| Subject: | Re: Opinions needed. Exhaust pipes too close? PICS |
| From: | neil N |
| Date: | Sun, 30 Mar 2008 23:37:32 -0700 |
Wow.
Lot's of good info to digest. :)
The inside bend (shorter piece) is "cheated" for sure and not a 90
degree obviously. I wondered if the gas flow/pulses wouldn't "hit" it
hard at the "corner" and create some kind of havoc. But I'm sure it
won't be to any great detriment.
I had two 7/8" "J" bends to play with. Funny story how I found them.
Anyhow.... had to cut them each roughly in "half", though I cut one
"long" for the outside bend, and the other short for the inside. I
will use the remaining pieces to make the 90 degree turn down to "Y".
From there it is 2" pipe to cat and muffler.
I recall seeing tacks on the flange attached to the 2" end of "Y".
(collector part of Jetta downpipe) I found it interesting to see tacks
on the outside and a weld on the inside, from the factory, and
wondered at the time why they didn't just weld on both sides. But it
was done as you suggested I do on the flange I'm attaching pipes to. I
will give some thought as to how the expansion aspect plays into this.
I'm using cold rolled mild steel btw.
I won't be using another flange on the 7/8" pipe or the 2" pipe though
I gave thought to bracing the exhaust system to the block somehow.
Likely bracing at muffler to engine will suffice. I will flange at cat
and muffler.
Hope my response makes sense......... more than a few Becks later.
Cheers,
Neil.
On Sun, Mar 30, 2008 at 9:09 PM, Jim Akiba <syncrolist@bostig.com> wrote:
> Yeah you can tack them, I'm sure the welder will appreciate it.. they
> like to be handed something, told exactly what you want done(so it's
> not his fault if it doesn't work) so they can do it, and then they get
> paid and you go away, and the whole thing happens quickly.
>
> You might get some chatter between the two... it would be better if
> they don't touch. If you have the option of going with a 90 on the
> outside bend instead of the sectioned 180, you could gain yourself
> some room and not have to cheat the inside bend("cheat" is the term
> used when your cut is not perpendicular to the tangent of the bend,
> and hurts flow... although you'll never ever notice for this
> application in a million years and cheating is fine, just some spacing
> would be nice)
>
> Also make sure to fully weld only the inside of the flange, and have
> four outside tacks about 1/8 the circumference of the pipe each, this
> is really important with stainless, less so with mild, but will allow
> for the different thermal expansion rates on the inboard/outboard side
> of the flange to help avoid cracking. You could also flip it and weld
> fully outside and tach inside, but the other way round will work
> better here for obvious reasons. do they both go into another flange
> after this? If so, and it's possible to use a married flange instead
> of two divorced flanges to do the job, you can nail the spacing and
> you'll never get noise or rubbing.
>
> Also if it's all mild steel, and .065" wall, and you live in an area
> where they salt, don't spend too much time, you'll be doing it in
> 1.5-2 seasons again anyhow.
>
> Looking good Neil..
>
> Jim Akiba
>
>
>
> On Sun, Mar 30, 2008 at 7:55 PM, neil N <musomuso@gmail.com> wrote:
> > Thanks for confirming Mike.
> >
> > Even though I'm "making it up" as I go along and have some wiggle room
> > on remaining parts of exhaust, I would like to get flange/primaries
> > lined up as accurately as I can. Good to know I can tack stuff in
> > place.
> >
> > Neil.
> >
> >
> >
> > On Sun, Mar 30, 2008 at 4:35 PM, Mike <mbucchino@charter.net> wrote:
> > > Yes to tacking before bringing to maintain positioning. You don't anything
> > > to shift at all.
> > >
> > > Yes to leaving room for welding inside flange. (so you don't to have to
> > > grind off any of the weld from the flange for a flat surface).
> > >
> > >
> > > Mike B.
> > >
> > > ----- Original Message -----
> > > From: "neil N" <musomuso@GMAIL.COM>
> > > To: <vanagon@GERRY.VANAGON.COM>
> > >
> > >
> > > Sent: Sunday, March 30, 2008 5:08 PM
> > > Subject: Re: Opinions needed. Exhaust pipes too close? PICS
> > >
> > >
> > > > Yes that was my thought. To get position where I want it.
> > > >
> > > > One thing I didn't express here was that I'm just not certain if pipe
> > > > should be inserted in flange hole half way (to leave room to weld
> > > > inside hole) or if pipe end should be flush with top of flange.
> > > >
> > > > Neil.
> > > >
> > > > On Sun, Mar 30, 2008 at 1:58 PM, Mike Collum <collum@verizon.net> wrote:
> > > >> My thought is that by initially tacking them yourself, you are more apt
> > > >> to get them "Where" you want them. Of course, you could always discuss
> > > >> it with the person who will be doing the final welding beforehand.
> > > >>
> > > >> Mike
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> neil N wrote:
> > > >> > Interesting to note your success with pipes that did touch. I just did
> > > >> > a little more tweaking. I got them closer to level, and about a 1/4"
> > > >> > gap.
> > > >> >
> > > >> > The pipes in the images are short, but I will be welding on another 90
> > > >> > degree to each, then of course, the rest of the exhaust system. I
> > > >> > didn't make that clear in my first post.
