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Looking for any turbo removal tips
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Beartooth  



Joined: 05 Apr 2022
Posts: 198
Location: Roberts, MT

PostPosted: Tue May 17, 2022 3:24 pm    Post subject: Looking for any turbo removal tips Reply with quote

Title mostly says it. A quick rehash in case you haven't read my other thread: I've got a US introduction edition '80 931 I bought cheap that hasn't been run in around a decade. I've been tinkering on it a couple weeks: I've changed the oil, emptied the gas tank, got a new fuel pump, gone through most of the injection components, and a few other things.

While I've got things relatively torn down, I feel like I should pull the turbo so I can see what I've got. If it's cooked, I'd rather know now, and I might find something I'd want to fix before I run it. Still, it looks like delivering a calf backwards is an easier job... So I'm wondering what needs to be undone to get it out, if there are any tricks to it. I'm working without a manual; been planning on buying the Haynes manual, but haven't gotten around to it. Thanks in advance!
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Cedric  



Joined: 27 Aug 2004
Posts: 2600
Location: Sweden

PostPosted: Tue May 17, 2022 3:53 pm    Post subject: Reply with quote

Maybe it could be worth to actually try the engine first, getting the turbo out just for checking might not be worth it due to the job involved. You can check the shaft play just by removing the exhaust, and compare it to the factory manual specs (if you need those send me a private message).
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
Location: MI

PostPosted: Wed May 18, 2022 1:04 am    Post subject: Reply with quote

I probably wouldn’t..

I have done it a bunch of times, but wouldn’t just for exploring..

If you just pull the upper charge tube and it’s not terribly full of oil and doesn’t have aluminum shavings in it, that’s where I’d stop..

You could get yourself into a huge mess of broken exhaust bolts and a lot of trouble..

I’d be more worried about a compression test and the condition of your cam..

Just start the thing..
But make darn sure you put a new timing belt and tensioner on it before you even crank it over!!! <100% most important!!
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Beartooth  



Joined: 05 Apr 2022
Posts: 198
Location: Roberts, MT

PostPosted: Wed May 18, 2022 4:05 am    Post subject: Reply with quote

Wow, it looks bad, but that bad? I'll admit I'm the type who'll take something apart even though it's working just out of curiosity. I've got everything disconnected from it and haven't found anything that looks bad, but it's been sitting so long that it could have been puking oil and it would have all settled somewhere and not been obvious. I got the new timing belt and tensioner on yesterday. I did crank it over with the old belt before I bought it, but it turns out that'd been replaced be the PO, and I didn't try to start it anyway. The old tensioner sounds like it's going dry, so I don't think I'd have got far on that.

Anyway, I'm getting the sense that removing the turbo with the engine installed was an afterthought at best; kind of a bummer. The layout of the system seems to have been designed around the car, and wasn't on the engineers' minds when the 924 was developed. It is what it is; part of the "turbo tax," I guess.
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Fasteddie313  



Joined: 29 Sep 2013
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PostPosted: Wed May 18, 2022 6:28 am    Post subject: Reply with quote

It’s not impossible.. Just quite a difficult job, especially on old hardware..

Once you’ve broken everything that is going to break, drilled broken studs out of everywhere, and replaced all the studs on everything, it gets easier to repeat the job.. Especially wastegate studs..

Break any of the studs in the manifold and then you might as well pull the whole head..

Id replace every stud/bolt you can except the titanium ones with cheese heads, unless you break them too (I even broke one of those)..

You’ll need a high grade extension about 12” and a high grade swivel, or those might break first..

I guess you if you already have most of it off have at it..
The exhaust side is the hard part, and it’s mount to the block..

And then when you put it back on make sure to do the turbo to manifold bolts and block mount bolts first and snug them all up all at the same time before you tighten anything..

Their is no flex in any of that so if you tighten one thing without the others sitting nice and flat, like the block mount, you’ll put a lot of stress on everything and maybe break something..


Turbo is pretty simple, really only one moving part in there..

Pretty sure I drop the sway bar to get it out the front eventually..

Put new gaskets on the recirculating BOV end caps while your at it..
Probably a new 90 rubber elbow on its vac line..
New VITON o ring on the oil inlet..
New gasket on the oil drain.
Depending if you have a gasket or crush ring in the turbo to manifold..
I’ll admit I don’t even put a gasket on the turbo to down pipe..

