Cat/muffler mounting

[AlfromNH]

I bought the exhaust hardware kit from Bus Depot which included a couple of the “donut” gaskets and this foil gasket. Is this foil gasket the only seal between the cat and muffler? It doesn’t seem adequate, but the muffler has a flat flange so a donut doesn’t seem right either.

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‘88 2wd Auto Westy project

[zerotofifty]

On the Digifant Vans, the pipe that is upstream of the Catalyst has the donut gasket on the end near the 2 into 1 manifold which is further upstream.
The catalyst gets the flat gaskets on BOTH ends of it.

The donut is not used on the catalyst

Earlier vans did not have a joint at this point, thus no need for the donut there

LATER VANS, Digifant...

and...

Earlier Vans... (no donut, no joint at the 2 into 1 manifold, it is one peice with the pipe that enters the catalyst

This said, I have seen folks use the donut on the inlet side of the catalyst as some do have the correct seat for a donut gasket, but these often if not always can accept the flat gasket too

My 1986 Vanagon, is the later Digifant type and I use flat gaskets on both ends of the catalyst. Just like on the first image I posted here.

It really helps on some of the nuts that are used to secure the catalyst to use nuts with 12 mm verses 13 mm heads, as that can make a big help in getting the nuts on and off, as a 12 mm wrench give more clearance. I use copper plated exhaust nuts, along with copious amounts of antiseize paste on these nuts and bolts. The copper planting really helps to stop rust on them. Makes them easy to remove later (but I still use antiseize on them)

Nuts....

https://www.jbugs.com/product/9525.html



One of the catalyst nut and bolts can be very challenging to tighten or loosen (unless you drop the muffler, which is a lot more work) So I use a special wrench for this...

Note this a 12 mm wrench as I use the 12 mm headed copper exhaust nuts.



Have fun, But it can be exhausting work.
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Sorry About That Chief.

Give Peace a Chance.

Words to live by.

[1988M5]

This is a problem in the mechanic world. They make these;
https://www.kctool.com/half-moon-box-ended-wrenches/


BK
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1991 tin top GL
2002 Winnebago Vista. VW VR6 24V Eurovan front clip powered class C 21' RV.
Some BMWs.

[zerotofifty]

[Wildthings]

I have a donut on both ends of the "L" shaped exhaust pipe on my '91. Pretty sure that is the way it came from the factory. My '87 Syncro has one donut at the wye connector and a flat gasket at the cat. No clue if with is how it came or not. My 83 1/2 also has the two donuts but am not sure what year 2.1L the exhaust came from

[AlfromNH]

I’m using a donut on both ends of the L pipe also, because looking at it that’s what it’s calling for. The muffler end of the cat has a separate flange which leaves a gap between it and the muffler flange, and the foil gasket doesn’t seem adequate to fill that gap.
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‘88 2wd Auto Westy project

[wesitarz]

For a good seal use Permatex Copper on those gaskets.