This build is getting down to just the oh-so-very short strokes. Though, still on the "to do" list is one biggie: Getting the ECU chip tuned correctly for this motor.
First, the update:
I cut the oil cooler holes out of the OEM euro M5 chin and sprayed on a coat of SEM (a stain black intended for plastic, IIRC?) to cover the newly cut portions. The original pressed plastic part is actually a gray material that comes painted from the factory. So when you cut the oil cooler holes, you expose the gray. I spent some time to make sure the holes were cleaned up and I'm pretty pleased with the result.
I also modified the "low beam" connections for the H4 bulb & holder so that the high beam filament in the H4 bulb will light up when I put my high beams on. (In a euro car, the high beam filament in the H4 bulb never gets lit.) I did this by buying a spare back-plate and cannibalizing it for the missing connections, then digging out the sealer on my backplates, and using a hot Xacto knife blade to melt new slots where the cannibalized connections fit in. (This isn't my process; this was described in a couple of threads here in the forum.) After slotting in the new connectors, I put epoxy in to replace the removed sealer.
I've put new vapor barriers on all the doors. I bought about four meters of the stuff that W&N is currently offering
, and I'm very happy with this material. Very strong, very sticky, easy to cut, mostly easy to pull off if you need to reposition (as long as you haven't really pressed it on hard yet). My method was to (i) put masking tape on the edge of the door so that the inside edge of the masking tape outlined where the final edge of the trimming foil should be; (ii) cut a section off the roll that is about the right length (30" in the rear, 32" for the fronts), (iii) pull a bit of the backing off and stick the foil onto the door just along the top edge; (iv) hold the foil against the door and cut the foil (with the backing still on there) along the inside edge of the masking tape (the yellow-on-black provided a very visible guide through the foil backing), and then (v) finally pull the backing off and pressing the foil into position. On most of the doors, I detached the inside door handles first then cut the foil in place.
So now you might say, "Hmm. Fabric in the door cards. Interesting. Not what the M5 had originally, is it?" Nope, it ain't. I gave this quite a bit of thought. First, the smooth leather door card inserts are one of my least favorite parts of these interiors. It's expensive material for sure, but it looks plain and gives me a "cold" impression of that surface. So what to do instead? I could have done perforated leather (one of the big suppliers offers a really nice perforated leather that would have perfectly matched the new 'natur' leather), but that would have looked just like the basic E28 interior, so that was a no-go. I could have done Alcantara, but I did that on the last car. I tried hard to find a nice wool houndstooth check pattern cloth as a way of doing a bit of a tip 'o the hat to the old BMW check pattern interiors, but I had no luck finding a material I liked. So with my daughter's help, we picked out a nice upholstery at a local place that we felt matched my interior. The cards are easy to modify, so this can be changed later if my mood changes (and more on that later).
I now have the entire interior in. A few notable items ... the two-part center section around the parking brake has always puzzled me. I glued the top to the bottom section and we upholstered it as one. It's stiffer and cleaner this way, though I assume that adjusting the parking brake will be very slightly more complicated in the future. And it looks nice next to the new (and very red!) seat belt receptacles.
A note on those receptacles. The solution I described above (use E30 parts, add spacers to accommodate the E28 sport seats) did not end up working. As it turns out, receptacles with the correct "offset" for E28 sport seats are readily available, but the PN is technically for the E24 seat. Puzzling. (Try 72111945991 if you want it with the seatbelt warning pigtail, or 72111945992 if you don't care about that. Or one for each side with I think is maybe what BMW had in mind?)
One bummer (for now at least), I wasn't able to get my replacement center "AC blower vent" section properly covered in natur leather. (The US M5 has the area around the ashtray covered in matching leather.) Although I like the black-on-tan look of that part, it's not correct. I have a plan on how to fix that (again, more on that later).
I ordered the wrong-wrong-wrong floor mats from Lloyds. That color doesn't match *at all* and the pattern I later discovered was for an M6, not an M5 (my mistake). I'll be offering a new set of Lloyds mats for an E24 shortly. Groan. I then did what I should have done in the first place - I ordered swatches from Lloyds. Here there are. Number 2 is the closest match in the pics, but in real life #1 is better, so that's what I ordered. And this time I double & triple checked that I was actually ordering mats for an E28 pattern.
OK, on the interior (as hinted above), here's what I'm thinking: If you look closely in the pics above, the seam stitching has a pretty long "pitch." That is, each individual stitch is maybe 3-4mm long, but the original seams were much tighter and shorter (maybe 1-1.5mm?). The parts I have in the car will have to do for now. I want to turn to engine tuning & get this car on the road! But longer-term, my thought is to source another set of interior parts to replace the ones that are currently covered in leather and that have or are supposed to have any seams (dash, door caps, armrests, center sections, glove box, knee bolster) and have them redone in the same leather by a new shop that can do the much closer "baseball stitching" seams and can also shave the leather so that it's thinner and can be worked onto these surfaces in a way that's closer to the original. I love my current guy, but he doesn't have the leather shaver tools or a sewing machine that can do the dense stitches.
Speaking of engine tuning, here's what's currently going on. The motor has been fully converted to Motronic 1.3. The only chip I have is for an M30-B35. With that chip, the car runs, drives & idles (in fact, here's a short driving video!
The 'check engine light' was because the AFM wasn't connected, and the ABS light is because I have at least one bad sensor. The AFM issue is corrected; new ABS sensors are in-bound.), but I've found at least one odd issue. After the car is warmed up, the exhaust temps where the headers connect to the head are extremely hot. On my 535, I never saw temps over about 580-600 deg F. But on this car, the surface temps on the headers are getting up to 820 deg F. The best explanation I've heard is that the current timing is very retarded so that the air-fuel mixture is still in the process of burning as the exhaust valve opens and the pistons start the exhaust stroke. I have a company in Seattle (22nd RPD) that is going to try to do the chip tuning remotely, but I do have some concern that these super-high temps may warp the head before the timing is corrected. I've checked surface temps elsewhere on the motor and everything else looks normal. And the engine coolant temp gauge sits happily at about "noon," so this doesn't seem to be an oil or coolant issue.
Here are a couple of current pics as I start to work through my punch list.