[hmmwvj]

On finding there are no OCC kits specifically for B48/58 engines (except the BMS kit which requires installing their billet intake) I decided to improvise a mount for a generic oil catch can.

There is a convenient space between the engine fans and the stock airbox, within easy distance of the PCV valves. Under the hood catch is a gap about a half inch tall. In the bottom is a roughly 8mm hole that isn’t used for anything and which I used to mount the OCC.

Here’s the mounting location and path of the hoses:



And the bolt hole that will hold the improvised bracket:



Parts needed:
• Mishimoto compact baffled oil catch can, 2 port. This is a high quality generic OCC that has the ports at a 45 degree angle and a direction-adjustable mounting bracket. Which makes it the only one I could find that would fit in said location.
• Two hose barbs, 3/8” NPT threads and 19mm diameter on the hose end. I chose 19mm hose and barbs to match the size of the barb on the stock PCV connectors.
• HPS 3/4" (19mm) High Temp Reinforced Silicone Heater Hose. 5ft is a safe amount to buy but you'll use closer to 3ft.
• Piece of L-shaped hard plastic to improvise a mounting bracket. 45x40mm on one face, 45x10mm on the other. This will be attached to the bracket that comes with the OCC.
• Four hose clamps, 25mm diameter
• One 18x7mm nut and bolt. This is the longest that will fit in the gap where the bracket is attached.
• Two 15x4mm nuts and bolts.
• Medium strength threadlocker.

Tools required:
• Power drill
• Heat gun or hair dryer
• Allen key and Philips head screwdriver



1. Drill a hole for the 7mm bolt in the large face of the plastic bracket. Bolt the OCC bracket to one side of the narrow face with the two 4mm bolts and secure with threadlocker. Note the OCC bracket screw holes may have to be widened slightly.



2. Mount the bracket. Secure the 7mm bolt with threadlocker. Then attach the OCC to its bracket with the two screws provided. Angle the ports for the hoses to pass over and under the intake air duct.



3. Squeeze the two catches to remove the PCV connector from the intake air duct.



4. Remove the airflow sensor from the connector. With a heatgun on low, remove the stock hose from the PCV connector. Replace the airflow sensor. Replace the PCV connector to face the opposite direction to stock.

5. Attach 19mm hose to PCV connector. Secure with hose clamp.



6. Pass the OCC outlet hose around the air intake duct to the OCC. This will ultimately require a little more than one foot length of hose. It is better to allocate length to excess and trim as necessary to avoid compressing the hose into kinks. Secure with hose clamp.

7. With a heatgun, remove the stock hose from the PCV connector on the crankcase. It is not necessary to remove the connector from the crankcase.

8. Attach 19mm hose to PCV connector and secure with hose clamp.

9. Pass the OCC inlet hose under the intake air duct to the OCC. This will ultimately require approximately one foot length of hose.

10. When the hoses have been positioned to avoid kinks, tighten the hose clamps and the screws holding the OCC to the bracket. Installation is complete.

[gobigkid]

thanks for the great post

[hmmwvj]

Found the oil had been forced out through the can's screw threads and was running down the side of the can. Either I did not screw the can on tight, or the 50 micron filter is too restrictive and is forcing the oil out. If so, it should be removed. That amount of pressure in the crankcase could cause a leak.

[Fatandre]

Whats the reason for a oil catch can?

[Sweeney921]

Originally Posted by Fatandre

Whats the reason for a oil catch can?

https://youtu.be/PWz6vCnJ4CA

OP, how much gunk has your catch can been trapping?

[GOLDENDUSt86]

Originally Posted by Sweeney921

https://youtu.be/PWz6vCnJ4CA

OP, how much gunk has your catch can been trapping?

I am sorry but this guy is super boring ,,, I hardly stand his videos ,,,
Back to Our subject ,,,Just search for videos about oil catch cans for BMW on Youtube, You will only find installation videos and non about its effectiveness ,, I wish i could see someone making one after a month or so from installation , so we can see how much oil it catches
cheers all

[hmmwvj]

Originally Posted by Sweeney921

https://youtu.be/PWz6vCnJ4CA

OP, how much gunk has your catch can been trapping?

Thanks for asking.

I mentioned finding oil forced out through the can's screw threads, and reasoned it was caused either by a weak seal there or an airflow bottleneck potentially causing excessive crankcase pressure (hose kinks or the 50 micron filter being too restrictive).

-Oil leaked through the threads on the hose barbs, drain plug and can's body when I tightened these in turn, even when I temporarily removed the filter. The solution was to reconnect all of them with plumber's tape.

-I reasoned the pressure did not exceed the filter's rate considering the stock PCV hose is thin plastic and loosely connected. The BMS OCC installation instructions also mention a "very low pressure system." Found the filter easily allowed air blown by mouth and water run from a tap. Leaks must have been caused by oil and air following the path of least resistance rather than any obstruction to flow.

-Just to be on the safe side I applied a hose clam to a mild kink in the hose, which had the effect of restoring a round cross section. I doubt this was a flow bottleneck, though.

