Since most of the guys here are actual gearheads I figure I'd get a good response here!

The BMW V8's have been having issues with carbon buildup on the heads causing a CrankCase Ventilation CEL, and as well the valve stem seals are going bad and causing white smoke (oil burning).

I guess this is partially due to BMW's long oil changes, but in any case a lot of folks are looking for a prevention to the whole problem. I'm thinking that the crankcase ventilation system is getting caked up with oil and thus hardening causing all of the issues, and an oil catch can would GREATLY help stop the problem!

Also FYI, the newer V8's are burning through a quart about every 3-4K miles, the older ones that aren't turboed are going though a quart every 5-6K.

Now comes the question, do you guys think it will help?

 

same problem as on the e39 M5(i know its basicly same engine)... which oil are you using ??

 

There's a lot of debate on how effective an oil catch can truly is, regarding the crank case ventalation and EGR valves. The MZR DISI's in Mazdaspeed3s and 6s are notorious for getting carbon build up on the valves and in the EGR valves. 3 days after I bought my MS6 I had a CEL for a clogged EGR valve/tube. I recently had an oil catch can installed on mine and after two drainings during an oil change I can tell you it's definitely doing it's job, collecting oil, but what I can't tell you is if it's preventing carbon build up on the valves, EGR, both or neither. I personally feel better knowing that oil/gas isn't getting redistributed back into my engine how ever it would be effecting it.

 

well this isn't an issue for the V12 guys as far I've seen but moreso for the V8 guys. Most of them are using BMW Syn. 5W-30 for 15K intervals or something around there.

Since I'm not a guru with these systems I'd figure you guys would know how to put one on then! Here's a diagram of the Crank Case System as far as hoses go, so would the catch can go right before it goes into the cylinder head?

 

As your theory goes...wouldn't simply changing the oil more often solve this issue?

Or, are you looking for a project?

 

some steel wool inside the catch can will help

 

Catch cans do in fact work to stop the carbon buildup.

Sidebar: I am close friends with a Service Manager for a Japanese Luxury Automaker. When they were having carbon build-up issues, the mfg. asked the techs to come up with proposed solutions. One solution that worked across the board almost 100% was a simple catch can. Simple, cost effective, and solved the problem.

...however the mfg. decided to redesign the cylinder heads and other parts of the combustion chamber.....and decided to replace it all under warranty. Same result to fix the problem of carbon build-up, but much more costly.

In the end it was not direct injection that caused the carbon build-up problems, it was the oil.

 

This reminds me...I probably need to empty my catch can...

 

Audi has the same problem. If I bought a new Audi, that would be the very first thing I'd do.

 

been debating if i want to install one of these on my MS3

 

What's the debate? Do eet.

 

me too.

 

it helps or just get the crank case breather can & that would eliminate the smoke

 

changing the oil would help out, but I know there is oil being burnt off, like I said in my orignal post, some folks are loosing a quart in 3-4K miles! That quart of oil has to be going somewhere, and my hunch is that it's being burned and recirculated through and a catch-can would help it.

 

You are correct, it's going back into the combustion chamber.
Install the catch can.