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Header Install Notes

Kurt Sussman wrote:

I just put mine on (95 200SX SE-R, though most of this is the same for the Sentra SE-R), and have a few suggestions for future header installers.

Make sure you have the following before you start:

  • 10, 12, 14mm sockets. You may want deep sockets too, but I didn't need them. A swivel, medium and long extensions are useful too.
  • a torque wrench is essential. Don't use the cheapo pointer type.
  • anti-seize compound (to keep everything from being 'welded' from the heat)
  • some kind of breaker bar; I used a 14" 1/2 drive bar (not ratchet) and a 4' pipe for the motor mount bracket (more on this later).
  • all gaskets (cat, steel secondary, manifold to head), bolts, etc, and some spare exhaust studs (at least one always pulls out, and if you snap one you want to be prepared). The secondary gasket to use if you have a Dremel or a good punch is the steel Z gasket #20691-01P80. The cat part is #20692-65J00.
  • some 3/8" washers; I used 2 flat and 2 lock washers (for the front motor mount)

Since I'll probably forget to mention all the safety stuff, I'll just say be careful. Your car is big, sharp, and heavy. You are soft and squishy. Block your tires, use jack stands, stay awake, etc.

  1. Jack up the front of the car. You need to get to the front of the cat, as well as a few screws and nuts under the front. Use tire blocks and jack stands. If you don't have any, borrow some.
  2. I removed the passenger-side splash shield under the engine so I could reach the secondary and front motor mount. Unbolt the cat end of the secondary first, being careful not to rip the ground strap (the cat has to be grounded so the second O2 sensor reads accurately). Then remove the bolt on the top side of the secondary (to the front motor mount) and the nuts holding the secondary to the manifold.
  3. Bolt your new secondary/flex pipe on, using enough anti-seize. Don't get any on your clothes. Let it hang in the front.
  4. Put your jack under the oil pan, and find a small block of wood to protect the pan. Support (don't lift!) the engine, and remove the front motor mount. You have to get rid of the bracket between the mount and the engine, and since the bolts will bottom out without it, you'll have to use washers when you put the motor mount back on.
  5. Unscrew the O2 sensor (and AIV, if you have one).
  6. Remove the manifold, loosening the bolts in a spiral from the outside toward the center (2-4-6-8-7-5-3-1). To get the EGR tube out of the driver's side of the manifold, loosen the manifold end, then loosen the two bolts on the smaller manifold at the other end of the tube. 12mm, swivel, medium extension.
  7. Scrape the gasket surface on the head until it is shiny and smooth. You don't want to do this again. Use a gasket scraper or dull (but straight!) chisel. Don't nick the aluminum, just get all the old gasket material off.
  8. Put the new gasket on and maneuver the header into place. Put all the nuts and washers back on, but don't tighten them until they're all snug. Torque them to 27 ft-lbs in a spiral from the center bolts to the outside (8-6-4-2-1-3-5-7). Put everything together, using anti-seize on everything that might get hot.
  9. Double check your work. Did you remember to tighten the little manifold at the back end of the EGR tube?
  10. Warm the car up. Listen for exhaust leaks and rattles. The header will smoke a little. Don't panic. Drive around a little. Park the car.
  11. In the morning (when it's cold), torque the manifold nuts again in the same pattern. This time, set your wrench to 35 ft-lbs.

Now go kick some Honda butt...

David Pertuz wrote:

Having done it twice now, here is a step-by-step on installing headers on Sentra SE-Rs and 200SX SE-Rs. In both cases the headers were Hotshots.

If you haven’t done it before, plan on it taking twice as long as you think it will. At worst you will have extra time at the end. At best you will have budgeted for making tool runs, etc. The second time I did it, it took me about four hours form car-up to car-down, and I was taking my time.

Tools: It’s good to remember that you can never, ever possibly have too many tools. Too many tools just sit on the floor next to you, while not enough tools make you take unnecessary and time-wasting trips to get more tools. Here is a pretty comprehensive list:

  • ratchets - one is OK, two better, three better yet. I had one 1/4in drive, one 3/8in drive and one in drive.
  • 10mm, 12mm and 14mm sockets. At least 3/8in drive unless they’re all deep.
  • 17mm deep socket, 14mm deep is good, too.
  • 9/16in socket, preferably two (for HS headers)
  • 9/16in box-end wrench (HS headers)
  • 22mm crescent wrench
  • 24mm crescent wrench (15/16in works fine, or a medium adjustable)
  • Vise Grips
  • spatula/gasket scraper
  • long piece of tubing or pipe, also a shorter one (or strong arms)
  • tweezers (optional)
  • torque wrench (a good one, and not a pointer-type wrench.)
  • zip tie (optional)
  • floor jack (much, much easier than using the tire-changing jack, but that will work)
  • two jack stands (or ramps)
  • 12mm allen wrench (HS headers) - if you forgot it like I did, you can use a 12mm bolt and nut.
  • Short extensions, long extension, universal (flex) joints, adapters, etc. More is better.

