My buddy is going to install his headers himself on his 02 m3 and I am going to help.

Any advice you guys can give prior to heading into it?

Thanks

Find someone with tiny hands, and brings lots of beer...you are in for it :stickoutt

But low profile 11mm (it was 11mm on my e36, I'm assuming it hasnt changed) ratcheting wrenches will save your life.

Not hard just a PITA. Give it a few hours. Some nuts from above, some from below. Good luck!

Do some searches, there is a photo install DIY from Ferris for doing it on his M Coupe, and I'll post my written guide here.

It is NOT a difficult thing to do. It requires lots of patience. You will swear that the nuts change size while you're working on removing the old headers, you will have to use a different tool for just about every nut on the old headers, and you will wonder how you'll ever get them out, but you will do it. The installation goes a lot faster.

Things you'll need:
every metric wrench, socket, and swivel you have
a soda can with the top cut off to catch the coolant from disconnecting a small rigid cooling line that is exactly in your way
an extra gallon of BMW coolant
nitrile work gloves (I use Harbor Freight gloves. The ones from auto parts stores suck)
two vehicle stands, and a floor jack
a cell phone headset, because your phone will ring dozens of times the minute you get under the car
clean rags
acetone, laquer thinner, or mineral spirits, in case you need to clean any surfaces

You'll also need a complete gasket set, including one manifold gasket for each cylinder, one EGR gasket, a complete set of replacement copper nuts for the manifold studs (they're reusable but its nice to have replacements available because you're going to lose at least one), and a couple of crush rings for the collector ends in case you crack one.

Advice: Do NOT jack up just one side of the car. Jack up the entire front and stand the car. Block the rear wheels to keep it in place and make sure the brake is set and the vehicle is in gear. If you jack up one side, when you pull off the reinforcement plate to access the headers, the alignment will slip. The service manager at my dealership told me it was impossible, but the three times that plate came off I needed an alignment all three times. Once for when I installed my euro headers, once when the engine bearing recall was performed, and once when I pulled the headers back off to put the car back to stock. If you look in the parts catalog, it even lists that plate under "front axle support".

Next: the install guide

Get a drink - this is a long read but I hope it answers your questions.

Provided you have all the tools required, as well as uninterrupted time to work, space to move around, drop lights, someone to keep you company and hand you things, yes you're looking at about 6 to 7 hours. It is excruciating if you lack any of the above.

Stop by your friendly BMW dealer and get 6 exhaust manifold gaskets, P/N 11627830667, approximately $6 each, or $4.20 online at places like realoem.com. Maybe get a couple extra header nuts, P/N 11721437202, 35 cents each. I lost one during the last install, so they're good to have around.

Depending on how old your car is, you will most likely be able to reuse the cat gaskets which join the cat section to the rear resonator section. I've reused mine numerous times without problems, but if you want to be thorough, get two for this install: P/N 18307830674 $7 each.

As best I can recall from memory, the steps are as follows:

1. remove strut brace

2. remove coolant overflow tank. This requires pulling a single bolt out of the right fender. You will need to pull the hose off the bottom as well.

3. remove overflow hose from the coolant return pipe. This will spill coolant all over your heat shields unless you do two things - have a catch basin ready, like a Planter's Nuts can - and cut the finger off a blue nitrile work glove to seal off the coolant return pipe. Stupid, but it works well.

4. remove EGR valve from the side of the block. It sits just above the top heat shield, in its own little cutout.

5. unbolt heat shields. Its two aluminum plates sitting one atop the other. Three cheap slot nuts are all that secure them to the body, and 5 bolts attach them to the block.

6. remove the 6 nuts holding the head cover to the head. take off the oil filler cap, pull the head cover, then put the filler cap back into the head to prevent crap from falling into that sacred valvetrain.

7. Look at all the wires under the cam cover!! Run! Run Forrest!

j/k..

Those are your O2 and EGT wires. They're loomed nicely under that plastic retainer. You'll pull that off later and take the wires out from under it in order to get extra length so you don't have to cut and splice your O2 sensor wires. I used to tell people to buy the euro O2 set, but as it turns out the USA sensors are actually longer so going euro on the O2 wires will actually cause problems. Just unloom the wires - without breaking the plastic loom - and you can run them down behind the motor to your new cats.
If you are going catless and you have the software to do the rear O2 sensor delete, then just remove the sensors and put them away someplace safe. Or, if your new headers have provisions for all 4 sensors, install them in the proper location.

Until you are ready to pull the headers, thats it for the top of the motor for now.

8. jack up the car and put jackstands under the front jack pads.

9. pull all the bolts holding the giant thrust plate to the bottom of the chassis. Two plastic shields next to the thrust plate also have to come out. You'll know which ones I'm talking about when you get under there.

10. If you are installing a new front exhaust section (either euro/custom cats, or an Eisenman or SS replacement section) then pull the bolts holding the forward resonator section to both the US headers and to the rear resonator section.

11. drop the forward section and pack it away. You may need to upend it for a few hours so moisture drains out of it first.

Take a look at the headers. you have a sausage shaped cat in each collector, with precat and postcat O2 sensors in each, 4 total. Take some masking tape and label each one so you remember which is which. My system is to call them by their bank number plus a position letter. Therefore, you'd have "123F", "123R", "456F", "456R". The 456 header also has the EGT sensor in it.

Be careful with all the sensors. Don't drop them or bang them into anything. Get your numbering system worked out right, because if you reverse the O2 sensors, you'll burn them out and the car will run like a dead dog.

Now it gets funky...

12. You'll have to pull the header nuts off. They are copper nuts with a dent in them for retention against motor vibration. Make sure you have a nice selection of 1/4 inch drives and sockets, plus a couple of different universal swivels, some short extensions, etc. Depending on how tired and frustrated you are by now, you may think the car is changing the requirements for each single nut. I was up the entire night before, racing with my friends, and by the time I got to this point I was nearly psychotic.

13. with all the nuts out, crawl under the car and see if you can jockey the headers enough to gain access to the O2 sensors. If you can, then take an open end wrench and try to get them out. If that fails, you'll have to pull their connectors apart in the above mentioned plastic bracket. Same goes for the EGT wires. Number the connectors you pull apart so you know who attaches to who.

14. drop the headers. Marvel at their ugliness compared to the beautiful, traditional euro headers. Curse the EPA for their ridiculous cold start emissions reuirements. How many times a day is your car cold anyway?

15. gently clean the exhaust ports on the head to remove any adhered gasket material. Its probably not necessary since the BMW gaskets are really high quality, but just give it a look to be sure.

Installation is, as they say, "the reverse of the removal". Its a lot easier though, because none of the aftermarket headers have cats in them so you'll have more room to work. Just pay attention to the details and don't drop anything if you can help it.

I have to say that as a veteran of this type of swap, its a very interesting thing to do. You will learn a lot about your vehicle and the way it was designed and assembled. Things fit together so well on an M3 you'll wonder why the US manufacturers haven't been able to do things like that. Though the install is time consuming, I don't find it to be oppressively difficult. I'm about to install my new Evosport headers and I'm actually looking forward to it. Now if I just can find the time...

Chuck,

Nice write-up.

Thx

You're welcome, guys. If anyone has questions feel free to ask. I just sold my Evosport headers and the car was sold last fall, but I still consider myself an M3 fan. I'm saving my pennies for the E92 M3. :devillook