Category Archives: e21

Checkpoint 1 – 10 Day Build – E21 S54

So 10 days is over. Now I’m posting in checkpoints. Every few days I post updates. I won’t be working on it as much, so daily updates might not be worth the post, so I’ll have probably 3 of these checkpoint postings until I’m done with the car. Some of the things I was going to do if I had the time is – Paint red, Euro Bumper Shortening. I must wait for that for a while.

I’ve made some progress since day 10. I managed to use the MSS5X binary tool to re-flash my MSS52HP to the specifications below. Remove Post O2 Cats, Remove Secondary Air Pump, Remove EWS, Increase rev limiter, sport mode, changed sport mode settings for my accelerator pedal.

First, I got my license!

capturemss54hp-reflash-snapshot-1 mss54hp-reflash-snapshot-2 mss54hp-reflash-snapshot-3


Then I completed the shifter assembly using Garagistics bushings!img_5280


Wired up the battery cable from the trunk to the starter. I added power wiring to the Fuse Box as well as power to the ECU as well. img_5281 img_5282


Upper Radiator Hose Mocked up. img_5283


Then I went into the details of replacing the oil pump chain and E34 M50 Oil Pumpimg_5286 img_5287 img_5288 img_5290 img_5296 img_5298 img_5299 img_5300


Drilled out the oil pan, tapped with 9/16-18 thread for an O-Ring fitting allowing a barbed hose to drain from the head.  I used a 9/16-18 nut just in case the thinner walled oil pan didn’t take the threading. img_5301 img_5302 img_5303 img_5359


Finally I started doing some other preparations, like rebuild the rear calipers and exhaust work. img_5289 img_5294 img_5295


My next post will be in another few days. If I’m lucky, I’ll have this thing running and driving by week’s end!

Day 10 – 10 Day Build – E21 S54

So here we are, Day 10. And I’m about 3/4 the way done. But the hard part is really over. The last 10 days have been very taxing on me – Very stressful. But I’ve learned a lot about my capabilities, my problem solving abilities, and how simple it really is when you have a lift.

While I might be relenquishing the Lift shortly, and temporarily, I will still be able to completemore tasks. Here’s what I have 100% completed:

  1. Coolant System
  2. Fuel System
  3. Electrical Thought – Not yet implemented
  4. Steering (no change)

Need to complete the following

  1. Brakes – Need to re-install booster – I will modify the S54 Intake to clear the booster for now.
  2. Oil
    1. Pump – Going E34 M50 pump/sprocket/chain,
    2. Pan – VAC Baffle
    3. Tap Oil Drain for 5/16 Hose
  3. Exhaust – Need to completely weld
  4. Rear Suspension. Need TA welded, Diff Mount,
  5. Receive Elongated Driveshaft
  6. Assemble Diff

Many of these tasks are relatively simple installation tasks, so they should take no more than an afternoon to complete.

Now here are some pictures of some of my accomplishments today. I do not plan to update daily anymore. My next update will likely be Saturday Night or Sunday. Thanks again for tuning in…

img_5251 img_5252 img_5253 img_5254 img_5255 img_5256 img_5259 img_5260 img_5262 img_5244 img_5249 img_5250 img_5257

Day 9 – 10 Day Build – E21 S54

Day 9, A good amount of progress today. I sorted out many of the nuisance things that were bothering me. I accomplished alot on my plate. I now know where I stand with brakes. And there is a lot of work to do there.

You can see below that after fitting the intake manifoldimg_5221

Need a new upper radiator hose. Based on the position of the radiator and the low position of the engine, I need a custom hose. Easy.


Pressed Garagistic’s 95A differential Mount in the rear carrier!


Pressed in some new flange bushings as well.


Relocated the battery in the rear. And no, I didn’t just throw it back there. There’s a battery hold-down mechanism there that will hold it in nice and tight. You can see the ground lug to the right there. This will help offset the front-heavy weight distribution.


Got my Walbro 255lph pump in. No issues getting it to fit. Re-used some of the stock hardware, but other than that, it’s tight in there with no interference. Just need to add an in-line filter somewhere. !


No intereferences anymore (about 1/2″ of clearance) between the overflow tank and the alternator Pulley. It’s important that I make sure the radiator is married to the body with minimal movement so that this does not move anywhere.