If your going to pull the waste gate too that’s a whole other ball of worms and possible breakage..


I don’t think the turbo is likely to get messed up from sitting..
If their is oil in the exhaust it’ll burn out eventually..
I’d have shot oil in the cylinders and have expected it to smoke on first start..
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Gatornapper  



Joined: 23 Oct 2021
Posts: 294
Location: VA

PostPosted: Sat May 28, 2022 11:53 am    Post subject: Re: Looking for any turbo removal tips Reply with quote

I totally agree with Cedric and FastEddie -

Why pull it when it may be fine? You don't say how many miles on the car.

I have the same car, sat for 17 years. Mechanic friend in Ohio squirted ether in intake and it started right up, ran great.

I was pleasantly surprised to find after cleansing the whole fuel system, new pump, filter, flush fuel distributor, new injectors, and rebuild WUR/WUV, the car ran like new.

Who knows? Maybe you'll have the same results.

Turbo won't kill it from running - get it started and then find out condition of turbo.

GN

Beartooth wrote:
Title mostly says it. A quick rehash in case you haven't read my other thread: I've got a US introduction edition '80 931 I bought cheap that hasn't been run in around a decade. I've been tinkering on it a couple weeks: I've changed the oil, emptied the gas tank, got a new fuel pump, gone through most of the injection components, and a few other things.

While I've got things relatively torn down, I feel like I should pull the turbo so I can see what I've got. If it's cooked, I'd rather know now, and I might find something I'd want to fix before I run it. Still, it looks like delivering a calf backwards is an easier job... So I'm wondering what needs to be undone to get it out, if there are any tricks to it. I'm working without a manual; been planning on buying the Haynes manual, but haven't gotten around to it. Thanks in advance!

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'87 944 S, looks & runs like new - sold my sweet 931; '76 914 2.0 mostly restored; 2011 Porsche Cayman S in Meteor Grey, 3.4L, Softronics ECU tune 355+hp , PDK w/Sport Chrono. Got this thing for Porsche's.......
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Gatornapper  



Joined: 23 Oct 2021
Posts: 294
Location: VA

PostPosted: Sat May 28, 2022 11:57 am    Post subject: Re: Looking for any turbo removal tips Reply with quote

BTW - you know you have a rare car? Introductory Models started at #015000 - mine is #201. Only 600 I.M.'s made - love to know how many still on road.....

What's yours?

GN


Beartooth wrote:
Title mostly says it. A quick rehash in case you haven't read my other thread: I've got a US introduction edition '80 931 I bought cheap that hasn't been run in around a decade. I've been tinkering on it a couple weeks: I've changed the oil, emptied the gas tank, got a new fuel pump, gone through most of the injection components, and a few other things.

While I've got things relatively torn down, I feel like I should pull the turbo so I can see what I've got. If it's cooked, I'd rather know now, and I might find something I'd want to fix before I run it. Still, it looks like delivering a calf backwards is an easier job... So I'm wondering what needs to be undone to get it out, if there are any tricks to it. I'm working without a manual; been planning on buying the Haynes manual, but haven't gotten around to it. Thanks in advance!

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'87 944 S, looks & runs like new - sold my sweet 931; '76 914 2.0 mostly restored; 2011 Porsche Cayman S in Meteor Grey, 3.4L, Softronics ECU tune 355+hp , PDK w/Sport Chrono. Got this thing for Porsche's.......
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Beartooth  



Joined: 05 Apr 2022
Posts: 198
Location: Roberts, MT

PostPosted: Thu Jun 23, 2022 3:41 am    Post subject: Reply with quote

My motivation for pulling the turbo is mostly because I'd like to know what the condition is, rather than chasing low boost or other issues down the road, and a bad turbo would change the equation as to whether it's worth putting money into the car. Given how nasty the job is, I'll probably hold off and just see what I get. The possibility of broken hardware is another issue I hadn't thought of. I do think it'd be a no-brainer to pull the turbo and inspect if it weren't so hard to get to. I have no history on the car, other than it sat here in MT for the last 10 years, but I don't think it spent any time in the rust belt. There's no significant rust on the car, so hopefully the turbo would come out without too much drama if I go down that road.

