83' 320i S52 swap and eventual rebuild

[carstereoguy]

Been sitting on this car for over a decade, and I'm finally getting around to making some progress. I dropped an M50b25NV in it in 2009, and never finished the install - life has a way to detouring you. But hey, over 10 years on the car is only more of a classic.

A friend called me a couple of months ago and mentioned he was parting out his friends E36 which he had put an S52 in. He called an asked if I wanted the engine and trans for my E21 project. Seems it was the kick in the ass I needed to get restarted...

I don't actually have any good pictures of the car on me, but it's a solid shell with a couple of rust spots (windshield and above rear bumper) that look to be much less severe than the average e21 I see these days. Plan is to pretty up this S52 that's apparently been sitting for many years since the car was crashed. Paint the block, replace the seals, waterpump, thermostat (housing too!), and do the Vanos and clutch before it goes it. It's not like there's room to spare in the engine bay with a 6 in there. Might paint the engine bay while I'm at it.

Some pictures of the progress so far:


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Engine after my buddy dropped it off. Looks like it comes with some nice headers. PO also did a M50 manifold and OBD1 swap.
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Engine on the stand with the car waiting
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This was after a lot of wire wheeling of the block

[carstereoguy]

After some rust converter.
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And paint
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I decided I wanted to retain the OEM M3 hydraulic mounts, and the E30 steel mounts seemed like the best starting point.
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You can see the gap where the mount doesn't sit against the engine flush cause of the difference in angles. I cut them apart, bent them to the right angle and added in some extra metal for support (pictures of that to come later)
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Modifying the passenger side. A stock mount above for comparison. With the passenger side it needed to be shortened and the angle decreased.
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After bending but before welding and reinforcing.
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With mounts tack welded to verify clearance to brake booster

[carstereoguy]

Are there any E21 fans on this site?

Progress is being made! Pulled the M50B25NV mockup block to get ready to drop the S52 in. As the OCD gets away with me, I'm now thinking I should paint the engine bay, and powdercoat the engine crossmember. Also considering changing the color of the car.

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Non Vanos block ready to be picked up by it's new owner
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Engine bay definitely in need of some cleanup. Thinking I'll shave off some of the mounts for things I don't need anymore to make it look cleaner.
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[carstereoguy]

Euro crossmember sporting M engine mounts. Hoping the added stiffness of those mounts will help with the tight clearances and making sure the engine doesn't contact the brake booster or radiator with driving.
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Also managed to get acquainted with NCS expert/Ediabas/Romraider software to get rid of the CEL from my manual swap on the E36 M3. The hope is now that I understand enough to use MS41 as the ECU in this swap - with the EWS/ secondary air pump/ rear O2 turned off, rather than the OBDI Bosch ECU the previous owner was using with this engine with a chip.
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[SoCalE21]

Great project!
i also have a swapped E21.
as far as any E21 fans on the site, it does seem like 80s BMW participation on here sites has dropped quite a bit over the past few years.
not just E21 boards, but also E24, E28 etc.
There was a lot of posting in the heydays of 2000 to around 2012 or so.
not sure where everyone went?

[carstereoguy]

Thanks!

Oh, interesting. Maybe they're getting to be too much work with their age. Oh well, it's nice to document the progress during the downtime.

More Progress!

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[pofo]

Love my S52 swap, its a weapon on the track. Good luck on the build.

[carstereoguy]

You track your S52 powered E21? How do you find the handling?

More progress has been made over the holidays, I've prepped the engine bay, and painted it. Hoping to get the engine in this weekend.
Prepping
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Prepping
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Primed
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Painted!
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New shift detents for the trans before it goes in.
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[hotdish]

There's plenty of room for a six on a late e21 lol, at least you have the radiator cutout in the nose panel. Shift detents were a good idea, I should have done those the last time I had the tranny out of my E36 M3.

[carstereoguy]

Sure didn't feel like there was any extra room as we dropped the engine in! I dropped her in without the transmission, which was smoother than when I put the original M50 in with trans attached. Then I dropped the crossmember slightly to allow room to slip the trans into place.
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And I got my euro bumpers that I managed to find in Canada on a car being parted out. A few pieces were too far gone, so replacement pieces were ordered. At least now I had a full setup with the rubber bump strips for a reasonable price. Also got the euro rear panel for if I feel ambitious to do the swap properly.
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[pofo]

I have some headers I used with my first set up I would sell cheap.

[carstereoguy]

I have some headers I used with my first set up I would sell cheap.

Appreciate the offer, but the engine came with Supersprints which I'm hoping to adapt.

The wiring is getting close, just waiting on an intake boot and some sensors and hopefully try for a first start sometime this month!

