Gt3076r - Wastegate Leaking

[huddy]

hey guys...

my .63 IW housing had the wastegate ported and a larger flap fitted - professionally done by a workshop

I also have a stainless dump/front with screamer from AM performance - it was thought that this was the problem and Andrew went out of his way MANY MANY times to try and correct the pipe to eliminate this leak. and now we've come to the conclusion it cannot be the dump:

- the back of the exhaust housing is all flush and it has a divider between the exhaust wheel and wastegate anyway (5bolt garrett housing).

- the correct flange was made and wastegate port was made slightly larger to compensate for larger flap

- there's a pipe welded onto dump that press fits (as you tighten it up)into the rear housing to the exhaust wheel so gasses cannot go into screamer pipe.

- copper gasket is being used

- and a high temp sealant to seal it up.

this is why we've decided it cannot be the dump...so if it is the wastegate, obviously it is going to immediately effect response which is a big problem on a RB20 based engine (RB24) and this size turbo.

- i've had the car running and disconnected the actuator rod to the flap/lever and opened it (immediately gets louder)

- i re-close it and it will not close any more, and still leaks

- the actuator rod has been adjusted to max tension just to try and eliminate the leak. and it still persists to leak.

Has anyone got any ideas of what the problem/leak may be or coming from????

Has anyone had any similar problems????

...only other variable that i can think of is that the wastegate flap can spin around on the tab, it wasn't welded into a fixed position...

IT IS VERY STRANGE - as it has not leaked on some previous occasions! but then it would start...(without adjusting anything on the car at all)

Edited February 28, 2008 by huddy

[Simon-S14]

well as you said, you've eliminated it down to the gate, take it back to the guy who did the job, pro or not, he should fix it if there is a prob with it.

[huddy]

here are some pics

**EDIT** sorry should've added i know it is leaking as i can hear it on the screamer pipe, and when i put my hand over the screamer pipe (can feel gasses) to create a seal the exhaust note changes slightly...

Edited February 24, 2008 by huddy

[Cubes]

As simonmeister has said.. get the flapper looked at.

Possibly when there's a little positive pressure pushing the flapper open it seats different when the actuator closes.

[Al]

**This is only my opinion and not sure if it is right or not**

An IW has no seals, so it is just metal-to-metal, thus you'll always get some leakage as it is not 100% sealed. It is also a well known fact the Ext wastegates produce better response, hence the leakage and seals theory.

In short if you want a screamer pipe, you need to go external

[Dale FZ1]

Can you explain what is happening to lead you to believe there is a problem?

ie. is there a sound of exhaust leaking at idle? perceived problem with rate of building boost?

Also would you drop in a picture of the dump pipe design please. If it is a screamer I promise not to comment about that part of it. More interested in how it mates up to the turbine flange.

Generally the only setup problem I see is insufficient preload on the valve so that it's not seated firmly.

edit: On reflection it might be worthwhile to check how much play there is on the wastegate shaft. Perhaps the valve has just enough movement to contact the side of the housing and stop it settling nicely? In any event the guy who did the work on the turbo needs to have a closer look. He's a specialist, he should be able to see the cause.

Edited February 24, 2008 by Dale FZ1

[Simon-S14]

al: yeah its never going to be 100% but should be damn close to 99%!

i run internal gate with a screamer, and after flapper issues of my own, i ended up tig welding the flap so it didnt rotate around, its perfect now, no leaks and sounds tough

Edited February 24, 2008 by Simon-R32

[huddy]

sorry dale i edited that in later with the pics

**EDIT** sorry should've added i know it is leaking as i can hear it on the screamer pipe, and when i put my hand over the screamer pipe (can feel gasses) to create a seal the exhaust note changes slightly...

and the design itself looks like this - BUT there has been a pipe welded on and added to go into the back of the exhaust housing (rear wheel)

MINE is the stainless one...

The Black one is an example of how the pipe had been added on...

the actuator has full tension atm - theh hole on the rod is 1 full circle/hole behind the flap/lever *if that makes sense* - pliers are needed to pull it onto it, and a fair bit of force to pull the rod...

Edited February 24, 2008 by huddy

[Simon-S14]

with the screamer, there is a resonation through the pipe but thats not to say that it is leaking. with mine you can put you hand over it, no gas is coming out but you can feel and hear a resonation going through it, not sure if the note changes or not i cant remember.

[crack]

is the flap actually closing onto the machined section? make sure it is not closing onto a rough part of the casting. isn't there supposed to be more surface area than what you have for the flap to go onto?

[Al]

is the flap actually closing onto the machined section? make sure it is not closing onto a rough part of the casting. isn't there supposed to be more surface area than what you have for the flap to go onto?

On closer inspection Craig has a valid point. Looking at your pic the flap is off centre to the machined hole.

[R31Nismoid]

yeah - you can tell as Al has posted - the "professional" has stuffed the job up and said "professional" owes you a new housing

Its not fully sealing judging by the pic, and im sure if you put some water in it'll probably leak out, or spray some deodorant or similar gas if the water isnt passing (just to be sure) and i bet you see stuff getting past.

[huddy]

well i removed the turbo today and i had a look around again... i put a torch into the exhaust housing (bright led one) and in darkness shone the torch into the housing to see if light was coming through... i did this with the actuator rod attached and also without it.

no light came through (i could only see some sort of light through the rear wheel) which makes me think it is not leaking... which adds more confusion to it all...

the flap has about 1mm play in direction (hence being off centre in the pic...), so i was opening, rotating/moving the flap and re-trying... and had no luck at seeing any light...

I actually was hoping to find a fault so i could pinpoint it to something...

any more relevant posts? keep em coming...

[R31Nismoid]

were you in a pitch black room?

hard to tell otherwise by using light

[Simon-S14]

bullshit, light is as good as usiing exhaust gas to tell if there is a leak or not.

Its quite a common technique to use to verify leaks or not, you dont even need to be in a pitch black room, if you cant see light coming through, then its not leaking, you could use water too which is prob a little more verifiable however not too many people are keen on pouroing water through their turbo.

the job is to shine a bright light through the turbine housing, and see if you can see the light coming through area's it shouldnt.

[R31Nismoid]

Well not if its a tiny leak and your not in a very dark room now is it? The angle that the leak could possibly not even send light directly at you.

It might well be uneven and not closing correctly, let alone letting stuff past as the pics dont give you a full view of the inside right side at all.

Not keen on pouring water through a turbo?

lol... it runs exhaust gas over 500 degree's through it.

[Simon-S14]

water is corrosive. but hey its your turbo.

the flap is never going to seal 100% there will always be some leakage thought it, and spillage of light in a dark room, might look like a solar eclipse but the reality is we're looking for larger leaks.

[GeeTR]

Interesting issue.

You say you can feel gases escaping at idle; what if you tug on the actuator arm closed at the same time?

If it was a used turbo, id suggest it could be leaking where the flap axle (spindle?) goes through the housing, if that makes sense.

[huddy]

yep it was pretty dark - i could see light throught the rear wheel... and when i opened the flap it was a bright glow...

i'm still thinking wastegate though... as the exhaust its flawless imo... and if it was leaking, it wouldn't be leaking out the screamer as it is completely divided on the turbo and the dump + gasket + sealant... so if it was leaking it would leak around the housing, not into the screamer...

[1400r]

Interesting issue.

You say you can feel gases escaping at idle; what if you tug on the actuator arm closed at the same time?

If it was a used turbo, id suggest it could be leaking where the flap axle (spindle?) goes through the housing, if that makes sense.

arm was being held closed by me etc while huddy was checking under the car for leaking