V6 Block Hugger / DIY Exhaust

Since this will be a "project" I figured I'd may as well chronicle it here. I have a 1968 CJ5 with a Dauntless V6 and existing Saginaw steering conversion. My intent is to replace the fenderwell headers with block-hugger headers and build my own exhaust system. I plan to single it into a turbo muffler and exit at the rear corner. This will all be tucked up neatly within the frame rails for optimal clearance. Or at least that is what I'm hoping for.

A week or so ago I had posted about the demise of my well used fenderwell headers. Based on some good advise, which is in great abundance here, I placed an order with Novak for a pair of V6 block hugger beaders. Went for the ceramic coating. I received a pair of headers manufactured by Sanderson. They are of fine craftsmanship and excellent finish. Although not cheap I feel my money was well spent.

As there is other work to be done while I'm at it the fenders came off. The drivers side was my immediate focus since the steering shaft would most likely be the biggest obstacle. And yea, it is.

This is the first fit up. Steering is not going to happen like this.



So my first thought is lengthen the steering shaft and shorten the shaft forward to drop the u-joint below the header. So I went about tearing all that stuff loose. Now the u-joint is lowered the forward shaft (does it have a proper name?) is teetering on the motor mount. And even with that the clearances are too close. I could notch the motor mount but I'm thinking if the u-joint was smaller I'd have more room to work with. Somewhere in my garage is a nice Borgeson joint but it can't find it! So at this point I'll search the net for a smaller u-joint.



Before starting all this the steering was pretty straight forward shooting right under the fenderwell header. Ahhh, fat, dumb and happy!

 

CJ Joe

As you mentioned , first off I would find a more compact U-joint....Looking at your picture are you still using the old column that you cut off? It looks like you sleeved the one steering shaft and the proper way would be to have a D-shaped collapsible shaft in that area , infact the portion coming from your front U-joint is already the double d 3/4" material.
I know it's a PITA but I would go forward as far as you can and look at building new shafts all the way back to the column............Borgeson and others have some nice stuff to do so............And nothing saying you can't do some surgery to that motor mount by taking a piece of heavy wall tube and cut and weld a sleeve in there for shaft clearance...............Might be a combination of both?

 

My steering is similar to yours.. I was thinking about the block hugger headers as well.. It' sgonna eb a bit of a fight I see.. Well we shall see.. If I ever manage to get time to get back to my CJ...

 

So I went to install my new headers and and major steering modification breaks out!

Going to need to move the u-joint down lower, under the header pipe bend and use new, more compact u-joints. Since the shaft angle change is about 45d I really need to use a double joint. FWIW the old joint never gave me any problems at that angle. Since I'm adding the second u-joint I'll need support on the intermediate shaft. That is most easily done with a rod end. Spent time measuring and making sure the new design would work OK. I'll need to notch the motor mount too.

So I ordered the u-joints, some new bronze bushings for the column, rod end, roll pins and stuff all from McMaster-Carr. Had it all two days later.

I ordered all the exhaust tubing this morning. Bends, flanges, straight pipe, etc from Columbia River Mandrel Bending. I like these guys. They carry steel, aluminized steel, aluminum and stainless tubing in a variety of gauges, as well as all the flanges, copper gaskets everything you'd need for any level of exhaust system. Nice website, organized, easy to navigate. All reasonably priced.

Got the day off tomorrow so I'm looking to get the steering rework behind me since the pipe is in transit.

Old parts, new parts.

 

What are you doing at the steering box end? I have a new spud shaft left over that I ended up not using when I re-did my steering.

 

Hey thanks Mike, but the forward end is going to stay as is.

So the new steering layout is shaping up. Looks like I won't need to notch the motor mount. The shaft in the column needs to be lengthened a few inches to lower the u-joint location. That shaft is 7/8" od tube with .120" wall. Dosen't seem to be standard but I don't want to change my steering wheel/hub so I'll just lengthen what I've got. Used some 3/4" CR rod and jigged it up to keep it all nice and straight while welding.



The two u-joints were welded together and ground smooth.



While the paint is drying on the modified steering parts I got back to the exhaust. I was anxious to get the passenger side header in place to see what new challenges I'd have to deal with. That was not too bad. I'll need to re-route the wiring and cable the starter. And after everything is in place I'll most likely fab up a heat shield for the starter.

Here's a picture looking straight up on the drivers side. I'll need to re-route some brake lines and the oil temp sender tube. You can see where the steering shaft comes through the firewall. The shaft is not in place, but it's that bronze bushing left of (forward and above) the master cylinder.



And here's a picture looking up on the passenger side.



