The [Ongoing] Story of Hilde30

[dice2012]

Trying this again. Decided I should probably stop putting off doing a write up for my car. It’s been about 8 months since I dove into the first phase of my project, and I keep telling myself I’ll just write it later. So here we are.

My hope in writing this is to keep a log detailing everything I do to the car, not just for personal satisfaction when looking back, but also in case the info can help someone else. Never done a write up like this so hopefully it’s decent to read. Kind of torn between doing this as a scientific style write up or a narrative. Guess we’ll see where this lands.


Part Zero: My First Mistake
I got this car back in early 2021. I was a freshman in college who decided that his pockets were too heavy and that engineering courses hadn’t gotten hard enough yet.

After months of browsing the local car listings and seeing one too many rotting S chassis, I found a listing on Facebook marketplace for a 4 door late model in delphin metallic and instantly knew it was the one.

I ended up scrapping together every last cent to my name and bought the car. It was far from perfect. It had no AC, the car would shut off if I turned the blinkers on, it knocked on a cold start, and the headlights would somehow trigger the ABS. But it was mine, and I thought it was the coolest thing ever. I named it Hilde, short for Hildegarde, after looking up cool old German names (I was a bit naive at the time but looking back I could’ve picked worse).

I drove it every summer when I was back from school, wrenching and doing small fixes to keep it running. I learned the ins and outs of the ignition system, became a pro at diagnosing a gunked up idle control valve, and cleaned out my fair share of rats nests. I also ended up replacing the melted motor mounts and the exhaust (which had about an 8” long rust hole???) in my college apartment driveway.

By 2023, the engine knock got so bad that it wouldn’t go away when warmed up. On top of that, one day while parking at my apartment, I drove too far to the left, so one of my wheels was in a dip, causing the car to rest on the oil pan, giving it a decent sized crack. So I deemed it too risky to drive and decided that I would learn to rebuild an engine, but I wasn’t ready to dive in (engineering classes turned out to be pretty hard!). So I parked it up in the barn back home, and there it sat until Summer 2025.


Part One: Barn Find (Unfortunately Mine)
After moving back home from grad school, I got bored of the LinkedIn 9-5 job search, and needed to find an out. One day, I wandered out to the barn, and there it was in all of its rusty dusty glory: my beloved E30.

After giving it some gas and starting it up, it was immediately apparent why I had forgotten about this car in the first place. The engine knock was horrific. I never did figure out what the noise was, but there was only one way to find out.

I started my diagnosis by doing a compression test. The results weren’t perfect, but the difference between cylinders wasn’t enough to cause alarm, given it was a cold comp test, not warm. I decided that pulling the motor would give me the best opportunity to determine cause of death. So I got to work labeling all the wires and hoses, drained all the fluids, and disconnected the shift linkage and guibo (about to fall apart by looking at it wrong) from the transmission.

After pulling the transmission brace, I was greeted with yet another pair of melted mounts! It’s a miracle the entire driveline hadn’t dropped out on its own accord previously. Also for some reason somebody had left a yoyo on top of my transmission?? (String shown in the pic below)

After that, it was pretty much just carefully pulling out the motor/trans in one piece. Way easier than expected. Definitely helped to have an extra set of hands and a leveler for the hoist.

Took advantage of the car still rolling for a quick photo op. Still can't get over this pic.

From there, it was smooth sailing. Take the head off, strip the block down, and discover… pretty scored up pistons and cylinder wall. We found the culprit! It was piston slap all along. Unfortunately, that meant that I’d need to get some machining done, along with oversized pistons.

Yeesh…
I thought long and hard, and ended up buying all the replacement parts I’d need to rebuild the engine. Only then had I realized that I’d need to ALSO pay a machine shop to work on the block and just about everything else. You know what they say, measure once cut twice. I also received some pretty gross looking “refurbished” connecting rods, which didn’t instill confidence in the direction I was taking.

So, back to the drawing board I went. Ended up getting a refund for pretty much everything! My new plan was to find a good engine to swap in, as it seemed that doing an engine swap would actually be cheaper than rebuilding my M20 (RIP).

