Leaking Wastegate flapper on my 14b. Possible fixes?

[Drift_SM]

Yeah well.... with something new you find something old.

After installing my new o2 housing dump....I can hear, and feel exh gas comming from the dump tube...at idle and when cruising at light throttle. Thats not good for my daily driver.

If I push on the flapper arm it seals up. I noticed the actuator arm was a bit crooked...so threw in a nice new thick cotter pin and straited the arm to sit right on the flapper. I HAVE NOT had a chance to start it because its to late a night.

So my questions are...what causes the flapper to leak?
What are my options to fix it?

-alex

 

[shaunman1979]

Well if you can push the flapper closed, all you would need is a few small washers inbetween where the actuator bolts to the turbo. This should pull the flapper closed if thats what the problem is.

 

[Drift_SM]

Yes I also thought of this. This morrning when comming to school it is still leaking after
I straitend the actuator arm. Im in class right now and when
I get home, im going to shim the actuator where it meets the turbo like you said and hopfuly it holds.

Could back pressure also cause the flapper to open at idle and light acceleration?
I ask becasue its a 2.5 inch o2 housing on a 2 inch stock dp with a 2.5 inch cat-back.


Ps: To anyone who reads this. Please help. I very rarely post up threads in the tech forums. Its usualy because I can find everything I need by searching. But when I have a real issue that cant be found, and casues me to open a thread ..it seems no one ever has the answer. Or they just dont care enough to post.

Thats my .02 cents.

 

[exile]

Wastegate actuators are pretty strong and idle/low throttle exhaust flow isn't going to force it open. I have a question for you, if the car is turned off completely is it still lose? If it's hooked up wrong you could be getting a air source from something weird.

If it's a stock actuator which part is lose? Say you're looking at it from the side, the hole where the arm connects to the flapper with the pin in it, is that lose? does that part move in and out? (if it does it doesnt mean anything) or does the arm move in and out of the actuator?

If it moves in and out of the actuator freely, then you need a new actuator. Typically, theres nothing that should "losen" on an internal wastegate, if the arm isnt connected to the flapper 100% and wiggles that isnt going to make it stick open. If it is open slightly then your actuator is like, out of alignment somehow (hyper-extended? broke?) and you have two choices.

1) Put washers under the two bolts where the actuator connects (may bring it out too far so read option 2) *EASY*

2) Cut about 1" out of the middle of the arm. Use a tap and dye set to thread both sides of where you cut and use an all-thread joint (female-female) to join the arm back together, use two nuts to on each peice of the arm to secure it in place and adjust it to where it needs to be. If you go this route I will show you a picture of a t4 wastegate from another car (thats where I got the idea.) *HARD*

Regardless though, if it moves in and out it's broken anyway and you should replace it.

 

[Drift_SM]

Thank you. Finaly a real answer. You just made my day.

Members like you make DSM tuners what it is.

Slow boy has actuators for 140. With employee discount at mitsu i can get one for 190. uhg.

You know if where it would be possible to find one cheaper?

Thanks agian.

 

[Drift_SM]

ok new development.

I tryed holding the flapper down a couple differnet pays by bracing it with tools then revving it from the throttle cable and it still has no change what so ever.

So Im thinking no matter how tight i get the actuator arm its stil gogin to leak.

So now im starting to think possibly gas from the turbine is leaking into the dump passage from the gasket. Possibly?

Either that or somthing is wrong witht he flapper. because no matter how tuff I hold it...or at w/e angle ......its still sounds the same. I am using a 2g o2 gasket on the 14b...###### not the right thing to do seeing as it doesnt line up right with the new 02 or 14b right...

So now Im really thinking there is actual exh air from the turbine leaking into the dump passage.

 

[Drift_SM]

ok new development.

I tryed holding the flapper down a couple differnet pays by bracing it with tools then revving it from the throttle cable and it still has no change what so ever.

So Im thinking no matter how tight i get the actuator arm its stil gogin to leak.

So now im starting to think possibly gas from the turbine is leaking into the dump passage from the gasket. Possibly?

