My long-term E24 project.

I came by this car in a unique way. I will occasionally post an ad to buy older BMWs. The owner called me, asked if I’d consider buying a complete E24 project instead of the E30 parts I had been advertising. Sounded interesting. I went up to see it; as described, the car didn’t have a motor. That is certainly a handicap, but I’m pretty handy with motor swaps. What was left was pretty spectacular. The car didn’t appear to have any rust at all! That’s a very unusual thing in the world of E24s. The chassis also had some tasty upgrades (full Bilstein Sport setup, M5 brakes, upgraded roll bars). The car was also fitted with most options, including the very desirable power leather sport seats, a Momo steering wheel, rear spoiler, rear sunshade, even an r134 A/C upgrade! In all things, it’s important to see what is there instead of what isn’t.

The owner had bought the car many years ago with a complete M5 powertrain swap, essentially an M6. The car was parked after the S38B35 spun a bearing. The motor had been removed, the crank was repaired, but it was all still in boxes. The Getrag 280 and 3.91 large case LSD were still in the car. Nice parts, very rare and expensive. I was tempted to make an offer on those parts too, but while an S38 is a lovely motor, they are expensive motors to maintain. Unhappily, I was a little short on cash. So we struck a deal. I’d buy only the chassis. Additionally, I’d remove all M5 parts (including the transmission, differential, brakes, etc.), and assist with selling them off.

So that’s exactly how the deal went down. I sold the transmission, driveshaft and diff to a nice fellow out east, parted out the motor (Bimmerforums, CL, Panjo, eBay) and proceeded to look for a decent replacement powertrain. Eventually, I found a donor. It was once a very desirable car: an ’82 635CSi in full European trim, imported via the “grey market.” Time has not been kind. It was a complete wreck – no title, sitting in a field, infested with vermin, a totaled flood victim. Why would I buy a piece of junk like this? As a parts car, it’s not really that bad…I’ve had far worse. The rugged Getrag 265 transmission and Euro “dirty” (high-compression) M30B34 will provide a heart transplant for the American-spec Zinnoberrot.

Well, I had hoped to make one car from two…but that’s certainly not how it ended up. Here’s the breakdown:

  1. My original 635CSi project was just a chassis and suspension.
  2. The motor & transmission were harvested from an ’82 European-spec 635CSi.
  3. I found a limited-slip differential in a ’99 Z3. It’s the rare Torsen geared type, not the common clutch-type.
  4. Some decent E32 ‘style 5’ wheels came as part of an ’85 635CSiA purchase. These updated 16″ wheels are a very popular choice. They’re relatively common and have far more choices for performance rubber than the base-model 14″ wheels. They’re also far more economical to replace than the 390mm Michelin TRX tires I bought with the car!
  5. Finally (I hope) a ’91 535i donated the DME/ECU and engine harness.

If you’re keeping count, that’s five donors. There would have been two more if I hadn’t missed out on a few really good deals. These are the best parts I could find & fund; hopefully the sum of these parts ends up being better than the original!