(Let's hope the pics actually show up this time. Is there a secret to getting more than 5 pics on a post?)

[2mAn]

If at first you dont succeed, try again...

(and a MOD will delete the old one so nobody really knows)

[grandeswag]

That piston looks absolutely minty dude..

You can host the images on another site to have more than 5.

[dice2012]

Thanks for the tips guys, R3vNoob here.

That piston looks absolutely minty dude..

Shoot, maybe I should have just shined em up and ran it would have been a lot less expensive. Jokes aside, I'm excited to show what I have in the works now. Cooking up some good updates, just tough with living in a new city and new job.

[delamaize]

(Snip) My new plan was to find a good engine to swap in, as it seemed that doing an engine swap would actually be cheaper than rebuilding my M20 (RIP).(snip)

Psst....Hey......M60 swaps are pretty cool.

[dice2012]

Ok so it has been quite a few months since my last update, BUT I have not been neglecting my project (as much as this thread). In this time, I started a new job at a big hospital (starting a new lab and putting my degree to use!!!) and moved to a shoebox room in a cozy (tiny) apartment in the city. The new source of income to fund my money pit was very nice, as there have been a lot of expected and unexpected costs to sink; unfortunately, I am learning that the 40 hour work week makes it hard to work on personal projects, but I persist.





Phase 2: Eating my veggies before my dessert


Getting into the technical side of things, I started cleaning out the entire engine bay, because what good would a shiny new engine be if it was sitting in a dirty, rusty engine bay?








It was hard to figure out where to start. Everything was on top of something else; bolts were rusty, connectors were stuck with the strength of 10 strongmen while also being as fragile as an ancient ceramic vase used to store dates (or perhaps wine ).





I decided to tackle the driver's side headlight, as it was the easiest thing to get to (and the AC compressor was not budging yet). I found that the headlight wiring harness must have corroded pretty badly previously, as it was repaired by soldering the ground line onto a wire with a fork connector, which was then bolted to the rear driver's side hood bracket. Maybe this was the source of the incessant buzzing that played over the radio when I turned my headlights on??? Gotta respect the engineering; however, I’m going to replace the permanent temporary fix with a true permanent fix (as a child I always wanted to grow up to be a previous owner who left the car BETTER than he found it).


From there, it started getting easier. The AC condenser and passenger headlight came out like butter. With a lot of Kroil and a big wrench and mallet, the AC compressor broke free. Next came the fenders and front valance. At this point, the engine bay was already looking a little less cluttered (and unfortunately the rust issue was progressively creeping out...).





The ABS unit was scary. The screw securing the plastic cover felt super soft, and I thought it was going to strip even using the right allen key. Most of the nuts on the brake lines were stuck tight, and I didn't feel confident without having the right wrench. I sprayed everything down with penetrating oil in response and moved on.


The airbag sensors, power steering pump and reservoir, and charcoal canister were all easy enough. After removing the AC lines and wiring, the passenger side was free!! I gave everything a quick vacuum to tidy it up and clear out some of the old acorns that some temporary residents had left. Needing some motivation, I sat in the driver's seat to visualize the end product and instinctively pressed the clutch in. The pop of my clutch slave cylinder exploding was accompanied by the splattering of all of my brake/clutch fluid ejecting over the floor of the garage.





Whoops.


On the bright side, the ABS unit came out pretty easily after that. Flared end wrenches were really helpful. The brake booster and master cylinder came out so easily too. I definitely recommend some extensions and swivels, especially if there is still an engine in the car.





Fast forwarding as I’m getting tired of writing and the rest was all pretty self explanatory: The original rubber brake lines were shot and need to be replaced, one of the brake booster to ABS lines needs to be replaced, there was about a pound of rat poop and a rats nest under the cowl next to the AC fan(hey maybe thats why my car smelled so bad), there was a shop towel zip tied to the wiring harness coming off the fuse box/hood latch cable (hopefully not structural???), and I got the wiring harness free from the front of the bay. I tore off all the rubber sound deadening/heat shielding panels at the firewall and discovered original paint in mint condition!!! Even better was 0 rust under the fuse box.





