Header Installation



From Nissan 350Z & 370Z Wiki

test
This article is part of our special collection:
This article is part of our special collection:

another zippysedan edit. I put Megan headers and Kinetix cats in my car (2005 G35x) in 11 hours with help and tons of tools. Major issues, the OEM nuts I was supposed to use only fit at half of the 12 locations. I scavenged nuts from the cats, they fit and did not have flanges. The OEM nuts are flanged, and the flanges interfere with some of the welds on the Megan headers. I did not take anything off my block except the intake system, not even the power steering coupling. I got everything in, although at times it felt like I was trying to do a rubics cube in the dark, both removing the manifolds (esp. the passenger side) and getting the headers into place. I was only able to get 10 out of the 12 nuts tightened, and had to pay a mechanic to tighten up the other 2. Better than paying him for the full install. I guess I saved about a grand on "better" headers and a professional installation, good thing because I am going turbo when money permits.

Peace out,

Jesse


Contents

Introduction

  • Take your time. Plan at least 12-16 hours over two days. Do not plan any other installs at the same time, except for replacement cats or a replacement intake.
  • You do not need a lift to complete this install. We completed it only with Jack stands. However, Crawford Z Car Performance states that a lift is required. We do understand why they state this. A lift would certainly make things easier and faster. However, it is completely possible with only tall jack stands.
  • Make sure to stay well fed. When you are hungry, you will get aggravated and rushed. If you feel hungry, take a break and eat. It is better to take longer than begin making mistakes.
  • All machine screws should thread back into their holes easily. You should be able to get them at least half way in by hand. If you have trouble screwing them in by hand, or even with a wrench, they are cross-threaded. Be very careful.
  • When you have the engine lifted on the jack, be careful not to rock the engine too far. We doubt it will fall off the jack head, but we don’t want you to find out.
  • The heat shielding on the fuel line is not critical. However, IF the fuel line were to rupture, it would spray fuel all over the hot header. You would instantly loose your car in a ball of fire. It is better to have the shielding than to loose your car in a fire.
  • Below is a list to tools. You should have TWO FULL SETS. One set is for you and one for your friend who is helping. While you can use one set, you will find yourself fighting over tools. We had two sets and we still were looking for each other’s tools.
  • Be creative with your tool use. If a ratchet won’t fit, use a box-end wrench. If you can’t reach a fastener from under the car, try from the top with extensions. Some of the tools on the list can be “daisy chained” together to make them more useful.
  • Hunter “peptidbond” Harrison, Bill “Buff” Buffington and all members of Crawford Z Car Performance & others that have helped with this manual, accept no responsibility. If you make a mistake or damage a system, you are on your own. At best, we may be able to provide some suggestions through the online forums. The instructions below are believed to be accurate, but please use your own common sense. We do not warranty these instructions.

Tools & Supplies:

  • LARGE Floor jack
  • 4 Jack stands (bigger the better)
  • 3/8” drive ratchet
  • 1/2" drive ratchet
  • 18” breaker bar
  • 2 ratchet knuckles
  • Ratchet drive adaptors
  • 3/8” drive metric shallow sockets 10mm-19mm
  • 3/8” drive metric standard sockets 10mm-19mm
  • 3/8” drive metric deep sockets 10mm-19mm
  • 3/8” drive socket extensions (4”, 6”, 10”, and 2 1/2”)
  • Metric 10mm-22mm box-end wrenches
  • Standard Phillips-head driver
  • Small Phillips-head driver
  • Standard flathead driver
  • Small flathead driver
  • Channel-lock pliers
  • Small pliers
  • Small needle-nose pliers
  • Long needle-nose pliers
  • Bull-nose cutters
  • Large spanner (crescent wrench)
  • Rubber Coated Hammer (or other type of “persuader”)
  • A few corded hand-held work lights.
  • Creeper
  • White out ink correction
  • Drain pan for coolant
  • 2 gallons of coolant
  • Funnel
  • Paper towels
  • Sharpie Marker
  • Zip lock bags with write-on labels to hold parts
  • 2X4 wood stud to support engine during jacking (2x8 preferred with total length not longer than 18 inches).
  • 3 inch X 3 foot piece of aluminized Nomex heat shielding fabric (Optional)
  • Zip ties, to secure heat shielding in place. (Optional)

