H2 OBX Long Tube Header w/ High Flow Cat Install With Pictures

[pdxrealtor]

Ok.. Finally got these things installed and at 100%. Love the power gain, and can't wait to get a chip or tune. The low end grunt is finally there albeit nothing like a roots blower powered five liter mustang.

These tips and pics will help you with your long tube header install.

I got the OBX high flow cat system. With this system you will need the following additional items:

- 2 M18x1.5 short bolts or drain plugs. You'll plug extra O2 bung holes with these.
- 12 M8-1.25 x 30mm header bolts. I got mine from Fastenall M8-1.25 x 30mm DIN 6921 Class Class 90 Yellow Zinc Serrated Flange Bolt
- An EGR block off plate. Hummer H2 has no EGR to connect to the OBX header. Or you can do what I did.... read below.
- Spark plug wire heat shields or custom plug wires.


Soak for a few days with penetrating oil.. I used some CRC screw loose..

1) Put it on jack stands, ramps won't work. I tried it. Why? Because for the easy breezy removal/install you must remove your tires. Don't fight it, it's not worth it!

2) Remove your wheel well liners. Another must.

3) On passenger side remove the oil dipstick tube, 15mm socket. Remove the bolt. From below, through your awesome wide open access space, work the tube up and out of the hole. Drop a flanged bolt in the exposed hole- MAKE SURE IT's LARGER than the hole! Or use a rag, whatever. I used a bolt because it was non intrusive to other work or test drives.

4) Disconnect all spark plug wires at the spark plug and tuck them up out of the way. I think the only one I didn't have to disconnect was driver side front of engine.

5) Start removing those header bolts. Warm the engine up and then let it cool down a bit so it's just warm to the touch. This will help in bolt removal.

[pdxrealtor]

Shot of trying to do it with tires on - NOPE







Tires off- see how much better that is ??




Plug wires tucked up out of the way



15mm bolt to remove dipstick tube



Dipstick tube hole plugged with bolt

[pdxrealtor]

6)Take your skid plate off, and your brush guard... the one below the tranny pan.

7) Remove your O2 sensors. The only one I had to unplug was pass. side front. The rest were easily tucked out of harms way.

8) Once all your header bolts are loose you're onto the underside of the truck to remove the pipes from cat forward (if you got the high flow cat kit, which I did). There's two ways to do this. Cut it out, or unbolt everything nice and neat. Why you'd want to do the second way is beyond me. I grabbed my sawzall and started cutting. I did save 3 or so inches on each side of the cat so I can sell them. They only have 50k on them.

TIP- leave one header bolt partly bolted in, that way the headers don't fall to the ground when you remove the under car pipes. This advice is all based on the fact that you're doing yourself a huge favor and cutting these b*tches out...

The headers will come out of the bottom. If you have any height at all (jack stands), nothing goes on under the hood. It's all from the wheel well and under the car.

See my cut points in these pics, and the entire system removed shows the cut points as well.

[pdxrealtor]

9) Alright... system is now removed. Like most people you now have broken bolts to deal with. These bolts are compliment of GM and they stick in your aluminum head. If you're lucky the stud is sticking out of the head. Use vice grips or a stud remover on a ratchet. If you're not lucky the bolt is inside the head. Couple of choices.... drill it and easy out it, or research ways to weld a nut on the bolt to ratchet it out with a socket.

I had one broken bolt, drive side closest to the firewall. There was a VERY nice stud sticking out and I just happened to remember I had this bad a*ss stud remover kit from Sears. AWESOME...right?? Ya.. it was awesome until I took two turns of the ratchet and the damn bolt snapped again.. YES.. again. A second time. So this one bolt snapped twice. Second time inside the head. Great. I was very fortunate to have a buddy over with more experience in this area than I.

We had to remove the fender well heat shield, use a drill bit with a hex end so it would fit in a socket. This socket was attached to 18" of 1/4" extension in order to reach the bolt on the head. I've heard people say right angle drill to get these busted bolts out.. I don't see it. No way.

My buddy drilled the perfect hole in this busted bolt, and then used his snap on extractor to back it out. Couldn't believe how great it turned out. Check out pics of the bolt. Two pieces... the one piece is the one I busted off with my stud remover (I was literally using the strength of my thumb!) the other piece is obviously the piece my buddy rock star drilled.

I don't have any pictures of the drill setup we used, but it's no different than the ratchet setup in other pics. A lot of length and a dead straight aim. To put in perspective the drill was outside of the fender well.



Old bolt next to new bolt - Fastenall M8-1.25 x 30mm DIN 6921 Class Class 90 Yellow Zinc Serrated Flange Bolt --- Thanks NJH2!!

[pdxrealtor]

10) Alright ... easy easy from here on. You're ready to install. Start with new headers. They GO UP from underneath the truck. Don't even waste your time trying to get them in from above. This part is easy easy. I used copper gasket spray on my gaskets. The OBX kit doesn't come with stainless, it's a graphite type gasket.

Install both headers. They both slide up and in like.. well... you know..

Don't leave them loose, tighten them up.

Torque is 11 then 18 ft. lbs. Remember if you're using an extension you need to give it a little more torque. (Obvious to many, but not all).

[pdxrealtor]

11) Alright-- making progress! Now you're going to install the cats and y-pipe. This is all self explanatory once your to this point. There's no tricks or hang ups. Install it all, but don't tighten anything. You'll need to rotate your cats to position the o2 sensors in the right spot and get the rest of it to all line up. NO O2 EXTENDERS NEEDED WITH THIS KIT NOT EVEN CLOSE.

You' use the same clamp on the muffler, so don't remove it.