N62 Z3 Part 21: Paint & Reassembly

And finally... the first coat of 2K epoxy primer. I did a light dusting for the first few coats

I was pretty happy with how the seams came out

And another coat

It's nice to see everything in one color now

Then a slighter thicker coat was applied

Then it was all scuffed up a bit to make for a smooth surface and check for any imperfections

If I was building a show car, there were a few more spots I could have touched up, but I plan on driving the car and the things it needed were very minor, so with that in mind I decided to move forward from here


After a final layer of primer was applied. It will cure overnight and be painted the following morning. The final result after the final primer layer looks pretty nice, especially the areas I focused the most on which is that seam from the fender panel to the shock tower

The next morning it looked like this and I scuffed it again and started painting

After the first two coats of paint - I took the pictures while the paint was wet so it looks a little splotchy

I was originally planning on painting an original radiator core support (so that if I wanted to ditch the dual intake someday it was already color matched) but I didn't have enough paint to paint two so I just did this one. There are certainly some areas on this panel that could have used more work but those will be covered when installed anyways

After the final coat

The following day I started re-assembly and finished attaching the brake lines. I still have to bend the ones between master cylinder and the ABS unit

Some more photos from the following day after the touchup areas had dried. We did have a dust storm the night before these photos were taken (or at least it got really windy, my cars were filthy) so there are specks of dust here and there but gives a better idea of the overall look

Then I added some clips for the brake lines to hold them in place, I rivnutted through one side of them to keep them secure and allow the lines to be removable without the clip flopping around

There is a multi-line holder here under the steering shaft - it holds in the two lines that go to the rear

Next I cleaned up some of the wiring around this area, it's starting to come together, everything in this area is just about done except the lines from master to ABS

Some DEI "reflect-a-cool" heat rejecting wrap in the transmission tunnel

Then started to tidy up the electronics area a little bit

Starting to come together

I think this came out pretty well although if the green had a little more contrast against the black I think it would look even nicer


Next was to work on something I had been avoiding for a little while if I am being honest and that is to finish the last little bits of wiring. When I got it running there were a few jumper cables here and there sort of making everything work and my goal was to integrate all of that and also now that the pedal wires were routed through the firewall and it was painted, it was time to install the pedal harness too

Not a lot to show picture wise but there is a little visual evidence of the work... the coolant temperature sensor harness is all wired in and the PWM fan wires are all installed although I don't have a harness on those yet though because I haven't decided what fan to run and different fans have different harnesses. These wires are a couple gauges thicker than stock wiring for this application, just in case that fan is running heavy duty to keep things cool I don't want to worry about the wires melting or anything

I actually went back to the shop one late night because I got so excited about this idea I had and by the time I got there I had worked out an even better version of the idea. The problem I was facing was that I wanted to install the stock electronic pedal that the M54/S54 Z3's got. However, to be perfectly honest, the later assemblies are a more reliable system overall and I didn't want to work myself into a corner where I wasn't able to swap to the newer style pedal if I wanted to. So my initial idea was to pigtail two harnesses off the wires, so that they would effectively "both" be installed but only one would be plugged in at any given time


Then I just thought, well, why don't I just use an extra connector to make an adapter... and because the one side was cut so long I just crimped the pins onto the ends so there aren't any splices in the middle - just nice crimps like factory

I'm probably way more excited about this than I should be but I thought it was pretty clever. It allows me to plug the newer style pedal into the older style connector

After the PWM fan harness is on, I believe I only have one more wire to run, which is the main positive to supply the fuse box. I also was not able to finish wiring the Z3 pedal stuff because I was out of male pins... once those arrive I will finish that and reinstall the pedal box


Then I decided to install the suspension, the first step was pressing out the old bushings and pressing new ones into the "lollipops"

Then installed and the control arms were "complete" - I was given this suspension kit for free and I've always been curious about the quality of Uro suspension parts since some of their parts are actually quite good. I utilized many of their parts for my engine build and those parts seemed well engineered so I will install the kit and give it an honest review once running

This was the steering rack I decided I will be running so I swapped on the new tie rod ends, being very careful to match the lengths as close as possible (although once I hooked up the steering linkage, it felt a little weirder than the old one, so I miiight be looking for another rack some point)

And the suspension all installed! Next is to find or buy some good 3.0 brake rotors and calipers/pads

Installed the PWM harness after deciding what fan I was going to run

Installed the stock Z3 power steering line from the rack to the cooler and the only line I will need to worry about as far as getting that system to work will be the high pressure line from the rack to the pump

Then my male pins arrived so I could finish the pedal wiring

All installed!

