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Replacing or refurbing wastegate (Tial, perhaps?)
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bureau13  



Joined: 07 Sep 2017
Posts: 196
Location: South Florida

PostPosted: Sat Jul 13, 2019 1:11 am    Post subject: Replacing or refurbing wastegate (Tial, perhaps?) Reply with quote

I haven't confirmed it yet, but I'm pretty sure my overboosting is due to a bad wastegate. I'm a little afraid of taking it off and snapping off one of those studs I keep reading about.

First off, the studs usually break off in the wastegate body, right? I assume the procedure is to remove the J-pipe and then pulling it off the other exhaust pipe (not sure what that one is called) and the mounting bracket...or do I need to remove more of the exhaust?

Given the cost of a new wastegate diaphragm, etc I will very likely just buy a Tial and sell the original to someone who wants to rebuild it. The Tial comes with stainless steel bolts. Can I use those on the 931 instead of stock studs? Or do I need to use studs and nuts for this application?

Final (ha!) question: Do I need to get the narrow body version, F46P, or does the standard F46 fit on these cars? I believe the only difference is the F46P has the fins machined down a bit to avoid hitting on some bits in the 930, the application for which it was originally designed. I just don't know if the 931 requires that.

Thanks
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1843
Location: MI

PostPosted: Sat Jul 13, 2019 3:15 am    Post subject: Reply with quote

On mine I need to take all of the exhaust pipes off, including the J-pipe, but the turbo can stay...

I don't have 1st hand experience with a Tial but I think they were designed to be a direct fit replacement, but I don't know about the the signal line or its mount to the torque tube stuff though..

I broke about half the studs in mine..
I set it up on my drill press table by putting one of the remaining studs in my chuck to get it prefectly straight with the studs, then moved the table and drilled the other studs out till I could see some threads, then put the correct tap in my chuck still perfectly straight and turned the chuck by hand with a little bar to tap the holes out perfectly straight down.. Worked..
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1885
Location: Somerset, UK

PostPosted: Sat Jul 13, 2019 3:16 am    Post subject: Reply with quote

Aren't Tials in the region of $600? A new diaphragm, if needed, is $150. I'd put the extra money into an inter/charge cooler and use the boost more efficiently. a Tial will add nothing to the car or performance, but will take a lot of $ from your bank balance.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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bureau13  



Joined: 07 Sep 2017
Posts: 196
Location: South Florida

PostPosted: Sat Jul 13, 2019 5:00 am    Post subject: Reply with quote

I commonly see them for around $480, but your point is still valid. That's a lot more than $150. I see a lot of them on Ebay for close to the price of the Tial (or even more) but they're probably not in need of a rebuild, and being listed and being sold are two different things. The main factor was I see folks talking about valve guides or something in the wastegate that had to be machined or something? That's outside of my skill set for sure, and I'm not sure I'd know by looking at it if such a thing were needed.

Carrera RSR wrote:
Aren't Tials in the region of $600? A new diaphragm, if needed, is $150. I'd put the extra money into an inter/charge cooler and use the boost more efficiently. a Tial will add nothing to the car or performance, but will take a lot of $ from your bank balance.

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1843
Location: MI

PostPosted: Sat Jul 13, 2019 5:07 am    Post subject: Reply with quote

You used to have to get one of these made by a machine shop but it looks like you can just buy one now..

https://www.ebay.com/itm/Qty-1-Porsche-930-935-965-931-turbo-wastegate-essential-rebuild-kit/113813352340?hash=item1a7fcdef94:g:pj4AAOSw9~Jc4v7K
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bureau13  



Joined: 07 Sep 2017
Posts: 196
Location: South Florida

PostPosted: Sat Jul 13, 2019 5:08 am    Post subject: Reply with quote

Also, what do you guys think about using a low-power impact driver on the nuts, at least those that can be reached that way? When I changed the water pump in my 928 I broke off a bolt, after which I used an impact driver and had no additional problems. I got to learn about Timeserts, which are cool, but I don't want to learn about them again...
_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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bureau13  



Joined: 07 Sep 2017
Posts: 196
Location: South Florida

PostPosted: Sat Jul 13, 2019 5:46 am    Post subject: Reply with quote

Oh, that's good to know! Definitely takes some of the worry out of it for me...

Fasteddie313 wrote:
You used to have to get one of these made by a machine shop but it looks like you can just buy one now..

https://www.ebay.com/itm/Qty-1-Porsche-930-935-965-931-turbo-wastegate-essential-rebuild-kit/113813352340?hash=item1a7fcdef94:g:pj4AAOSw9~Jc4v7K

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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peterld  



Joined: 10 Dec 2006
Posts: 761
Location: Noosa Heads QLD Australia

PostPosted: Sat Jul 13, 2019 10:50 pm    Post subject: Reply with quote

The wastegates are extremely robust.....never seen one off a 924 that needed more than a new diaphragm and the usual broken stud, or two. Yes, there is a valve in there, but again I've never seen one that required a new valve guide. Certainly if you have one apart, I'd suggest you lap in the valve......a rudimentary task.
I've even rescued one from the trash (ex-930), which had a crack through the fins. This was welded up and the wastegate went on to lead a happy, long life doing what it was designed to do.
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chuck21401  



Joined: 20 Feb 2005
Posts: 163
Location: Annapolis, MD

PostPosted: Sun Jul 14, 2019 12:17 am    Post subject: Reply with quote

I'm just about to start this project. Bought the valve guide and gasket kit on Ebay.

