Ironsides Reader
11/3/21 3:41 p.m.

As the fun with cars outside season quickly draws to a close here in New England, I found myself scratching my head in search of something to keep my occupied in the garage throughout the winter months. The brz only needs fluids and a thorough washing following a fun summer of autocross and track days, and the probe gt is sitting on the lift while i decide what to do with it. 

Funny enough, a familiar project seemed to fall right into my lap. 

Some history :

Back in college (circa 2009) A good friend of mine owned a pretty cherry, low mileage cirrus blue 4dr 1987 BMW 325e. He had owned the car for several years after purchasing it from the original owner, cleaning up the interior and suspension, turning it into a fun weekend cruiser. This particular car was equipped with the auto gearbox and 2.7L, so not a very quick car, but still fun to drag out to cars and coffee. 

Fast forward to 2013ish, we've all grown up a bit and moved on to other vehicular interests, the e30 wasn't being used as much and the decision was made by my friend to pass the e30 along to someone who would enjoy it! 

Around the summer of 2018, the car popped for sale locally, looking a bit worse for wear cosmetically and limping with a bad auto gearbox. As many of us do, my friend made the decision to repurchase the car with intentions to return it to it's former glory, and maybe even throw in a few upgrades that were not limited by a broke college kids budget. 

Not too long after, a change in employment requiring a cross country move left the little blue e30 sitting in another friends garage, where it would reside for the next few years and that brings us to today! 

Me: looking for a winter project

Friend: looking to park his usable vehicle in his single car garage and evict an e30 with a bum gearbox. 

The Car (haven't even brought it home yet): 

Comes with most of the interior and some extras, does currently run and trans can limp around a driveway, exhaust is currently off the car (because race car), has a small rust hole in the normal place where a sunroof e30 would have a small rust hole lol. Also comes with most parts to swap the bad auto transmission, w/getrag 260 manual, including the gearbox.


I have almost no experience working on classic German cars, this will be a first for me. I do come armed with many years experience swearing at domestic and Japanese cars of a similar vintage, as well as an above average internet search skillset.


Being an avid autocross/track rat, the aim would be to have a fun reliable cruiser that can survive a day of thrashing here and there. After educating myself on the spectrum of e30's and their respective powertrains, the current m20 2.7L seemed extremely unappealing with its hopeful 129hp, and I began pricing out a Kpower kit. 

Upon arriving at the bottom of the parts list for a kswap, and looking at the conservative estimate, I determined that despite the 200hp/8000rpm of vtec joy this just wasn't a viable option financially. 

So what now? 

Well it just so happens, that there are many engines that are commonly shoehorned into e30's! And several of them can be tossed together with parts bin BMW bits creating a rather tidy swap on a budget.

After evaluating all of my options, a 24v engine swap was chosen, due to its relatively cheap costs, parts availability and wealth of supporting info across the internet. 

Now you can piece together this swap with a whole variety of engine, transmission, wiring harnesses, ecu's etc. but the one particular thing you need for a 24v engine to fit in an e30:

BMW E34 front sump oil pan  

And of course, since everyone needs one for this swap you pay a premium if you want the oil pan alone ($3-500)

Parts Car: 

After surveying the prices for an M5x engine, and the correct e34 oil pan, it seemed like a the best plan would be to just find an e34 parts car, which would net me the engine w/correct oil pan, throttle cable, useable engine harness, and DME (ecu) 

Lucky enough, some Craiglist hunting netted me 1995 525i auto, for a princely sum of $500. 

Caveat: no key, and has been sitting for quite some time. 

Upon arrival to collect the parts car, the sellers friend had destroyed most of the ignition, allowing me to jam a screwdriver in and disengage te steering lock, I disassembled the shifter and yanked the trans into neutral and away we went. 

Some notes on the donor: 

This particular engine is the M50B25TU, a vanos equipped 2.5L inline 6, making a healthy 189hp (hopefully) a nice improvement over the stock 325e lump. 

I will hopefully yank the motor out this coming week and get it on the stand for a good once over. 

I'm hoping to salvage some of the unneeded e34 parts and recoup some if not all of the parts car costs, seems doable. 

Also given Black Friday sales coming up, hoping to score a few deals on the necessary 24v swap parts needed for the conversion. 

