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N62 Z3 Part 23: First Drive

This is taking forever haha

The next time I worked on the car was also two steps forward and one step back. A lot of the final details were sorted out and I got as far as filling the cooling system... it did not hold pressure, after closer inspection I noticed a leak around the expansion tank bleeder connection on the radiator. So I am going to order a larger capacity aluminum radiator and swap it out. I've already started to remove the radiator here... I'm also probably going to repaint the fan shroud

I then took some time doing a pointless task since I found the goil tape when I was looking for some parts in storage

One of the main tasks remaining was to tighten the engine mount nuts and that proved a little more difficult than I originally anticipated. I ended up having to remove the alternator in order to get to the top one (although the bottom one was no different than working on a stock Z3). If I had an A/C compressor installed at the time then that also would have had to been removed to get access... in any case, it was nice having the radiator and everything out for that little bit of extra access

Then a local friend brought me a spare S52 radiator he had and I got it installed

Which unfortunately revealed that my expansion tank had a pinhole leak at around 12psi. I spent awhile diagnosing it as it looked like the hose quick connect but then from just the right angle you could see it bubbling right out of the tank

As a temporary measure, because I want to test drive it ASAP, I have epoxied the area the in JB Weld and will pressure test it again the following day after 24 hours has passed.

Wasn't super important but I also spent some time getting this recess sized correctly. It is the perfect size now, the badge fits in there snug but with just a hair gap around the perimeter like the stock M badge. Just needs some more sanding to the panel itself now but the recess will be maintained from here

I've also been working on the rear bumper but haven't taken any pictures of that yet

Speaking of cosmetics, while waiting for the JB Weld to cure I also took some time to clean the car up a bit to get it ready for it's maiden voyage

Needs the carpet cleaned in a few places but it cleans up pretty well I think... still needs a few odds and ends here and there but it's about how it will look for the first drive I imagine. I'm not going to put a passenger seat in until I upgrade the fuel pump as it sits behind the passenger seat on Z3's

The following morning I tested the electric fan

Since I am running without power steering for now, the first step to finding the accessory belt I needed was to determine the routing. Below in red is the original routing and in blue is the routing I am going with until I install the power steering pump

This routing allows for either the same amount of belt wrap as original or more. To actually physically measure the length needed I wrapped a string around the belt routing and then taped it together so it became one whole "piece". Then I cut it through the tape and measured the length. It measured about 56"

I then took a little length out to account for the tensioner and the belt that ended up fitting was a 55 5/8" belt

I also adjusted the tie rods to take out all the excess toe-out and spent a few minutes wiping down the engine bay. As I write this I am just waiting for the JB weld on the expansion tank to cure a bit longer and am killing time by going through my mental checklist over and over trying to anticipate any problems before they arise. But I think it's at the point where I need to turn the key, put it in gear and see what happens

For a little while after that I kicked some rocks around for a little bit to kill some time allowing the JB Weld to cure but the anxiety was killing me. I just had to know, was it going to move? Would the steering shaft work, or bind and feel really weird? Would the driveshaft work? Is the clutch going to work? There were a million questions but I knew that I had the engine running previously and that as it sat now, it had the stuff it needed, in theory, to be an actual car. It was time to test it out...

The oil light concerned me so I shut it off and double checked the oil level - it was on the low side of the dipstick so I topped it up and continued

Then as I was driving down the block in the above video, the linkage for the throttle pedal got disconnected! When I went to fix it, I noticed my neighbor glaring at me (the car was very loud) plus it wasn't running great so I just decided to back it up and get it home

Has codes for VANOS Outlet 2, ambient air temperature sensor and a few random misfires as well so I'm not going to call it entirely a success but as far as testing the clutch, driveshaft, shift linkage etc it all seems good so far. Now I just need to get the engine running right (again, lol, feels like every time I restart it I end up diagnosing some issues like this at first) and I will drive it a bit further

