Date:         Fri, 7 Feb 2014 10:43:27 -0800
Reply-To:     Neil N <musomuso@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Neil N <musomuso@GMAIL.COM>
Subject:      Re: Exhaust Bushing Inner Weave Premature Failure
Comments: To: Dennis Haynes <d23haynes57@hotmail.com>
In-Reply-To:  <BAY179-DS46FA8DD32A3CEDBA0C46EA0970@phx.gbl>
Content-Type: text/plain; charset=UTF-8

Hi Dennis. This exhaust is on a Jetta 2.0 mounted at 15º with KEP
adaptor and parts I fabricated. Exhaust (muffler) is mounted to engine
via diesel Vanagon type brackets I made. Each set uses 2 diesel
Vanagon Bosal isolators similar to the OEM diesel Vanagon driver side
bracket. Images:

https://lh5.googleusercontent.com/-bDtROeOoKMA/UO-vpmh_jxI/AAAAAAAAGi0/96axhi3D9pQ/s640/Fabricate.jpg

https://lh5.googleusercontent.com/-Xbvt0RxXI-I/Ubu5njRjtzI/AAAAAAAAHvQ/70LDMGc-QtI/s600/Exhaust%2520v3%25201.jpg

1/3 of braided metal weave on ID was gone (Crap. Now I wonder where it
went! In my cat??). With the braid gone, my guess is that the metal
sleeve was damaged by heat over time then the final small impact
caused the crack. Or, opened up an existing crack further.

Ok, I wondered about the location of the flex bushing. I had one
mounted in the fore/aft position at one point but that was on a
different design of exhaust. The turn from downpipe to fore/aft pipe
was a bit tricky to make. IIRC, the bushing may have been offset on
the parallel.

The issue with running the cat in line with the muffler was that even
when it and muffler were supported, the cat inlet, or muffler inlet
would crack (exhaust mounted off engine using Diesel Vanagon
isolators). This happened on each different exhaust design.

I could have built a 3rd arm off the engine I guess.



On 2/6/14, Dennis Haynes <d23haynes57@hotmail.com> wrote:
> Did it fail due to heat damage or did the impact cause it to shear and the
> leakage caused it burn up? That part is mostly designed to take some angular
> miss alignment. It is too short to tolerate any parallel miss alignment or
> any side loading from impact. If the muffler is completely supported off the
> engine as done with the factory Waterboxers that flex connection should not
> be needed for vibration. Having the cat in that location probably is not the
> best place due to expansion putting a side load on that part. I would
> suggest welding that part on the pipe in line with the cat, not the down
> pipe. Then it can take the vibration and also the expansion-contraction of
> the cat in the direction it will work with.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Neil N
> Sent: Thursday, February 6, 2014 6:20 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Exhaust Bushing Inner Weave Premature Failure
>
>.....I installed this bushing:   .....  on my engine swap. (image of it installed):
>
> https://lh3.googleusercontent.com/-ozMqBRgLXD8/Ubu5n5CAFoI/AAAAAAAAHvU/P9YKIPdcSMI/s500/Exhaust%2520v3%25203.jpg


-- 
Neil n

Blog: tubaneil.blogspot.ca

'88 Westy http://tinyurl.com/c8rlw6p

'81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/

Vanagon VAG *Gas* inline-VR Engine Swap Group:

http://tinyurl.com/d7gd5ej