So 9 days down, and an estimated 4 days to go. I’ve put in a total of 50hours into this build since September 10th. I estimate I have another 30 to finalize it.

So tomorrow I’ll need to weld the shifters, engine ground, and a big one……Rear Subframe Bushings. They should be completed tomorrow at which point I can re-focus on the rear end and getting the subframe, trailing arms, and suspension installed.
Almost there – Getting very tired.


Day 8 – 10 Day Build – E21 S54

It’s clear that this will not be a 10 day build. More like 13-15 days. But I’ve done my best and Garagistic has been an excellent proponent. Today, I got the Differential reluctor ring installed. It involved contracting the carrier by freezing it overnight….img_5199

Putting the reluctor ring in the oven at 500 degrees F for 1hr….img_5200

Then immediately, after install it. Within 10 seconds, it will have contracted enough to stay on. Then after 1hr, almost impossible to remove without a press. Very easy way to install!


Got some front subframe work done today. It’s not pretty, but it works, and now the S54 sits on its own weight in the car. Nice an aligned!!img_5203 img_5204 img_5205

For the driver side mount, using the E36 Arms, I found out that I was only able to utilize 2 of the bolts. So I had Garagistic cut me a custom piece that adapted 2 other holes, thereby allowing me the use of at least 3 holes in the assembly. img_5208

Had to shave off the Aluminum arm to make room for the 11ga bracket. img_5209

I might end up utilizing an additional hole. Not sure yet. img_5211

Shortened the shifter mechanism. Just need to weld it up!img_5213

After final alignment of the drivetrain, I couldn’t push the engine back any further. Disappointing because now the driveshaft is just too short to feel comfortable. Therefore, I’m having the rear half lengthened and re balanced professionally.

Stay tuned for tomorrow – no welding work, but alot of ancillary tasks like intake, brakes,

Day 7 – 10 Day Build – E21 S54

It may not look like it, but a lot of progress was made this Satuday, Day 7. I was able to effectively place Garagistic’s M60 80A poly mounts in place on the modified/shortened E36 M50 Arms. The Arms bolted right to the S54 Block. The Driver side mount only has 2 bolts utilized, so I must add an adapter plate to adapt the 2 unused holes to the block’s other holes. Not a big deal. More on that later this week. Here are some of the pics: Final pics will not be posted until later this week:

Passenger Side:


Drive Side:


I also took some time to update the subframe brackets. While Garagistic works hard at creating my custom offset rear subframe bushings, I am working on holdiong those bushings down by virtue of the modified brackets, now holding down on the OUTSIDE of the body as opposed to the inside. The reason for this is because of the wider E30 subframe would make contact with the weld nuts on the existing version E21 subframe bracket. So with some modifications of the bracket, weld bolts, we’ve got a pretty solid setup!


I also had a chance to shorten the shifter lever arm as well as the shift carrier, but I have not welded it yet. More on that this coming week.

Due to the final placement of the drivetrain, I had to modify the placement of the center bearing location and I decided to add rivet nuts as opposed to weld studs. This was actually pretty easy to implement.


Day 8 is Monday. I’m taking off this Sunday, so no work or progress is being made today. I want to accomplish the following:

  1. Weld the entire Front Subframe complete – Paint it.
  2. Side Radiator Clearance – Cut/Weld if necessary
  3. Install rear subframe bushings – Weld Diff Mount to Frame
  4. Measure rear driveshaft length – send out for lengthening
  5. Weld downpipes.

A lot planned – Stay tuned!

Day 6 – 10 Day Build – E21 S54

Today I got a couple hours to work on her, but I did go a long way in establishing engine position. Using E36 Arms, I was able to get very close on both sides using Garagistic’s M60 mounts. I might shave them down to get the right size, but the M20 ones might be more appropriate. I’ll  try it with that tomorrow

Drive side: No interference with Steering shaftimg_5166

Passenger Side – No interference with Headersimg_5164

Got the Transmission mounts in, This is just temporary and will EITHER be welded together and utilize 4 rail bolts, OR I’ll adapt an E30 trans brace and extend the arms to install into the 4 rail bolts.