Finally, I yanked out the cruise control and airbag control harness, and with that, the engine bay was pretty much empty!!! The airbag module was cake, just dropped the kick panel (already down from the brake booster), took down the body ECU, and then pulled the SRS module and the airbag sensor wires.








The only thing left to do now was give the bay a good scrub to see what was hiding underneath the 36ish years of grease and grime.






With some degreaser and a hand brush, I took care of most of the grime inside the garage to minimize the amount of mess I made. I finished it off with a spray from the pressure washer and was so excited to see the bright shiny rust patches all over the bay. It was on the wheel wells, the lower bay panels, and holes just where the panels met the wheel well. The windshield wash bracket was toast; the base of the passenger side wheel well/suspension tower had some rot where the 3 panels overlapped.





Way more work than I first bargained for





This started out as a simple “why is my engine making that noise?”, yet it is slowly turning into a full on front end restoration.


Somehow I f*cked up my e30, and I couldn't be happier.

[Northern]

My AFM and washer res brackets were quite crusty underneath and my front right corner is not that far behind how yours looks. Seems to be a fairly common spot but at least it's all fairly flat/accessible/not visible.

[82eye]

great progress. jealous of all the work.

[dice2012]

My AFM and washer res brackets were quite crusty underneath and my front right corner is not that far behind how yours looks. Seems to be a fairly common spot but at least it's all fairly flat/accessible/not visible.

Yeah, for real, glad I'm not alone! I wish I had a better pic of the washer reservoir bracket. The entire left side of it was rotted away other than where it was welded to the wheel well panel. It was pretty scary seeing all the rot for the first time. I've already dealt with some of the problem areas, and it's definitely more daunting to look at than it is to actually repair (although making it look pretty might be another story for me)

great progress. jealous of all the work.

Thank you for the support!! It's crazy how far it's come. I definitely still have a ways to go, but it's nice to see the progress compiled.

[dice2012]

It's update time!!! There are rumors going around the NE30 group that there's going to be a meetup in September, so the race to finish is officially on.

Part 3: So anyway, I started grinding
Not sure why I said phase before, when these are clearly parts of a multi-phase project car



This phase was easily one of the most daunting for me so far. The engine bay is obviously covered in rust, and once I get the engine in, it would be magnitudes harder to weld and paint. I have zero welding experience, so I pretty much went into this knowing I could completely f*ck everything up. Fortunately, it seems like most of this stuff can always be cut out and redone if I messed it up.



With my limited expertise on the matter, I decided that the best place to start would be the part that looks the scariest, with many bends, turns, and overlapping panels.



Starting with the wheel well, I drilled out the spot welds, and used a dremel to make small cuts. This area has definitely been repaired previously, and the geometry was hard to follow at times. There was a small hole in the frame that I decided to cut out and patch with some 16ga steel first, as it did not seem too crazy, and it would be hard to get to later on.



Following that, I drilled the spot welds out of the engine bay frame rail panel (This was so annoying in some spots. Plus whoever did this last made some welds which were difficult to get at with a grinder or dremel.)



With some determination, I ended up getting the crusty portion out of the bay!



I cut out the rotted portions with my dremel, and made some patches. Once it looked right, I welded everything back in the reverse order.





Following that, everything else flowed in a similar manner. Mostly cut out a square, fabricate a patch, realize I overshot and made it too big, trim, realize I overshot and made it too small, repeat.

I had to address both frame rail panels, bracket holes on both wheel wells, a few firewall and transmission tunnel rot holes, and the hood support bracket. All in all, I hacked away at it on and off over the course of the past 5 months, taking breaks to work on other things when I got frustrated or felt unsure.



The transmission tunnel and firewall were really annoying to patch, as I had to pull back the carpet, which required pulling the seat and some of the HVAC/interior bits, but I'm glad I did it.



