New Exhaust – Making Ends Meet

[stuzbot]

Time to replace my silencer box, which had cracked at the joint with the downpipe. So, on eBay, I found a guy in Poland selling the complete kit [downpipe and silencer] for not much more than other people where selling silencer alone. He had 100% feedback, so I thought I'd take a punt, given that, if the silencer's rotted through, the tailpipe can't be far off doing likewise.

Anyway, first impressions were pretty good. The parcel took only a few days to arrive in UK from Poland and the parts looked to be decent quality; the welding was a bit crude and the silencer was obviously a generic one with brackets welded on to fit the Transporter. But the steel was nice and thick and it seemed well made and matched pretty well with the original.

Anyway, onto this weekend and fitting time and I've run into a problem:

Although all the bolt holes and brackets lined up correctly and everything looked like it was going well, I've been left with a bigger gap than expected and some misalignment where the downpipe and silencer fit together:

As you can see, I've got a couple of cm or around an inch gap there. Now it's not a complete disaster as the brass gasketty washer thing which goes between the two sections is pretty fat:

And there's enough flex in the downpipe that I can, using only one hand, squeeze the two ends close enough together that I could probably 'persuade' it all to join up:

and, with a normal run of the mill exhaust fitting, I'd probably do just that and think no more about it. However, with the JX 1,6TD, the other end of the downpipe bolts to the turbo housing, so I'm a bit worried about forcing the ends to meet as that will be putting some tension into the downpipe and possibly the turbo –although the pipe should flex a helluva lot more than the solid turbo housing.

When I loosen all the mounting bolts; downpipe turbo end and those holding the silencer box in place, I can get the ends even closer together, to the point where it looks like they'd bolt together without difficulty:

But looking from underneath, it's apparent that this is pushing the front-to-back-alignment out instead:

So I'm looking for options and Suggestions now. So far I'm thinking:

1: Reuse the existing downpipe [which of course assumes it's the downpipe that's the culprit and not the silencer box].

2: Bolt everything up using a bit of 'persuasion' and hope that the exhaust heat will temper the metal slightly and allow it to settle into its new position

3: Try to alter the mounting of the silencer box to line up better with the downpipe –using spacers on its mounting bolts or drilling new mounting holes in the bracket on the back of the silencer... or suchlike.

Anybody got any other suggestions or comments?


Putting the usual spanner in the works , when working with these vans [and one reason I'm a bit wary of prematurely jumping to the conclusion my Polski mate has sold me a dud exhaust] is the fact that you're never entirely sure whether or not what you've got on there at the moment is original or has been 'messed with' by a PO.

For example, I noticed this when replacing the rubber mounting plate bolt thingies for the silencer...

The mounting bracket is pressed right up against the oil filler pipe:

So I actually had to loosen the bracket and swing it down so I could get at the back of the bolt holding the rubbery doodad in place:

As you can see, the oil filler pipe has been flattened to allow room for the bolt head:

So, it looks like either the wrong oil filler pipe is fitted, or it's twisted, or the exhaust mounting bracket there is somehow wrong

???
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1992 VW LT35 2,4D [SOLD]
1993 VW LT35 2,4D [SOLD]
1992 VW T3 1,6TD Syncro [SOLD]
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[rmcd]

I don’t understand the whole setup so sorry if this is off base.
Can you weld in a flex pipe in the middle to give it more play in the ends to meet?
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VW LT40 build. Like a Vanagon but 30% larger in every direction and 40% slower even in metric.
https://www.thesamba.com/vw/forum/viewtopic.php?t=749359&highlight=

[stuzbot]

[DanHoug]

all the above is why i really like the MV exhaust system... the muffler can be positioned in quite a wide lateral span to accomodate different length cats, etc.

any chance to inexpensively convert?
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[Alaskaberrys]

[stuzbot]

[outcaststudios]

mine has that same piece where it connects back to the turbo, but i thought i thought it was an insulating cover? maybe it is flexible. ill look...
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'88Doka JX td
'69 westy
(rip)couple bugs
(rip)three type III"s
(rip) '81 vanagon
a bunch of french stuff,and 9 motorcycles.

https://www.thesamba.com/vw/classifieds/detail.php?id=2573791

[stuzbot]

[outcaststudios]

_________________
'88Doka JX td
'69 westy
(rip)couple bugs
(rip)three type III"s
(rip) '81 vanagon
a bunch of french stuff,and 9 motorcycles.

https://www.thesamba.com/vw/classifieds/detail.php?id=2573791

[stuzbot]

That looks like some kind of insulation to me. It's completely porous and appears to be wrapped relatively loosely round the pipe, so wouldn't be airtight enough to be part of the exhaust pipe itself.

I wonder if that's what was being indicated on the exploded diagram I posted above. Maybe it wasn't a flexi section after all?
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Click to view image
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1992 VW LT35 2,4D [SOLD]
1993 VW LT35 2,4D [SOLD]
1992 VW T3 1,6TD Syncro [SOLD]
*****************************

[Wildthings]

On my Waterboxers I have added a slip joint in the equivalent pipe so that I can adjust the length and angle a bit.

[outcaststudios]

its definitelt not a flexible section. my experience with exhaust is if you loosen up all the connections and then do a little tightening at a time they all will end up coming together just fine. i wouldnt worry too much about that part. id be focused on getting that stabilizing brace in place to prevent vibration on the whole mess. as you know these diesel jx's really shake, even just at idle.
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'88Doka JX td
'69 westy
(rip)couple bugs
(rip)three type III"s
(rip) '81 vanagon
a bunch of french stuff,and 9 motorcycles.

https://www.thesamba.com/vw/classifieds/detail.php?id=2573791

[mini t]

why not just get some bolts started in the flanges then take a torch and heat the pipe red hot then tighten the bolts that should relieve any tension you only need that small of a gap to close up.

[drj434343]

I'm no JX expert, but in most of the turbo setups I've seen, there is usually some sort of flex section shortly downstream of the turbo housing to relieve any stress the remaining exhaust may impart. I think the cast iron of the turbo exhaust side generally doesn't like cyclic loading, which can encourage fatigue cracking.

If it were me, I would find a way to minimize that gap before finalizing the installation (heating and bending, flex pipe, etc).

[Wildthings]

I agree that the flex coupling should lessen the loads on the turbo, though any kind of joint will help.

[stuzbot]

I know that [as others have suggested] I could go round nipping up the bolts in turn and it would likely all squeeze together in the end. But I just don't like the idea of having that tension in there. It would keep niggling at the back of my mind.

[Alaskaberrys]

Sounds like you might have your situation figured outl now, but I thought I'd post pics of my set up that has the flexi joint installed for reference -

Can see a fair amount of bend made up at this angle.

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'91 Westfalia, Bordeaux Red Pearl 2.1L 2wd Auto
'91 T3 Syncro Doka, Escorial Green 1.9L TD AAZ “Gremian” (to provoke, irritate, exasperate, vex...)