The headers include the reducer at the collector flange. At the collector flange the exhaust is pointing straight down. I need to get it to horizontal in the shortest distance possible for ground clearance reasons. The included reducer is slightly angled and that helps. Since a 2-1/4" to 2" adapter would only encroach on ground clearance I'm going directly to the 2" pipe. I also shortened the reducer by about 3/8". Then I made 6 slits to make the transition to 2".



Since I'll be making a lot of cuts I made up a template for marking the pipe. That way all the cuts will be on the radial and the result will be clean and proper. When I was researching this project I came across an article in a 4-Wheel & Offroad magazine that showed a custom exhaust install on a jeep. The bent joints were cut off tangent, some mild corners where just mitered straight pipe. It looked absolutely horrible and this was done by a muffler shop! It was a good example of what I didn't want.



Here's a picture with the pipe fitted in place. From flange face to lowest point of pipe is 4-1/4". Not bad for collector flange, reducer and 90* sweep on 2" pipe with a 3" centerline bend radius. This is the passenger side and the pipe actually sweeps up past horizontal here so I can gain some clearance over the front drive shaft. It will go forward and around the front of the oil pan then back to join the other side.

 

I've made some good progress the past few days. Into the thick of it laying out the pipe. Taking my time with measurements and the geometry, not rushing.

I tack each joint in three places before figuring out the next piece. I made up this welding fixture by grinding three "windows" in the pipe clamp. I can see the witness marks for alignment and tack weld with the clamp in place.



Working on the second collector flange here. Nice tight joints will make for a good weld.



So I normally don't bring my iPhone into the work area but this is a handy app. There was one point were I needed an angle reading under the jeep. The toolbox angle finder wouldn't fit, couldn't have got my head in place to read it anyway. With the app, once I held it steady a computer voice would read off the angle. Pretty cool.



Starting to get tricky here. Good thing I know my geometry (although I suck at algebra).



The next difficult piece is the Y. Could have bought a ready made one but this arrangement is not wasting any space.



I was able to get this far tonight. This is a milestone since it's all easy from here back. On the right (passenger side) the pipe goes forward and slightly inboard. Then up and over the front driveshaft. It's right above were the shaft yoke and diff housing meet. Runs straight sideways across under the oil pan, 90* sweep back to pick up the left side. I'll add about another 12" to get past the crossmember then put in a flange to make assembly and any future removal easier. Aft of that will be the muffler and tailpipe. I'll finish welding the joints on this piece before continuing. I'll have to weld it in short segments and keep it cool or it could distort to the point where I'd never get it back on the collector flanges. I ordered a Flowmaster Series 50 from Summit yesterday. It should arrive Friday.

 

Nice Job........................Looks like you tacked those with a Mig? Do you have a Tig welder? That would be the best method to finish welding those up.

 

Nice work Joe
(as always)

 

Excellent craftsmanship and documentation! Great idea with that clamp!

 

I started with a sawzall. But found I can get more precise cuts with a plain 'ol 12" hacksaw. This material cuts easily. The oval hole for the Y wasn't as straight forward. Roughed it out with a small cutoff on the die grinder, burr bit, small zirconium flap wheel.

I'm using a MIG welder with .023" wire and that works just fine. I had been grinding off the aluminum plating but I may just skip that. I've read that muffler shops don't bother with it as there is so little aluminum it doesn't affect the weld. When it's all done I'll paint it all with high temp paint. Except the headers of course which have a very nice ceramic finish.

 

So far I've run piping to just behind the crossmember. There will be a flange joint there for ease of installation and removal. I'm very happy with it being well up and out of the way. Finished up the welds and painted it. Should I have ground down the welds? I think it's fine just like it is.



I spent some time getting the Flowmaster where I think it should be. Again it is well up and out of the way. Since a portion of it is under the underseat gas tank I decided to add a heat shield. It has 3/4" air gap and the heat shield is about 3/4" from under side of the pan. I welded on 3/8" rod for the rubber hanger isolators and welded in brackets to the frame for the hangers. Unlike my previous system the isolators will bolt to the brackets so should I ever need to remove them it is easy. It's already been in and out many times just carefully fitting everything.

 

Great work!

 

Very nice work. You have me just about convinced to order a set of those same headers from Novak. The only thing I still wonder about is the clearance for a hydralic slave cylinder on the driver side header collector.

Don

 

Well...I suppose it'll do... Carry on, Sir! Awesome job!!atriot:

 

What about switching to a pull-type slave? I got mine from Speedway. It mounts to a bracket about a foot aft of the clutch release fork. The ball nut, jam nut and a little bit of the threaded rod are all that stick forward of the fork.

 

69Willys, not sure how your slave is setup but the drivers side collector is just about centered below the dipstick. Seems like that would be out of the way.

 

Joe, my rod is right where your cable is in that photo.