Intake Valves - How to Access?

[CarAbuser]

Hi,

Been reading about the coking up of intake valves in the 335i and other N54 cars and been starting to wonder about the state of my own valves at 32k miles.

I do have some of the symptoms and before I go down the route of changing plugs and coils I would like to visually check my intake valves and if needed get some walnut blasting done.

I have found plenty of information on the 335i but nothing on the Z4. So does anyone know how to get to the intake valves on the Z4 35i? I would just like to view them initially.

[HerrK]

Originally Posted by CarAbuser

... I have found plenty of information on the 335i but nothing on the Z4. So does anyone know how to get to the intake valves on the Z4 35i? I would just like to view them initially.

An N54 is an N54 no matter what vehicle in which it is installed. Definetly more access in a Z that a 3er. Seriously I'd rather dump the money: first Fuel System/ engine Cleaner, second Plugs, & lastly Injectors. Threading a boroscope through the intake manifold to view the back side of the Intake valves or taking off the head and disassembling it to get it blasted is rather extreme.

[CarAbuser]

Originally Posted by HerrK

An N54 is an N54 no matter what vehicle in which it is installed. Definetly more access in a Z that a 3er. Seriously I'd rather dump the money: first Fuel System/ engine Cleaner, second Plugs, & lastly Injectors. Threading a boroscope through the intake manifold to view the back side of the Intake valves or taking off the head and disassembling it to get it blasted is rather extreme.

Thanks for the reply.

I was under the impression from the 335i intake cleaning DIY that I could just spend 1hr stripping down to the intakes and then easily take a look at the (if any) carbon build-up.

The car is low mileage so I'm not fully convinced that there will be any cleaning required of the intake valves.
The shake at idle is only very slight. It feels a bit like the sort of bump you would get from the speakers during a bass-heavy song.

The HPFP was replaced 2k miles ago and I have manually reset the throttle body adaptations.

You mention changing the plugs but is it also not possible that the coils cause the issue? Or would an issue with coils cause a fault code?

[Lambobimmer]

The intake manifold is pretty easy to remove, but I would suggest that you get the valves professionally walnut blasted. I cleaned my previous 135i by hand and it is a very dirty and nasty job and I would not recommend it. You are better off to pay someone $300 or so to do this job for you.

You have to spin the engine to move the valves if you are going to do it on your own and this job will take you 4 to 6 hours if you do it properly. My guess is at least 30 minutes per cylinder not including taking it apart and putting it back together.

You should have erratic idle if you your valves are caked with carbon.

[CarAbuser]

Originally Posted by Lambobimmer

The intake manifold is pretty easy to remove, but I would suggest that you get the valves professionally walnut blasted. I cleaned my previous 135i by hand and it is a very dirty and nasty job and I would not recommend it. You are better off to pay someone $300 or so to do this job for you.

You have to spin the engine to move the valves if you are going to do it on your own and this job will take you 4 to 6 hours if you do it properly. My guess is at least 30 minutes per cylinder not including taking it apart and putting it back together.

You should have erratic idle if you your valves are caked with carbon.

Not planning on doing it myself. There is a place that will do it for £300 in the UK.

I just want to see what the valves look like. If they are really bad then I would just go straight for a clean. If they are just a little black then no worries.

I thought erratic idle was HPFP. That's certainly what was causing mine. My idle is fairly consistent since it was replaced. It's just that the engine seems to slightly shake on idle.

They said plugs would be £120 to change so I thought before getting that done I would take a look at the intake valves first.

I think the car is on it's original plugs. It's 5 years old but only covered 30k miles.

[Lambobimmer]

Originally Posted by CarAbuser

Not planning on doing it myself. There is a place that will do it for £300 in the UK.

I just want to see what the valves look like. If they are really bad then I would just go straight for a clean. If they are just a little black then no worries.

I thought erratic idle was HPFP. That's certainly what was causing mine. My idle is fairly consistent since it was replaced. It's just that the engine seems to slightly shake on idle.

They said plugs would be £120 to change so I thought before getting that done I would take a look at the intake valves first.

I think the car is on it's original plugs. It's 5 years old but only covered 30k miles.

I had a lumpy idle on my Z4 when I got it and my dealership walnut blasted them under warranty. hpfp, coils, injectors can also cause a rough idle so you would have to pull the intake manifold to truly see if your valves are caked up. BMW says that you are supposed to replace the gasket every time you pull the intake but you don't really need to.

[jparnes1]

Bav Auto just released a DIY video to walnut blast your N54 intake valves. They show it on a 335. I personally wouldn't entertain doing this as it looks pretty involved, but maybe some of you more skilled wrenchers would give it a try.

[bigendbob]

So an engine that's been around for 10 years plus, has a known design fault and has not been remedied by BMW?
Is there an after market oil separator and if so why doesn't BM fit it.
Glad I stuck with the N52. Or does that have similar problem?

I have experienced similar in an aircraft. A valve carboned up, got stuck in a guide and smashed hole in a piston.
The next 3 minutes were interesting!

Funny how design changes have consequences elsewhere.

[jparnes1]

Originally Posted by bigendbob

So an engine that's been around for 10 years plus, has a known design fault and has not been remedied by BMW?
Is there an after market oil separator and if so why doesn't BM fit it.
Glad I stuck with the N52. Or does that have similar problem?

I have experienced similar in an aircraft. A valve carboned up, got stuck in a guide and smashed hole in a piston.
The next 3 minutes were interesting!

Funny how design changes have consequences elsewhere.

N52 is port injected. N53 went to direct injection.

[bigendbob]

So I can sleep easy.
Still designing an engine with direct injection doesn't help the N54 design if they haven't designed out the coking problem.

Just had a customer who works for BMW UK. He used to work for VW. He doesn't rate BM after his time at VW.

[nicknaz]

My understanding is a great solution to carbon build up is to drive the car harder and consistently get the engine oil to its operating temperature

Apparently people used bore scopes to take a look at their VW turbo engines and consistently saw a reduction from driving >4k rpm for 20 minutes

check out post #19 below

http://www.planet-9.com/automotive-o...injection.html

[CarAbuser]

Originally Posted by nicknaz

My understanding is a great solution to carbon build up is to drive the car harder and consistently get the engine oil to its operating temperature

Apparently people used bore scopes to take a look at their VW turbo engines and consistently saw a reduction from driving >4k rpm for 20 minutes

check out post #19 below

http://www.planet-9.com/automotive-o...injection.html

I'll do the last 20min of my drive home on Friday in a lower gear and see how the car feels after. Think 5th gear should be over 4k revs at 85mph.