[carstereoguy]

1 year to the day after I got the S52, I did the test fire! Just ran it for a few seconds to see if all my wiring was correct. Unfortunately it looks like imgur won't let me host videos.
https://i.imgur.com/d1wL2AAh.mp4

First test fire was a fail cause I didn't properly disable the EWS (I'm no binary expert, but in the control bits I edited the 8th character, but byte 8 is actually the first one in the sequence in binary)
For any nerds out there - when editing the control bits, you want to change Byte 8 from a 0 to a 1 to disable EWS.
My computer had 22 which is 00010110 in binary, so I changed it to 10010110 which is 150 in decimal, saved and flashed that to the computer (along with a fullread from my M3 to convert this 528 ecu to M3 software)
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Handy intake air temperature sensor that works with the M50 manifold so you don't have to thread a plastic M52 sensor.
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Interesting thing for anyone doing one of these swaps. The intake boot with only one opening seemed like the better choice, but it puts the connection for the Idler motor closer to the throttle body and it fouls the master cylinder. So I ended up going with the one with 2 openings, and plugging one (anybody have a good source for a proper plug for this hole that doesn't cost a fortune?).
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You can kind of see it in the photo above, but the TPS was going to foul on the brake fluid reservoir, so I swapped to the S52/M52 throttle body that puts the TPS on to rather than on the back side.
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Next up I'm going to start on driveshaft and exhaust. I ended up finding an exhaust off a new 2 series for free, so I'm going to try and adapt that. Also got a driveshaft off a e46; miraculously the front half is the perfect length to put the OEM center bearing in line with the stock E21 mount holes. Also I had read that all the automatic driveshafts had the small guibo, but not the case for this one. The unfortunate thing is the back end is too short at 33" (and is one of the longer rear halves available I think). Anybody know of a rear driveshaft half longer than 33" (I think I need around 37"). I may have to resort to having something made.

Then after that it's some body work, and hopefully finding a set or recaros and re-do the interior and dash!

[Beam318ti]

Next up I'm going to start on driveshaft and exhaust. I ended up finding an exhaust off a new 2 series for free, so I'm going to try and adapt that. Also got a driveshaft off a e46; miraculously the front half is the perfect length to put the OEM center bearing in line with the stock E21 mount holes. Also I had read that all the automatic driveshafts had the small guibo, but not the case for this one. The unfortunate thing is the back end is too short at 33" (and is one of the longer rear halves available I think). Anybody know of a rear driveshaft half longer than 33" (I think I need around 37"). I may have to resort to having something made.

Then after that it's some body work, and hopefully finding a set or recaros and re-do the interior and dash!

I used a driveshaft off a E21 323i on my S52 swapped E21 with no modifications. I used a 5-speed trans off an E21 323i and an E21 3.64 LSD as well. With the S52 upfront, it was a tight fit but kept things simple for the speedo to work. The shifter required modification as the angle was terrible.

[carstereoguy]

I toyed with that idea for a bit, but then I had a ZF trans, and by the time I source a 5 speed from europe.... Well we'll see what I come up with for the driveshaft. Got any pictures of your swap?

[carstereoguy]

I guess I've made some decent progress over the summer, but still a long way to go.

I purchased a whole hoard of E21 parts to help me out getting this car to where I want it. That was my father's day - spent road tripping to pick all this up:
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I was most interested in the 323 rear end and the recaros, but it came with a spare set of euro bumper, E21 power steering, and a 323i 5 speed trans and flywheel, and a rear spoiler (unsure if I like the look or not) which I need to decide if I will use or sell.

Just got around to pulling the old rear subframe last week. The parts pile came with powdercoated suspension bits to go in. I tried flipping the rear subframe mounts upside-down as I've read a few times to get the subframe higher and control arm angle more neutral. This is where I ended up for clearance - just enough! Next I'll have to notch the frame so the trailing arm does hit as the suspension compresses.
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It should put my ride height about here with the control arm still horizontal - possibly a bit higher which I'm good with. Now hopefully the camber and toe are reasonable enough. Driveshaft clearance gets a bit tight here so I'm hoping that will work OK.
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[carstereoguy]

A little side project rebuilding the E36 LSD. I was told the diff was low mileage, and it seems to check out. Very happy with how the mating surfaces for the clutches look - don't seem to need machined. I put new clutch packs in it. Cleaned up the housing and painted it (anybody interested in the spare housing I have, could clean it up at the same time since I'm already doing one). New bearings on the way! (the large rear pinion bearing is in fact larger on the E21 than the E36).
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A bunch of wire wheeling, sanding, rust treatment and paint later - That looks better!
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New arrival - figured with the dent on the side from the previous owner I may as well start fresh.
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[carstereoguy]

For reference - this is what the E21 rear pinion bearing uses
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And the E36 (smaller)
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Still undecided if I want to run this spoiler...
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And I went from trying to find a 3.45 ring and pinion, to having two! Anybody need one?
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[carstereoguy]

It seems like the E21 diff housings were made without any provision to remove the races with a puller. This was my technique:

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I've got the pinion as close as I can get it with the 3 shims I have on hand, I think I might try and move it in a few more thousands. This is where I'm at for a pattern with 0.003" backlash dialed in
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[GraphitE21]

Just discovered this. Hopefully we will get to see this to completion. Thanks for sharing!