Preparation

  • Disconnect negative battery terminal
  • Jack up and place entire body on four jack stands. The car should be as high as possible. 3-ton jack stands will allow the car to be 18” or more in the air.
  • Remove both plastic panels underneath the engine. Place screws in a zip lock bag. Using the sharpie marker, write what the parts are for on the bag. Set aside. You will do this for all connects, clips, and other fasteners removed from the car. This is critical, as you will have at least 200-300 parts off the car.
  • Remove both front wheels. (Optional – But will make life easier)
  • The driver’s side bottom of the radiator has a coolant hose coming out of it. Next to this is the radiator pit-cock. Position your coolant drain pan under this. Using a large Phillips head or flat head, remove the pit-cock. Unscrew the radiator cap on top of the radiator. Watch coolant flush into drain pan. (Pit-cock is made of plastic so be careful not to tear out the threads when opening)
  • Open the air bleeder plug on the heater hose back by the battery. This will help to release more coolant out of the system so you do not make as big of a mess. There are additional drain plugs that will allow for further draining of fluid if you choose to do so.

Disassembly

  • Start standing at the front of the engine compartment
  • Using a 14mm socket, remove the 6 bolts and 2 nuts holding the strut bar in place. Unclip the wiring harnesses from the strut bar mounting brackets. Remove the bar from the car and set aside.
  • Remove Engine Cover (Plenum Cover) 2 10mm bolts & 2 10mm nuts
  • Remove large hose connecting the bottom driver’s side of the radiator to the thermostat.
  • Remove large hose connecting the top passenger’s side of radiator to the large passenger’s side water pipe.
  • Remove upper intake tube from the throttle body. Remove the MAF sensor. Remove the stock air-box if present. In other words, remove any intake parts located within the engine compartment to create room for access to bolts and parts that will be removed later.
  • Loosen the nuts on both belt tension pulleys using a 14mm socket. Using a 12mm socket, lower each pulley and remove both belts.
  • Unbolt the AC compressor from the car (it does not need to come out):
  1. From the top, remove the wires harness connected to the compressor
  2. Under the car, remove the two large bolts using a 14mm socket
  3. From the top, unscrew the final bolt again using a 14mm socket. DO NOT REMOVE the top bolt from the hole. Leave it in place. The AC compressor should now be free to move around.
  4. Using a utility knife, slice the 4” section of flexible tubing off the high-pressure line from the AC compressor. This is likely to catch on fire if left in place.
  • Remove the driver’s side hard coolant pipe:
  1. Disconnect any coolant hoses attached to the hard pipe.
  2. Disconnect any wire brackets connected to the hard pipe.
  3. Using a 10mm socket, remove the two bolts at the front of the pipe. BE CAREFUL. Coolant will come out quickly and there is a flat gasket in there. Make sure to grab the gasket.
  4. Using a 12mm socket, remove the final bolt in the middle of the pipe connecting its mounting flange to the block.
  • Remove the passenger’s side hard coolant pipe:
  1. Disconnect any coolant hoses attached to the hard pipe.
  2. Disconnect any wire brackets connected to the hard pipe.
  3. Using a 10mm socket, remove the bolt from the front mounting flange on the hard pipe.
  4. Using a 12mm socket (I think), remove the bolt from the bottom of the rear mounting flange. Note it may be easiest to reach this bolt with a long extension from the front of the engine rather than from underneath the car.
  5. SLOWLY AND CAREFULLY pull the hard pipe forward to remove it from the car. Be careful, as there is a O-ring you could damage. (See the troubleshooting section for info on obtaining replacement o-rings in a hurry and for cheap.)
  • Remove the driver’s side heat shield from the exhaust manifold using a 12mm socket on the 4 bolts.
