86 Turbo Crossover pipe hell

[Belgian951]

Hi everyone! I'm the owner of a 1986 Porsche 944 turbo which a few months ago has failed emissions testing because of a cracked crossover pipe. After having sourced 3 pipes (original from the car, second hand pipe, and now a new old stock pipe) I am coming to you with an installation problem.

I have scoured the internet far and wide, asked on Facebook and other forums to find the answer, but alas no definitive answer was found. I hope someone here can help me to get this car back on the road... it deserves to be driven, that's for sure.

So this is the story:

- I got a completely new OEM official Porsche part crossover. It is a one piece design.
- It's in the car but the bolt holes at the exhaust manifold pipes don't line up at all.
- Bolts are fitted on the turbo side, no issues here. Nuts fitted loosely
- Pipe is on the 4 studs of the OEM wastegate, nuts fitted loosely (the bolt that goes on the tacked nut is completely through though)
- All nuts on the exhaust headers are loose, which was the key to my succesful installation of the previous pipe, but now it doesn't seem to work.
- I still can't get a screwdriver in any of the 6 holes of the exhaust manifold to crossover connection.

Possible 'solutions' that I can see but which I don't really see as feasible:

- Force the crossover with a long ass pipe and swearing: I'm afraid I'll crack something, if not the exhaust header, maybe the crossover pipe itself, or perhaps my biggest fear, the flimsy rusted and already elongated bolts on the wastegate
- I've read various threads about 'clocking' the turbo: 1) I never touched the turbo for the previous 2 pipes, so why should I touch it now, the new pipe is the same as the 2 old pipes. 2) these topics never explain completely what clocking a turbo is, nor give a step by step tutorial on how to do it, nor do they mention how much of an effort it is, whether it can be done in the car or not


I am requesting this forum's wisdom in getting this car back on the road...! Thank you all.

A desperate 951 owner.

[ealoken]

I realy had to pry mine in to fit the first time.
After some heat cycles it fits supernice.

[gpr8er]

https://www.verociousmotorsports.com/Sh ... olid-liner

Cut and splice in a bellows. You'll need a pro welder to do it right. The pipe should be back purged with argon when welded to prevent sugaring on the inside.

[Belgian951]

I realy had to pry mine in to fit the first time.
After some heat cycles it fits supernice.

Can you tell me where you found leverage? Did you attach the turbo and wastegate sides first?
How hard can I pry?

https://www.verociousmotorsports.com/Sh ... olid-liner

Cut and splice in a bellows. You'll need a pro welder to do it right. The pipe should be back purged with argon when welded to prevent sugaring on the inside.

I really don't want to take another pipe to a welder. Last time they botched it so much the pipe is unusable. It also shouldn't be necessary since everything about this car and the new pipe is stock, so it should fit. But thanks for your advice, I do appreciate it!

[ealoken]

Turbo first, 90% tight, then headers 80%
I'm 120kg, so a bit of prying

[Belgian951]

Turbo first, 90% tight, then headers 80%
I'm 120kg, so a bit of prying

Ok so I guess I could pry a bit harder.
Do you happen to remember where you found leverage on the exhaust header side?

[ealoken]

I converted to exhaust studs and nuts, but how much out of order are your parts?
Pictures?

[Tom]

Can you clarify what you mean by a completely new one-piece cross-over? Is it from the dealer?? Porsche updated the cross-over to the 2-piece version (with the little elbow to the waste gate) decades ago, so I would have assumed that's all you can get from the dealer. If you mean it's used but completely new to you, then consider the possibility that something is warped. Compare the flange locations to the ones that fit. The 2-piece version is sooo much easier to deal with -- not to spend your money, but I'd look for a 2-piece either way. I struggled for years with a warped header, and had to jump through all sorts of hoops to get the flanges aligned. When I finally replaced it with one that wasn't warped, I was kicking myself over how much time I wasted over the years fitting the warped one. If yours is so far off that you can't even get a screwdriver through the holes, then you'll need to get creative to pry. Lumber sometimes works. Prying is definitely normal to get it on, but only within reason. The turbo is mounted on two smallish bolts, so you don't really want to put tons and tons of force on it. Are all the other bolts/nuts as loose as they can be without falling off? Give yourself as much play as you can. If the other crossovers fit, not sure why you'd need to clock the turbo. Clocking the turbo just means loosening the bolts holding the cold or hot housing to the center section and rotating it to make things fit better. Never tried doing that with a turbo installed -- just depends if you can get to all the bolts. But, bottom line, if all the bolts/nuts are as loose as possible, and you still can't get it close enough to put a screwdriver through the flange holes, I'd seriously consider looking for a 2-piece cross-over that naturally lines up better. As ealoken says, pictures would be good too...

[Belgian951]

I got another tip that loosening the exhaust hangers would perhaps help me with my problem. If anyone has some input/insight on that, would be welcome!

I converted to exhaust studs and nuts, but how much out of order are your parts?
Pictures?

I don't have a picture right now, and the car is not here but I would say 0.5 cm. This means no bolt holes at the exhaust to xover side line up. There's no opening visible, so can't get a screwdriver or anything really in the bolt holes.

Can you clarify what you mean by a completely new one-piece cross-over? Is it from the dealer?? Porsche updated the cross-over to the 2-piece version (with the little elbow to the waste gate) decades ago, so I would have assumed that's all you can get from the dealer. If you mean it's used but completely new to you, then consider the possibility that something is warped. Compare the flange locations to the ones that fit. The 2-piece version is sooo much easier to deal with -- not to spend your money, but I'd look for a 2-piece either way. I struggled for years with a warped header, and had to jump through all sorts of hoops to get the flanges aligned. When I finally replaced it with one that wasn't warped, I was kicking myself over how much time I wasted over the years fitting the warped one. If yours is so far off that you can't even get a screwdriver through the holes, then you'll need to get creative to pry. Lumber sometimes works. Prying is definitely normal to get it on, but only within reason. The turbo is mounted on two smallish bolts, so you don't really want to put tons and tons of force on it. Are all the other bolts/nuts as loose as they can be without falling off? Give yourself as much play as you can. If the other crossovers fit, not sure why you'd need to clock the turbo. Clocking the turbo just means loosening the bolts holding the cold or hot housing to the center section and rotating it to make things fit better. Never tried doing that with a turbo installed -- just depends if you can get to all the bolts. But, bottom line, if all the bolts/nuts are as loose as possible, and you still can't get it close enough to put a screwdriver through the flange holes, I'd seriously consider looking for a 2-piece cross-over that naturally lines up better. As ealoken says, pictures would be good too...

The xover pipe is completely new, never before used. It apparently was found in a warehouse. It's "new old stock", so it has never been fitted. It looks brand new, both inside and out. Welds are all clean, no rust to be seen anywhere, and there even is the original Porsche sticker on the part which would've burned if it was used.

All bolts on the turbo side are loose except for the bolt in the tacked on nut.. I guess I could remove that bolt. The xover pipe is on the studs at the wastegate though, it's a one piece pipe.

I was aware of the benefits of the 2 piece crossover, but unfortunately I couldn't find a new one.

I'll try to get a picture taken ASAP.

Thanks all for the help already!

[Tom]

hmmm... if I'm doing metric right, .5cm is 5mm? 5mm is darn close by exhaust pipe flange standards. If I am understanding that correctly, then you just need to muscle it into position with a screwdriver or whatever it takes.

That's quite a find on the one-piece crossover!