The car indicates 90,000 miles. I saw your other thread, and pretty sure I responded there. I've about got the fuel injection back together, so getting close to the point where I can fire it back up. Unfortunately, stuff seems to crop up every step of the way. It sat with the fuel filter un-done for quite a while, and while I was pleasantly surprised at how well the FD, WUR, and such cleaned up, I keep running into little sort part issues. I just applied pressure to the whole injection system, and a couple of the injection lines were spitting out fuel. I guess it wasn't a total surprise: some of the o-rings in the FD were noticeably swelled. I was able to dig up some replacement o-rings, but I'm not sure those will last (one was from an AC o-ring kit, another was from a Dorman-branded assortment, and didn't even say what type they were).

If it were a car I were committed to, I'd probably take a different approach and replace anything questionable as I go, but I need to get it roadworthy enough to get a good assessment. Could easily have something like a mosquito-fogging motor or lunched gearbox, so I need to get to the point where I can be reasonably sure that's not the case before I spend any more than the bare minimum. I'm a few-hundred into parts right now, where I'd be over a thousand easily if I were replacing things as I go. Also, it doesn't help that I'm waiting on the DMV. I sent the paperwork in for the title a month and a half ago, and I'm still waiting. The car is definitely worth what I paid for it, given how complete and rust-free it is. Thing is, I knew I was getting into a challenging project given how long it was derelict, and so far it hasn't disappointed...
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Fasteddie313  



Joined: 29 Sep 2013
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Location: MI

PostPosted: Thu Jun 23, 2022 4:12 am    Post subject: Reply with quote

Beartooth wrote:

If it were a car I were committed to, I'd probably take a different approach and replace anything questionable as I go, but I need to get it roadworthy enough to get a good assessment. Could easily have something like a mosquito-fogging motor or lunched gearbox, so I need to get to the point where I can be reasonably sure that's not the case before I spend any more than the bare minimum. I'm a few-hundred into parts right now, where I'd be over a thousand easily if I were replacing things as I go. Also, it doesn't help that I'm waiting on the DMV. I sent the paperwork in for the title a month and a half ago, and I'm still waiting. The car is definitely worth what I paid for it, given how complete and rust-free it is. Thing is, I knew I was getting into a challenging project given how long it was derelict, and so far it hasn't disappointed...


I took much the same approach when I first got mine..
I first got mine with a COMPLETELY lunched turbo..

Couple things about accessing the condition of the turbo..
You said you had the exhaust pipe off of it.. The down pipe..
Spin the shaft and wiggle it around.. If you can’t make the blades hit the housings by pushing it sideways and spinning it, they you have good wheels that haven’t been lunched..

If it doesn’t wiggle around more than a mm or so, it’s probably good.. Bearings wise..

When turbos fail they start smoking, long before the bearings get all that bad, and way long before the bearings are bad enough to let the wheels contact the housings..

Their isn’t much “inspecting” to do on a turbo other than feeling the shaft play..

If it’s quite worn you won’t know until you run it and see if it smokes..

If you are to the point where you’d get a “low boost” condition because of the turbo being bad, you are way way past the smoking stage of the turbo, because a worn smoking turbo will still boost very well, until the wheels hit the housings, then it’s just about scrap metal, because the expensive/hard to get/and likely damaged part of the turbo, is the exhaust turbine and its axle shaft..

We have parts for you.. Don’t worry..
We can scrounge you up a turbo (or parts) and working fuel injection system parts to get you into your “on the road” condition so you can further assess what you’ve got..

If your fuel distributor is bad let me know.. I have one you can at least borrow to use for testing..



I’d be most concerned about your pistons, cam, and valves..
Turbo is easy/cheap to repair/replace.. Engine internals not so much..
HG is pretty easy/cheap though..

Even a blown engine would be worth fixing if you have a pretty solid/clean 931 your starting with..
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2596
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PostPosted: Thu Jun 23, 2022 4:16 am    Post subject: Reply with quote

Yep you have pasha interior..
That alone makes your car worth fixing..

