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14,974 Posts
Discussion Starter · #1 · (Edited)
Well, this has been a long time coming to say the least. Some of you with long memories might remember I've wanted to do this swap since I bought the car.

A couple of years ago, I got around to doing the first phase of it, namely the LSD swap and the Turner subframe reinforcement kit:

I also picked up an S54 swap locally so I could get the ball rolling:

But there was no way I was going to do that in the carport at my apartment (and believe me, I was tempted since I had already changed the motor in the E30 there).

So I moved to a small house with a big garage and as luck would have it, found an M3 for sale with a blown motor. Perfect rolling test stand, right? I had to pop the motor in to test it out:

I learned a lot thanks that car and I felt ready to start working on the sedan. Unfortunately, projects came up, the house was torn down and I had to move yet again, so the swap was derailed once more. On the bright side, I've been using that M3 as a beater for a year now!

After the move, things didn't settle down at all. My garage was constantly occupied by local fanatics, which has been awesome, but I couldn't help feel a little restless about getting on with my own project. The nagging from the guys in Norcal General Chat certainly wasn't going to stop until I did something about it, haha. So I took a good long look at my Brigitte and resolved to gitterdone.

IMG_2102 copy by cyberkaa, on Flickr

2003 325i, steptronic, japanrot on sand, 54675 miles, lovingly cared for - a car that's been an absolute dream to own.

I gave her a bath the day before I planned to start disassembly and went out for her final photo shoot as a 325i along with Arrows and his boosted sedan. The next morning, I took her for the biennial smog check and the numbers came back darn near perfect.

That evening, Miles (mkodama) and I got to work.

The Plan:
-Swap in an S54 along with the M3 6MT.
-Make the MSS54 DME interface with the sedan body harness without hacking the OEM wiring up.
-Keep as many of the sedan modules as possible.
-Make it smog legal according to California's engine change and emissions requirements.

And so it begins...

Stock engine bay:

Starting disassembly. Intake and strut brace out.

Front end coming off. Wires all labeled. Bumper and lights removed.

Bumper shocks and front air duct off.

Coolant drained before removing the radiator. Here's the block drain for reference:

I'm amazed by how clean the aluminum looks under there:

Radiator out. I left the A/C and P/S lines connected. S54 in the background:

Working underneath the car, exhaust and coverings out. Next up, drive shaft:

This is the custom drive shaft I had made to bolt an M3 diff up to a steptronic:

Supervisors Drew (Drewdown) and Kyle (323ci newbie) make sure the swap goes smoothly:

Pull off the positive lead that runs across the engine. (Note reverse mounted hood sensor, modified for OEM strut brace).

Brake booster sucking jet pump coming out:

Next, the engine harness connectors get pulled from the DME. Harness stays with the motor.

Switching gears for a bit, we do a little prep work on the S54, starting with a valve adjustment and spark plug change. Parts:

Valve cover off and spark plug holes stuff to prevent things (especially shims) from falling in:

Pretty neat setup. Clearance is measured between the cam lobe (turned upwards) and the follower. Shim is barely visible above the valve spring retainer:

Newer heads (this one is an '04) have meshes covering the oil drains (just past the torx bolt head) so shims and large debris don't fall down:

All done. Add RTV to the joints as specified in TIS, replace gaskets, and we're done:

Valve cover was pretty clean:

Had a good crowd the day the engine was pulled. A couple of people took pictures of the process so I don't have them, but it's pretty straightforward. In any case, this boat anchor is out:

Empty engine bay. A/C components tied off to the side and P/S reservoir held in place to prevent spillage:

I had already accumulated a lot of the parts to do the swap, but I still needed to pick up many small items that fit in between the big components. The main areas that I needed parts for were:
-Fuel system
-Power steering
-Clutch control
-Cooling unit

We'll start with the fuel system upgrade. The M3 has a higher pressure fuel system and uses quick disconnect fittings on the high-pressure side. I already had the pumps and regulator, so I just had to pick up lines, fuel filter, o-rings and clamps. (Note: the return line is missing since it got stuck in customs on the way from Germany):

Fuel pressure regulator installed on filter. A bit different from the non-M. The M3 has a screw-on block that contains the return line and replaceable FPR. The non-M version has everything built into the filter.

Start off just like we're doing a fuel pump change. Here's the passenger side with the high-pressure line disconnected. Ear clamps are a pain. The new line has a quick-disconnect fitting on it instead of the barb+clamp non-M setup.

Roughly where the new line has to run:

I had less than half a tank of gas before starting. I guess the transfer pump did its job and moved all of the fuel to the right lobe. Down there is the plastic receptacle that the transfer pump line attaches to.

And here's the M3 baffle installed into it:

Moving on to the left side, pull the return line off the sending unit:

Before installing the sending unit, remove the old transfer pipe and install the M3 one into the baffle. I didn't see much of a difference between the non-M and M versions.