I've only driven 3000km since and the warm weather here is supposed to reduce oil blowby, so the can has trapped almost nothing. But there have been no leaks. I'll report back in a few K km.

[Sweeney921]

Thanks for the thorough feedback!

I'm going to have my intake valves walnut blasted in about 6 months at 50,000 miles. By comparing notes we can at least start to figure out whether or not the B46/B48 is susceptible to carbon deposits.

[hmmwvj]

Collected about 1 ml over 2,100km, in the eight weeks since last update. Tropical weather throughout.

The oil was dark and viscous, as oil in the sump might look. It was nothing like the brown soup that people collect in winter.

[tiju]

No trouble using a heater hose ?

The specification said they are not oil resistant !

tj

[Knifeedge2k1]

Any update from OP on this?

[Knifeedge2k1]

Btw i was looking on bimmercat and noticed there’s actually two lines connecting the block to the intake piping for the pcv system. There’s a big tube and a little tube. BMS and Mishimoto kits only intercept one of the lines. Anyone know why that is ?

https://bimmercat.com/bmw/en/search/...48/ECE/11_6376

[Knifeedge2k1]

Looks like the second line is for fuel breather system

[Knifeedge2k1]

Originally Posted by Sweeney921

Thanks for the thorough feedback!

I'm going to have my intake valves walnut blasted in about 6 months at 50,000 miles. By comparing notes we can at least start to figure out whether or not the B46/B48 is susceptible to carbon deposits.

Did you have much buildup at 50k?

[rikiship62]

Originally Posted by hmmwvj

On finding there are no OCC kits specifically for B48/58 engines (except the BMS kit which requires installing their billet intake) I decided to improvise a mount for a generic oil catch can.

There is a convenient space between the engine fans and the stock airbox, within easy distance of the PCV valves. Under the hood catch is a gap about a half inch tall. In the bottom is a roughly 8mm hole that isn’t used for anything and which I used to mount the OCC.

Here’s the mounting location and path of the hoses:

And the bolt hole that will hold the improvised bracket:

Parts needed:
• Mishimoto compact baffled oil catch can, 2 port. This is a high quality generic OCC that has the ports at a 45 degree angle and a direction-adjustable mounting bracket. Which makes it the only one I could find that would fit in said location.
• Two hose barbs, 3/8” NPT threads and 19mm diameter on the hose end. I chose 19mm hose and barbs to match the size of the barb on the stock PCV connectors.
• HPS 3/4" (19mm) High Temp Reinforced Silicone Heater Hose. 5ft is a safe amount to buy but you'll use closer to 3ft.
• Piece of L-shaped hard plastic to improvise a mounting bracket. 45x40mm on one face, 45x10mm on the other. This will be attached to the bracket that comes with the OCC.
• Four hose clamps, 25mm diameter
• One 18x7mm nut and bolt. This is the longest that will fit in the gap where the bracket is attached.
• Two 15x4mm nuts and bolts.
• Medium strength threadlocker.

Tools required:
• Power drill
• Heat gun or hair dryer
• Allen key and Philips head screwdriver


1. Drill a hole for the 7mm bolt in the large face of the plastic bracket. Bolt the OCC bracket to one side of the narrow face with the two 4mm bolts and secure with threadlocker. Note the OCC bracket screw holes may have to be widened slightly.

2. Mount the bracket. Secure the 7mm bolt with threadlocker. Then attach the OCC to its bracket with the two screws provided. Angle the ports for the hoses to pass over and under the intake air duct.

3. Squeeze the two catches to remove the PCV connector from the intake air duct.

4. Remove the airflow sensor from the connector. With a heatgun on low, remove the stock hose from the PCV connector. Replace the airflow sensor. Replace the PCV connector to face the opposite direction to stock.

5. Attach 19mm hose to PCV connector. Secure with hose clamp.

6. Pass the OCC outlet hose around the air intake duct to the OCC. This will ultimately require a little more than one foot length of hose. It is better to allocate length to excess and trim as necessary to avoid compressing the hose into kinks. Secure with hose clamp.

7. With a heatgun, remove the stock hose from the PCV connector on the crankcase. It is not necessary to remove the connector from the crankcase.

8. Attach 19mm hose to PCV connector and secure with hose clamp.

9. Pass the OCC inlet hose under the intake air duct to the OCC. This will ultimately require approximately one foot length of hose.

10. When the hoses have been positioned to avoid kinks, tighten the hose clamps and the screws holding the OCC to the bracket. Installation is complete.

Great post!
Question on this hmmwvj, as I am thinking of doing the same. I have seen Mishimoto doing two versions of that catch can. The one you have installed and also, MISHIMOTO XL COMPACT BAFFLED OIL CATCH CAN. From what I can see, same as your one but just a longer tank. Based on your experience would the longer tank fit with the area (from 3.8inch to 6.3inch)? - I'm trying to avoid emptying it too often.