> > > >> >
> > > >> > And speaking of "secure", I'll be incorporating a flex joint and will
> > > >> > brace the muffler to engine. Even so, I am glad I'll be getting a pro
> > > >> > to do the welds at flange. --- ;^)
> > > >> >
> > > >> > Anyone know if I can tack weld these in place before taking them to
> > > >> the welder?
> > > >> >
> > > >> > I imagine he would do his own tacks, grind off mine, then weld. But
> > > >> > I'm not sure of that.
> > > >> >
> > > >> > Neil.
> > > >> >
> > > >> >
> > > >> >
> > > >> > On Sun, Mar 30, 2008 at 12:50 PM, Mike <mbucchino@charter.net> wrote:
> > > >> >> These pipes appear to be very short, will be held very securely and
> > > >> the
> > > >> >> material is pretty rigid. I doubt it will 'grind holes' where they
> > > >> touch,
> > > >> >> but a small clearance would prevent even that possibility.
> > > >> >> I have had exhaust systems that had similar pipes touching, and
> > > >> they
> > > >> >> never failed where they touched.
> > > >> >>
> > > >> >> Mike B.
> > > >> >>
> > > >> >>
> > > >> >> ----- Original Message -----
> > > >> >> From: "Jake de Villiers" <crescentbeachguitar@GMAIL.COM>
> > > >> >> To: <vanagon@GERRY.VANAGON.COM>
> > > >> >>
> > > >> >>
> > > >> >> Sent: Sunday, March 30, 2008 3:29 PM
> > > >> >> Subject: Re: Opinions needed. Exhaust pipes too close? PICS
> > > >> >>
> > > >> >>
> > > >> >> > The vibrations will grind holes in the pipes where they're
> > > >> touching. I'd
> > > >> >> > move them, myself.
> > > >> >> >
> > > >> >> > On Sun, Mar 30, 2008 at 11:24 AM, Mike <mbucchino@charter.net>
> > > >> wrote:
> > > >> >> >
> > > >> >> >> Touching should be fine. Many other vehicle exhaust systems hav
> > > >> pipes
> > > >> >> >> that
> > > >> >> >> touch. Only corrosion-resistance may be affected, if its
> > > >> horizontal and
> > > >> >> >> tends to trap mud and water. You vertical arrangement shouldn't
> > > >> have
> > > >> >> >> that
> > > >> >> >> issue.
> > > >> >> >>
> > > >> >> >> Mike B.
> > > >> >> >>
> > > >> >> >> ----- Original Message -----
> > > >> >> >> From: "neil N" <musomuso@GMAIL.COM>
> > > >> >> >> To: <vanagon@GERRY.VANAGON.COM>
> > > >> >> >> Sent: Sunday, March 30, 2008 1:54 PM
> > > >> >> >> Subject: Opinions needed. Exhaust pipes too close? PICS
> > > >> >> >>
> > > >> >> >>
> > > >> >> >> > Hi all.
> > > >> >> >> >
> > > >> >> >> > http://tubaneil.googlepages.com/exhaust
> > > >> >> >> >
> > > >> >> >> > In one image I could leave them touching, (contact area small)
> > > >> the
> > > >> >> >> > other I could fudge the angles but would prefer not to.
> > > >> >> >> >
> > > >> >> >> > In either case, I'd be cutting these pipes shorter and welding
> > > >> 90
> > > >> >> >> > degree elbows to them.
> > > >> >> >> >
> > > >> >> >> > Is heat, where pipes touch, a problem? Should they have
> > > >> seperation?
> > > >> >> >> >
> > > >> >> >> > Thanks!
> > > >> >> >> >
> > > >> >> >> > Neil.
> > > >> >> >> >
> > > >> >> >> >
> > > >> >> >> > --
> > > >> >> >> > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> > > >> >> >> >
> > > >> >> >> > http://web.mac.com/tubaneil
> > > >> >> >> > http://tubaneil.googlepages.com/
> > > >> >> >> >
> > > >> >> >>
> > > >> >> >
> > > >> >> >
> > > >> >> >
> > > >> >> > --
> > > >> >> > Jake
> > > >> >> > 1984 Vanagon GL
> > > >> >> > 1986 Westy Weekender "Dixie"
> > > >> >> > Crescent Beach, BC
> > > >> >> > www.crescentbeachguitar.com
> > > >> >> > http://subyjake.googlepages.com/mydixiedarlin%27
> > > >> >> >
> > > >> >>
> > > >> >
> > > >> >
> > > >> >
> > > >> > --
> > > >> > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> > > >> >
> > > >> > http://web.mac.com/tubaneil
> > > >> > http://tubaneil.googlepages.com/
> > > >> >
> > > >>
> > > >
> > > >
> > > >
> > > > --
> > > > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> > > >
> > > > http://web.mac.com/tubaneil
> > > > http://tubaneil.googlepages.com/
> > > >
> > >
> > >
> >
> >
> >
> > --
> > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> >
> > http://web.mac.com/tubaneil
> > http://tubaneil.googlepages.com/
> >
>
--
Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
http://web.mac.com/tubaneil
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