My long-term E24 project.

I came by this car in a unique way. I posted an ad to buy older BMWs, specifying E30 parts in particular. I got an intriguing email from a potential seller, asked if I’d consider buying a complete E24 project. This sounded promising…as the seller described the project, it kept sounding better and better. First off, it was red. Other great news: it was a “Florida car” (thus little-to-no rust) and the original motor had been upgraded…with an S38B35! The current owner had bought this car many years ago with the complete M5 swap already performed, making it essentially into an M6. He parked it after the S38B35 spun a bearing, and had decided to cut his losses. The motor had been removed, the crank was repaired, but it was all still in boxes.

So I went up to see it. As described by the owner, there was no motor in the engine bay. That is certainly a handicap, but I’m pretty handy with motor swaps. However, the rest of it was pretty spectacular. Under the dust, the car didn’t appear to have any rust at all! ZERO! That’s a very unusual thing in the world of E24s. The car also had very low mileage…odometer stated 73815. The car was also fitted with most available factory options for that year (happily with the exception of an automatic transmission). All my personal favorites were present and accounted for: power leather sport seats, front & rear spoilers, driving lights, “HiFi” Stereo system, even the rear sunshade! The chassis also had some tasty factory and aftermarket upgrades (full Bilstein Sport setup, IE performance springs, M5 brakes, upgraded roll bars). The Getrag 280 and 3.91 large case LSD were still in the car. Nice parts, very rare and expensive, good investments, well worth buying. In addition, the car had some aftermarket improvements: a Momo leather/alcantara steering wheel and an r134 A/C upgrade. In so many things, it’s just as important to see what really IS there instead of what ISN’T. Best of all, the story made sense. A quick AutoCheck actually verified that number, and reported a relatively clean title history. It completely matched the seller’s description. I always steer clear of funny business especially as older cars can easily become a rat’s nest of paperwork if you’re not careful.

I was strongly tempted to make an offer on the entire lot of parts. Have you ever heard an S38 wide open at full throttle? It’s intoxicating! However, budgetary constraints kept my ambitions very modest. While an S38 is a lovely motor, they are quite expensive to rebuild & maintain. They’re also not a whole lot more powerful in American specification than the M30 they are loosely based on. Regardless, I was still a little short on cash. I made a low offer on the chassis alone, without the motor. The seller countered with a much more involved deal: he wanted it all gone, but perhaps we could split it up somehow. Would I be interested in buying only the chassis, then remove the M5 parts (transmission, differential, brakes, etc.), and assist him with selling them on a commission basis? It’d be a lot more work, but it would cost far less in the long run.

Sold!

So that’s exactly how the deal went down. I removed the transmission, driveshaft and diff; sold them to a nice fellow out east. The motor ended up being parted out. Several venues were helpful (enthusiast forums, CL, Panjo, eBay). We split those proceeds over the next year. In the meantime I 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.” Circumstances had not been kind. It was a totaled-out flood victim with no title, sitting in a field, infested with vermin. Why would I buy a piece of junk like this? As a car, it was a liability. But as a collection of parts…it had a huge amount of potential. It had only run 117K miles. The Euro “dirty” M30B34 (high-compression/no catalyst) was mated to a rugged Getrag 265/6 transmission with a single-mass flywheel and heavy-duty clutch. A large-case diff would complete the transplant into 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:

  • My original 635CSi project was a chassis with a suspension.
  • The motor, transmission and brakes were harvested from the ’82 European-spec 635CSi.
  • I found a limited-slip differential in a ’99 Z3 2.2. It’s the rare Torsen geared type, not the common clutch-type. Although the ratio is a little too tall for speed (3.46), but it’ll be great for highway driving. A true GT like this isn’t meant for the drag strip, is it?
  • Some decent wheels: 7.5×16″ cross-spokes originally fitted to an E32, but came to me with an ’85 635CSiA parts car. These updated 16″ “Style 5” “basketweave” 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!
  • A ’91 535i donated its Motronic 1.3 DME, sensors and mounting hardware.
  • It needed an exhaust system too; that was a well-used system pulled from an E28 535i at my buddy’s garage. It needs quite a bit of welding but is otherwise sufficient.

I’ve also pulled some electronics from other machines:

  • The injectors came from several scrapyard Volvos.
  • My scruffy E23 735i donated a sweet AEM wideband O2 sensor supporting emulated output (that replaced an older TechEdge wideband O2 from my OTHER E23 745i).
  • The Hella H4 E-Code headlights were part of an E30 purchase I made in Wisconsin.
  • A Hawaiian ’89 635CSi gave me an engine wiring harness of the proper version and length.
  • The OEM Alpine CM5907 stereo head unit is from a scrapyard E28.
  • The brakes are from an E32 740i…except the front rotors…they’re from an ’87 M5.

Finally, I needed quite a few new parts. The radiator had a hole, virtually all hoses needed replacement, the lift pump was dead, some suspension parts were badly worn and the motor needed many gaskets. I’m sure there was more but you get the general idea.

If you’re keeping count, that’s twelve donors (!). There could have been more, but I 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! Early driving tests have been very promising.

I’m still working on this project…As we roll into fall 2018, the delays have piled up. Time for another winter slumber. Before I roll her back into the garage, I was inspired to try newer wheel designs. What do you think of these Motorsport wheels? They’ll require fairly thick spacers to fit the E24 hubs, but the design is growing on me. If I don’t sell them first…maybe they’ll be part of the package next year.