Scout 80 exhaust routing

[Mastiff]

Took another test drive today in my 80 with lift and new (bigger) tires. Making tight turns it made a terrible noise and I thought something was binding, trans/tcase coming apart, etc. Turns out the tire is hitting the exhaust. Surfing around, I see this is not an uncommon issue with larger tires with the factory pipe routing. Of course I just replaced all the pipes.

anyway, I hear talk of an alternate routing inside the frame, up and over the cross member. Anyone have pics of this option? I'd like to know exactly what I'm asking for when I go back to the shop to get it fixed.

 

[Robert Kenney]

You have to favor the rear spring mount location when the pip passes between the frame and spring. And it will never rub. Exactly what I did.

 

[Mastiff]

you have to favor the rear spring mount location when the pip passes between the frame and spring. And it will never rub. Exactly what I did.

Yeah, I can probably ask the muffler guy to be a little more aggressive in keeping it back. That would be my cheapest option.

I found an old post by mm on bb about how much better the other routing option is. Getting over the crossmember looks very tight though, with the t-case bumpstop right there. It ends up with the muffler in the factory spot under the bed though, which would be nice. I'm not real crazy about having it under the passenger floor because it occasionally blocks access to things, and also makes it about impossible to ever add rocker protection.

 

[Michael Mayben]

There is plenty space to take the exhaust pipe over the crossmember, the pipe May need to be flattened a bit in that location, depends upon how good muffler dude is with his stuff. Flattening or "ovalizing" pipes is very common practice in exhaust shops.

The oem Scout 80 exhaust routing was really screwball, I've never seen anything done like that on any production system on any vehicle!

Mounting a muffler under the rear floor allows plenty of space along with options, tailpipe can go out the side or out the rear. It would not work however if in the future ya wanna attempt to add some kind of additional fuel tank in that space.

 

[Mastiff]

I just dropped the Scout at the muffler place. The dude was a little hesitant about going over the crossmember. It is a tight squeeze there. I assume people still have the t-case bump stop there when they do this? Without that it would be easy. He's going to call later and tell me what he thinks. He May claim he can't do it and want to just move the pipe back in the wheel well area to clear the tire.

The main reason I'd prefer routing over the crossmember is if I decide to gin up some sort of rocker protection later. I think it would be virtually impossible with the muffler outside the frame.

 

[Mastiff]

Michael (or anyone) what size pipes do you have that can get over the crossmember? The guy says 2" simply won't fit. He could neck down to 1.5" at the crossmember and make it. I need to make a fast decision here, so hopefully someone will check in soon!

 

[Robert Kenney]

2" minimum. No way let him neck it down below 2.

You are seeing the exact reason I went the oem route. I ran bigger than 2 because it would have a turbo on it some day. Iirc I went 2 1/4.

 

[Michael Mayben]

Mine is 2" pipe all the way.

A segment of pipe about 2ft. Long was shaped to fit right in the space above the crossmember, carefully bent to clear everything, then both ends were expanded so that 2" would fit inside the expanded sections and then welded around.

There is more than enough room to do this, but not in a "one-piece" head/exhaust pipe, otherwise there is no way to get it through the engine bay, over the crossmember and back to the muffler location. So the pipe run is in three segments, then once installed and aligned, it's finish welded.

It could be done in one piece if the crossmember is removed first.

 

[Mastiff]

Thanks for writing back so fast. The guy is telling me that there literally isn't space for 2". He's essentially saying that the space is exactly 2" and if he went down to 1.5" he'd have 1/4" on each side for clearance. Is the difference to do with the bumpstop thingy I have on the t-case? I can't tell for sure if it's there in your pic michael, but it's clearly visible in the attached pic (lower left, painted black). I think with that gone there'd be a lot more space.

I told him to just clear the tire with the factory routing for now. I'll go back later if I decide to install some rocker protection.

 

[Michael Mayben]

thanks for writing back so fast. The guy is telling me that there literally isn't space for 2". He's essentially saying that the space is exactly 2" and if he went down to 1.5" he'd have 1/4" on each side for clearance. Is the difference to do with the bumpstop thingy I have on the t-case? I can't tell for sure if it's there in your pic michael, but it's clearly visible in the attached pic (lower left, painted black). I think with that gone there'd be a lot more space.

I told him to just clear the tire with the factory routing for now. I'll go back later if I decide to install some rocker protection.

My rig does not have that extra snubber mounted.

It's my understanding that part was used only on vehicles equipped with a pto, but I haven't confirmed that.

So it's obviously in the way of running the exhaust pipe over the top of the crossmember.

 

[Mastiff]

Interesting. I went through two crossmembers so far and they both had the rubber stopper thing on there for the t-case bumper. It doesn't really seem necessary, but it was there so I reinstalled it. My tire isn't rubbing now in any case, so I'll live with the factory-ish routing until I have a reason to change it.