  • Remove the passenger’s side heat shield from the exhaust manifold using a 12mm socket on the 4 bolts.
  • Using a 14mm deep socket, mounted on a 3-foot daisy chain of extensions; stand at the front of the car. Slide the long extension down the engine compartment to the driver’s side cat. Remove the nut from the top cat stud. Repeat the same on the passenger’s side.
  • Move underneath the car with ALL OF YOUR TOOLS.
  • Remove the large chassis brace connecting the front suspension to the engine cross-member. Removing 2 19mm nuts & 8 14mm bolts should require deep 19mm, and 14mm sockets. Loosen the bolts first with an 18” breaker bar and then use a ratchet.
  • Disconnect the two O2 sensors wiring harness mounted on the transmission. After being disconnected, they should only be attached to each cat. Note it may be easiest to dismount the harness from the mounting bracket using a screwdriver first and then separating the plastic male and female ends.
  • Remove the small brace supporting the cats using a 14mm deep socket.
  • Using a 14mm deep socket, unbolt the two remaining nuts on the top of each cat. You may find it necessary to use a swivel adapter to remove. Note the bolt on the top that was not taken off from above the car can be reached by going over the backside of the cat with a long extension, this may only work if you have stock cats.
  • Using a 14mm deep socket, remove the two nuts connecting each cat to the y-pipe. Remove cats from the car. Remove O2 sensor from each cat using a 22mm wrench. Be very careful when removing these they are easy to damage if you don’t take your time.
  • Using whiteout, mark the steering shaft, steering knuckle, and connection to the steering rack. You may end up getting lucky & have marks from the factory, if so mark from the opposite side so you have 2 sets of marks. Using a 12mm socket, loosen the two bolts on the steering knuckle. Move the knuckle up the steering shaft so as to disengage it from the steering rack. Tighten the upper bolt so it does not fall off.
  • On the top of the engine cross-member, passenger’s side is a mounting bracket that holds two power steering lines. Using a 10mm socket, remove the two bolts holding this bracket. This is optional, but may provide the needed space to make the install a bit easier.
  • Using a 14mm socket, unbolt the bracket on the passenger’s side of the steering rack.
  • Using a 19mm socket, unbolt the steering rack on the driver’s side.
  • Allow the steering rack to slip off of its mounting on the engine cross-member and hang in place.
  • Using a 14mm socket, remove the two mounting bolts from the starter (passenger’s side, above steering rack). Using a 12mm socket, disconnect the large wire on the starter. Disconnect the small wiring harness on the starter’s solenoid. Set the starter aside.
  • Remove the engine mount bushings:
  1. Locate the engine mounts on each side of the engine.
  2. The lower bushing bolt goes through the engine cross-member. From below the cross-member, remove the 14mm nut using a 14mm deep socket and a ratchet extension.
  3. Remove the 14mm nut connecting the top of each engine mount bushing to the engine mount L-bracket.
  4. The driver’s side engine mount has a small bronze-colored bracket on it. This bracket should now to free to come off the car. Take it off. It will NOT go back on later.
  5. The bushings are now free from the mounts, but will remain in place until you jack the engine in the next few steps.
  • Move to the top of the car in front of the engine bay.
  • Using a 14mm deep socket and a breaker bar, loosen the six nuts holding on the passenger’s side exhaust manifold. Use a ratchet to remove them the rest of the way. Slide the manifold out to where you can get a large spanner on the O2 sensor. Remove the O2 sensor and set the manifold aside (hell, throw it off your roof if you like). Make sure to set the manifold gasket aside too (it will be re-used). Repeat on driver’s side.

