[gangzoom]

I'm going to get walnut blasting done on the car soon to get rid of the carbon build up on the intake vales, was also going to get an oil catch can to try and prevent more carbon build up....

But having read a few reviews am not convinced oil catches do anything to prevent carbon build up on the intake vales.

I know all about the 'theory' but have seen no real life proof of someone with an oil catch can installed and actually evidence it has prevented carbon build up on the intake valves??

Anyone one got any firm proof (pictures of intake valves post catch can install) that oil catchs cans actually prevent carbon build up??

Another forum member also recently ported a picture showing carob build up reoccurring very quickly after just 4k of usage which makes me wonder if cleaning the intake vales actually do anything at all longterm, unless you walnut blast every 10-15k??

[ukbeemerboy]

Surely you will never prevent carbon build up. Due to the very nature on the combustion cycles of the engine, carbon deposits will be inevitable.

Can't really see how a oil catch can could prevent the build up.

[phil200tdi]

http://www.106rallye.co.uk/members/d...hersystems.pdf

[gangzoom]

Originally Posted by phil200tdi

http://www.106rallye.co.uk/members/d...hersystems.pdf

So this explains the reason why oil/air mixtures get into the intake system, and a reason for oil catch cans....But I thought the reason the N54 engine was particularly bad was because the fuel is directly injected into the cylinder head, so no fuel actually goes on to the intake valves. Hence why VAG directly injected engines are also affected...

Reading around it looks like the carbon build up with DI injection has been a known problem for the best part of over a decade, and its only in the newest generation of DI engines it seems like the problem has been overcome...

http://www.edmunds.com/autoobserver-...-adopters.html

Surely if something as simple as oil catch can could/can prevent this issue, companies like GM/VAG wouldn't have spent ££££ redesigning entire engines to try and solve this issue?? Sadly I think on the N54 engine its just going to be another one of the 'known' problems

[phil200tdi]

Catch cans will get some of the oil from the breather system but they are a bandaid rather than a cure. I'd rather catch that oil than have it in my intake and baking on to the valves..

I'm very interested in seeing what my intake valves look like now - 30,000 miles after cleaning them.. I've had a catch can, Rob Beck valve and run meth since then. I'd hope they are clean as a result!! Anyone got a boroscope?!

[gangzoom]

Originally Posted by phil200tdi

I'm very interested in seeing what my intake valves look like now - 30,000 miles after cleaning them.. I've had a catch can, Rob Beck valve and run meth since then. I'd hope they are clean as a result!! Anyone got a boroscope?!

This is the kind of info/evidence I would love to see. I don't mind getting walnut blasting done every 50K or so, but if the carbon build up occurs every 10-20k regardless of oil catch cans than it seems like a waste of money to me . I should add my engine is running with NO problems at the moment, be that at idle or WOT at full boost, so just trying to decide if walnut blasting is actually going to do anything.

But at least we should be glad that despite carbon build up most N54 engines don't seem to loss power, and cause too much problems, unlike some of the VAG and Mini engines.

[doughboy]

Gangzoom, does a catch can work? You mean does it catch oil? Then yes of course it does.

Does it cure all issues, no.

You need to understand the detail of how each engine works, direct injection aside, the N54 breather system works in two distinct ways depending whether you are on boost or off.

Only under boost or wider throttle openings will crankcase oil vapour be "pushed" through a catch can on its way back to the inlet pipework, pre-turbo.

All other times the oil mist is "sucked" by the vacuum behind the throttle valve, via the check valve, directly into the inlet manifold (missing out turbo etc) but it still goes down the inlet tract of course and passes the valve stems.

So the catch can will only filter when boosting, all other times, overrun, idle etc it does nothing.

DI just makes it 100 times worse as there is no fuel wash to clean the inlet tract and valves.

Inlet carbonisation has nothing to do with an engines natural cycle as no combustion takes place in the inlet manifold. It is emissions requirements to return crankcase vapours that causes the issue.

