35iS oil catch tank

[techathy]

Has anyone fitted one to their car & if so what did you do?

My 2015 35iS is showing a very slight oil build up on the inlet valves, at 4500 miles , and I'd like to get this sorted quickly. So time for a catch tank or better still a breather tank. My initial thought was a burger tuning catch can but they simply said they don't have one to fit the Z4 35iS (despite the engine being identical to the 1M which is a listed application ).

My current thinking is a breather tank for the crank case breather & then a short length hose with an end plug for the intake side. Will that work or do I need catch tank with a through breather?

[Mike6]

Cannot really help on the BMW but my last car was a Lotus Esprit and I went down the catch tank route. All I can say is be careful you get what you pay for and you risk crankcase pressure build up with the dipstick coming out and oil spraying around. If you are tempted like I was with a nice looking alloy tank from ebay they have very small diameter inlet and outlets and the result can be serious damage. If you get a good one from a reputable supplier then they should do the job.

[techathy]

I was thinking something along the lines of this - http://www.demon-tweeks.co.uk/motorspor ... ther-tanks as a breather tank. JIC -12 is aprox 19mm ID hose & 15.5mm ID tube which looks to be very close to what BMW are using.

[SO8]

How has your 4500 miles been done ?

How did you find out about the buildup ?

[techathy]

A mix of over-20 mile rural/trunk road trips, about 50-60% of the mileage, & shorter 10-20 mile trips with a good urban/rural/trunk road driving, so the engine gets warmed up nicely every drive. My driving style is smooth but I'm not afraid to use the power.

A friend of mine had been having problems with his M135i & it came down to gummed up valves so I thought I'd take a look at mine.

[R.E92]

From what I've read you can eliminate the requirement for a catch-can on the N54 engine with an upgraded PCV valve from Rob@RBTurbo. The PCV is a much simpler install and helps prevent the cause of excessive blow-by into the intake rather than just collect it in a tub. Think it's also cheaper.

There's differing opinions out there but a lot of people with highly modded cars seem to install the modded PCV valve by default. But most of those people will be running at least 20psi of boost. If your car is still stock it will only be running 12psi so shouldn't have a need for such measures.

I can't remember exactly what the main cause of carbon buildup is said to be but from some reading on the intake buildup issue I remember seeing several articles stating that blowby is a very minor contributor to the problem. Something about crank case ventilation sticks in my memory but I don't understand the CCV system so I'll refrain from commenting there!

I'm surprised your friend with the M135i has buildup issues. The N55 engine supposedly alleviated the issue.

Some things which are said to help prevent the buildup are frequent oil changes (20k interval that BMW states on these cars seems mad) and driving the car hard to get it up to temp.

My advice is to stop worrying about it. You can get the car walnut blasted for £200 and even in the worst cases that means every 50k miles.

[techathy]

In the old days fuel going into the cylinder washed the intake ports of oil deposits keeping them clean. With modern engines often running their inlet systems dry, this doesn't happen and you get soft oil deposits in the intake system. So this was purely a performance issue. With modern engines running dry intakes there's no fuel to wash this oil deposit away & you get soft oil deposits in cylinder head intake track.

The reason frequent oil changes help is that as water vapour is expelled it also pulls very short fragmented oil molecule strands. Newer oil has far less of those oil molecule fragments in it & so this vapour does not have nearly as much oil in it. Ergo there's not as much oil heading towards the engine when cold.

During the warm up process the air inside the engine raises in temp causing positive pressure, this needs to go somewhere. With emission regs it really can only be burnt. However, this has consequences - you're pulling an awful lot of water vapour into the engine that would otherwise be vented atmosphere in a breathing catch tank (rather than an oil isolating catch tank). A harder warm up makes for faster air flow into the cylinder not giving the oil as much chance to settle & also reduces the problem.

The one thing you can't do without a catch tank is eliminate the problem, only reduce it. Hence why I'd like to run a catch tank, I'd like a breathing catch tank to also eliminate the issue entirely. However I don't know if the N54 engine actually needs that air from the crank breather or not.

[jamesbond]

Ok For this thread
Do other owners need to worry about this ? or as you said just go for the walnut blast procedure ??

Or is this another item to worry about ?

[techathy]

If you don't check your coolant often then don't worry about it and if you notice problems get it walnut blasted. If you're the sort of person who checks their coolant level every week then you're the sort of person who is better off with a breathing catch tank as there are other minor benefits - longer exhaust life, better performance & better fuel economy in petrol engines. Again this is very small changes.

It's ibuprofen v's a monthly visit to physiotherapist for a week tendon/muscle. The ibuprofen fixes the symptoms when you pull the tendon/muscle, the physio prevents you from pulling the tendon/muscle in the first place. Which one you do is personal choice.

[jamesbond]

Ok

Keep us updated to what you do, and how you do it (pics) as others may want to do this as well

regards

[R.E92]

I think you will find the catch can will do very little to the carbon buildup. It's certainly not a cure for the issue. I think methanol/water injection is the best prevention but will cause you grief with insurance and warranty work.

The EGR systen and intake/exhaust valve overlap will be a greater culprit. You will still have the problem unless you seriously modify the engine.

I don't want to come across too dismissive but oil catch cans have been pushed hard by vendor driven forums like E90post. It's quite refreshing on this forum that we aren't bombarded by vendors and shill users.

[techathy]

Okay so you didn't understand the first sentence in my previous post to you. I'm talking about soft oil build up on the intake. This is sticky, wet, oily build up on the intake track which is, very importantly, smooth & slightly milky in colour. It is not the powdery grey carbon build up which is intrinsically dry, but often seen to be wet as it captures stray fluid. Preventing oil build-up will, to some extent, reduce carbon build up by making the surface of the intake track less sticky & so particles are more likely to be drawn into the cylinder & re-burnt.

[jamesbond]

Hello

How did you get on .... check this link out which explain in more detail http://blog.modbargains.com/turbo-car-n ... catch-can/

regards

[techathy]

Still researching the implications on catch tank breathing to atmosphere, which is what I'd prefer to do.