That also allowed me to address some of the HVAC problems while I had stuff apart. The main problems were: rat poop on the recirculating flaps, rat nest on the AC evaporator, and a broken recirculating flap arm (turns out it was just a small clip that held the rod in the motor arm, super easy once I pulled out the radio). I have a new blower motor and proper brackets coming to replace the zip ties holding everything together. I figure now's the best time to address that before everything goes back together.



For having never touched a welder, I'm pretty happy with how it turned out. There are 100% some spots that don't look pretty, but I'm hoping that a light skim of body filler will take care of that. I'm hoping it ends up looking good, but this isn't a show car by any means.



Next up: paint!!!

[2mAn]

Nice job. cutting out rust and replacing with fresh metal is always a big task that seems daunting at first... but practice makes perfect

[dice2012]

Told you guys I was racing to the finish

Part 4: Call me Homer, the way I oughta see this project through

This part started well before paint even left the gun. I worked my *ss off all week so that I could leave work at 11AM on Friday. Lots of early mornings in the lab, many more late nights. But I had a long journey to get everything on my shopping list.

The first step was to get paint. The local Colours hooked me up with pretty much every consumable I needed (Paint, primer, seam sealer, body filler, stir rods, cups, strainers, etc etc etc) for about $300, which was way better than I expected. I went with a grey epoxy primer under a single-stage paint, and they mixed the Delphin metallic pretty well! Next up, I had to go home and grab my parents' trailer. I ended up driving about 3 hours up, borrowing a nice paint sprayer and seam sealer applicator from a local E30 guy, buying a supplied-air respirator system off Marketplace, and then grabbing an air compressor rental. I finally got home just after 8PM, having driven about 200 miles to grab everything.



I started prep the next day by thoroughly degreasing the bay, then sanding everything down to bare metal or original paint with 80 grit. This step took about 4 hours, even with my girlfriend helping. We celebrated this win by going out to a bar with some friends until 3AM. Maybe not the best time management decision.



After that, I put a nice coating of seam sealer over every seam I had unearthed during the rust repair, and did some on the backsides/over any very questionable welds for good measure. I found that using a bunch of chip brushes to smooth out the sealer helped a ton. I didn't go for the OEM ripple finish, but I like how it turned out.



I also threw on some body filler on most of the terrible divots left behind during welding. I finished up the day by sanding down the body filler, and then scuffing up everything with some 220 and 320 grit sandpaper. Probably would have worked better to get some scotch brite pads, but I couldn't find any at Lowe's.



We finished out the day by masking up the car, setting up a makeshift paint booth with a pop up tent and plastic sheeting, and masking off the firewall. It will make more sense later on why I did this, but the hope was that since the firewall paint was already pretty good, I could just prime the small patch areas, which would require less cure time, thus allowing me to apply some adhesive heat shielding to the firewall/transmission tunnel in a week or two. Also, I figured that since the heat shielding and engine would cover up most of it, you wouldn't be able to tell either way.



The next morning, I woke up in a cold sweat, realizing that I forgot to use seam sealer on one of the iffy welds. I ran out to the barn, fished the seam sealer tube out of the trash, threw on a new nozzle, and it still worked! Ended up finishing up the seam sealer there, and any other place I could find, and did a final once over with some 320 now that the masking lines were hard set.



After a final degrease, setting up my makeshift dust filter/intake fan, and wetting the floors, I was pretty much ready to go. All I had to do was hook up the air compressor to the compressor lines/spool hard-lined into my shop (my actual compressor is only 4cfm @ 90psi with 20gal, rental was 14-16cfm @ 90 psi with 20 gal, but my shop has an in-line air dryer/filter and hose spool which I wanted to use), and change out the quick-release fitting on the hose for a high flow fitting. I forgot that the hose was pressurized (about 30psi) since I had already plugged it into the new compressor and did a quick test startup, so when I did the final turn of the wrench, the fitting went flying across the shop (fortunately, I was pointing it at the ground and away from me. Boy Scout gun safety training coming back to me). I got the lines all hooked up, started up my dust fan, and turned on the supply air pump for my respirator.



