may not even get any failure scan codes, as it may take a catastrophic failure of the diaphragm material to generate a code.



PCV diaphragm well.

Crankcase gases are ventilated via the swirl channel on the right, and then out through the round port in the center to the PCV vent hose port in the upper left. The flexible diaphragm acts like a throttle to balance vacuum (negative) pressure against crankcase (positive) vapor pressure. The PCV vent hose connects the engine valve cover to the intake manifold, where crankcase vapors are sucked back into the engine intake and into each combustion chamber where the crankcase vapors are burned during ignition. Very neat and tidy.


Old cap and diaphragm with spring is lower. Note the broken clips from the sacrificial cap.

The interior of the flexible diaphragm has a hard disk in the center, which forms the seal over the round vent port that is in the center of the diaphragm well. Blow-by gas pressure builds up in the crankcase and is ventilated up through passages through the engine block and into the volume contained by the valve cover. A vent channel in the topmost interior surface of the valve cover opens into the swirl surface underneath the flexible diaphragm. The diaphragm material exerts a downward force over the vapor pressure in the area below the flexible diaphragm, that vapor pressure is released by the hard disk covering the vent port in the center of the diaphragm, The spring below the diaphragm provides enough upward force to keep the disk from completely sealing itself over the vent port. The small hole in the top of the PCV cap provides a pressure relief path in the space above the diaphragm, allowing the diaphragm to flex up and down in the space under the PCV cap. Complicated to explain, but simple in operation.

Note the encrustation in the bottom of the PCV cap, as compared to the new PCV cap below. That's a clue that oil mist from crankcase gas vapor is making it past the diaphragm seal in the channel that the edge of the diaphragm fits into. A crack or pinhole in the flexible diaphragm will allow this oil mist-laden crankcase vapor to leave some deposition in the inside surface of the PCV cap. Note the flow of crankcase vapor shown in the diagram at the beginning of this post to see how crankcase vapor can leak past the flexible diaphragm. The lip of the flexible diaphragm fits into the channel, completing the seal. It's not a perfect seal, there will be always be some small leakage past the edge of the diaphragm. I expect that is by design.


The old diaphragm is below the new parts. Note the sealing disk in the center of the diaphragm.

Now that you have a better understanding of how the PCV valve assembly works inside the engine valve cover, just fix the issue by replacing the diaphragm, along with a new spring and cap. Before you do that, inspect the well where the diaphragm will go. You may find several bits of plastic there, those will be what’s left after the sacrificial clips that hold the cap in place are broken when prying the cap loose. You’ll want to capture and remove those bits before fitting the new diaphragm in place.

Make sure the diaphragm is fully seated in the groove it fits into; the top edge of rim of the diaphragm should be completely flush with the top edge of the groove. If it isn’t flush, then check to make sure no debris is in the groove or stuck on the bottom side of the flexible diaphragm. Don’t forget the spring that goes underneath the diaphragm. Put the diaphragm and spring in place and run your finger over and around the top of the flexible diaphragm to make sure it is centered and where it’s supposed to be. It’ll be obvious if it isn’t situated properly.

Then place the cap over the diaphragm, centering it over the opening. Start with a hard push with the heel of your hand on top of the cap to engage the four clips of the cap onto their retainers. You only get one shot at this (sacrificial clips only work once), so work slowly to keep the cap properly centered over the opening. You may or may not hear the clips pop into place, but once it is fully seated the cap should be almost flush with the top of the valve cover. I used a rubber mallet, tapping with light force, to make sure the cap is fully seated. It won’t be perfectly flush with the valve cover, but almost.

Double check to make sure the PCV breather hose connection is tight and the hose connector is intact. You should not be able to move the hose connector in or out of the connection port connection. In its normal state that hose connector can be very difficult to remove, and that’s how it is supposed to be. Then you are done. Start ‘er up and take a test drive. Assuming you don’t have other more serious engine issues, the engine should run strong and idle smoothly, without smoking or stuttering.

 

Thanks for the detailed diagnosis and description. Just being devil's advocate here...if you really had your heart set on keeping that shiny alloy valve cover, couldn't you have replaced the deformed diaphragm similar to how you did it with the stock valve cover?

