Let's talk valve stem seals and piston rings

JayG335

Lurker
Apr 6, 2018
23
Yet another mystery blue smoke thread
I know! But I'm really here asking your experience with valve stem seals and piston rings. Who has replaced them, at what mileage, what were your symptoms, how common is it, I've seen the thread at https://bmw.spoolstreet.com/threads/valve-stem-seals-becoming-a-normal-thing.396/page-2
I'm starting to wonder if I'm in this boat. I'm about to order the seals but I'm also apprehensive, I'd hate to do the work for no reason. Also, should I replace my cam ledge bearing seals at the same time? Car is a 2007 and has never exhibited symptoms but if I'm in there anyway might as well, does anyone have the updated PN?
So to get down to the issue, the car has 101k, originally never smoked, only had a light burning oil smell when coming to a stop or idling. Then i blew my stock turbos. Replaced with VTT stage 2. Fast forward 8 months I can now see the blue smoke during deceleration after any kind of over half throttle pull, and its defintely a very noticable smell. Ive replaced the entire pcv system with external dual catch can kit with head port block off kit from VTT this past week, performed a walnut blast (valves looked good), index 12 injectors, still the same if not worse. I performed a compression check this morning and I get the following results
Cylinder 1 = 200
Cylinder 2 = 200
Cylinder 3 = 195
Cylinder 4 = 200
Cylinder 5 = 200
Cylinder 6= 185
I'm a little worried about number 6 being an outlier. It's not much but still concerning. I've heard of people having cracked ring lands and I'm really hoping this isnt the case. Theres no real good way of checking exhaust valve stem seals (without removing turbos) or the piston rings obviously. So I'm unsure how to continue addressing the issue. Its worsening despite my best efforts to fix it. Any and all information is greatly appreciated.
Thanks guys!
 
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JayG335

Lurker
Apr 6, 2018
23
Good point!
I'll get a leak down tester asap.

Yes I've checked for oil, they are all clean.
 

tisdrew

Specialist
Jun 27, 2017
56
I was having the smoking issue a little while back and during my research basically nobody (n5x platform) who did the valve stem seals had their problem solved -- it came back same day or days later. 90% of the time solution was replacing turbo (seals) and 10% of the time it was PCV.

Turn that MHD burble off if you haven't already. FWIW, new turbos fixed my issue but it also hasn't been 8 months yet
 

JayG335

Lurker
Apr 6, 2018
23
Kinked drain line. I got good leak down numbers. Determined I just bit the bullet and began to pull downpipes. I've been under this car 3 times in 500 miles. It's been bone dry. I noticed a drop on the oil drain between the gasket and a little in the shielding. Pulled the shielding off and saw this. Since ordered RB upgraded drains and installing now.
 

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JayG335

Lurker
Apr 6, 2018
23
It's back! So since the last post everything was good for maybe 100 miles no smoke under load, pulled great but then I could smell burning oil once again. I got under the car. Found a sizable puddle in the pan. No leak from the drains. A small amount of oil where the turbo vbands are. Pouring from the bottom of my bell housing. Wonderful a rear main . I needed to upgrade my clutch anyway and went ahead and got the 335is/550i clutch. Which bolted right up to my old 8 bolt flywheel. Upon removal the rear main was absolutely leaking. All back together now and I've put 130 miles on it. I know it's not quite broken it but its cold here in charleston, a brisk 30°F i was driving and couldn't resist just giving it half throttle out in 3rd. Car pulled wonderful but again it left a huge smoky trail out the back. Freaked out I asked a friend to follow me while I tried it out again and once again definite blue smoke, only under load though. I pulled it in to the garage, found the valve cover gasket near cylinder 6 blown out. Leaking around back and in the middle. Also in my newly installed VTT dual catch can system the first can is already full. Maybe 300 miles? I've ordered a gasket and will get on it today
I'm worried I'm blowing seals because of a underlying issue. Like I said I've recently installed VTT head block off kit and dual catch can system. I've been having these oil issues since install of my VTT stage 2. I'm either leaking it or burning it. She's under the knife more than on the road.
 

Bnks334

Corporal
Dec 1, 2016
231
New York
It's back!
Is the blue smoke coming from the exhaust? You aren't being clear on that.

External oil leaks are a problem for sure but generally don't cause smoking unless it's dripping directly onto the hot down-pipe.