And then I installed the rest of the pedals! It is so nice to finally have it starting to look a bit more like a complete car... I also plugged in the EWS and the gauge cluster as well as a few other random modules which were unplugged while I was welding. Everything is done with the pedals except the supply line from the brake reservoir to the master cylinder which is super simple to do

Next focus was the fuel line, I was not able to ascertain whether or not the fuel hardlines come pre-bent. My main holdup with doing it the way I am doing it now was that I wanted to maintain the quick-connect nipple on the fuel line. I did realize though that the quick connect nipple was broken on the fuel rail I have installed currently... I could install a different fuel rail but doing it this method let me kill two birds with one stone because I didn't have to worry about the quick connect anymore; I just cut the nipple off on the engine so it's a rubber softline and flared both ends of the fuel line with a standard brakeline flare. The fuel filter side is already installed and once the engine is installed the rubber softline will just use a normal hoseclamp to install in place. Not ideal but it will definitely work.

I also used my previous pictures to deduce where to route the line... I know I am in the right ballpark but can tweak it a bit if needed


Attached below is picture illustrating which is the supply line, this needs to mate to that hardline I just made. I think it's in the right spot

You can see it peeking up near the brake booster, most of it is covered in the heat protecting sheath though

Detail of how the lines fit into the chassis "pocket" I made earlier. The engine is very close right here, so if it ever hits the framerail now it won't contact any of the lines

Then I went ahead and worked on finishing up the brake lines from the master to the ABS unit and snugged everything down

I like the look, I will see if I can move the electrical wires out of the way a little bit next time I am at the shop

Really feels like it is coming together at this point

Then I added some struts and brakes. I went with stock struts and springs from an E36 M3 as a temporary measure, the stock struts that I removed from this car were pretty gross and those springs are meant to support the lighter aluminum I6 engine, whereas the M3 had an iron block engine (same as the Z3M). Down the road I plan to upgrade the suspension with some other parts I already have on hand but I want to wait until it's running before I throw those parts at it. Struts are very easy to swap out later


Brakes I went with stock E46 330i front brakes and stock rears. The stock brake rotor width was 286x22 and the Z3M including S54 are 315x28. The E46 330i front brake rotor is 325x25 so has 10mm increased diameter over the Z3M but compromises a little thickness, which seems fine to me. It seems like M models usually have thicker rotors as the larger thermal mass helps with heat dissipation, which is mostly a consideration on the track. I am not building this car with the intention of it being a track car so I think this setup fits the theme of the build

Next I finished the fuel pressure reference line, which means the fuel system is totally done as far as what I need to do before installing the engine. The fuel pump is inside the car so I can upgrade that down the road without much hassle


I am almost ready to bleed except I don't like how those E46 lines are sitting... I have some Z3 stainless steel lines on the way

Some minor work next, I got some hardware for the brake line clips to hold them down for good and sorted out the brake booster vacuum line

The final length will be set once the engine is in place but it's in the right position now


Next after the stainless steel lines were installed I was able to finally bleed the brakes

I also wasn't digging the gold tape wrapped DME partition so I decided to swap out a stock black one I had on hand. I'll use the gold one in some other future build but I decided to tone it back on the visible gold and keep the theme black and silver