So in summary, a catch can will keep ALL the oil out of the turbo and intercooler and pipework (which is good) and it will stop oil vapours passing the inlet valves when under boost.

But it will only reduce oil at the inlet tract and manifold as this "short cut" off-boost oil vapour path is unavoidable.

[stashtrey]

Originally Posted by gangzoom

This is the kind of info/evidence I would love to see. I don't mind getting walnut blasting done every 50K or so, but if the carbon build up occurs every 10-20k regardless of oil catch cans than it seems like a waste of money to me . I should add my engine is running with NO problems at the moment, be that at idle or WOT at full boost, so just trying to decide if walnut blasting is actually going to do anything.

But at least we should be glad that despite carbon build up most N54 engines don't seem to loss power, and cause too much problems, unlike some of the VAG and Mini engines.

Walnut blast works in terms of getting all the caked on crap off your intake valves. It made a noticeable difference on my n54 with smoother idle, noticeable throttle response and what felt like a much healthier motor.

I added a BMS catch can. They most definitely work in catching a good amount of blow by oil. Will be doing another blast in 10-15k miles. Its just a cost/function of caring for this engine. My BMW service advisors all agreed the catch can is great way to care for the motor and had zero problems with it.

Here's mine after a few thousand miles after first putting it on.

[#Tee]

yes it works in terms of instead of oil pooling inside the intercooler its now shared its oil catching capacity with the size of the catch can.

[doughboy]

Originally Posted by ukbeemerboy

Surely you will never prevent carbon build up. Due to the very nature on the combustion cycles of the engine, carbon deposits will be inevitable.

Can't really see how a oil catch can could prevent the build up.

Combustion only takes place in the combustion chamber. All carbon issues in intake tracts and valve stems are solely caused by crankcase vapours being recirculated.

Lack of fuel wash in direct injection engines makes it a problem. A regular injection engine constantly cleans it's intake tracts and valve stems.

On a DI engine the oil just cooks (carbonises) on the hot valve stems...

[nik patel]

Where you getting the walnut blasting done?

Originally Posted by gangzoom

I'm going to get walnut blasting done on the car soon to get rid of the carbon build up on the intake vales, was also going to get an oil catch can to try and prevent more carbon build up....

But having read a few reviews am not convinced oil catches do anything to prevent carbon build up on the intake vales.

I know all about the 'theory' but have seen no real life proof of someone with an oil catch can installed and actually evidence it has prevented carbon build up on the intake valves??

Anyone one got any firm proof (pictures of intake valves post catch can install) that oil catchs cans actually prevent carbon build up??

Another forum member also recently ported a picture showing carob build up reoccurring very quickly after just 4k of usage which makes me wonder if cleaning the intake vales actually do anything at all longterm, unless you walnut blast every 10-15k??

[Phil325i]

Originally Posted by doughboy

it will only reduce oil at the inlet tract and manifold as this "short cut" off-boost oil vapour path is unavoidable.

You're right doughboy, which is why the people I got my OCC from in the US make a double catch can set up for boosted engines, so they intercept oil in both paths - see 7th question on this page:

http://www.saikoumichi.com/faqs_page.html

[Greg330]

Interesting, answered a lot of my questions....

Where is the best place to get one in the UK?

[old grey steve]

Yes they do on a couple of cars I've seen that have had issues post work and check up's they've appeared to be performing as required also on mine which I done some time ago everything as stated in their blurb is what I'm seeing so yes they work and are worthy of an investment, but as we know they are not a cure for the problem they help manage it along with an uprated PCV valve its all you can really do on a 335i to keep things in check

[Phil325i]

Yes, been happy with mine - it collects about 0.5litres of oil per 16,000 miles by calculation. Mine went in easily...but then I don't have the turbo'd engine. I suggest you emial Mr Saikoumichi. He's very approachable and very knowledgeable. He'll want to know which car, engine size and the diameter of the breather pipes to advise you.