Again, this is temporary so I can get the proper driveshaft alignment.  img_5171 img_5175


Before I get the engine arms in the final spot, I had to ensure that the radiator AND coolant reservoir fit. Everything fits perfectly. Upper and Lower hoses must be adapted to fit. This is no big deal. The thing that concerns me is that the alternator pulley comes very close to the coolant reservoir. I think I must shift the reservoir a bit to the driver side so that the clearance is adequate, regardless of the polyurethane mounts (which should, by the way, hold the engine very steady with minimal movement).img_5177 img_5178 img_5179

Things are looking grim to get this done in 10 days, but I keep making progress each day. Saturday should be a big day. Stay tuned

Day 5 – 10 Day Build – E21 S54

Not too much progress. In fact, I realized that the sump on the S54 is rear and as a result I could barely install the subframe, let alone fit the steering rack. The result was to acquire an E34 525i M50 oil pan, which I then fitted and got a much more desirable result.


So today was a learning experience. I am at today where I thought I was yesterday, Now I need to acquire an E34 525i oil pump and pickup, probably going to mock additional front sump baffling and some pickup running to the rear of the pan as well. This prevents the engine from starving of oil during hard acceleration.

Other than that, just banged back the firewall a bit more to make the clearance I need to mate with the driveshaft. It’s going to be tight – real tight.


I’ve been resting the drivetrain on the ground as I drop the car down on it, then bring the hoist to lift it INTO the engine bay, guiding it on the trans side by a floor jack. That helps me then position the subframe.


So the advantage is further back center of gravity and radiator clearance. For all I know I might be able to fit the radiator without a hiccup. Let’s find out Friday!

Get the engine and trans brackets welded and it suspended on its own.

Slightly modify oil pan for steering rack clearance – easy.

Lower the car and start measuring for other items of concern!




Day 4 – 10 Day Build – E21 S54

Today was monumental. Got a whole lot done in 4hours!

Because the E30 parking brake cable did not fit into the E21 tunnel, I simply tacked it together. I’ll paint it later.


I welded the radiator mounts. Will be painted later. img_5101

So day 4 I got the S54 in the car. Lifted it by traditional means with a hoist. It wasn’t all that bad getting it in. I needed to cut the front radiator shroud area to get it fit. Please note that this is NOT the final resting place. it will get pushed back at least another 4-5 inches.

Below, I installed the front half of the driveshaft. I already got the rear half in and aligned to the E30 subframe. That already defined the center bearing location as shown in Day 2. Now that it’s sitting suspended as shown, I can place the engine and mate it to the driveshaft. Once mated, the engine is now in place.


It took no more than 45 minutes to get the engine in. It’s sitting much further forward than I’d like (aka the driveshaft and transmission are way off and the engine needs to sit further back).



As of today, the S54 is sitting on the subframe, unobstructed and the trans bracket is installed, but will need to move much further rearward to mate to the driveshaft.

I didn’t do too much with the subframe. Just grinded it down, but no welding today. Stay tuned for tomorrow! Garagistic has some pretty sweet 80A mounts that I plan to use that will allow it to sit exactly where it will live with minimal movement and minimal vibration transfer. img_5116

Got the exhaust setup ready to go. Days 6-8 will be reserved for welding of the downpipes, the muffler, and the midpipes. img_5113

I welded the exhaust hangers up a bit better today. I welded lips on the exhaust stem so that the hanger sits right in the center and doesn’t move side to side on harder cornering.


I also welded studs for the rear subframe lower poly hold-down brackets. I did this because the E30 subframe is wider and the subframe was actually hitting the bracket weld-nuts. So I removed the weld nuts from the brackets, I welded studs from the inside flush, and will now bolt the bracket on the OUTSIDE of the body. The only thing I need to do is elongate the subframe bolt.

Removed weld nuts in this pic…


Welded studs (countersink screws) from the backside pointing outward. img_5105

I need to clean these welds up, but the idea is that now the E30 subframe will not hit the body due to it being wider than the E21 subframe. img_5104

Thanks for reading. Standby for more work tomorrow as we set this drivetrain in it’s final resting spot!

Day 3 – 10 Day Build – E21 S54

Day 3, primarily reserved for Exhaust, Suspension, and radiator mounting.