Parts list: 

  • Engine harness adapter (condor speed shop)
  • g260 24v swap cross member (Condor) 
  • 24v swap mounts and trans mounts (Revshift) 
  • E36 engine mount arms (acquired) 
  • E30 IX booster (fits without modifying firewall - need to source) 
  • Modify shift linkage I have in the parts bin 
  • z3 steering rack and adapter, while im in there type deal, z3 racks are quicker than factory e30 unit (garagistic) 

The one area I still need to sort is the clutch and flywheel combo. It seems like the common practice when using a G260 gearbox is to use the M20 clutch and flywheel. But due to interferences with the M50 engine (oil pan I think) the m20 flywheels need machining. I think i would prefer to either just buy one already machined, or buy an aftermarket alternative that will just bolt up without the fuss.

Anyone who has experience or suggestions I am all ears. Surely I will have more questions along the way, but I am very excited to tear into this thing. Stay tuned for updates on progress and will try to keep a running tally for the budget.






r3vhappy New Reader
11/4/21 10:33 a.m.

You can use either clutch/flywheel combo. Just make sure it matches your starter. I recommend using an e36 m3 lightweight flywheel with clutch and an e36 starter if your budget allows. I use that setup with my S50 car running a G260 and I like it.

Folgers New Reader
11/4/21 8:45 p.m.

I came here for a Cummins swap into a bmw.

Well played op. Well played. 

classicJackets (FS)
classicJackets (FS) Dork
11/5/21 6:26 a.m.

I have no suggestions but I'm absolutely here to see how this plays out!

iansane GRM+ Memberand HalfDork
11/5/21 9:51 a.m.

Cool swap. The m50 isn't the latest and greatest but it's a great budget wakeup for the e30 chassis and a good introduction into modifying these old german cars.

Are you going poly on the mounts? Unless you're making an actual track rat I would just run the rubber BMW mounts. I think it's the e28 m5 versions? I ran the whites on the engine side and delrin trans mounts for years with very little NVH.

If you have any capability at all, I would suggest doing the wiring adapter yourself. On an early car it's insanely easy. There's really only a half dozen wires you need to connect if you use the e34 engine harness.

Get familiar with It's incredibly helpful even just having the diagrams of parts.

And for literally any old bmw wiring, go here:

What radiator are you going to use? I ran the m42 one for years with an electric pusher fan for years. It was switched off the factory A/C fan wiring and a lower temp switch. Cheap and incorporates the overflow tank. You just have to make the weird Y-heater hose from some e34 pieces and a t-connection.

Exhaust? The ebay stainless headers are a pretty good budget option making the exhaust routing easy. The big part is clearancing one of the collectors for the e36 mount arm as making sure the lollipop has room.

I ran the stock m20 single mass flywheel and had a machine shop cut a good 3/4" off the back of the flywheel to clear the oilpan. Saved weight, cheap and simple.

Good luck!


artur1808 GRM+ Memberand HalfDork
11/5/21 10:04 a.m.

You can still use the m20 clutch and flywheel, just need to grind down a few of the ribs on the e34 oil pan.

Picture stolen from page 93 of Josh's e30 build. He took lots of pictures and went into a lot of detail with this swap, I'd recommend reading through if you haven't already. (M50 swap starts at page 91)

artur1808 GRM+ Memberand HalfDork
11/5/21 2:26 p.m.

And I agree with iansane, the wiring really isn't bad. You just need to get organized and have a bit of patience

jr02518 HalfDork
11/5/21 6:20 p.m.

I will confirm the end result is worth the effort .  I will also confirm that I hit the easy button and purchased a running car with the conversion done.  Keeping it running has proved some clues that might help your car in the future

The first thing I would add are some access holes in the bell housing to get to the rear bolts on the back of the oil pan.  Once you have the flywheel on the motor and the transmission and engine bolted together you will loose access to those bolts.  One universal truth with BMW's is that oil pan will be coming off in the future.  Now that you will be running a front sump E34 oil pan it increases the likely hood even more. Adding a gard, I purchased a Red46 sump guard, and consider it well worth it.

Pulling the pan now also gives you access to the oil pump sprocket that you should absolutely safety wire. Then with a fresh pan gasket you will be saving lots of future grief.


Ironsides Reader
11/30/21 7:33 p.m.

Thanks all for the suggestions, I read through josh's thread and his m50 swap, lots of good info there and a few tricks I will take some inspiration from. 

Some big progress, albeit slow.

M50 engine is out and on the stand!

Extrication wasn't too bad. I removed the intake manifold and engine harness prior to engine pull. The alternator cooling bell was filled to the brim with acorns, I found that quite entertaining. 