 

Thanks for the info. Guessing this isn't something that can be inspected without replacement, since those clips are likely to break off.
I've only got 119k on mine, but do have some slight oil consumption & occasional rough/stumble idle [faint] that improved after replacing spark plugs.

 

Well, the replacement kit (new cap, diaphragm, and spring) only costs around $20 or so (± $10) so there's not much investment required beyond 30 minutes of your time. I certainly think it's worth the small effort needed to replace the diaphragm, it's an easy preventive maintenance task. From everything I've seen and read, the diaphragm is guaranteed to fail, with the consequences of failure being potentially catastrophic.

 

Sure I could, and I will. But there are lessons to be learned here, both for the MINI owner as well as for the vendor who shipped two failed valve covers to me. One failure like this is excusable. Two in a row is a trend. Hopefully the vendor(s) selling this particular part will take action to make sure they aren't providing crap parts to their customers. Reputation is everything.

Econ 101. In this example, all of these cast aluminum valve covers are only made by one or two Chinese manufacturers. It is likely that the failed installation of the two diaphragms occurred at that point when they were first cast, painted, and assembled. When a vehicle ceases production, a common practice is for a small shop to buy the mold for the part, or reverse-engineer a replacement part from an existing part. That can get expensive, so there's not a lot of duplication by these small manufacturers to make these parts. Creating parts for targeted application of automotive components that can only be used for a very specific installation means that the market for that component will not grow. The market peak for that specific part that is unique for only one type of vehicle occurs not long after the vehicle ceases production. Then the original manufacturer of a part that is relatively unique to a vehicle that is no longer being made will move their production capability to provide new components for whatever replaced that now-defunct vehicle. A potential vendor for a new replacement part would need to be creative in finding a way to make this part, without running afoul of patents and intellectual properties that belong to the original manufacturer of that part. That is why you will often see some small differences in the design and fitment of the new replacement part. The new part will be marketed as functionally equivalent, but will not be considered to be an OEM-equivalent part.

 

Thanks, may just add that to my to-do PM list.

 

New sub-thread on the subject of crankcase ventilation...

A short time ago I set out to test an idea that cropped up while I was wrestling with the PCV diaphragm and valve cover issue a few months back. I was considering whether or not there would be any benefit from having a catch can installed in my normally-aspirated (non-turbo, non-S) Coupe. The idea there was that having a catch can in place between the crankcase ventilation outlet and the intake manifold could extract oil from vapor emitted by the crankcase ventilation system, where said oily vapor would build up on the back side of the intake valves as it was being sucked into the combustion chambers. The Coupe's N16 motor is a direct-injection design, where fuel is injected directly above the pistons instead of just after the intake manifold. In older fuel injection designs, fuel is used to wash down the intake plenum and the backside of the intake valves, preventing carbon deposits from building up to the point where it can disrupt the swirl needed to properly mix the fuel air mixture before ignition in the combustion chamber. This buildup of crud is a recurring issue in many turbocharged direct injection engines, where clearing away the accumulated crud is a costly routine maintenance item at about 80-100K miles. This has been less of an issue with non-turbo designs, where engine vacuum is strong enough to not be overpowered by turbo pressure.

I had installed catch cans on two turbocharged VW TSI engines some years ago, after having to pay for walnut blasting of the intakes and valves to clear away the accumulated crud. I did find some relatively minor soot deposits in my non-turbo Coupe's intakes when I had the engine partially disassembled some months back, so I was interested in seeing if a catch can could prevent some of those deposits.


Some crud buildup in the intake plenum and backside of one of the intake valves, a few months ago

Bottom line up front (BLUF) - I don't think there is much value added from a catch can in the N16 motor. But not for the reasons you might think, but rather because of gravity.

A catch can needs to be mounted in a location where it can be easily inspected and drained when necessary. In the very cramped confines of the MINI's engine compartment, there is only one area that I could find where there was enough room to mount a catch can to where I could easily get at it for maintenance. That one area is along the firewall below the windshield wipers, where a catch can mount is high enough to be accessible.


Catch can trial-mounted on firewall

In the first trial location for the valve cover vent hose path, I tried this configuration:


Configuration #1. Trying to create a path for the vent hose without any 90 degree bends. But that created a whopping big low point that filled with oily water.

