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1990 Jeep YJ 4.2 i6 with 32/36 Weber, 33" KO2's, 4.56 diff, Rusty's steering, RE 5520 4.5" lift
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29 Posts
Discussion Starter · #1 ·
Any tips from those have done this before? I'm not welding, just using the two clamps. I bought everything Walker. Asides from the 2 clamps I purchased, I have no hardware. Questions:
  1. Which bolts to get for attaching exhaust pipe to manifold?
  2. Which bolts for the cat to exhaust pipe?
  3. Cat outlet and exhaust inlet are exactly the same. Shouldn't they be slightly offset to fit in each other?
  4. How to plug the bung hole on exhaust pipe that fed pulse air system? I read somewhere a 5/8 bolt?
 

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1- If I recall correctly, the bolts that attach the exhaust pipe to the manifold are actually studs that are pressed into the manifold. You can drill and tap the old studs and use a conventional hex head bolt, but for ease of installing the exhaust pipe, I'd reuse the old studs if they aren't rusted away. If they need to be replaced, I'd much rather replace the studs. You'll likely have to remove the manifold to do so and the EGR tube between the intake manifold and the exhaust manifold can be a real pain to remove. I used a couple plugs to close off the EGR pipe holes.
When installing the exhaust pipe be sure to use Anti-Seize on the studs or bolts, whichever you end up using. If you have your manifold off, check carefully for cracks.

2- I'd simply use conventional nuts and bolts. I like to use grade 8 nuts and bolts, but that may be overkill for that particular application. Again, liberal application of Anti-Seize will make any future removal much easier.

3- Your local auto parts store should have a sleeve that will fit over both pipes. You might contact Walker and ask them if you have the correct parts or ask them what they suggest.

4- There should be a bung hole or a short tube on the cat and another on the exhaust pipe. If your cat doesn't have that short tube, that's even better, assuming you don't have to pass emissions and have deleted the pulse air system.
For the exhaust pipe, I put a copper plumbing cap over the open end and secured it with a screw. The cap fit loose so I wrapped it with exhaust tape and secured the tape with mechanics wire. See attached pic. That's the tube off the cat but I did the tube off the exhaust pipe the same way.
If you have a welder, an even neater way to close off the tube is to pinch it shut and weld the pinched seam shut.

Good Luck, L.M.
 

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Registered
1990 Jeep YJ 4.2 i6 with 32/36 Weber, 33" KO2's, 4.56 diff, Rusty's steering, RE 5520 4.5" lift
Joined
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29 Posts
Discussion Starter · #3 ·
To close the loop on this one:
I caved in and took everything to my local muffler shop so everything could be welded instead of clamped. They used the same rusty bolts to attach the exhaust pipe to the manifold, bummer, but the seal is good. Took most of my day waiting for it as I wasn't about to leave my topless YJ in the hood. Otherwise, it looks great! The Walker muffler does have a deeper rumble that I wasn't really expecting. The old exhaust pipe was loose where it went into the old muffler and it was still somewhat quieter. I asked the shop guy and he said that's what Walker SoundFX mufflers sound like. Definitely no leaks as I went through everything with a fine toothed comb when I returned home.
 
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