The Haynes manual has procedure to remove the wastegate and I found this online:



Not sure why the starter has to come off...but a good reminder to disconnect the battery before diving in.

Will post pics and progress updates on the other thread.

I messaged the seller of the valve guide kit; he used a hydraulic press to carefully remove the old valve guide. Well, I don't have one of those so will need to take it somewhere...but it will be a while before I get to that point.
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Last edited by chuck21401 on Tue Jul 23, 2019 1:47 am; edited 1 time in total
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peterld  



Joined: 10 Dec 2006
Posts: 761
Location: Noosa Heads QLD Australia

PostPosted: Sun Jul 14, 2019 1:20 am    Post subject: Reply with quote

If you have to replace the valve guide (which I seriously doubt), any engine shop will be able to press out the old one and press in a new one.
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chuck21401  



Joined: 20 Feb 2005
Posts: 163
Location: Annapolis, MD

PostPosted: Sun Jul 14, 2019 3:25 am    Post subject: Reply with quote

peterld wrote:
If you have to replace the valve guide (which I seriously doubt), any engine shop will be able to press out the old one and press in a new one.


Thanks.

re: installation

This thread on Pelican discusses a neat trick...guide is frozen...hot side of WG heated in oven to 450 degrees...the new guide drops in....apparently.

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/972314-930-wastegate-rebuild-nla-parts-2.html

Hopefully the valve guide is fine...but I'm running out of suspects. Hopefully will know something new soon.

Also curious to find out what bureau13 finds...
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1885
Location: Somerset, UK

PostPosted: Sun Jul 14, 2019 4:29 am    Post subject: Reply with quote

Quote:
Not sure why the starter has to come off...but a good reminder to disconnect the battery before diving in.


Youíll soon realise far more has to come off a turbo than you think with most maintenance jobs. Make sure you have spare fixing, gaskets, band aids, patience etc. Enjoy
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
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bureau13  



Joined: 07 Sep 2017
Posts: 196
Location: South Florida

PostPosted: Sun Jul 14, 2019 3:26 pm    Post subject: Reply with quote

So the starter thing is confirmed? Good grief...it's on the other side of the engine lol. There must be something in the exhaust that has to come off that interfered with the starter? Although I just replaced my starter and I can't recall anything obvious...

Carrera RSR wrote:
Quote:
Not sure why the starter has to come off...but a good reminder to disconnect the battery before diving in.


Youíll soon realise far more has to come off a turbo than you think with most maintenance jobs. Make sure you have spare fixing, gaskets, band aids, patience etc. Enjoy

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1885
Location: Somerset, UK

PostPosted: Sun Jul 14, 2019 6:59 pm    Post subject: Reply with quote

bureau13 wrote:
So the starter thing is confirmed? Good grief...it's on the other side of the engine lol. There must be something in the exhaust that has to come off that interfered with the starter? Although I just replaced my starter and I can't recall anything obvious...

Carrera RSR wrote:
Quote:
Not sure why the starter has to come off...but a good reminder to disconnect the battery before diving in.


Youíll soon realise far more has to come off a turbo than you think with most maintenance jobs. Make sure you have spare fixing, gaskets, band aids, patience etc. Enjoy


No. The starter is right next to the exhaust, j pipe and wastegate. You need spanner and hand room. Removing the starter gives you this room. You may be lucky, I wasnít . I did this job a few months ago to replace my turbo.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
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bureau13  



Joined: 07 Sep 2017
Posts: 196
Location: South Florida

PostPosted: Mon Jul 15, 2019 2:03 am    Post subject: Reply with quote

Could this be a LHD vs RHD thing? My starter is on the (LHD) driver's side, and my wastegate is on the passenger side, as is the turbo.

Carrera RSR wrote:
bureau13 wrote:
So the starter thing is confirmed? Good grief...it's on the other side of the engine lol. There must be something in the exhaust that has to come off that interfered with the starter? Although I just replaced my starter and I can't recall anything obvious...

Carrera RSR wrote:
Quote:
Not sure why the starter has to come off...but a good reminder to disconnect the battery before diving in.


Youíll soon realise far more has to come off a turbo than you think with most maintenance jobs. Make sure you have spare fixing, gaskets, band aids, patience etc. Enjoy


No. The starter is right next to the exhaust, j pipe and wastegate. You need spanner and hand room. Removing the starter gives you this room. You may be lucky, I wasnít . I did this job a few months ago to replace my turbo.

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
Back to top
View user's profile Send private message
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