Cut the exhaust and driveshaft due to some frozen bolts and otherwise came out without much drama. I'd estimate that the whole assembly weighed about 800-900lbs, but it certainly gave the 1 ton HF load leveler a challenge, i would not trust it for a second act. 

Intake manifold off: 

Some of the goodies that will move over to the e30:

Out she came, quite the angle to get it over the core support but just barely has enough room:


Detached the trans and got it on the stand, surprisingly enough, the only evidence of oil leaking was a slight seep from the valve cover:

Good news for me, engine turns over freely and the intake valves look clean at least. General plan of attack will be a full set of seals/gaskets, plugs, safety wire the oil pump nut, knock sensors and probably a belt drive refresh. Will also have the injectors cleaned and replace the exhaust studs

Think I will end up going with a M50 clutch setup, the single mass e36 kits from Valeo seem pretty reasonably priced, although a local guy has a new lightweight flywheel and clutch that may be an option. 

Exhaust will likely be a set of ebay long tubes, may splurge to have them cerokoted, and I think I will be going with an ebay stainless e36 rad (maybe a nicer one if Ifeel spendy) and a Spal electric fan. 

The Brakes:

After reviewing booster options (smaller booster needed to clear intake manifold) It looks like some folks have been using an e90 booster and master, requires minor modification but the brake line ports on the master are on the wrong side. 

An alternative that also works and can be had cheap is to use and E83 X3 booster and master, which has the ports on the correct side to match with the e30 brake lines, I think this will be the route I take.


UK e90 booster also has the master ports on the correct side, but need to confirm if the booster vaccum hose attachment is workable due to it also being on the opposing side. 

Parts collecting:

I preemptively loaded the parts cannon to take advantage of black friday savings: 

- Condor 24v g260 crossmember 

- brass clutch fork pivot

-C101 adapter (taking the electrical cowards way out) 

-Revshift 24v poly engine and trans mounts 

-Revshift rear subframe, diff and trailing arm bushings, along with offset lollipop bushings 

- Chase bays 24v power steering line kit to make installing an z3 rack essentially plug and play 

Still have a very long list of things needed but that knocked out some of the bug stuff, and I still don't even have the car yet!

So far recoup on the e34 part sales has been $350, still have both cats the cash in and the shell to scrap so I estimate I should come out in the green! 

Hopefully have the e30 home in the garage this week, I'll share some pics onces she's home. 




Ironsides Reader
12/6/21 8:07 p.m.

Made some moves this weekend, E34 is now out of the way. 

Sold a bunch of body panels, cashed in the cats and some aluminum and scrapped the shell. 

Purchased E34: - $500 

Towing (x2, pickup and removal) - $140

Sold parts: + $780

Scrapped shell: + $234

Total money made: $374 + free engine/harness/DME/throttle cable 

After depositing the E34 at the recyclers, we headed up to collect the actual project!

While is does run, it did not want to stay running long enough to make it on the trailer, likely bad gas as its been sitting a while. Fortunately some curious neighbors were happy enough to help muscle it up on the trailer. 

Haven't had much time to look the car over, did notice is has a bit of rust on the drivers side floor, as well as small spot below one of the tail lamps. I'm sure there is more hiding that I will uncover, but overall pretty solid as far as new england e30's go. 

Shes back at home base, I need to do a detailed inventory on what came with the car, and make some purchases. 

More to come.




iansane GRM+ Memberand HalfDork
12/7/21 11:30 a.m.
Ironsides said:

The Brakes:

After reviewing booster options (smaller booster needed to clear intake manifold) It looks like some folks have been using an e90 booster and master, requires minor modification but the brake line ports on the master are on the wrong side. 

An alternative that also works and can be had cheap is to use and E83 X3 booster and master, which has the ports on the correct side to match with the e30 brake lines, I think this will be the route I take.

Interesting. Do these require mod'ing the clevis at all? 

StripesSA1 Reader
12/7/21 1:06 p.m.
iansane said:
Ironsides said:

The Brakes:

After reviewing booster options (smaller booster needed to clear intake manifold) It looks like some folks have been using an e90 booster and master, requires minor modification but the brake line ports on the master are on the wrong side. 

An alternative that also works and can be had cheap is to use and E83 X3 booster and master, which has the ports on the correct side to match with the e30 brake lines, I think this will be the route I take.

Interesting. Do these require mod'ing the clevis at all? 