[carstereoguy]

Been slowing picking away at the project. I decided to flip the rear subframe bushings to get the rear subframe up higher for better suspension geometry with lower ride height. I'm hoping between that and the offset rear trailing arm bushings I can get the camber under 2 degrees at a ride height that looks nice. I was initially thinking about welding in the camber adjustment plates, but then I read some people mention that with that much adjustment you can get the axis of the 2 bolts that the trailing arm pivots around so far off each other that the trailing arm binds as it articulates which I certainly don't want.

To make room for the trailing arm with the subframe higher I notched and welded the frame, which paired nicely with patching the 2 rust spots in the front of the wheel well. Man did this take longer than anticipated.
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I decided to get shiny new hardware since this rear end swap is just snowballing. While I'm in there I may as well replace the..... and on it goes. I ordered the new bushings from walloth and netch. My first experience with them, and I thought most of their stuff seems to be OE, but in fact the bushings they carry are Febi, which I've had terrible experiences with in the past. No indications on the website that it's aftermarket crap. Buyer beware.
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All patched up. I just sprayed the area I welded for now, as the long term plan is to weld in a euro rear end, and then I'll hopefully undercoat everything at once.
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Now I'm just debating on whether I'm into the red suspension bits or not. If there's a time to paint it it's now....
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[carstereoguy]

Now I don't have the rear diff in yet as I'm waiting for a part - so this is just a rough mockup as the angle of the rear subframe could still change slightly as I finalize the driveshaft angles with the subframe raised (I was surprised how much letting the subframe angle a degree up or down impacts the amount of rear camber).
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If this is correct though, I think a degree and a half of camber will be pretty reasonable for the ride height I've got there.
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Then I got thinking about the front. In the long run I'm probably going to have to re-weld the front subframe to make sure I'm getting good control arm geometry with the car a bit lower. But then I might also run into the strut bottoming out. These are the larger 323i struts so I was just starting to price out E30 325iX Koni's which are shorter (and then shorten the housing to match)....Pricey! I happened to walk past a set of Koni adjustables I had from my old Volvo 940, sure enough, same outside diameter, but with waaaay more travel.
323i Bilstein
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Koni off the Volvo
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Only challenge is it's larger through the threaded section at the top, so for now I'm going to run a larger bearing. Might go with adjustable camber plates in the future, but this'll get it going for now. Just ordered an M48 tap so I can shorten the housing and rethread it properly.
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P.S. I now have a full set of Bilsteins for a 320i and a full set for a 323i that I won't be using if anyone is looking for a set.

[carstereoguy]

Among other little bits of progress: A nice shiney mounting plate for the brake booster - powdercoated in black, with new shiney clutch master (I love the gold hue plating).
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And a new ignition cylinder while I had the column out (the old one had a melted wire!!) with my assistant in the background.
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I found there was no way to get the cylinder in without putting way more pressure than I was comfortable with on the plastic cylinder. I ended up shaving the rib behind the cylinder in this photo (just barely visible) and it made it so much easier.
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Found out the hard way that the later cars use a different part than the early cars (early cars have a cylinder with a metal body vs plastic body on the late cars). I have a spare new in bag early cylinder if anyone needs...
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Mmm completely unnecessary replacement of bolts. I've heard these subframe bolts can really rust in, but I think this is a testament to how good this frame is compared to average. Probably took 20 hits with the sledge to get them out.

[carstereoguy]

Look at me making consistent progress. This friggin diff only took 4 months with other distractions.
The work area:
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Pinion preload
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Final backlash measurement. 3 thou, love it.
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Calling that done! Hopefully on to install over Xmas holidays.
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[carstereoguy]

Also added one of these Steel top caps in as they're apparently the weak point. I was quite impressed with the quality, everything measured exactly the same or within an thou of the stock one. We'll see how this 168mm LSD does with the S52. Have the original E36 top cap if any E30 guys want it for an upgrade.
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Aaaand my neurotic need to add struts with more travel. Will probably come back at some point to convert it to coilovers, but this is a good start.
Huuuge metric tap (M48x1). I went with the thread pitch of the volvo gland nuts which I already had, but if I had to to it again I would do the BMW spec of M48x1.5 so I could use the existing threads to get everything lined up, and then just extend them down the housing before cutting it to length. Getting this thing centered and started was a huge pain.
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Noooo don't do it, those are priceless 323 strut housings you fool!
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A better fit (I still used a small spacer below to bring the strut housing up to final height.
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Shortened with Volvo insert in!
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