Exhaust Pipe Flange ID: Gap Normal? PICS

[vanagon nut]

Hi all.

This is for 2" aftermarket pipe and flanges.

Bought 4 flanges, same PN (Walker). 2 fit nicely on pipe and welded fine (un-tested though) 2 had an obviously larger ID.

Is it a general "rule" that a given exhaust flange will actually measure larger than it's stated size? i.e. 2-1/8" for 2" ID flange? (root gap?)

I've welded a few formed (thicker plate) flanges that had the same (nearly) ID as OD of pipe. Welds held up fine.

In image #2, would this idea produce a weak join?

Much thanks,

Neil.

Walker " 2" " ID flange on actual 2" OD pipe:

Weld inside/outside of sleeve to pipe then flange to that? Structurally sound? (ignore gap on sleeve. It's a cut piece of 2" pipe)

Actual 2" ID flanges on cat. Welds look ok. .... to my amateur eye.

 

[AndyStobbs]

in my experience of welding car exhausts, you can pretty much get away with anything, as long as you get some penetration into both flange and pipe it'll outlast the cat converter.

'course the neater the better but its hardly a high stress application.
RE: the different sizes, somethings seem to be 'metric equivalent', others are still IMP.

 

[vanagon nut]

Thanks for the quick reply AndyStobbs.

Found this (ROL Exhaust parts): http://www.rol-tech.com/rol/HOME/home.html Catalogue PDF file is large!

The catalogue has a note to the effect of: 'size flange ID 1/16" or 1/8" larger than pipe'

I was going by what was sold to me so was "flying" somewhat ignorantly.

The project is a Jetta gas 2.0 in a VW Vanagon. Exhaust will mount similarly to a diesel Vanagon; entirely to engine with isolators. The exhaust sees a fair amount of vibration from engine.

re: "metric equivalent/IMP." Except for the Jetta down pipe stub, all pipes and flanges are Imperial size. But that's a great point!

Neil.

 

[vanagon nut]

Setting up the flange weld was tricky, but overall, the exhaust worked out "ok"

several images starting here:

https://picasaweb.google.com/musomuso/EngineConversionJettaABA20#5833900188803408802

if link takes you to page of all images, try refreshing.

.023" wire for pipes helped but that was my first time using .023 so welds (wire speed too high) were proud at one join.

Filling the gap at the flange in question worked out ok too. Had to fill from both sides and add/shape at flange face, but it worked.

Thanks

Neil.