Either that or somthing is wrong witht he flapper. because no matter how tuff I hold it...or at w/e angle ......its still sounds the same. I am using a 2g o2 gasket on the 14b...###### not the right thing to do seeing as it doesnt line up right with the new 02 or 14b right...

So now Im really thinking there is actual exh air from the turbine leaking into the dump passage throught the gasket

 

[spaceball]

the most likely cause is a cracked and eroded turbine housing. take off your o2 housing and inspect the housing under and around the flapper door.

 

[shaunman1979]

It could be your gasket, I am not sure on how the fittment between the 2g gasket would affect it. But if it were the gasket then the exhaust has already passed by the turbine wheel before it meets with the possible bad gasket. Did you notice any cracks in the exhaust housing? That could cause some leakage. I have also seen on my turbo the flapper had shifted over time so that it was not covering the hole allowing exhaust gasses to pass by before the turbine.

 

[DSMcrazy3]

Those wastegate passages are notorious for cracking, and eventually leaking over time. Go ahead and pull the wastegate actuator off and inspect it for any free play in and out. If there is none it's fine and you've most likely got one or two serious cracks where the flapper normally seals shut and it needs replacing.

 

[gsxnate99]

i had a 16g that did the same thing... its really no big deal other then u sound like u have one helll of a exhaust leak at idle. But it wont result in power loss or nething of that nature

 

[PieEyedPiper]

i had a 16g that did the same thing... its really no big deal other then u sound like u have one helll of a exhaust leak at idle. But it wont result in power loss or nething of that nature

Wouldn't you think you would have slower spool up if the wastegate flapper/area was leaking?

 

[exile]

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[DSMcrazy3]

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A crack there wouldn't explain why pressure on the flapper would cause the leak to cease. There is either a crack in the seat for the flapper, which adding pressure forces a better seal restricting that air from escaping, or the actuator arm is still bent a bit holding the door open slightly, OR the actuator is on it's way out.

 

[Drift_SM]

Ok well this is what i came up with.

When I had the o2 housing out, I set the mitsu o2 housing gasket on it. I noticed that the thin section between the wastegate passage and turbine passage was way off. Less the an 8th of an inch that could seal the two passages apart. Leading me to belive that the exhaust from the turbine side is leaking into the dump passage...witch would explain why it is heard instantly when hitting the throttle..even lightly. Plus it sounds and acts like an exhaust leak. It gets a little quieter after warming up.

I pulled the actuator off the flapper arm and wore some gloves and held the flapper a bunch of different ways to make a perfect seal on the flapper seat. Every time I reved the car when doing this test it always sounded the same.

I put the actuator arm back on and is secured correctly.

So now it is narrowed down to either a large crack on the flapper seat. Or a leak in the o2 housing gasket (most likely).

This 14b only had about 50,000 miles on it when I put it on my car 8,000 miles ago. It had the normal 16g cracking....but no large cracks or chunks missing. IT has never seen anything over 17 psi.

Im pulling the turbo next week. If the flapper seat is cracked is it possible I can weld it and slowly smooth it out with a dremel. I also will probably fab up my own 02 housing gasket, to fit the new housing.

 

[spaceball]

who did you buy your o2 housing from? i bought mine from punishment and the gasket surface was bowed in preventing adequate pressure to seal the gasket between the wg passage and the turbine passage. solution; i finagled the o2 house into a shop press and bowed the flange out so the surface between the two passages has the most pressure on it.

 

[Drift_SM]

who did you buy your o2 housing from? i bought mine from punishment and the gasket surface was bowed in preventing adequate pressure to seal the gasket between the wg passage and the turbine passage. solution; i finagled the o2 house into a shop press and bowed the flange out so the surface between the two passages has the most pressure on it.

funny you said that because i think it was already a little bit bent to seal the middle part. But even still... I think my problem in the gasket itself....It seemed the turbine passage on the 02 housing was to large, the gasket could not seal up. I put it on anyway. MAybe i shoudl try a 2g 02 housing gasket. Becasue i know the waste gate passage is shapped a bit different. Maybe the 2g will seal it better. Or im just going to make my own gasket.

Question: what direction was it bowed. top ( corner closest to manifold) to bottom ( corner closest to dp)
or left( closest to radiator) to right (closest to block)?