I also am going to work on the exhaust to make it quieter. I didn't like how low the one I made was hanging so decided I'm going to modify it further... I think for now though I will throw it on so when I idle it to diagnose it it won't be so annoying to the neighbors

Later on some diagnosing revealed this

The wiring here was very brittle and it was cracked in quite a few places. I'm not sure if it was completely broken before I took a closer look but it was hanging on for dear life. I cut the wires out up to where the insulation was a bit more pliable and then spliced in some connectors I had. Luckily BMW chose to use a pretty generic connector here

I also addressed the ambient air temperature sensor (which an INPA test makes me think didn't actually change anything as it still has that code)

And I installed the proper lock washer on the pedal linkage

The next day the ambient air temperature sensor code came back (drats) but after swapping on a new MAF and a few other changes, I got it to idle a bit better

However it is still a little laggy with the throttle. There are a few possible reasons for this so I am going to be working on fixing that before driving it again

I also did get a "generator" error - meaning the alternator isn't charging correctly (or isn't reporting to the DME correctly). There could be a few reasons for this and I suspect it may partly explain the laggy throttle so I will be working on figuring that out as well

Some further digging revealed I had the wrong spark plugs installed. When I bought the parts for the engine refresh I was still planning on using a 4.8 for the final iteration - however I kept the 4.4, which uses different plugs. I don't think that's the whole reason for the laggy throttle but I have a hunch it's at least part of the reason

To remove the coils on bank 1 I have to remove the DME partition, which requires unplugging the DME and IVM... this is a little bit more involved than I intended for a basic maintenance job. I think I will modify a DME partition to allow access. Bank 2 I can acccess as-is

Before even getting to the plugs I decided to clean the area up. I can still re-install the DME partition, but as it is now everything is routed a bit nicer and the alternator cable has a direct connection to the battery positive, whereas before there was an intermediary cable. Both DME's are also in the DME box now (whereas before the Valvetronic DME was ziptied to the harness and just kind of "out of the way"

Cosmetically I do prefer the look with the DME partition so it will definitely be going back in once modified. And looking back on it, when I was designing the DME box I would have been much better off if I had done so with the engine harness mocked up in place. I was designing it with the modules and fuses and everything but the harness itself. I did not properly account for how bulky the wiring itself was nor the natural routing of the wires. Next time I do a project of this caliber I will definitely approach that part of the swap differently

I also installed a Mishimoto aluminum radiator a buddy sent me for just the cost of shipping. It definitely holds a bit more volume over stock. After some wrestling I was able to get the electric fan in place too

I also installed a Daytime Running Light module, just personal preference, I like the DRL's

A bit later on I got a new voltage regulator installed as well as a thorough cleaning of the alternator and that seemed to fix the stumbling when giving it throttle

Throttle seemed much better so I took it for it's "first scoot" ...not really a first drive but it did move under it's own power which was super exciting in itself!

I then took it on it's first real drive down the street and back

It had open headers there and was quite loud. After putting the midpipe on I then took it for a bit more spirited of a drive, though I'm only barely getting to half throttle in this video

From here on out it's mostly small things... I need to finish the power steering. I'd also like to add A/C. And I need to change the exhaust a bit - I love the exhaust note it makes but it's too loud so I want to try to tame it down without changing the sound too much

This is a very exciting feeling for me as there were quite a few moments I was not sure this would happen. But here it is! To those who read the build thread and supported my crazy dream to do this swap, I want to give a


Without the support and encouragement of a lot of you along the way I don't think this would have been possible!

The build started September 1st 2020 and I am writing this just after the last video was recorded on 4/14/2022. That's 590 days - just over a year and a half of blood, sweat, tears and welding splatter. But it was all totally worth it! I am so thankful I challenged myself to do this and excited to start thinking of what I will do next. If I had to guess I will be putting an N62 into something else

As with all projects of this caliber, it is never truly finished. The build marches on



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