Quick & sloppy engine swap (part 2)

As previously mentioned, this project was back in the accumulation stage, but I’ve scrounged enough parts to get it back on the road.

  • A 535i getting an engine swap donated a B34 engine & transmission. They’re a backup option, but might be getting installed if they check out OK. Many minor parts like the air cleaner assembly & pulleys are getting swapped onto the B32 engine.
  • I also lucked out with a Bimmerforums connection – he had saved a spare (and rare) 1989 E24 B35 harness from the scrapper!
  • A 633CSi getting parted out in Cleveland donated the engine. The E24 chassis was a rusty mess, but the engine & transmission appeared to be in excellent shape. Up on a stand she went to get a full set of new gaskets and seals.

The chassis has been patiently waiting for the motor transplant. It has a running Euro B34 installed, but that motor has a lot of blowby & very low compression.

Since I’ve sold virtually everything else in the fleet, I decided the time has come to finish up the swap and get her back on the road. Here’s how that went:

  • Disconnected the battery, drained the coolant & oil.
  • Pulled the wiring harness out of the cabin, coiled carefully on top of the motor.
  • Disconnected all the coolant hoses, drained system of all coolant. Don’t forget about the block plug, it’s a 17mm bolt low on the rear passenger side behind the oil drain channel. Removed the clutch fan, shroud & radiator.
  • Disconnected the power steering pump and A/C compressor, left them dangling out of the way.
  • Removed v-belts, front pulley & harmonic damper/trigger wheel.
  • Removed the front anti-sway bar.
  • Disconnected the exhaust pipes, dragged the complete exhaust system out of the car.
  • Pulled the transmission bolts one by one, with some ridiculous combination of 3/8″ & 1/2″ extensions & adapters.
  • Pry engine away from transmission. (Done 8/17)
  • Hoist that big old thing out of there! (Done 8/17)
  • Strip necessary parts (B35 harness, fuel rail, damper, trigger wheel, pulleys) and install them on the B32. (Done 3/20)
  • Reverse the entire process to install the B32. (Done 4/20)
  • Drop the new motor in. (Done 4/20)

Aug 17 was very productive:

As October slips by, I removed a few more parts from the Euro B34. These have mostly been installed onto the B32. The new B35 harness is also mounted, along with the intake and some brackets. Once the oil pan is on the block I’ll be installing it into the car (if I hadn’t misplaced my Reinzoplast I’d have had it done by now).

So that was a little bit of fun, wasn’t it? I noted a few differences with the E24 B35 harness that will need taken care of, I’ll update after I have a few pics.

2021 03 update: I was helping someone out with a defunct temperature gauge, and it reminded me of how I “broke-in” this B32 engine swap. As this swap included a large combination of different/new/used/hacked-together parts, nobody can really tell how they’ll run as a team. To lower the chances of major engine damage or a disabled car, I have a routine that I thought should be shared with the world. Here’s the forum post:

I was driving my car for a while without a working temp sensor. It was during the engine swap, it took me a while to figure out what was functional. Since I’m both cheap AND impatient, I took the car out regardless. I just took my cheap IR thermometer along for the ride, and drove around the neighborhood more or less within walking distance of home. I’d just pull over about every ten minutes to take the car’s temperature. I was very happy with that IR thermometer’s performance. You can check radiator effectiveness, fanstat function, block & head temperature, even which injectors are sticky (lean cylinders run far hotter at the exhaust pipes). All in all, an amazing tool.

I ended up using the thermostat housing as the baseline temperature. It was convenient, consistent, easy to get at. My favorite discovery of the day was that the entire cooling system wasn’t really working at all. The engine-driven cooling fan clutch wasn’t working. The fanstat switches were both functional, but the low-speed AND high-speed relays were defunct. Thank goodness the A/C could still turn on the aux fan. When the housing got up over 200 degrees F, I stopped off for a coffee break to let it cool off.

So the moral of the story, if you’re interested, is that a cheap IR thermostat is FAR more accurate than the VDO gauge in an expensive BMW. Who knew?

Be aware, if you follow in my footsteps , that an IR thermostat is not foolproof. It will not take a good temperature off highly reflective surfaces. I found that out when trying to tune carbs by temp. The motorcycle had chrome exhaust pipes, it was almost completely futile.

Might make a good complete post of its own, now that I’m re-reading it. Cheers!