^Used a 1080 micorparticle hvac filter, probably $10. And duct tape obviously.



I used the same 1.4mm tip for primer and paint. Probably could have used a bigger one for primer, but I sprayed it on thick and got good coverage. Not much to say for the spraying process, got bored during the 15-30 min flash times between coats and sat outside while listening to some liquid dnb/uk garage. Felt absolutely calm despite the 2 cups of coffee I had downed in lieu of breakfast.



I ended up doing 2 coats of primer, sand down with 400 grit, and then 3 coats of color (just on the engine bay, no paint on the firewall or under the wheel wells since they're getting different treatments like chip/rock guard and insulation). After about 8 hours of painting, waiting, and a few breaks for food and water, I had a repainted engine bay. So here it is:





Some before and after of the drivers side for comparison









And with that, the engine bay is ready to be reassembled. At this point, the boxes of parts are pretty much overflowing out of the garage, but I should have everything to finish the job.

Next up, finishing the engine I've secretly been working on and reassembling the engine bay.






Afterthought:

I am actually so happy I finally got the paint done. Maybe not the best finish, but the bay is relatively one color, and I love how dark the color turned out. I think the paint matching to the firewall was pretty great despite masking it off, and I'm hoping to cover it all up, anyways. My goal is to refinish the rest of the car in delphin, hopefully ending up darker than what it is currently, whether due to factory paint or sun fading.

The supplied air respirator may be overkill to some, but it was reassuring knowing that I had fresh air while spraying nasty isocyanates and other harmful solvents. Plus, at $500 for a new in box two-mask setup (normally MSRP is $2500 ), that made it CHEAPER than just buying 2 full-face respirators (for me and gf) with the pink filters while being way safer for HDI/Iso. Gonna have to find a nice low-profile half mask that I can wear under my welding hood; the fresh cold air supplied by the pump makes life so much more bearable when doing these jobs.

Let me know what you guys think. I think I won't be able to fully tell until everything is put back together, but I'm honestly pretty happy with myself for having never done welding, bodywork, or paint before this project. Also, I think I only used half of the quarts of paint/primer that I got, so I have a LOT of extra paint. Anyone have ideas what I should do with it? Maybe spray the fender I did some sh*tty rust repair on, or the is lip I have sitting in the attic? Only problem is it is so much darker than the rest of the panels.

About the title: My girlfriend really wanted to see the Odyssey this weekend. Instead, she got to help me prep and mask a car for two days straight. I owe her a movie night and a nice dinner next weekend...

[dice2012]

Buckle your seatbelts (assuming your buckle receiver still works). It's been a packed few weeks.


Part 5: Hilde gets an S52 – the good, the bad, the ugly


I started off putting the engine bay back together. I used DEI tunnel heat shielding, with their aluminum tape to cover the seams. While I did that, my girlfriend kindly painted the subframe with a random engine enamel.








For the brake booster, I was originally going to use a 944 booster and E32 master, but I ultimately chose to go with an e9x booster for better brake assist, with very little modification needed to install it. I got the booster and master cylinder together from a UK car in order to have the ports on the right. I used M12-M10 bubble flare adapters to make my original brake lines work, and used a remote reservoir/e9x booster conversion kit for the bigger clevis pin to the brake pedal. The original ABS unit and brake hard lines went back in, as they had no rust or kinks. I also finally replaced the clutch slave cylinder that exploded, along with a new clutch hose and master cylinder elbow.





I kept the G260, as I didn’t want to deal with sourcing a new driveshaft/differential (for now), but I also already had a lot of the bushings needed from when I was going to rebuild the M20. I started with the output flange (came off easily with the right socket and impact gun), selector shaft seal, and input shaft seal. It took 3 cans of brake cleaner to clean off the baked-on clutch material and transmission fluid, and I used some Curil T2 on the input/output flange mating surfaces.








I finished it off with new selector bushings, hardware, and a DSSR with the 10-degree twist. I mocked up my new Z3 1.9 shifter to see how it would go, and some of you might already see the problem I faced a bit further on.