Stuff: there are a few non-tool things you need, or are nice to have.

  • anti-seize compound
  • liquid gasket compound, if you don’t use the steel 300ZX gasket. I used Permatex copper. Make sure that it says it’s safe for oxygen sensors.
  • Teflon tape or liquid thread sealer (optional)
  • spray lube / rust-off stuff
  • work light (optional)

Gaskets: You’ll need to get a new head/manifold gasket. The part no. is 14036-53J00, and it costs about $13. It doesn’t hurt to get a new cat-secondary gasket, too. It’s part no. 20692-65J00, and costs about $7. If you don’t want to use the HS or Stillen gasket, you can use a steel 300ZX gasket and enlarge the hole a bit. The part no. is 20691-01P80.

Safety: Be safe, dangit. Never, ever work under a car supported by a tie-changing jack. Use good stands, or ramps. Leave the jack under the car as insurance. Block the rear tires. Falling cars suck.


  1. Jack up the front of the car, and chock the rear wheels.
  2. Remove the passenger’s side splash shield behind the bumper (10mm)
  3. Up top, remove the oil collector thing form the front of the engine (12mm) hold the hose clamp with Vise grips and wiggle it out.
  4. Remove the PAIR valve and AIV ("91 - ’93 cars) and hoses
  5. Unscrew the oxygen sensor (22mm crescent) Do it after the oil collector thing is off so you don’t twist the wires, as the wires are fastened to it. Unplug the other end of the oxy sensor line, and set the PAIR, AIV, oil collector thing and oxy sensor aside.
  6. Remove the manifold heat shield (10mm, extension for the lower ones)
  7. Underneath the car, remove the bolts at the rear end of the secondary and the cat. Use a 17mm deep socket, as a regular one won’t fit. Spray them with rust-off beforehand. The short piece of tubing is useful here.
  8. Remove the bolts attaching the rubber exhaust hangers to the chassis. 12mm socket on the right, 12mm crescent wrench on the left because of a bracket that gets in the way. Be careful not to lose any of the washers.
  9. From under the car, remove the nuts from the manifold-secondary joint. It helps to give them a shot of rust-off beforehand, especially if you car’s old or in the north. Use a 14mm socket (1/2in drive preferable) and a long extension. The long pipe is useful here to break them loose easily.
  10. Remove the bolt attaching a bracket on the secondary to a bracket on the engine mount. (12mm) Note: With the HS, at least, it does not appear necessary to remove the bracket attached to the mount. I left mine there, as it would have taken me another half-hour to remove it. It does not hit the HS secondary.
  11. Now, drop the front of the secondary down and pull it forward to get the rear off. Set the exhaust hanger aside.
  12. Under the hood, unscrew the EGR fitting (24mm or 15/16 crescent, or medium-sized adjustable.) On ’91 - ’93 cars, unscrew the AIV tube (same size wrench) and remove the tube. Loosen (do not remove) the intake manifold end of the EGR tube. (12mm, extensions, swivels as necessary, tentacles are nice J ) This is very hard to reach on ’94 - up cars.
  13. Remove the exhaust manifold bolts, going form right to left, outside to inside. (14mm socket, short extension on some)
  14. Pull the manifold out. You’ll have to pull the EGR tube out a bit. This is why you loosened the other end.
  15. Scrape any remaining old gasket material off the head with a spatula. There will be a little there. Be sure to get it all off - just feel the surface with your finger ‘til it’s all smooth.
  16. Install the new secondary. It helps to support it with the jack as you maneuver it into place. Put the new gasket on the cat, put some anti-seize on the threads and put the exhaust hanger on the secondary. Screw the 17mm nuts loosely on, screw the rubber- hanger bolts into the chassis, then tighten everything up. Tighten the 17mm nuts to 35 ft-lbs or so. It’s not critical, so you can use your organic torque wrench. Don’t forget the grounding strap! Support the front end of the secondary with the jack.
  17. Put a ring of gasket goo on the mating surface at the front of the secondary, spread it around a bit. Stick the gasket on, and spread a little more gasket goo on top. If you use the 300ZX gasket, no goo.
  18. If your car is ’94 - up, screw the AIV plug into the lowermost fitting on the header.
  19. Put the new head/header gasket on, and maneuver the header onto the head studs. Start the EGR fitting into the threads on the header. Make sure they’re threaded correctly.
  20. Put the washers and nuts back onto the head studs. Make sure you put the washers in the same way they came out - the header-flange side will be clean and flat, the nut side will be bulged slightly. You can use new hardware if you want, but it’s not necessary unless your car’s really old. Thread the nuts on finger-tight.
  21. Tighten the header bolts, going from the inside out, left to right [see below - MM]. I got them all finger-tight, then tightened them all to 30 ft-lbs, then all to 37 ft-lbs. (A little extra so I wouldn’t have to go back later.) Finish threading the EGR tube in, and tighten the bolts at the other end.
  22. Slide the bolts in at the header-secondary joint, put all the nuts on. They are all 9/16in. Tighten them all to 35 ft-lbs or so. The rearmost bolt on the HS is rather hard to reach, and since they’re not studs you do have to use two wrenches. You’ll need a crescent for the top of one, and assorted extensions, swivels and dexterity.
  23. Screw the oxy sensor back in. If you undid the clip on the line you can screw it in first without twisting the line. Reattach the AIV tube if you have one (easiest form the bottom.) Reattach the PAIR and AIV if you have them, and reattach the oil collector thing (do the collector first.) Tie the oxy sensor wires to the collector with a zip tie, as the new location on the header is a bit further south, and the wire is stretched taut with the standard clip. Plug it back in.
  24. Refit the splash shield, check everything and lower the car. You’re done! Fire it up and let it idle for a couple of minutes. You’ll see a faint smoke coming off the header. Don’t worry, it’s normal.

