Short-term E23 project

Time for some updates! The 2017 holiday season has been very productive, although this poor car paid most of the price. Big parts have been rapidly selling. The driveshaft went out a few weeks ago, then someone snagged the differential on eBay.  The engine sold last weekend, the manual swap kit went out a few days back (shifter lever, transmission mount, pedal cluster parts), and the transmission sold today. I still have a few select pieces but I don’t expect they’ll be here for a lot longer. Two examples: 240mm single-mass flywheel & a hard-to-find Miller Performance M20 MAF upgrade kit.  While those are looking for buyers I’ll pull a few more parts from the car, then the shell goes off to the recycler. I’d have scrapped the car a while back but I’m salvaging as much as possible. Want to know one good reason why? There’s another potential project car on the horizon…details to follow!

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This is the scruffy car I picked up for the transmission. It seems like there are a lot of great parts waiting to be assembled into something a little less disreputable.

I’ve discovered a few surprises along the way. One never knows what you’ll find with a car like this. The seller offered it to me for a pretty good price, and although towing was fairly expensive, I’m figuring I’ll easily make my money back. I’ll also get some decent parts to use on the other cars, or get into another enthusiast’s hands.

The first surprise was when I looked at the car. The 1985 735i has a 50:50 chance of the superior Getrag 265 being installed. According to BMW, they switched over to the far inferior G260/5 in August ’85. When I checked it out, I confirmed the detachable bell housing, three-section design and waffle-pattern of the 265 gearbox casting. I was quietly thrilled. Those are rugged old gearboxes, well worth the purchase price.

The next pleasant surprise was the engine. I was excited to find the small ‘turbo’ casting mark of an M106 head when I checked the car out. With any luck the whole motor was there too. I confirmed it once the car was delivered: the M106 block is very distinctive due to two knock sensor mounts and an oil drain for the turbocharger. After delivery I’d also pulled the DME out of its little cubbyhole. It certainly wasn’t the M106 DME; just looked like the  ‘normal’ 059 unit originally fitted to this car. However, it had been opened…so I checked and discovered a TCD chip had been installed. These are a really nice addition since the DME will adjust timing specifically for the turbocharged engine. Without the chip, advanced timing can rapidly cause pre-ignition damage at higher boost levels. Although this car didn’t have one, TCD also offers options for improved turbochargers. They machine the K27 housing to accept an improved compressor wheel, improving efficiency for the old blower. It’s a bolt-in upgrade. These motors cannot fit any newer turbos without substantial modifications to the exhaust manifold.

This process hasn’t been without some problems. While the car started OK, it runs like crap until it warms up, then leaks coolant from several places. The parking brake has been totally removed. Many OEM parts are missing. The car was also upgraded with Summit stainless fuel line. That’s not usually a problem since it’s high-quality stuff…unless it’s been installed poorly. Those hoses abraded the brake lines in two places, the worst was at the hacked-up ABS bypass hard lines. Even moving the car around the driveway was an adventure! The rear diff is OK, but all four CV joint boots are split & likely completely worn out. I’m surprised they still hold the driveshafts! One of the front wheels also has a stripped lug bolt. I’ll eventually get that out, one way or another.

I bought a new tool to remove the stripped lug. I used an Irwin 17mm deep well extractor socket, and I can recommend it without reservations. It worked perfectly! I also found out that the driveshaft was damaged internally. Much to my surprise, it pulled apart as I was removing the differential. BMW uses a two-piece shaft with a rubber isolator bushing that is trapped by a large flange nut. The nut wasn’t fully tightened, allowing the rubber to stretch. Once that happens, the splined front shaft will strip out the rubber bushing. It really had me worried; what if the transmission was damaged? That’s the whole reason I bought the entire car!

Speaking of the differential, it turned out to be a 3.46 limited-slip unit. With the exception of the RTV used to seal it up, it’s in pretty nice shape too.