You might want to describe your PCV setup for people. Did you convert to VTA? Is blow-by still being recirculated back to the intake tract post catch can?
 

JayG335

Lurker
Apr 6, 2018
23
Sorry for lack of detail.
Yes heavy blue smoke from the tailpipe for sure. Light burning from passenger rear corner of valve cover causing very light smoke under the hood. Hard to catch in the act unless I do a quick pull, pop the hood, hop out and look. Smoke out the back is only under load now.
My catch can system is recirculated I did not opt for the high side breather, so it does return to the intake. I've installed the one way check valve and flapper delete. I'll get a picture in a few and post it. Thank for the reply.
 

JayG335

Lurker
Apr 6, 2018
23
Yes here are some pictures I took while in there. I don't see any distinct trailing and also my inlets and outlets are clean. The last one is the oil build up on the vband that is pretty constant. I clean it up everytime I'm under there and everytime I come back there just that small amount. I haven't thought much of it since it's such a minor amount
 

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Bnks334

Corporal
Dec 1, 2016
231
New York
Have you pulled the downpipes yet?
He wouldn't be getting significant blue smoke out of the valve cover leak if it were an exhaust side oil leak. Or, did he mean that the failed valve cover gasket is allowing oil to drip out burn off on the exhaust manifold???

Fix the valve cover gasket first and foremost. Check valve installed correctly?
 

Torgus

Lieutenant
Nov 6, 2016
815
Boston
Yes here are some pictures I took while in there. I don't see any distinct trailing and also my inlets and outlets are clean. The last one is the oil build up on the vband that is pretty constant. I clean it up everytime I'm under there and everytime I come back there just that small amount. I haven't thought much of it since it's such a minor amount
Your Vband should not be leaking ANY oil. I would contact VTT about that immediately. I don't know if the V2s or whatever model you have have all the issues that the GC series have had. Might be worth inquiring.
 
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Dmak

Specialist
Nov 19, 2017
50
Agree with what everyone said. Verify the pcv set up is installed correctly. Fix the valve cover.
Now, since you live in colder weather, it is possible for external pcv set up/valve to freeze due to condentsation build up inside the engine.
If you fixed all external leak and verified pcv system working correctly, and still seeing oil on turbo v band. Your turbos are leaking. My stock turbos are leaking at the excat same spot(at the center section v band). Good luck
 

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Sergeant
Free Vendor
Dec 7, 2016
492
I will tell you it makes me cringe when vendors say "We have this, that, and the other; this way you can set these things up however you want!". It is like great let us give the masses the option to continue to break things that do not otherwise need fixing. The amount of emails we get from those "wanting to do things their own way" who have absolutely no idea on what they are doing, is enough to make a person go bonkers.

At any rate agree with the above on the ventilation stuff- post up some information on how you have it setup.

Rob
 
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JayG335

Lurker
Apr 6, 2018
23
Here is my pcv set up. I purchased the entire kit as one piece as I didn't want to risk putting stuff together like you all mentioned. I still haven't done the vcg yet as I've been out of town for a wedding. Hopefully I'll get to it today. but I'm not so sure its leaking anymore. Last week it was rainy all week and I think water just got in around the valve cover and mixed with old residual oil, because as I've driven it today all the water has evaporated and there is no pooling near cylinder 6. That being said it still smells like oil in the cabin immediately after coming to a stop and I still get heavy blue smoke under load. None at idle or light load. Ive run my finger over the back corner after running it and its dry. I'll pull it into the shop today after work and have a good look once again. Might just do it to do it. If that doesn't fix it. It must be the turbos. Possibly leaking from the vband and burning off on the manifold? Such a shame. Only 5k miles on the build and fighting oil leaks/burning ever since. Frustrating to say the least.
 

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Sergeant
Free Vendor
Dec 7, 2016
492
JayG335,

Correct me if I'm wrong here about your "ventilation" arrangement-

1) Low Side:
PCV Delete fitting to Hose to Low side OCC.
Low side OCC to hose to Intake manifold vacuum reference.

Is this is a complete and accurate statement, or are there any missing pieces of hardware/components that I did not specify?

2) High side:
Flapper Delete fitting to hose to High side OCC.
High side OCC to hose to rear inlet fresh air intake reference.

Is this is a complete and accurate statement, or are there any missing pieces of hardware/components that I did not specify?

Thanks,
Rob
 
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