M3 sending unit installed:

14,974 Posts
Discussion Starter · #2 · (Edited)
M3 fuel pump installed:

Time for the lines. Here's a comparison shot. The non-M lines are on top and the M3 ones are below. The return lines are identical, but the high-pressure lines have different fittings, as above.

Have to unclip the line on the far right from the brackets on top of the fuel tank. These are really tough to see, but you can feel for them. The line to be removed is on the far right:

There's also a bracket at the front of the tank:

I had to lower the tank one side at a time to make enough room to clip the new line in. Left brace undone:

Mounting nut in the middle removed and e-brake lines unclipped:

Once that's done, switch to the right side. Similar bracket here:

Finally, fuel line connected:

Same for the sender:

And here's the metal high pressure line installed. The return line is left hanging until I get that shipment.

Might as well change the shifter. Steptronic gearshift on the way out:

Lot's of pieces to pull off and wires to unplug:


While we're here, might as well put the new boot and lever in. The foam insulation is also specific to the manual shifter.

Now we get to the most annoying part of the manual swap - pedals. Start by taking the trim off:

And the lower trim piece on the inner sill. First time this was ever removed and it's like that with almost everything else on the car - untouched since it was assembled at the factory:

Dead pedal out:

325i EWS out.

M3 EWS in.

Here's how the auto pedal setup starts off. Note the faint X in the insulation for reservoir hose to the master cylinder. (See next pic):

Popped the covering plastic out and pushed the hose through to open it up. New grommet on the hose. It won't really be installed until later, though:

Need to pull the carpet back, so remove the plastic hold-down:

We need to shove this hydraulic line behind the carpet:

Pulled the carpet back as much as I could. That half-visible black plastic grommet needs to be popped out of the opening from which the high-pressure line will exit. We'll do that from underneath.

Stopping on the way there, I cleared the e-box out. Only body harness connectors left in there now:

The insulation is already perforated, so just needs to be persuaded a bit. The plastic cap is right behind it:

And once it's out, there's nothing but carpet, so we'll have to make some more room:

But first, install the new grommet:

I was tired of wrestling with the carpet so I did some research on wiring using WDS. Going to have to make a harness for the clutch switch module anyway:

Harness installed. I have a pic of a similar harness in my garage thread from Rick's 5spd swap. The M3 wiring I'm upgrading to doesn't have a clutch switch - only a clutch switch module (on the master cyl.) - so the harness is even simpler.

Back to the carpet. Drive-by-wire cars have a pedal module that holds the carpet down, so it's going to have to come out. Loosen the allen-head screw that holds the white bracket down. No need to remove the bracket. The black plastic hold-down on the back wall is also removed (where the clutch stop screws into later).

People always ask, so here's a clear pic of how the pedal is attached to the carpet. The white bracket stays with the carpet (this is a spare from my parts bin). The white tooth in the middle holds onto the PWG module, so the clip has to be pressed downwards (with a bit of force) and the pedal slides off to the left. Note that there are two notches it can grab onto in succession. That means, press, slide 1/2", press, slide off all the way.

I shoved a socket extension through the hole to make sure I had room for the pipe:

And the pipe is through! The grommet on the pipe locks into the large grommet previously installed in the floor from underneath.

Need some new hardware for the master cylinder:

That reservoir hose needs to go on first. Lube with a little brake fluid. It's a pain.

Bolted up (well sorta, the clutch pedal pin still needs to go in, so the front bolt should stay out):

Pedal hardware:

And done. Wires were tucked away neatly after this part:

Here's the clutch stop installed:

And that's all for now. Next up will be some more engine prep and more clutch hydraulic work. Still missing a part for the slave cylinder tubing, but hopefully UPS will be quick.

2016 M235i 6-spd
25,996 Posts
99,954 and counting.

All I can say, Kalim, is that when I do this, this thread will be very helpful. I'm thinking of losing my 2.8L engine and putting in a 2.3L one...but I'll compensate by putting on 14s hella flush!

Nice going so far. I'm beginning to believe you're really doing this. So far, it's not taken you as long as Delmarco's rear cup holder, so there's nothing much to be terribly ashamed of quite yet! You have plenty of time...a whole 46 posts!

7,752 Posts
when i got the fb notification with the link to this thread, i got all excited cuz i thought you finally finished the swap. :facepalm: i should've known better. lol.
you have about 2 - 3 weeks to finish the swap before i come up there :)

great job though Kalim (and the rest of NGC). glad to see that the swap is finally well on it's way. i didn't think it was gonna happen anymore since you were too happy driving around your beater M3 :rofl:

1,445 Posts

1,788 Posts
Can't wait to stop by and see the finished project man!

Keep up the great work! :thumbup:

1,788 Posts
Awesome job. Dumb question, but why didn't you just keep the engine in the white M3?
Um, because it wouldn't be an M3 sedan, which is what he is going for.
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