Anyone try replacing the "MINI Crankcase Vent Hose - Valve Cover to Intake Manifold" Part #11157605186 with rubber vacuum hose or water heater hose?

Just curious how long a piece I need to make the 90 degree bend into the intake manifold.

I've gone through two of these cheap plastic pieces of crap from BMW and don't wanna pay for OEM again.

 

Some people will tell you to just block off those ports. I’m not going to suggest that. I would add a catch can to that vent tube circuit. Also, you need to be careful to get the correct type of tubing. Make sure it’s oil and gas rated, or it will deteriorate from the exposure.

 

No way in hell i would block that port.

Finding 3/4 inch vacuum hose isn't that easy. Maybe Napa. AutoZone didn't have any. I tested the fitment last night with some 3/4 water heater hose i had on hand and it definitely requires a 90 elbow to make the connection into the intake manifold. Maybe Napa has one of those as well.

 

I have been run with those ports blocked off for over 40,000 miles no issues.

 

Where does you excess crankcase pressure escape if you blocked the PCV ports?

 

passenger side blocked, driver side runs to oil catch can.

 

3/4 inch automotive specific vacuum hose is not available at the standard retail stores in my area, Amazon or eBay.

Anyone have any other location I could check? Maybe a a heavy truck part store...

 

I trimmed the plastic tube off the connections and used 3/4 heater hose i purchased at the auto parts store in a 3 foot length.




it was not the ideal hose but held up just fine.

I have since added a catch can and plugged these ports and have no issues.

 

Thanks that's what the video shows. I have 3/4 inch water heater hose. Def not ideal but should suffice.

 

Tangentially related : This mechanic thinks excess crankcase pressures caused an engine plug (Part 11117540058) above the "front" crank seal (I changed mine twice on the original engine) to leak.


Proper PCV is most important.

 

Heater hose is ok for a short term solution but its not rated for oil or the aromatics found in PCV fumes. Over time the oil will soften and degrade the hose. I suggest looking for Gates 4219XL in 3/4" size. It's rated for fuel or PCV usage.

 

Oh cool. thanks for the tip. I suppose it wont collapse under vacuum like my the Mini OEM PCV hose did?




I guess Ebay is my best bet...

or

 

Can your recommend a hose adaptor to go from 3/4 to 5/8 for this generic catch can? It come with hose ends, the largest being 5/8th...perhaps smaller. Might be 1/2 not sure. The 5/8th automotive water hose I have slips over but isnt very tight.

 

A SharkBite 3/4 to 5/8 adapter from Home Depot should do the trick.

 

Brass only?

 

Thats just what that particular one is made of that I used in my system.

 

I had to order an entire 25 foot roll. I couldnt find it anywhere locally. Nuts. Not even heavy truck parts store carried it. Ebay wasnt much cheaper for just 6 feet.





Maybe Ill do a second CC since I have so much hose.

 

I use dual (universal RacerX) catch cans to
1) reduce crankcase pressures (I opted not to cap the rear PCV port as this resulted in oil leaks caused by high crankcase pressures in my car – other owners likely do not encounter this)
2) reduce carbon fouling of intake valves

I am trying polyethylene (PEX) tubing to prevent an unexpected consequence of the rubber tubing I used for years -- oil vapor smell emanating from the rubber hose pores and into the cabin air vents. MINI opted to use a plastic connector tube rather than a more logical(?) rubbing hose for the rear PCV, perhaps to trap the oil vapors.

I found low vapor tubing and fuel line of the correct dimensions online but wanted to try the PEX tubing alternative. I am testing the robustness of the PEX with Sharkbite adapters -- it was unfortunate the Sharkbite or Zurn does not make 45 deg internal couplers, so I had to use the bulkier 1" and 3/4" push-to-fit adapters.


I wanted to keep the same diameter tubing as the original tubing the MINI used for the front 5/8' ID and rear 3/4" PCV outlets, translating to 3/4" and 1" PEX, respectively. Keeping the same diameter meant the resistance to flow through each port would only be affected by the length and not the radius.

I estimated that the rear plastic PCV hose provided by the factory was 2 feet, and the retrofitted oil catch can system adds about 2 feet, so the resistance to flow increased 2-fold.