Assembly

  • Locate the two fuel lines mounted to the passenger’s side frame. A mounting bracket holds them on. Remove them from the bracket by unclipping it with a flathead.
  • Using your aluminized Nomex heat shield, wrap each line separately and zip tie the heat shield in place. Make sure not to bend or kink either line. Clip the lines back into the bracket. LEAVING THEM LOOSE COULD CAUSE PROBLEMS.
  • Place the head of your large jack under the oil pan. Place your piece of wood on top of the head. Slowly raise the jack until it engages with the oil pan and lifts the engine 1” – 2”.
  • Under the car, remove the two engine mount bushings you loosened earlier. They should be completely off the car at this point.
  • Lower the engine back down by about an inch. This will make it easier to rock the engine later on.
  • Hold the headers near the engine and reinstall the O2 sensors into the headers. These sensors are still connected to the car, so you will need to hold the header close to their stock location.
  • Working from underneath the car, start to slip the passenger’s side header into place. A Friend will need to slightly rock the engine to the driver’s side so that the header will slip into place. You must do the passenger’s side first. Your friend should also hold the stock manifold gasket to the block while you work the new header onto the mounting studs. Once in place, screw the six stock manifold nuts onto the mounting studs. Repeat the same for the driver’s side. Both headers should now be in place.
  • Keep the engine lifted. Do not lower it at this time.
  • Re-install the starter using the two stock mounting bolts (14mm head). Reconnect the starter wire using a 12mm socket. Reconnect the wiring harness to the solenoid.
  • Lift the steering rack back into position and replace stock 19mm bolts on driver’s side. Just start the bolts. Replace the passenger’s side mounting bracket and tighten it down using the stock 14mm bolts. Tighten all bolts on the rack, including the 19mm bolts.
  • Locate the mounting bracket for power steering lines on passenger’s side engine cross-member. Slip it back into the stock mounting location and remount with stock 10mm bolts.
  • Reconnect each engine mount bushing to the engine mounts. Screw in the 14mm nut connecting each mount to the top of each bushing.
  • One person should be under the car to watch the engine mounts; the other should operate the jack. Slowly lower the engine back into place while guiding the lower bushing back into their seat. Replace the two stock 14mm nuts connecting the bottom of the bushings to the engine cross-member.
  • Replace the driver’s side cat and tighten the stock mounting bolts to the header. Crawford sends some bolts with the headers and they can be used as necessary on the cats. You may find that one of the shorter bolts works well, so you can interchange if need be. You will need to tighten two bolts from under the car and the other one from the engine bay using the daisy chain of extensions. Repeat for the passenger’s side.
  • Reconnect both cats to the stock y-pipe using the stock nuts and bolts.
  • Before reconnecting the steering knuckle, make sure your steering wheel is straight. Reconnect the steering knuckle to the steering rack using a 12mm socket. MAKE SURE YOUR WHITEOUT MARKS MATCH UP.
  • Replace the stock cat support bracket and bolt to the frame and each cat.
  • Reconnect the cat O2 sensors to their wiring harness and attach harness to car as necessary.
  • Replace the large under-body chassis brace using 14mm and 19mm deep sockets. Torque down to about 70-85 ft/lbs.
  • Move to the top of the car with ALL OF YOUR TOOLS.
  • Reinstall the driver’s side hard coolant pipe by first inserting the middle 12mm bolt into the block. Thread the bolt in by hand just a little. Now, replace the gasket and the two front 10mm bolts. Tighten all three bolts. Replace all water hoses to the pipe. Replace any wiring harnesses that were connected to the pipe (likely none).
  • Reinstall the passenger’s side hard coolant pipe by VERY, VERY CAREFULLY slipping the rear of the pipe back into its mounting location. DO NOT DAMAGE THE O-RING. To help prevent damage to the o-ring, consider using a little grease. Replace the rear 12mm bolt into the mounting location and carefully screw in place. Replace the mounting bolt at the front of the pipe using a 10mm socket. Connect all coolant hoses to the pipe.
  • The passenger’s side hard coolant pipe has a mounting flange on the side. Previously attached to this flange was a mounting bracket that held a wire harness in place. Remove the mounting bracket from the wiring harness and flip it so it faces the other way. Screw the wire harness bracket to the mounting flange so that the wires are held away from the header. This is critical to keep the wires from melting to the header.
  • Reconnect any other wiring harnesses to the passenger’s side coolant pipe.
  • Place the AC compressor bolts into their holes and then lift the AC compressor back into position. Use a 14mm socket to screw in the bottom two bolts. Screw in the top bolt (it should still be in its hole). Reattach the wiring harness for the AC compressor.
  • Replace both belts. Use a 12mm socket to raise the tension pulleys until you have proper tension on the belts. Screw the center nut of each pulley in place until they are tight.
  • Reinstall the intake system working from the bumper to the throttle body. If you have a stock air-box, start with it. Then the MAF sensor and the upper intake pipe. Reconnect the MAF sensor wiring harness.
  • Reconnect the coolant hose to the top of the radiator and the passenger’s side water pipe.
  • Reconnect the coolant hose to the bottom of the radiator and the thermostat.
  • Reinstall the strut brace using a 14mm socket on the 6 bolts and 2 nuts. Reinstall any wiring clips to the strut brace brackets.
  • Replace the radiator pit-cock using a flat or Phillips head screwdriver (remember that this is plastic & will strip out if you try & tighten too much)
  • Refill the radiator with fresh coolant. Make sure you have the proper mixture.
  • Replace radiator cap.
  • Start the car:
  1. Carefully watch and smell for anything burning. A missed wiring harness may touch the header and begin to melt.
  2. Carefully watch the coolant temp gauge. It should not rise above normal.
  3. Once the car is up to temperature, turn your heat on full blast. Are you getting hot air in the cabin? If not, check the troubleshooting section below.
  4. NOTE – You will smell the cats & headers the first couple of times you start the engine. Smells somewhat foul – like burning plastic.
  5. Shut the car off.
  6. Check for proper coolant level and any other trouble.
  7. Drink a beer or see the troubleshooting section.