If you decide not, I call dibs on buying that interior..
Especially the door cards..
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Beartooth  



Joined: 05 Apr 2022
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Location: Roberts, MT

PostPosted: Mon Aug 29, 2022 3:47 pm    Post subject: Reply with quote

Ha, I missed the offer on the interior; things were looking pretty good for a while, but maybe the needle moved a little more that way. I noticed oil on the intake manifold, so I took the charge pipe off, and it was coming from where it interfaces with the throttle body. Seems it was accumulating just before the throttle body and seeping past the boot. So it looks like, come hell or high water, that turbo has to come out. Not worth driving a mosquito fogger and spending as much money on oil as gas to me... At least I'll be able to kill two birds with that stone though (assuming I'm successful): I've got a significant exhaust leak, so something needs attention down there anyway. At least being a Montana car, it's got virtually no rust, and maybe that means the nut and bolt gods will smile on me. So wish me luck! Now, assuming the turbo hasn't eaten itself (and I'm not seeing any metal anywhere) where's a good place to get parts?
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Beartooth  



Joined: 05 Apr 2022
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PostPosted: Fri Sep 02, 2022 5:17 pm    Post subject: Reply with quote

Well, the turbo is out, and the patient is resting comfortably, but another risky operation is required. Almost everything came apart without any major issues, but then one of the turbine to manifold bolts broke. The three bolts in the foreground were what was (kind of) holding the turbo on. Might not be obvious, but the threads on the two that didn't break are mangled, and the turbo wasn't tight to the flange. That had to be the source of my exhaust leak. The bolts were just standard 8.8 grade bolts, and I have a suspicion they only stayed in because the flanges weren't square to each other. Other problems and oddities: the wastegate to torque tube mount is broken; the turbo to block mount had studs instead of allen bolts; the manifold to wastegate line must have cracked and been repaired, the welds didn't look factory and interfered with one of the nuts. So, quite clearly, this car had not only been wrenched on, it'd been wrenched on by someone who didn't know or didn't care too much what they were doing... One piece of good news is the wastegate seems to work perfectly. I applied a little pressure with the air hose, and it opened smoothly, with no apparent leaks. I don't see any reason to go spelunking there: even if it were to fail down the road, it's not the worst thing to get to.





Anyway, I pulled the compressor and turbine scrolls off, and it's not all good news. The wheel turns freely and doesn't have a lot of play, which is good. The outer end of the turbine blades are in bad shape though. I'm not sure at what point it's trash (no evidence of any contact with the scroll); it's just too bad because the rest of the turbo looks great (minus the oil in the compressor section). In fact, the compressor wheel looks perfect; I can find no evidence of wear. The turbine scroll does have a crack in it, but I gather it's pretty rare to find one that doesn't.







Anyway, is it good enough to do a bearing and seal job, or do I need to go further than that? I'm ok with "just ok," but I don't know enough to even guess how bad that turbine is. Also, it looks like replacement turbines aren't too hard to find, but I'm pretty sure just slapping it together with a new turbine without balancing it is a recipe for failure. It's not a terrible expenditure if I have to go that route (around $150 for the new turbine/shaft, $75 for a bearing and seal kit, and $100 for balancing), just not something I want to throw money at if I don't have to.

Finally, while I ended up going down this road, I totally agree with the "don't touch it if you don't have to" opinions. In my case, I don't think I had much choice, given how much oil it was slinging in relatively little time, plus an exhaust leak that I'd have to deal with at some point. Then there's the broken wastegate mounts... and the hardware store turbo bolts... But if I'd been lucky enough to have stumbled on a car that'd been taken care of and put together right, taking the turbo off just because would be a lot of work if everything went well, and maybe a lot more if something didn't come apart right, or broke in the process. And I'm lucky to live where they don't salt the roads, so things came apart nicely except for the Goofus's turbo hardware (those idiots at Porsche! You know how many generic bolts you can buy for that price!). Next, I have to see if I can get the manifold off because of the broken bolt; hope that doesn't turn into having to pull the head! I'm not sure what the likelihood of a fully original car making it this far without the turbo needing some attention is, but even in hindsight, blindly going after the turbo doesn't make much sense. If I were to start on another such car, I'd take the same path I did: get the car running and keep working on other things until something forces you down this path. It's not the worst thing if you have to, but I'd agree with Fasteddie: not a job you want to tackle if you don't have to, and not one you can do in a set timeframe unless you've had it apart before and replaced every nut, bolt, and stud.
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Cedric  



Joined: 27 Aug 2004
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PostPosted: Fri Sep 02, 2022 8:37 pm    Post subject: Reply with quote

That turbine is a complete write of in my opinion, not the end of the world though. the turbine housing and compressor looks fine though.

