Muffler Backwards

[brickster]

On my (new to me) 84 2WD with 1.9, the muffler is installed backwards (there is an arrow indicating flow stamped into it).

It's not overly loud and runs smoothly, but I'm concerned about long-term backflow and curious if it would be quieter installed correctly?

Since it was installed fairly recently, it looks like it will be easy to fix (no rust), but I've never done any exhaust work on these before, so looking for BTDT advice.

Looks like just a matter of removing clamp, both sets of bolts and reversing. Should I be replacing gaskets despite the fact that they are so new, or just assess once I have it apart?

[Sodo]

Yes definitely wanna correct the flow direction.
I’d assume the arrow is meaningful.
Backwards might cause too much back pressure or blow the packing out.
It depends on how the muffler is constructed.
Quiet mufflers will have a required flow direction.

Assess gaskets when you have it apart.
If the old gaskets haven’t fallen apart you can use hi-temp silicone as a sealant.
This is not a critical seal.
But its certainly better to get a good seal at your exhaust connections.
Its better for the operation of the Oxy sensor etc, and prevents jalopiness.
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[dobryan]

Likely the gaskets are fine, but you'll know when you get it apart.

Yes, no magic, unbolt everything and reinstall. Do not final tighten the bolts until all the bolts are finger tight or you may have trouble aligning things. This is normal for an exhaust installation.
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

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[brickster]

[dobryan]

[brickster]

[Sodo]

[brickster]

[Wildthings]

Hit the fasteners with a quality penetrant at least a few hours before you put a wrench on them, if not a full day.

[harvgwen]

I usually figure on 3-4 times the projected time
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1986 Westfalia Vanagon, 2.2 Subaru
British Columbia, Canada

[Wildthings]

[brickster]

Following up: I couldn’t reverse the muffler because the tailpipe flange is a different size than the catalytic converter flange. I will try and find one that allows me to run it in the correct direction.

[Abscate]

Or just drive it reverse?
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.ssS!

[Red Ryder]

[quote="brickster"]

[brickster]

Let's do the time warp again...

Thanks to everyone who already responded. I've still got this on my always growing list of small stuff. When I disconnected the muffler and tail pipe, the muffler holes didn't match up on either side. I had a trip coming up, so I put it back as-is.

Is there a standard hole spacing, etc. for these, or am I dealing with an aftermarket variance? I wonder if I rotated the converter 180 relative to the header if things would line up?

Just wanted to tap into the group mind before I start taking things apart again.

This is on a stock 1.9 Federal setup.

(FYI: this photo is purposefully flipped to make the markings easier to read)

[ALIKA T3]

I'm surprised to see reinforcements for the tail pipe end if it's mounted backwards then.

Do you have pics of the current tail pipe?
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[DanHoug]

mufflers ARE directional but sometimes it doesn't matter. the MagnaFlow one i have is straight through BUT it has perforations into the outer canister that are angled to 'catch' exhaust flow. if it was installed backwards, it would simply be louder.

very few modern mufflers are "glass packed" with fiberglass so it won't ruin that but much care is taken in a modern baffled muffler to ensure maximum flow with minimum resistance and noise. this typically includes cuts into expansion chambers that are scooped into the exhaust flow.

bottom line: reverse it to the proper direction. it's just nuts and bolts. snap 'em off and use new ones.
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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

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[Wildthings]

If you have the bolts in, as per the pictures, just tighten them down and see if you get a seal. If you have no leaks you should be fine for years until some other exhaust part needs replacement.

Looks like your bolts might be a good candidate for using acorn nuts. Buy a few SS washers as well to shim the nut out a bit if it bottoms out on the bolt and doesn't apply enough pressure to the joint.

[brickster]

[brickster]