Hi All

 

I changed my exhaust at the weekend and while doing so noticed that the wastegate flap had a gap.

At the time I thought nothing of it. The car runs fine apart from a very slight rough idle.

However, while looking at the following post I noticed the flap covers the opening completely:

http://www.briskoda.net/forums/topic/290876-k03k04-hybrid-turbo-with-k04-billet-compressor-wheel/

Mine fits flush against the opening it's just got a crescent shaped gap i.e. it's not centred.

It looks like the flap spindle isn't centered and can be rotated, perhaps to get a better fit?

Should I fix this or is it part of the turbo 'setup'?

 

Cheers

 

 

I've been investigating a bit more and the flap is supposed to have a bit of play in it so it sits flush against the opening. This makes my idea that it can be 'adjusted' highly unlikely.

It also seems that it's not something that can be repaired without replacing at least half the turbo :-(

I'll have to take the down pipe off and have a proper look.

Problem sorted 

I took the down pipe off and could see:

and on the outside:

The spindle for the flapper had moved out of the turbo housing.

I just lifted the flapper and with a little force pushed the spindle back into the housing.

I now have:

and:

And also an extra 4psi to my peak boost.

It was peaking at ~18, but now goes to ~22 (not sure if that's a little too high!).

Not sure how it manged to get into the position it did. Everything appears tight. I can only assume it's been like this since I bought it ~2 years ago.

 

No idea if this is a common problem, but it's something people can easily check.

Edited 9 October, 201312 yr by Bobmonga

So the bush walked out of the turbine housing then. If it happens repeatedly you'll need to replace the turbine housing assembly as the interference fit obviously isn't up to it. Odd one!

 

The power loss must have been quite noticeable with the valve not seated like that.

 

You're right about the valve head movement. They are designed to rotate and articulate. Stops the valve catching on the seat and allows the valve to seat itself as well as it can. Interestingly the seats are also not machined flat. The seat face is machined at a slight angle, with the highest point on the inner edge. This also allows the valve to wear into the seat to improve sealing, plus it's much easier to seal an edge to a face.

 

Good job you're observant enough to have spotted that!

So the bush walked out of the turbine housing then. If it happens repeatedly you'll need to replace the turbine housing assembly as the interference fit obviously isn't up to it. Odd one!

 

The power loss must have been quite noticeable with the valve not seated like that.

 

You're right about the valve head movement. They are designed to rotate and articulate. Stops the valve catching on the seat and allows the valve to seat itself as well as it can. Interestingly the seats are also not machined flat. The seat face is machined at a slight angle, with the highest point on the inner edge. This also allows the valve to wear into the seat to improve sealing, plus it's much easier to seal an edge to a face.

 

Good job you're observant enough to have spotted that!

 

I'm hoping it will stay in place or at least works its way out slowly. I don't mind pushing it back in now and again if it saves time and money.

 

I hadn't noticed the power loss, but I do notice the power gain! If it had slowly moved out I guess I might have missed the gradual loss, but I think I would have noticed the peak boost drop.

Next time the bush comes out of the turbine housing (which I think it prob will) try knocking the bush out as far as you can, give it a clean up with wire wool etc then apply some lock tight and knock it back into place. 

 

I almost always use lock tight when fitting valve guides and valve seats into cylinder heads and have never had a single one come loose. 

 

Even though the turbocharger turbine housing runs much hotter than an air cooled or water cooled cylinder head, from my experience I'd say its worth a try. 

 

HTH

 

Bill.

Cheers, I'll try that if needed.

Which Loctite do you use? I've had a look around and it seems Loctite 2620 has the highest working temp at 350 degrees, but couldn't find anyone who sells it. Also looks like it's a paste which I think wouldn't penetrate well.

Loctite 727 seems the next best thing.

22psi mines the same I was worried this is to high with just a custom code phase1 even though it's bin this way for 44k wit no probs what mods does your car have

Loctite won't last long at all on a turbo, don't waste your time

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22psi mines the same I was worried this is to high with just a custom code phase1 even though it's bin this way for 44k wit no probs what mods does your car have

Revo Stage 1, CAI, Sports Cat, N249 bypass, N75 J Valve.

I'm going to log a run with VCDS to see what the requested and actual boost is. I don't think my gauge is far out though.

It's going in for stage 2 on the 22nd so it will be interesting to see what they say.

Loctite won't last long at all on a turbo, don't waste your time

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It probably wont like the temps no. The 'baked' loctite may loose it's grip, but the left over residue may be enough to keep it in place.

I've also got some ThermoSteel left over from an exhaust manifold repair. This may become plan B.

Plan C would be to hammer a little notch in the housing next to the bush. I saw this in a thread while researching the issue.

I'm still hoping it will stay in place though 

Plan C would be your best bet I reckon

Revo Stage 1, CAI, Sports Cat, N249 bypass, N75 J Valve.

I'm going to log a run with VCDS to see what the requested and actual boost is. I don't think my gauge is far out though.

It's going in for stage 2 on the 22nd so it will be interesting to see what they say.

Did some logging last night. A few runs 1500-3500rpm WOT in 4th.

They all looked like:

i.e. a bit behind, but then giving more than requested.

Not what I'd expect from a standard car, but not sure if this is expected with my mods?

It confirms my boost gauge is pretty accurate though.