This was a messy disaster, as I discovered that the ¾" vent hose can hold a lot of oily water that made its way to freedom after I disconnected the hose while trying design #2. I discovered that the location of the hose from the valve cover to the catch can was a problem as I was moving the hoses around to try to get the shortest distance from the valve cover vent port to the catch can. In the process of disconnecting the vent hose, I found that it was full of oily water at the low point of the hose, while the catch can was nearly bone dry after about 800 miles of driving. All that watery filth that had accumulated in the hose then dumped itself over my engine, my shoes, and onto my garage floor when I disconnected the hose.

With my next attempt I connected the valve cover vent hose to the catch can by putting a 90 degree bend at the low connection point, then making an uphill run to the catch can on the firewall while using the shortest length of hose. Gravity would not be denied, however.


Configuration #2. Shorter hose length = better. Running uphill against gravity remained as the deal breaker.

The problem (I discovered) with both designs is that it places the catch can at a higher elevation than the PCV vent port on the valve cover. Much of what accumulates in a catch can is oily water, and that needs to run downhill into the intake manifold. For the catch can hoses, I used 3/4" hose rated for use in gasoline fuel systems. The ID of the 3/4" hose is wide enough to not restrict PCV vapor as it is being sucked out from the valve cover by engine vacuum. I found that with the catch can mounted on the backside of the engine compartment, the catch can’s intake hose has to run uphill from the valve cover’s PCV vent port to get to the catch can regardless of how I tried to make it work. The catch can’s discharge hose will run downhill to the intake manifold, which would be good if the catch can was actually collecting anything.


Catch can after ~800 miles. Almost nothing, but the vent hose from the valve cover was full of oily water. Not good.

Note the uphill flow path from PCV vent port on the passenger side of the valve cover, then through the ¾" ID hose to the catch can on the firewall (the forward vent hose, closest to the oil fill cap). I discovered that this configuration was a non-starter, where oily water vapor condensate would not be sucked uphill into the catch can. That suction was totally reliant upon engine vacuum drawn from the intake manifold to the catch can outlet hose (the aft most vent hose, alongside the air filter box). There is some positive pressure coming up from the crankcase past the timing chains and then into the valve cover, but it's not enough to push oily water condensate up though the valve cover vent hose out to the catch can. After 1500 miles of driving, I expected to see some accumulation in the catch can, but all I saw was this:


Not much here, after 1500 miles, I expected more. Much more. My concern is that the missing oil/water condensate has drained back into the valve cover, and thus into the crankcase.

My conclusion? Engine vacuum in the normally-aspirated N16 motor cannot overcome gravity in this configuration. Unless one can locate the catch can at a serviceable location in the non-turbo MINI engine compartment at a point to where the vent hose from the valve cover to the can could be routed to provide a continuous downhill path, then installing a catch can in an N16 motor is a waste of time at best. At worst, the vent hose could fill up with enough oily water to the point where the PCV vent system will not be able to relieve crankcase ventilation pressure due to the vent hose being plugged full of oily water (configuration #1). Alternatively, having that oily water draining back into the valve cover and then back down into the crankcase oil could be even worse over time (configuration #2). That would be disastrous, where water-contaminated engine oil could score and ruin the crankshaft bearings, or by having gas pressure from the crankcase building up to the point where it can cause gasket failures, oil leaks, and even blow out the crankshaft main seals.

I removed all of this catch can nonsense and brought the engine back into its stock PCV configuration. I cannot say that this issue with the position and height of the catch can is applicable to turbocharged N14 and N18 MINI engines. The turbo motor would still need to create enough vacuum to reliably suck all the oily water condensate uphill and into the catch can. I doubt that the turbo engines can do that. Discussion would be welcome.

 

Spring maintenance time coming up - biggest task in the queue is to replace the OEM shocks and struts all around. Assembling all the bits and bobs now.

Experimenting with this relatively new OBD2 scanner device - "EDIAG Elite" from company called Kingbolen. Works well enough as best as I can determine, as well as scanning for and clearing codes. Interesting reporting functions as well, all controlled through a smartphone app. I configured the device to run a report which it then sends to a website where I was able to download the report. That was pretty cool. It does offer some basic module control functions as well. The big news with this is the price - full bust out retail is less than $100, though I think most folks would end up paying about half that much depending upon where you get it.

https://kingbolentool.com/products/k...t-obd2-scanner

Quite a few reviews on YouTube. Start with the always entertaining (!) Scotty Kilmer and go on from there:

 

Ah Springtime in New England. Winter wheels and tires are off, summer wheels and tires are on!

