BMW e46 swap with a Chevy LS series engine LOTS of pics

As of mid December 2018, the car is officially on the road and I’ll be bringing it to most of the Cars and Coffee car meets at Michelin HQ this upcoming year if you want to check it out. Build log over the past two years posted below, and I’ll add on as there’s a few more ideas I have in mind with it.

Goal # 1 is to get the car moving under its own power.

Loose timeline:
X- Pull BMW drivetrain around xmas
X- Clean car
X- Install motor/trans mounts (already ordered)
X- Purchase motor/trans around new years
x Test fit to determine oil pan route - If I cant modify the truck LS pan to clear, I’ll grab the holley retrofit pan
x Measure and have custom driveshaft made
x Test fit headers. If I can make the log manifolds work, those are going in.
x Tack up rest of exhaust

Going to look at the car

Day 1

Day 3

Day 7

Engine + trans mount

Just got done pulling this today. Grabbed a 411 ECU ,harness, and drive by wire pedal while i was at it.


Neighbor who gave me a hand posing with the crane. Release the beast!

Day 10 - Motor out

I took a timelapse vid but my neighbor came over and knocked the plug without me realizing. Ah well

Day 11

Built the rear carriages and got the car level. This will be useful for measuring the new driveshaft and building the exhaust.


Old motor out



Alllllmost in. I forgot to take the oil pan off that I knew wouldn’t clear/fit, and didn’t have time to drain and remove. Mounts are already in, should be good to go tomorrow ( or later this week). Ahead of schedule either way :tup:

Day 13

BAM. In.

Trans tunnel took some massaging and it didn’t click that the trans mount (made for the T56) doesn’t quite go around the big ass transmission pan.

Sooooo I’ll be playing with the CNC plasma cutter after I design a new one.

In the mean time, it’s in!

Tacked a few pieces in tonight with the tig. Tomorrow I’ll remove it and lay some thick welds with a neighbor’s MIG along with a few corner pieces for bracing.

FYI, trans isn’t rotated. One side of the frame rail actually sits lower than the other. :Shrug:

Probably something there that took up space, but I pulled everything out before I noticed. Ahwell :slight_smile:

Trans mount is at a buddy shop getting MIG’d. Kept blowing my 110 Tig and this thing doesn’t need to be pretty. For now it’s complete.

Next step is the driveshaft to finish the drivetrain. I’m kinda sorta interested in modifying (shortening) a stock chevy driveshaft, though to have one made and balanced isn’t too much. Part of the hobby I guess.

I made a thing while waiting for parts

I modeled this one (Camaro depth) and made my ghetto one from those dimensions. Not sure how much shorter the vette stuff is.

Super precise work going on. Printed 1:1 scale and used a punch to line up mounting holes (after I already welded on top of it, heh)

Bam. Like it was store bought

Estimated cost savings by making my own mount - at least $3.

worth it

This is the money maker. Custom ground and sleeved flange specifically for the BMW e36/46 giving you the 1310 U joint. Mucho Happio

Finally started on the oil pan. Bottom will be built back up and will have roughly the same the dimensions as the Holley LSx retrofit pan ( which is known to work in this application) and measured to hold 5.5 quarts in the sump and 6qts total with the oil filter

Few other parts coming in and will be aiming to get a driveshaft this weekend along with 2.5 exhaust to continue work on the manifolds.

I’ll have to clarify upfront that while this may look like a brand new shaft from a professional shop I assure you it was hacked together in my garage. Measured up and fits absolutely perfect

Will get it balanced , and probably still have one made another time.

For now it will make the car move so I’m happy.

Need to lay another pass on the oil pan , and next focus is on the exhaust . Manifolds currently point at the firewall. No bueno

Got a new water pump, crank pulley/bolt, radiator, and will be working on getting the front accessory stuff all buttoned up after exhaust is done.

I took a stab at making my own manifolds. The passenger side came out pretty good, but I think I mashed up the driver side too much. And welding cast = no bueno. I worked on a few other odds and ends but ultimately I’ve been starved of time the past month.

I just dropped some coin on headers made for the swap, which I still need to cut up because they wont fit around the trans i’m using, but will get me there quicker.

Loose to-do list

  • Get the new headers on
  • Make power steering mount (using the stock BMW pump/pulley)
  • Shorten oil pickup tube
  • Rewire (re-tube) ABS - this has already been relocated, though there might be a chance the new headers will clear , so holding off
  • install new shifter/connect to trans
  • figure out the pedal/drive by wire deal. I already have the pedal/module from the donor car
  • Wire motor ( still no plans to make the dash/etc work, just turn the key for now)
  • Install radiator/fluids/etc

Attempt at pass side manifold. Unfortunately there is NO room on the driver side, so that manifold got mangled.

Pulled engine today… Shortened Oil pickup tube, trimmed steering rack brackets ( the lip was touching the oil pan, felt better seeing a gap) and removed all 3 broken exhaust manifold bolts - they came out SUPER easy after welding nuts to them.