Troubleshooting

  • I have no heat:
  1. This has to do with air in the coolant pipes. An air bubble might be blocking the coolant from reaching the heater core. There is an air bleeder valve on a coolant pipe at the passenger’s side rear of the plenum. Try removing it with the car running to allow any air out (be careful of hot coolant).
  2. Another option is to take the car to a 30-minute oil lube place and have them do a flush and fill. Most places use a pressurized machine to quickly flush out your system. This will certainly clear out any air and should fix your heat problem. THIS HAS NOT BEEN TESTED, but should work fine.
  • The car is over heating according to the coolant temp gauge
  1. Immediately shut down the car.
  2. DO NOT open the radiator cap.
  3. Let the car cool off.
  4. Open the radiator and see if you can get more coolant in.
  5. If no coolant can be added, you probably have an air bubble in the pipes blocking the coolant from reaching the engine. There is an air bleeder valve on a coolant pipe at the passenger’s side rear of the plenum. Try removing it (This may need to be done multiple times to get all the air out of the system)
  6. Have a professional flush and fill done at a 30-minute oil change place. THIS HAS NOT BEEN TESTED, but should work fine.
  • I have an exhaust leak:
  1. Starting at the rear of each cat, feel around for leaking gases. Work your way back to the header.
  2. When you find the leak, tighten the bolts for that section down. If it is at the header, you may need to remove some parts to reach the bolts.
  • I have a coolant leak on the passenger’s side:
  1. Shut down the engine immediately
  2. Check each hose connection to make sure the hose is properly seated and sealed.
  3. Check the rear mounting point for the hard coolant pipe. If you damaged the o-ring, it will be leaking from this location. If it is, get a new o-ring from Home Depot. They sell a combo pack of o-rings with two large rings. One of them fits perfectly. No need for the Nissan part.
  • I have a coolant leak on the driver’s side:
  1. Shut down the engine immediately.
  2. Check each hose connected to the driver’s side hard coolant pipe.
  3. Make sure the hard coolant pipe is mounted to the block tightly and that the stock gasket is in place and not damaged. If damage, order a new one from your local dealer.
  • FIRE!
  1. You’re on your own…and we were never here.
  • Ever since I installed the headers, my accelerator remains planted to the floor.
  1. This is to be expected. Just watch out for cops and keep plenty cash on hand for gas.

Leftover parts

  • Both exhaust manifolds
  • Both exhaust manifold heat shields
  • Plastic tubing from the AC compressor
  • Little bronze mounting clip off the driver’s side engine mount
  • Mounting bracket that used to hold the fuel lines to the passenger’s side frame and the two associated nuts.

Contact

If you find that you have additional questions or find that you need help you can contact the following individuals:

Bill Buffington – “Buff” Hunter Harrison – “peptidbond”

Doug – (615) 327-4159 (office) “douggrace zs”

We have all been there before & know what you’re going through. PM’s before you start will help to make sure that at least one of us is available for comment while you’re doing the install.

Retrieved from "http://www.350z-tech.com/zwiki/Header_Installation"