[Jamers2021]

I think your setup has some functional design flaws. The factory PCV connectors and hose is 3/4" however you are effectively reducing that down to 1/2" into the Mishimoto Compact Oil Catch Can. I understand your hose and fittings are still 3/4" however the inlet/outlet on the can itself is only 1/2" thus creating a bottleneck. You are restricting air flow which under high boost could create back-pressure and potentially stress and damage various engine seals. I'm not sure what other negative effects this could have on the engine. Also, you have Brass fittings threaded into an Aluminum can. This will corrode over time as the two metals do not play well together.

Mishimoto does make an oil catch catch specifically to accommodate the larger 3/4" diameter in the BWM engines. The F8X, N54, N55/N56, N20/N26 cans all have larger inlet and outlets for greater air flow. All of those kits are they same exact Oil Catch Can but with differences in the supplied hoses and mounting bracket.

I'm in the process of installing one on my 2021 330i so I will post pictures when I am done.

[hmmwvj]

Originally Posted by Jamers2021

I think your setup has some functional design flaws. The factory PCV connectors and hose is 3/4" however you are effectively reducing that down to 1/2" into the Mishimoto Compact Oil Catch Can. I understand your hose and fittings are still 3/4" however the inlet/outlet on the can itself is only 1/2" thus creating a bottleneck. You are restricting air flow which under high boost could create back-pressure and potentially stress and damage various engine seals. I'm not sure what other negative effects this could have on the engine.

I admittedly didn't consider the risk of back-pressure because I was led to believe the pressures involved are low. The stock plastic PCV hose is lightly constructed and attaches to the crankcase with very little strength. I also took a cue from the BMS catch can installation instructions which state "This is a very low pressure system so hose clamps are not needed."

Originally Posted by Jamers2021

Mishimoto does make an oil catch catch specifically to accommodate the larger 3/4" diameter in the BWM engines. The F8X, N54, N55/N56, N20/N26 cans all have larger inlet and outlets for greater air flow. All of those kits are they same exact Oil Catch Can but with differences in the supplied hoses and mounting bracket.

The N20 bracket attaches to the strut tower, so it cannot be installed on B48 cars because the strut tower has 5 bolts instead of 3. In any case it probably affects the security with which the top strut mounting attaches to the strut tower.

Originally Posted by Jamers2021

I'm in the process of installing one on my 2021 330i so I will post pictures when I am done.

Do the internal air channels machined into the top half of the can introduce a pressure bottleneck? On the Compact the channels are smaller ie more restrictive than the hose fittings. I suspect the channels are the same size on the N20/F80 cans.

[hmmwvj]

Originally Posted by Knifeedge2k1

Did you have much buildup at 50k?

I'm at 45k. There was very modest buildup in the can, then again I live in a hot climate. I also found an equal amount of oil in the intake.

It's impossible to know how much oil blew by and how much the can failed to catch, but is 50% efficiency a good standard for a catch can?

[Billfitz]

I get around a half a can in spring, and that's only driving maybe 1000 miles over the winter. The main source of crud is water that condenses in the crankcase, made worse if you drive short trips where the engine doesn't come up to full temperature long enough to boil it off. I get almost none in the fall, even though I drive three times as much in summer as winter.

Update 3/8/2022: It's been colder than usual this winter, and as a result I've been getting a lot more crud in the can. I've had to empty it twice, both times it was close to full.

The N20 bracket attaches to the strut tower,

Mishimoto and others do it that way to use existing bolts. I saved a lot of money with a generic can that I mounted like so, by drilling two holes:

[trevifloyd]

Going to be installing the FTP G20-B48 "OIL CATCH CAN" on my F30 330i b48 (2017). Got a CEL for 102a22 (airmass too high) & 180001 (catalytic converter efficiency too low) checked my engine out and their was oil coming from my inlet and intake. Cleaned the oil out of my breather hose, inlet and intake pipe.
After clearing the codes only got the 180001. Taking her in for an oil change tomorrow going to get emission test to see if its actually bad or might check the oxygen sensors.


https://www.ftpmotorsport.com.tw/pro...to-be-modified

2017 330i | bm3 stage 1 93 octane | Injen intake

[tananrules]

Originally Posted by trevifloyd

Going to be installing the FTP G20-B48 "OIL CATCH CAN" on my F30 330i b48 (2017). Got a CEL for 102a22 (airmass too high) & 180001 (catalytic converter efficiency too low) checked my engine out and their was oil coming from my inlet and intake. Cleaned the oil out of my breather hose, inlet and intake pipe.
After clearing the codes only got the 180001. Taking her in for an oil change tomorrow going to get emission test to see if its actually bad or might check the oxygen sensors.


https://www.ftpmotorsport.com.tw/pro...to-be-modified

2017 330i | bm3 stage 1 93 octane | Injen intake

@trevifloyd Were you able to successfully install it. I am also looking for a catch can for my f30 330i

[Billfitz]

With some ingenuity anything is possible. I installed mine by cutting the stock pipe, using adapters like these to splice the hoses to and from the can to it. Use long enough hoses and you can put the can anywhere. https://www.amazon.com/Reducing-Coup...QaAitCEALw_wcB