When I swapped the steering rack the new one felt really weird so the next task was to figure out why, since previously it had felt really good. After more inspection it ended up being the U-joint, I recall when I was installing it onto the rack I hit it a couple times with the hammer to get it all the way down and it must have deformed part of the joint bearing or something. It felt weird when wobbled in one direction Before I even knew what was wrong I had another U-joint purchased and on hand "just in case" and I ended up installing it. A $130 mistake but, I was very careful reinstalling the joint onto the splines to not deform it and am very glad the steering no longer has that binding feel

I also tried to demonstrate how "tight" the steering is, I am hoping this will translate into good steering feel when on the road like the Z3/E36 is known for

I then focused on finishing the engine which first meant welding the V-bands onto the headers


I wanted the flange to sit just between the transmission and oil pan - the OE catalytic converter sits right in that spot so there is room there for exhaust and I had noted previously that there was space there. So I found some exhaust pipe I had laying around that was the right diameter with the correct bend I needed then trimmed it to shape

Tack welded into position

Fully welded in place. The upper part that is "open" is an outer insulating tube, at this point I am not sure if I want to close that up so I left it as is for now and tack welded it in a few places so it didn't rattle or anything. I also test fit the O2 sensors after welding and they fit properly

The other side was a little easier as it mostly just needed some straight pipe

It was a really great fit, no warping of the flange at all. Welding this stuff was way easier than welding the chassis panels. I don't think I will have any problem building the rest of the exhaust myself

Working on the last details on the engine... had to make an adapter for the brake booster hose so JB welding it into place

I had to adjust the steering rack location a little bit as well. The reason for this was because the steering was ok as it was but moved even just a little it would bind. So I wanted more "buffer" area to account for chassis flex


I ultimately decided to do two things - move it forward and rotate it. The goal was to move the U-joint further away from the center U-joint so as to lessen the center angle. Moving it forward translated to a direct increase in distance, rotating it altered the input angle which effectively "lowered" the joint location. Here I am using clamps and washers of various sizes underneath to try to narrow down where I want it

After the modifications were made

And with the headers finished it was finally time for the exhaust gaskets

And the engine is finally ready to install, save for maybe a couple hoseclamps here or there

And the chassis is finally ready to accept it... so, here it goes!


First I threw on some new transmission mounts though

Trying my best to protect the fresh paint

The last thing the transmission tunnel sees...

Took a lot of maneuvering, but eventually popped right into place

Then I got to work on finalizing some of the stuff like the coolant bleeder line, making sure the brake booster vacuum line and fuel supply line/reference line were the correct length. Everything was perfect except the brake booster line needed a little trimming. I thought it might so had left it a little long

Here (and above) you can see the coolant bleeder line. It has a line that comes from the engine so I bought an OE line with a "T" and it ended up being a very nice length, running all the way to the radiator from where I wanted it near the shock tower. I have oetiker clamps I will install on three locations, but two (the radiator and the engine-side line) will be hose clamps so it will be removable. The hard line has bubble flares to allow the hose clamp to clamp adequetely

Then I decided to throw the rest of the stuff on just for a test fit, I've just been dieing to see how it was going to look when it all comes together. The electrical area is a mess and that might need addressing... but I love how the engine bay looks overall

I plugged everything in and tested the pedal too... works perfectly

Underneath, things mostly looked good... but I am going to take the engine back out because it looks like I actually can use the original O2 sensor locations, but on the passenger side I will need to hammer forge the metal just a bit where the O2 sensor harness sticks out. You can get it screwed in as-is but it ends up resting against the chassis. Over time it would rub over time and the wires would get damaged. So I'm going to add some clearance for it and then install both O2 sensors before installing the engine next time but that's great to not have to worry about that moving forward as far as exhaust construction. Especially because they are wideband O2's I didn't want to mess with their location if I could avoid it

I then test fit the driveshaft and much to my surprise... they somehow used the wrong CSB?

I noticed it was different than original when I brought it home but I figured if it was the right distance from hole to hole it'd be ok but... it wasn't


The length was good though

All in all a huge win and I am looking forward to making the few changes done to finalize everything. It's definitely getting there!


I think that will also conclude this post, so on to the next part!

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