924Board.org

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

how the heck do you get at the nuts on these pipes?! i'm actually pretty proud that i have the J-pipe to wastegate disconnected. but before i could remove the two nuts at the J-pipe to manifold, the j-pipe fell down in my hands. doh! it's not cracked off, the pipe has just cleanly pulled out of the flange. i saw a suggestion in the tech section about welding a "slip-sleeve" in the center of the pipe. could someone tell me what a "slip-sleeve" refers too? is it one of those steel braided flex pipe things that jc whitney sells? oh well, i'm not too sure that i would have been able to get to those two nuts up near the manifold anyway.

the next disaster was that one of the wastegate to cat pipe nuts stripped. argh! all of them came out fine except one. there might be enough room for a nut-cracker in there, i'm going to give it a try tomorrow- or bust out the cobalt drill bits...

and last is just a simple question- how do you get a wrench on the bottom exhaust to turbo nut? i can't fit a closed end wrench on there because there isn't enough room between the nut and the pipe. i'm afraid of stipping out the nut if i use an open ended wrench. what works?

ps- anybody take the cat to a muffler shop to make a test pipe replacement with the extra wastegate piping out the side? i'm thinking of doing this since the cat is probably cooked anyway and i can't justify paying thousands for new one. of course the shop would have to get the wastegate pipe in just the right place off the test pipe. anyone have experience with this?

thanks
-nick

81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

A cat can be had for $390 new I posted a link to it last week. A test pipe will be costly to fabricate. I say you just gut the cat and put it back on. Also get a used J-pipe. They sell on ebay for around $30-$40. It is alot easier than having the local muffler shop weld it up (you have no quality control). Replace all of the exhaust nuts with copper or other type self locking nuts. Think how much nicer it is to remove them when they are new. Also since you are doing a rebuild replace all of the exhaust studs in the system.

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Your J-pipe just fell out of the flange?!?! Sounds like you've had a big exhaust leak for some time. Is all this work on the car that was just given to you? There's no secret to getting at the manifold-->J-pipe flange nuts, you just need the right metric wrench and some patience. If I remember right I needed a long extension to get the socket way up there. As for the turbo-->exhaust pipe nuts, an open end wrench or a thin-walled socket. It is a real PITA getting at all the nuts and bolts. Removing/replacing the actual turbo is even more fun.

Drop the exhaust pipe with the wastegate still attached. You'll need to work up in the small recess where the trapazoidal shaped bracket is to disconnect the wastegate from where it attaches to the body. Once you have it out, use a dremmel tool with a cut-off wheel to cut the nut in a couple places and then oil things up. Get a hammer and chisel to break the nuts once they've been cut all the way down to the studs. I had to cut two of the nuts off this way. If I remember right, ther is not enough room on these nuts to get a socket on all of them either.

I second the motion to use copper locknuts on re-installation. When you buy the new locknuts, make sure that the cross-flats dimension is small enough so they will rotate all the way down. For example, some 10x1.5mm locknuts are 13 mm cross flats, others are 14 I think. The larger ones won't screw all the way down because of the weld bead.
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'79 Eurospec 931

F924T · Joined: 11 Mar 2003 Posts: 11 Location: Worcester, MA

Why not just got out the Catalytic Converter?...are there any disavantadges to this?

81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

got out?

numbbers · Posted: Wed Mar 19, 2003 10:47 am Post subject:

No disadvantages with gutting the cat. However, most of them have self gutted. The cermic substrate just crumbles and goes out the tailpipe.
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1980 924 Turbo

Smoothie

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

hey thanks guys. i don't think the j-pipe is a tight enough fit as is. the exhaust did sound a little off when it ran. if these are that prone to breaking then i might weld in one of those steel braided flexi pipe sections. a small section of that should give it just enough ability to twist. this is what i'm thinking of:

http://www.jcwhitney.com/product.jhtml?CATID=176678&BQ=jcw2

sound like a good idea? i wouldn't want to put in a new one if it's just going to crack.

i guess just gutting the cat is probably the way to go. seems like somewhat of a restriction with the diameter changing, but it likely doesn't make much of a difference, and certainly not worth a bunch of money to reengineer.

i'll pick up some cutting discs tomorrow and give those bolts a try. grr...

ps- where would i find brass locknuts? i doubt the local hardware store has them! any mailorder sources?

thanks for the help
-nick

Smoothie · Posted: Wed Mar 19, 2003 12:10 pm Post subject:

I was thinking the slip joint idea was to make installation/removal easier because of some fasteners that were impossible to reach. I guess I could be wrong, it did happen once before.

A flex pipe like you're considering allows a different movement - side-to-side. A slip joint would allow in-out and/or twisting movement. I guess...if it's needed. I wasn't aware of a problem with those pipes.

I don't remember specifics - it's been a long time since I've dealt with those parts, but I do remember stacking a few extensions together and I think I added a flex joint for one or more of the exhaust to turbo nuts. For that top nut, try socket wrench -> long extension/s -> flex joint -> another ~6" extension -> socket.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

For the locknuts I went down to the local VW restore shop with a nut and stud in hand and matched them up.

As for that JC Whitney thing, I really don't think that is a good idea. Again you are looking to re-engineer the j-pipe. They are not terribly prone to crack unless they are hit from the bottom. If you are paranoid about it get a replacement (good core) and have some additional strength welding done to it. I would also get a replacement and the under tray to protect it.

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

ah, okay i didn't realize the movement was vetical. i'll try out a stock pipe.

thanks again
-nick

Paul · Posted: Wed Mar 19, 2003 2:29 pm Post subject:

The J pipe seldom breaks unless one or both of the wastegate mounts break first.

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

dead on Paul! i just pulled the cat and the wastegate is hanging there by only the two banjo bolt lines. the mount that attaches to the wastegate is sheared. add that to my parts list...

so one final question on this topic, how to get to that top banjo bolt on the wastegate? i can barely fit my hand up there and there's definately no room for any kind of wrench in my toolbox. am i going to have to pull the head before i can get to it?! it's going to be done anyway...

-nick

sandgroper · Joined: 07 Dec 2002 Posts: 108 Location: in limbo

soon i intend to run my wastegate pipe all the way to the rear separate from the main exhaust which will just have the front resonater.i am hoping my neighbors like it when i go on that early morning sunday run with no gestapo out patroling so the unmuffled boost wakes them from their cheap wine saturday nite hangover.

Paul · Posted: Thu Mar 20, 2003 11:09 am Post subject:

nick,

The top joint is the last thing you unhook. Unbolt the top of the vent pipe from the head, then lower the whole wastegate until you can reach it.