With all this talk of E90 booster and E36 M3, I started searching down the worm hole for a possible manual swap for my VW FOX, since you guys are saying the booster is smaller, and in RSA, the VW Mk1 chassis had the booster and master on the left side with a link and pivots. 

So the I found this video and had to share it. 


Ironsides Reader
4/21/22 2:30 p.m.

So admittedly, it got cold(no heat in the garage), holidays got busy, work got busy and I got distracted and not much got done. 

Follow that with a mad dash to get the brz prepped for autocross season and the e30 had sat pretty dormant until last couple weeks. I did spend some time poking around the car and doing some planning. Things discovered: 

We have some rust....(and apparently an ant problem at some point?)

The passenger floor corner and corner square were assumed, but did find a few holes and weak areas on the firewall. Bonus points for whoever jacked up the floor pan on the passenger side as well lol. 

Perforated firewall, some on the driver side as well: 


Drivers side pan doesn't get a pass either after some prodding...

So, placed an order for a pair of corners and pans from Valcas garage in Lithuania, which sells these bits at a pretty reasonable price. hopefully have those in a couple weeks, opting to replace the pans as a whole due to the bending and what not as well as the rust. I should be able to spot patch the few areas on the firewall easy enough. 

The rest of the shell actually seems pretty solid, battery tray area, rear trunk area, there's a small spot below the drivers tail lamp but I'm going to ignore that for now. 

Spent last Saturday prepping for the motor pull, exhaust remnants and driveshaft/trans cross member are out, hoses and wiring all disconnected. So the 2.7L in the car did run okay, but I drained a pan full of chocolate milk out. 

Should have the drivetrain out this weekend. Aiming to keep the momentum going and pull the front and rear cross members as well, those will be sent out to sandblasting ahead of welding in reinforcement plates, camber and toe adjusters in the rear, and new bushings, hoping to do this in the interim while i wait for sheet metal. 

Picked up this little 120v rig over the holidays while eastwood was running a sale, should be able to tackle the extent of what i need to do here: 

In other news was able to score an E46 M3 steering rack for a reasonable price, which will make a nice upgrade over the stock unit (leaking) Also found a medium case 3.46 torsen LSD out of a z3 on ebay, this is a bolt on upgrade for the e30 and the gear ratio was the one I was after, which will replace the open diff 2.93 in it currently. 

Hopefully progress will start to accelerate now that the weather is turning and I have a bit more free time!


Ironsides Reader
4/22/22 7:34 p.m.

Found some time this afternoon and out came the motor and trans. Overall pretty easy, finding the right angle with the load leveler to finagle the large auto gearbox out was the bulk of the job. Looks like there's a reman'd torque converter in it, could be the culprit for auto trans issues?


Mess on the floor is all cleaned up, gearbox and remaining aluminum scrap will go to the metal recycler tomorrow. 

Also more poking revealed the firewall rot on the drivers side pokes into the front fender well... sigh, should be simple enough. 

Next up:

- Pulling firewall insulation off and get a better picture of the firewall repair needs

- Remove  brake booster,

- Remove all the ac lines

- Give engine bay a proper cleaning

- Remove dash

Lots to keep busy will, hopefully tackle some this weekend. 

Ironsides Reader
4/29/22 3:39 p.m.

Parts starting to arrive, sheet metal repair panels are here, 7 days from Lithuania to the US, impressive! 

Quick mock up shows it should remedy most of the floor rot, and the outter jack corners will seal up the outside, leaving a few spots to patch in on the firewall/wheel well. 

Diff also arrived, labeled from an '01 z3 with 107K, its a 3.46 ratio with torsen diff, will swap over output flanges and diff cover when i drop the rear subframe for refurb.

This gearset w/23" tire and the getrag 260 will give me 63mph in 2nd at 7000rpm. Should make for the perfect autocross setup :) 

E46 rack - 3.2 turns lock to lock vs 4.0 e30: 

Last piece to adapter steering rack into car - adapter and spacer kit with a new delrin coupler to replace the factory worn out rubber unit. Also weld in camber and toe adjusters for the rear subframe: 

Also splurged on a lightweight flywheel, m20 fitment (will bolt to m50) - this one was lighter and cheaper than the m50 equivalent, will accept the single mass e30 clutch kit simply and should have the clearance needed to since it has thinner mass than an oem m20 fw to clear oil pan. 

Should have more than enough projects to keep busy with now and make some progress. 

Our Preferred Partners