 

Been a while. How are things?

 

Things are good, life is good. I did have a trip planned for London later this month to catch the Chelsea Flower Show and perhaps take a tour of Plant Oxford just to gawk at the MINI assembly line, but it's not a traveler-friendly world right now. Canceling the trip and reservations was uneventful, thank goodness.

https://en.wikipedia.org/wiki/Plant_Oxford

 

This year's spring refit is done - biggest part of the project was removal and replacement of all four shocks/struts. No drama (not much anyway), the work is straightforward, only issues I had were with two of the struts. First was with one of the struts (right rear) being slightly incorrect as received, with a different locating nipple on the bottom of the strut. Different, as it was missing entirely:


Won't work, returned to the vendor.

I couldn't wait for the replacement to arrive so I bought a replacement strut from another vendor. That went well. Installing the rear struts is stupefyingly easy to do, no special tools needed beyond a breaker bar and the usual nuts and bolts (all installed new).

The front struts were another matter entirely. As many of us know, non-OEM replacement parts are sometimes bedeviled with fitment issues, as the parts will mostly fit without issue but sometimes they may need a little coaxing to make them fit as well as the (typically) more expensive original-spec parts. I ran into that issue with the front struts, where the length of each strut was a few fractions of an inch more (taller) than the originals. On most cars there is often enough slop in the mount point locations where they'll bolt together and a semi-skilled DIYer can figure out a solution. But the second generation MINIs have the front struts being captured at the bottom of the strut body, secured in place through what amounts to be a press-fit collar in the top of the steering knuckle. It can take some work to separate the bottom of the strut from the steering knuckle. As you can see in this excellent video from 1A Auto, pounding out the old strut and slipping the new strut into its mount point on the steering knuckle can take some physical effort:


Where I had to get creative was with installing the new strut. As you can see in 1A Auto's strut install video, lining up the new strut over the receiver collar on the steering knuckle is very tight fit, very little clearance is available to lift the bottom of the strut over the top of the knuckle and then line it up in its location point in the knuckle. Unfortunately with the replacement struts I had there was almost-but-not-quite enough room to clear the top of the steering knuckle. I tried using a spring compression tool to make the total length of the strut short enough to give me the clearance - the compression tool was able to shorten the vertical length of the struts, but there was just not enough room to fit the struts with the compression tool installed to allow it to fit inside the well where I could bolt in the top three nuts to the top of the fender:


Strut with spring compression tool installed

What saved my bacon was that I had the coupe up on a mid-rise lift I have in my garage. I had the idea that I could use the lift to lower the car while keeping the bottom of the strut fixed in place, and to do that without damaging the car or myself in the process. After some experimentation, I ended up bolting a long piece of heavy gauge angle iron to the strong tab on the strut body that serves to link the strut to the previously disconnected anti-sway bar:


Strut with angle iron bolted to the anti-sway bar link location

I was pleasantly surprised to see that this actually worked pretty well; with the angle iron fixed in place in the cup of a floor lift I was able to slowly lower the lift while having the angle iron pushing up against the strut vertically. That served to compress the strut's spring just enough to where I could strong-arm the bottom of the strut into the receiver collar on the top of the steering knuckle. Once the bottom of the strut was positioned over the collar, I was able to lower the lift and allow the weight of the car to press the bottom of the strut into its fully-seated position. Hearing the "thunk" of the strut hitting its fully-seated position in the steering knuckle was a very satisfying experience.

After a test drive everything felt great. There is one stretch of road near my house where it ascends up a hill and the road curves to the right - before I did the work I had noticed that if I accelerated up the hill and over the curve there is a bump in the road that would invariably have the back end of the coupe hop up and the wheels would be briefly airborne. Then the coupe would slew to the side - not a comfortable feeling, especially when it was unexpected. After the new struts were installed I could not get the coupe to hop in the air over that bump, no matter how hard I tried to make that happen. A good thing. After that I had the coupe's wheels aligned and was grateful to see that each corner only needed minor tweaking to get good alignment numbers. Better than I had expected to see, and I was happy.