I returned to the engine bay, taking out the HVAC upper housing/flaps in order to give everything a good spray down. I also discovered ANOTHER rat’s nest, this time ABOVE the HVAC housing. It was hidden by the housing, which explained why the cowl still smelled like pee and a hamster cage. I put everything back together with a new blower motor, motor strap, and finished it up with new plastic housing straps (seriously BMW, why are these $40 new???). The rats bit through the wiper wiring insulation, but the strands inside were fine, so I just wrapped it up with some electrical tape and called it a day.





I also did some failure analysis on the recirc. flap arm. The screws holding the motor in the HVAC box came loose, allowing the motor to move around, resulting in the motor arm swinging past the metal stop. This resulted in the arm overextending, snapping off the plastic bushing that held the rod in place. I tightened everything back up, put a new bushing in, and it worked perfectly again.





Also, here’s some gore of the HVAC upper housing, where the rats decided to chew all up on.





Back to the engine bay, I bolted up the E46 gold tag rack that I got from a salvage yard (only 100k miles!) using metal swap spacers on top of the rack. I put the subframe and rack in, along with the steering column and knuckle, which had a new poly steering coupler to replace the old rubber one that was held on with one bolt, and was almost completely fallen apart.





The coupler looked almost as bad as the driveshaft guibo, which I then took off to replace with new OEM rubber. The vibration dampener came off to give the DSSR space. It came out easily enough with nuts on the ends of the knurled studs and a hammer/drift.





Much better





I finished up the suspension by installing new control arms, CABS (which I will have to replace as I did not heed the warnings about orientation, and now have CABS 180 degrees from how they are supposed to be aligned), and the old struts/housings with new rubber brake lines. Sway bar install to come, I still need to harvest the brackets off the old control arms.





Now comes the fun part. The engine I chose is an S52 out of a 1998 Z3 M Roadster with around 110k miles on the clock.





I drove 4 hours away to the middle of New York, and used the trip as an excuse to stop by FCP Euro to make some returns from the M20. This all happened back in October of last year, and it sat until mid-April, when I needed a break from welding and felt ready to tear apart another engine.





The oil looked fine, but the coolant was brown and murky, so I suspected that someone ran a bad mix of coolants. There were no flecks of rust, so I’m hoping a good flush can fix things. I pretty much stripped the engine down to the head and block to assess the cams and rods. The head stayed on as it had good compression before being pulled, and I was not feeling like learning how to time an engine or deal with cams or valves yet.





The cams looked great, and the rods didn’t move when I gave them a wiggle, so I gave it a fresh coat of black engine enamel and started to rebuild it.





I replaced all the gaskets I could without pulling the front timing cover or head (or cams). As standard with most swaps, I used a drilled oil pump nut with safety wire and loctite and sealed it up with an E34 oil pan.





I replaced the thermostat housing with a fresh OEM plastic unit, used an 80C E30 thermostat and a Stewart high performance water pump for better temperatures, and an aluminum water pump pulley (I cracked the plastic one while attempting to take off a stubborn clutch fan). After throwing on the alternator, power steering pump, and tensioner pulleys, it was looking like an engine again. I also got a rethreaded brown top coolant sensor to replace the throttle body heater port, which connected to the E30 temp gauge.





I hammered out two broken studs on the exhaust manifolds and then bolted them and the secondary air injection system up to the block with fresh gaskets. I wanted the SAI as I thought that it would be good to keep the new cat in my exhaust healthy for longer (future me learned that the hose routing and wiring length make mounting the air pump a pain, so this may be getting a revision in the future).





I opted to stick with the M20 clutch/FW as I already had a full clutch kit for it. I got the FW resurfaced at a local machine shop and took a rotary tool with cutoff wheel and carbide bit to the bits on the back of the oil pan that stuck out too far. I was fortunate to still have the hardware from my M20 oil pan, as they were the perfect length to fit in the two rear bolt holes holding the oil pan to the rear main seal housing.