NOTE: resistance to flow decreases by the power of 4 as the diameter of the tubing decreases (example: if a length of tubing decreases from 3/4" to 5/8", then resistance to flow increases by a factor of 2 (3/4 divided by 5/8 raised to the 4th power = 2). Had I used 5/8" tubing instead of 3/4" tubing in my catch can setup, the flow resistance would have increased 4-fold (2-fold length x 2-fold decreased diameter).

The resistance to flow is more extreme for the retrofitted front PCV outlet. The factory tube is about 10" with a 5/8" ID. Increasing the tubing diameter for the catch can setup would slightly offset the flow resistance caused by the longer lengths of tubing needed to install the can. However, larger (1" PEX) tubes would interfere with closing the hood. 3/4" PEX has a 5/8" ID (that remained unchanged relative to the factory tube), but the length of tubing used for the catch can setup is about 42" (therefore, the resistance to flow is about 4-fold higher than the factory setup).

While the boost discharge and evacuation routes for the crankcase pressures through the front and rear PCV valve ports have higher flow resistance than the factory setup, I believe (more so, hope) the pressure relief pathways will be sufficient in the long term.

More importantly, I do not smell any oil vapors within the cabin vent system!

 

Oh my!

Flow resistance is also related to velocity, and I don’t think there is nearly the flow velocity through those “pipes” that you’ll even notice a difference. Are you a plumber in your real life?

 

That's interesting, but is PEX rated for petroleum?

I'm finally gonna do the install on my 2008 this weekend. I was hung up on how to connect the huge 3/4 inch PVC hose to the generic catch cans. Then I saw this guy's video where he uses a 15/32 section over the nipples on the generic catch can (shown in his video) and then the 3/4 over that to make a proper seal.

 

I agree, the minimal increase in resistance will only slightly slow the flow rate since the tubing lengths are still the same order of magnitude. The residence time of air volume in the catch can piping is likely only milliseconds slower than the factory setup.

I am perplexed when I see catch cans with what looks like 1/4 inch tubing compared to factory tubing, particularly for the r55/r56 MINIs, for both the front and rear PCV ports. The overall flow rate through the system is choked dramatically and crankcase pressures will increase.


​​​​​No.

 

Mini definitely chose some huge piping. 3/4 is as big as it gets. But does it matter if the catch can is choking the entire system? It is a filter after all.

 

The diameter of the tube is not critical at all, its gas at a low pressure (no more than 1 atmosphere by definition for the vacuum side), not fluid, so any friction with the tube walls is a negligible effect. I replaced the stock crappy brittle hose with a GTT catch can. The main attraction was the high quality machined metal fittings. They run a much smaller diameter hose with no issues. To accomodate this of course I needed to change the intake and fabricate a bracket to support it, but thats half the fun.

 

Then why is Mini using 3/4?

 

I got this from the introduction of a Manual titled: PEX PIPE DESIGN MANUAL (2018) by the Plastics-Pipe Institute
"Polyethylene (PE) has been the material of choice for pressure piping applications such as water and oil/gas for over 40 years, both in North America and internationally. PE materials can be crosslinked to achieve even higher performance properties as crosslinked polyethylene (PEX)"
Later in the Manual it states that for an extreme industrial scale setting (I deem the MINI Cooper setup as "baby" scale)
"3.2.3. Oil and Gas/Natural gas pipes: PEX pipelines designed for gas gathering or oil/gas applications shall meet the requirements of ASTM F2968, ASTM F2905, or ISO 14531." (ASTM = American Society for Testing and Materials)

I will assess how long this PEX system lasts. If it does not hold up to petroleum as described through the hot summer, then I will go back to wrapping rubber tubing with FiberFix, which worked okay-ish for blocking the vapors passing through the rubber, but was difficult to handle before hardening.

After several runs on the highway, I checked the surface temperature and the front PEX tubing is around 150 to 160 F and the rear tubing is 90 to 100 F. The maximum service temperature for liquids is 200 F for PEX, but I consider the low pressure gases passing through the PEX Catch Can system to more benign.

Yes, I saw this video too. I recommend for the MINI (r55/r56 at least) to drill more holes into the center post to relieve back pressure from your can. My RacerX cans came originally with fritted filters on the inlet and outlet ports. The backpressure created was so significant that oil was pushed up through my turbo oil drain line back into my turbo -- which started to smoke. Note, the rear PCV port was plugged as described by many NAM users. Removing the frits solved that problem. Other smaller leaks still persisted, and those were remedied (for me) by removing the rear plug and adding a second catch can (like other NAM forum users).