If it looks hard, it really isn’t, unless perhaps your car has spent six years in New York and everything is rusted in place. If you have a really hard time with stuck bolts, that is what the rust-off and cheater bars are for. Use an impact wrench if they’re really tough. I wrote this out in many steps for the benefit of people who are a little daunted by it, so it sounds longer than it is. Now get the car down and go drive the thing!

Martin Baker wrote:

Car: 1995 200SX SE-R, 68K Connecticut Miles Header: Hotshot

I just want to point out a couple of snags that we ran into.

1. Despite repeated soakings in liquid penetrant over the course of a week, the cat bolts refused to budge. Heating helped to get them moving. We kept adding penetrant and slowly worked them back and forth. They eventually came off without breaking a stud. The lesson: be patient.

2. The cat flange was a rusty mess when we got the secondary and old gasket off. The only way to get the wire wheel in there to clean it up properly was to remove the cat heat shield. Predictably, we broke off three of the four bolts. Two came out after repeated heating / penetrant treatments and grabbing and twisting the bolts from the back (to avoid trashing threads any further). One had to be drilled out, ruining the threads in the process. A J-nut (from a ’63 Land Rover of all things) was used on this one, and new stainless steel hardware was used to attach the heat shield. The up side to all this is that the flange cleaned up nicely this is a good thing to do.

3. Where the heck do you find a 12 mm allen key (for the AIV plug) anyway? We couldn’t even find a bolt with the correct head size to fit the hex hole. We ended up grinding down the head of a larger bolt so that it fit snugly in the hex hole.

4. The flange welds on the manifold portion of the new header interfered with some of the manifold washers. We had to grind the edge of four of the washers to get them to clear the welds. Pay attention to this, as it would have been really easy to just tighten them down without noticing that some of the washers were up on the welds and not flush with the manifold. If the washer doesn’t sit flat against the flange, the nut can not be properly torqued, and you will be trying to bend the stud as you are tightening the nut ( not good ).

5. We had to bend the bracket attached to the front motor mount by about 5 mm to get enough clearance to the downpipe. No biggie.

6. Bolted to the top of the big engine / transmission support beam is a hunk of iron with flexible rubber bits at each end. Each end also has tabs that stick out to each side. One of the tabs was touching the flex joint on the new secondary. While it was really tempting to just get rid of this piece (could not figure out what the heck it does vibration damper of some sort?), we took it out, ground down the offending tab, repainted the tab, and remounted it (to do whatever it is that it does).

7. When we fired up the car for the first time, the EGR fitting on the header was leaking a little. The adjustable wrench was too unwieldy to get it tight enough. We thought the installation notes identified the EGR fitting as a 22mm, so a trip to Sears was made, where we purchased a couple of ‘crows foot‘ wrenches in what we thought were the closest SAE sizes, as well as a 22mm ‘stubby’ combination wrench. We quickly found that this is not a 22mm fitting. So out came the grinder again, and we modified a 7/8ths crows foot to fit (I guess I’m keeping that one). We got the EGR tightened up, it stopped leaking, and we went for a drive.

Bill the arcstarter writes:

Other people have had problems with the upper fitting, which I believe is an air injection port or something.  This port requires a 24x? mm tap, which is very difficult to locate.  Luckily, my fitting was OK. I would strongly suggest that, before you put the header on, you try threading in the O2 sensor, and, if possible, the upper air tube fitting into the appropriate port.  This way if you have to tap them out, at least the header isn't already on the engine!

What is the proper tightening sequence?

George Roffe writes:

First question should be what is the loosening sequence.  See below:

    x x          x x              
x   4 6   x x    5 3   x
2         8 7          1 

What is the proper tightening sequence? Tightening sequence as shown below:

    x x          x x
x   5 3   x x    4 6   x
7         1 2          8