Using only 15/16 of a slice of bread, the back of a valve stem tool, and a rubber mallet, I pushed the pilot bearing out of the crank. With the new bearing installed, I installed the S52 bell housing dust shield and mounted the M20 flywheel and clutch setup.








Mounting the transmission took some lifting, but it was not terrible. I only used the four large torx head bolts, as the other mounting holes on the G260 did not line up with the S52 threads.





At that point, the only thing left to do was drop in the engine. Took about 45 minutes all said and done, with one extra set of hands, an engine hoist, and a jack. Cake.





I seated it on AKG swap mounts, a condor speed shop transmission brace, condor speed shop poly transmission mounts, and AKG aluminum transmission mount cups.





The shift carrier was very far off at first, so I had to jack up the engine and transmission a bit to shimmy everything around a bit. The shift carrier is still a bit further to the passenger side than I’d like, but it’ll work for now.





I found that the shifter would hit the far right corner of the console in fifth gear, and reverse was nearly centered. It was only after an hour of trial and error trying to shimmy the engine that I realized the Z3 shifter was backwards. After rotating it 180 degrees, it sat almost perfectly centered.


(forgot to grab a pic. Next post I promise)


The wiring was a breeze. Every connector seemed to have an exact match, and the diagrams people have shared made it so much easier. I think my harness is weird, as the connector for the evap comes off with the bulk of the wiring on the engine, rather than next to the MAF plug, as it's shown in just about every wiring picture (maybe just a Z3 thing). I bought a custom wiring harness for my E30 and engine harness configuration, and all I had to do was plug in the harness adapter, tap into some pins on the C101 and AC connector, and zip tie everything to make the cable management look a little better. I still have to tap into a switched +12v for the ABS signal, but other than that, the harness is hooked up to the car.





Next up, I dropped in the Z3's radiator, using the S52's upper radiator hose along with a NAPA 8484 hose trimmed to fit as the bottom hose. The lower hose may need to be redone, as the elbow is a little bit flexed, but it should work for now. There is about 1.5” between the water pump nut and radiator, so it seems like no modification will be needed there.





I used the original heater core plumbing from the M20, with a cut section of the big T shaped hose to connect the return line to the block. (also, I mixed up the supply and return, so these will need to be switched)


I mounted a 16” medium pusher SPAL fan to the radiator using some M8 hardware and 3 SPAL brackets. I also put some pieces of foam on the corners of the SPAL fan to try and prevent it from rubbing against the fins. For the wiring, I am using the stock aux fan circuit/relays. I salvaged the plug and wiring from the original aux fan, used crimps and heat shrink to splice in a new aux fan resistor (old one was DEAD), and crimped on some insulated spade connectors to plug into the SPAL plug. I also installed an 80C/88C temperature switch from a 318I onto the radiator to make it turn on when the thermostat opens, along with a fresh pigtail connector. Pushing the AC button turns it on, but I will have to wait until the cooling system is fully bled to see if it turns on with the radiator switch.





I dropped in the charcoal canister, which my dad helped rebuild with some activated carbon and filter sheets from Petco. I used fuel hose to connect the canister’s big port to the fuel tank line, and left the small port open to atmosphere, as I tuned out the EVAP pcv. It was fully painted black, but when I was attempting to put a vacuum line on the small nipple to see if I could connect it to the intake port, the JB weld I used to reinforce the top cracked, so I had to spread some more on top, ruining the finish.





This meant that I could finally unwrap a part that I had been hoarding for months, an e39 fuel rail with the FPR built in, courtesy of Chilezen. The injectors came off the old rail, were given new O-rings and dropped into the new rail, all assembled on the intake manifold.





After dropping in the intake, I routed the new fuel lines. I cut and welded the CCV drain nipple from the Z3 dipstick onto the E34 dipstick, which went pretty well. So I finished up the routing of the CCV drain line, ICV, and intake tubes.