Im not sure the exman is possible to remove with the engine in place, the head can be removed with exman and intake man as a unit, though head removal makes even more stuff to be needed and bought if you want to make it properly.

In many cases, depending on what garage you have, its often easier and faster to just pull the engine and make the work on the bench. With better quality on the work due to the better acess.

Keep fighting
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Beartooth  



Joined: 05 Apr 2022
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PostPosted: Sat Sep 03, 2022 7:13 am    Post subject: Reply with quote

Well, I just chatted with somebody at G-Pop Shop, and they said they could put a new turbine wheel on, balance it, and replace the soft parts for $500. Just a kit and new turbine wheel/shaft would be over $200, and it'd probably be silly to go that way without balancing it, so you're already over $300 even if you squeeze every penny. It's kind of a bummer to start in hoping to spend $150 or so between a kit and new gaskets, and have it quickly shoot up over $500, especially when you've still got a lot of unknowns. On the other hand, even if I hit big issues farther down the line, at least I can get some money back out of the turbo. If I could just go to the pick-a-part and get my hands on another turbo, I'd consider rolling the dice, but since I've got a good core, a proper rebuild would fit with the "do it right, do it once" approach. If anybody's got a good turbo kicking around, shoot me a PM; I'm not set on rebuilding mine, although $500 isn't crazy expensive to me, considering how much work it is if I have to go in again.

On the turbine damage, I described it to the guy I talked to, and he said it's gotta be FOD damage. So the immediate question is, "from what?" I know what just a small chunk of metal in a cylinder can do: my Dad has a Powerstroke that broke a tip off an injector (a piece the size of a BB), and the result was like someone had wailed on the piston and head with a pickax; I bore-scoped each cylinder before I got it running and didn't see any damage like that on the pistons, but there was some scratching on #1, maybe from someone using a screwdriver to find TDC. Obviously, one possibility is Goofus put it back together with something in the turbine or manifold. Another is something dropped through a spark plug hole (they're like catch cans for grit and debris; I cleaned those all out as best I could before I pulled the spark plugs, then again with a plug in the hole to get the rest). It's not a good sign, obviously, but even with the oil out the compressor, the car really didn't smoke, and compression was ok. I think I'll just keep on keeping on; I might be leaning a little on the optimistic side, but you're always taking some kind of chance on something like this.
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Beartooth  



Joined: 05 Apr 2022
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PostPosted: Sun Sep 04, 2022 9:24 am    Post subject: Reply with quote

Well, some good news finally: I got the manifold off without any drama. A couple of the studs came out with the nut, and I had to work those a little to keep from eating up the threads. A tip I discovered a few years ago on that (and I'm sure it's no particular secret of mine) is if you're working with aluminum and a bolt or stud isn't backing out freely, work it back and forth rather than just trying to muscle it straight out. I discovered that when I was taking heim joints out of some aluminum radius arms on my snowmobile: I had a couple that mangled the threads beyond repair or just broke, but as soon as I started working back and forth my success rate jumped to around three out of four (back it out a half turn or so or until resistance builds, then work it in and out a quarter turn or so until it loosens, then out another half turn or so and work it again).

Anyway, I'll probably have to take the manifold to a machine shop. I have a pretty good extractor set, plus I tried heating the manifold on that end, but those cheap bolts are so soft that the extractor is just digging metal out as soon as they start to grab. Cheap hardware like that is not worth using on anything mechanical unless it's a "get you home" situation. Anybody who knows engines will know there are some things you don't use generic hardware on, even high grade stuff, if you don't have to. I hope Goofus didn't do any internal work on the engine: I wouldn't put it past him to come up with a similar budget "solution" to, say, replacement connecting rod bolts...

I did notice a crack in the exhaust manifold. As you can see from the picture, it's about an inch long. It doesn't look like it's been leaking, but I do think I can see it on the inside of that port. It's small enough that it's not an issue right now, and for all I know, welding it might cause more harm than good. So I'm curious if it's the kind of thing any of you guys would get welded. I've got a MIG, but I'd definitely take it to someone experienced with that kind of thing over trying to do it myself.


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