Fuel filter stuff removed. I am going to a walbro 255 external pump for this assembly. I’m sticking with the same fuel filter (new), and fuel accumulator to keep fuel pressure up on starts.    img_5090


Front hubs cleaned up, installing new bearings and races. Then install onto GC struts.  img_5083

Mounted the E46 M3 exhaust – Had to cut out some of the piping to fit. I didn’t want to do a completely custom exhaust system, but it looks like that’s what may happen. Everything is custom.

Thus far, I’m going with 2 mounts for the muffler assembly itself. Then after I start welding the mid pipe, I’ll be adding a 3rd one in the same vicinity.

The top of the muffler is just at the top of the spare wheel well I cut out. Might need to figure out a new method of capping the wheel well. img_5065img_5088 img_5067

I decided to use the new exhaust cut outs to plug the old exhaust outlet. I maintain the same curvature, bend, and character line, so it’s seamless. img_5082


For now, I’d like to simply add weather stripping, but in the future outlook, we’ve got some cool Ares LS1 ideas for this exhaust.

The radiator mounting is being prototyped, but at the moment this works very well. Used some M12 bolts, 19mm head actually fits these poly bushings perfectly. img_5074

Clamp the bolts down – to be welded later. img_5076

Bushings slip right on top. Square off the head of the poly bushing so it accompanies the radiator and it’s not moving anywhere!img_5078img_5079

Out with the old!img_5080

In with the new, Let’s get that S54 in tomorrow!

Day 2 – 10 Day Build – E21 S54

Today was all cutting and grinding. Turns out I didn’t need to do any E21 fuel tank siphoning. I just needed to bang it back a little. So with a bit of persuasion, it turned out just fine and cleared the subframe.

Installed parking brakes. E30 parking brakes fit just fine, but the crimp does not fit into the tunnel like the E21 does, so I will need to simply tack weld it in place so it stays solid.



You can clearly see the offset. I did have to cut the frame to get it to fit. You’ll see I cut much more later. i will weld more metal in place later. img_4989

Cutting out the rear wheel well. Making room for the exhaust. That’s for tuesday. img_4987

Look at the interference on the E30 subframe to the E21 body. img_4993

img_4999installed the diff housing and got a rear engine position. Very exciting.  img_5002

The E46 driveshaft has more of a nub than the E30 diff will allow, so I had to grind down the driveshaft to get it to fit squarely on the e30 diff input flange.



Much better!img_5015

Installed the driveshaft just to make sure it clears the gas tank hose. It clears!!img_5005


Now that I have the diff in place, I can see where the rear cover ear will mount up. Very close, but still offset. I’ll need Garagistic’s custom offset diff ear mounts to get this mounted!

After the installation of the diff housing,  I just needed to get the input shaft location. Attached the driveshaft and now I am defining my engine position.

I welded the driveshaft center bearing brackets to the body and the front half driveshaft now attaches to the body without the need for the rear half. Effectively separating both halves independently so that I can work on the front or the rear. This is a big convenience factor for the swap.



Did some sizing on the shifter position. I can easily cut and tig this shorter to be the perfect size. This part of the swap is a cinch. img_5032

Some more pics of the extra cut out. There are actually like 3 layers of 14 gauge metal here that make up the subframe. I plan to weld more metal higher in the frame to strengthen it back to stock. img_5030


Some shots of the engine bay where I fit the E46 325i radiator. This has the quick connects to make it easier for installation. Perfect width. thin enough for the swap. Bad part of this is that I need to push the engine further back, if the driveshaft will allow me. Good part is I have coolant temp by going to this route on the lower radiator hose. img_5034


Some pics of the E21 in all its glory. Not bad for a days work.img_5036

Continued to collect parts for the entire swap. Thanks Garagistic for the stainless steel brake lines, clutch line, and Z3 shifter!!


One of the setbacks i can see is a resistance of the subframe from getting pushed up as high as possible and that’s due to the fuel filler. It will hit it. not that big of a deal .

Next is to sort out the fuel filter/pump/regulator area. it’s clearly going to hit the half shaft.



Weld subframe triangle holes in, hang muffler, cut rear skirt, relocate gas filter, put my battery on a charer, rear trailing arm work for the shock mount. Assembly ZF trans to S54! Stay tuned!!