Trimmed brackets to clear oil pan

Shortened oil pickup

Removed broken manifold bolts

Inspected bottom end - looks good (at least for who its being built for).

New oil pan gasket and pan is now on - off the checklist

Made a flywheel lock. The balancer is still 1/4in away from being seated. F-er is tough. I may take the pulley back off and heat it then slide it on.

I started planning on the final accessory mount using the stock BMW steering pump and pulley, along with modifying the truck idle tensioner ( needs to be shortened). I’d like to use the stock length truck belt if I can. But it’s looooong. We’ll see.

-Started on bracket to use BMW P/S pump. All but another brace or two and its done.
-Modified truck-spaced belt tensioner. Shortened it by 7/8 and removed the 3rd mounting point to clear.

Put motor back in to work on a few things.

-P/S pump lines up perfectly with stock line location. Glad I dont have to mess with anything there.

-Modified BMW bracket to hold P/S reservoir

Measured for a belt and got one that fits 110% perfect. A buddy suggested adding an idler pulley between the alt and pump. I may do that at a later time.

Installed exhaust. It fit perfect (as in, cleared the trans). It also allowed the ABS to go back in place with plenty of room - woo hoo! Next time I pull the engine I’ll add a heatshield back in. Glad I dont have to re-route.

And the not so good part. The pass side exhaust, which has all the room in the world, doesnt fit. The collector points towards the trans. I bought a 3in pipe and going to try my hand at pie cutting to make it bend away

Thanks Matt!

Right now the focus is on getting this thing wired and fired.

The injectors I need use a different plug than what’s on my harness so the pigtails connectors are on their way, new knock sensors, and I’m shopping around for a camaro shifter ( though I’m interested in seeing if I can adapt the GM cable to work on the BMW shifter, that would be tits).

This is the point where it seems there is slower progress, in reality there’s just a 100 little things to do and not much to update on, but we’re chugging along.

Had a chance to work on a few small things -

  • Installed knock senors
  • Made a new (better) alternator mount
  • Made modifications to set motor back another 3/4 inch ( this was necessary for the manifolds to clear the control arm bushings)
  • Removed BMW shifter assembly - not going to use it
  • Started manifold modification to bend collector away from the trans pan.

Pic dump of random stuff -

as of yesterday I verified the ECU turns on with the car and im getting fuel primed , starter works with the ignition while retaining the BMWs EWS (anti theft) and OBD reader connects and nothing looks out of place. Waiting for fuel regulator for first start- but I don’t anticipate the BMW fuel system playing nice, so that will need more looking in to. For now -

Harness rework stuff/VATs flashed from ECU

Going through the BMW stuff - removed a ton of wires/plugs - basically went through and depinned every wire that wouldnt trip the EWS. That part cleaned up excellent.

O2 bungs welded in

Shortening firebird shifter

Harness/ECU wired in for testing


Done with school/certifications for now,will finish this to completion in the upcoming weeks. Time flys!

I’ve poked around with it a few times since the last update, to bring up to speed-

Heatshield for the ABS

Chevy pedal electronics Frankenstein’d in to the BMW pedal.

Camaro shifter in

Exhaust 100% complete (junkyard FTW)

Gas line

Box of goodies - new radiator , holley lsx pan, air filter, trans cooler , etc

As of yesterday, cleaning up the harness so everything gets routed correctly(nicer) and going through to make sure as I put stuff in, it doesn’t come back out. My hunch is the trans cable will be a tad tight, and may have to find a longer one. Can’t think of any other hangups moving forward at the moment.

Minor things to tidy up and I’ll see if I can pull it out of the garage this week

Arduino powered gauges. This takes the protocol Chevy uses to output signals to your gauges and converts them to CANBUS that BMW uses so I can retain the stock BMW Speedometer, RPM, temp, and check engine light. Really cool piece!


Got the shifter to fit in the stock bezel - so at this point aside from noticing it’s not a BMW shifter, the car inside and out looks stock.

Harness cleanup. The bulk was due to the truck harness being routed on the driver side. Moving it to the passenger resulted in excess/looped wire.

Last minute work and car is officially on the road

New head gaskets, milled heads, new valve springs, new valve guides, lapped valves/seats, new pushrods.


No other plans for it right now other than driving it and working out small kinks that come up. I’ve designed and made some rear subframe reinforcements to install at a later time with anticipation of doing something with the differential ( M3 diff, ford rear end, something).

Part of making the reinforcement plates required me to bend some 12ga plate, and whipped up this guy to do the job, so that was fun.

test on 1/4in x 1in

Subframe reinforcements complete. Once I sort out what to do with the differential I’ll install these during the swap. I’ll have to pick up mig welder as well as I don’t want to glue or Tig these in ( both of which are viable, but want an excuse for a mig anyway)

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Nice! We have Mig at the Mill if you need it before you get around to buying it :grin:

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