The last piece of the puzzle was the exhaust, and I went with a Syncro Design Works swap exhaust. The install went well, though getting the downpipe onto the manifolds was a PITA. I had to jack up the bottom of the engine with a 2x4 to get clearance past the exhaust studs (cursing my past self for laziness and trying to save a buck instead of buying 4 more bolts and replacing the studs). But after a few hours of fiddling around, I finally got the exhaust bolted up!





It sits very tucked up into the car. I wish the exhaust tips and muffler sat a little lower, but I couldn't quite get it to adjust the way I wanted it to, and this unfortunately was exactly what happened with my previous exhaust too, so it’s either user error, or my car is FUCKED. (Maybe both?)





The only thing left for me to do was fill the car with fluids, prime the oil pump, and start the car, and the thought of forgetting something was making me sweat.


I got to work putting distilled water in (coolant would come later once I confirmed no leaks, plus it would be good to flush the engine once or twice). I filled the engine with about 6.6 qts of 5W40, put some DEX III ATF in the power steering reservoir. I disconnected the ignition coils, pulled fuse #11 to disable the fuel pump, and turned the key to start priming the engine. The power initially went out, making me think I messed something up. I realized that I had completely neglected to charge the battery, which had been sitting for about a year now. I hooked up the jump pack, and the engine turned over. After about 30-60 seconds of on and off cranking, the oil light went out.





Now, at this point, I’m terrified. I started doing my final checks, all the wiring looked right, hoses and lines looked right, and I topped up the half tank of gas with some 93 to bring the octane to about 89-90, not great but good enough for a first start.


I connected the ignition coils and plugged in fuse #11.


I turned the key to accessory, then ignition. Turned it a click further to crank the engine over annnnndddd it fired up and immediately died. Tried it one or two more times before I decided to pull the big bulky e36 air filter, as I figured it might be causing the intake boot or ICV hose to not seat right.


I turned the key one more time and this is what happened:


https://imgur.com/a/s52-build-AXEHOkr


I kept my foot on the pedal lightly just in case the ICV was stuck, causing it to stall, and it stabilized itself after a minute.


It's alive!!!


https://imgur.com/MPovvNd


So the good is my S52 swap runs! The clutch works, transmission spins the wheels, and the shifter is so crisp (maybe too much, I almost miss the sloppiness of the shifter before). Steering feels fine with the wheels off the ground, I have new all-seasons to go on the old basketweaves until next summer, and the E34 oil level sensor works, confirmed by the oil level light turning off for the first time in years (surprising, as the plug housing was completely gone when I got it, so I had to plug the spade connections directly into the plug by hand).





The tread is looking like the hairline of someone going into their 30s…





Over on the bad side, there is a water leak under the intake manifold, probably around the area of the heater circuit. It started up lightly, but after turning off the engine while warm, it dumped about half a gallon of water on the ground. So along with that, I still need to put actual coolant in, and the cooling system needs to be fully bled (the e fan won't turn on at the first or second tick mark on the temp gauge). The throttle cable feels super stiff when the throttle is fully closed (mostly with the engine on), the idle stumbles and sometimes dies when letting off the gas, and I still need to re-boot the passenger axle, assemble the front end body panels, and wire up new connectors for the lights and side markers. Also, the CEL is on.


Finally, onto the ugly. Unfortunately, while testing how the brakes felt, one of the brake hard lines on the rear passenger side exploded, dumping brake fluid all over the floor. Also, a number of hoses turned out to need replacing, including a few on the heater circuit, the ICV to intake boot connection, and the brake booster vacuum setup.


Not much else to say for now, but the S52 swap is getting there. My hope is to drive this thing once before the snow hits, but there is definitely still a lot to be done before it’s roadworthy.

[grandeswag]

Great work man!

I'm just about to turn the key on my new S52 as well. SDW exhaust comes in today.

[JasonWilson48]

I second what grandeswag said.

Great job, and keep going. Plenty of time before the snow hits to get it on the road.

Also, coincendentally I am about to start up my new-to-me S52 as well. My project is a bit of a mess, and took some weird turns. I'll post my updates when I get it running.