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Re: Rebuilding My 1988 US-spec M5

Posted: Jan 26, 2021 12:30 AM
by M5BB
Just catching up.
Great work and attention to detail.
I own some pretty cool BMW's but Black Betty is my fav and may be the fastest too!

:popcorn:

Re: Rebuilding My 1988 US-spec M5

Posted: Jan 26, 2021 12:24 PM
by jhh925
cek wrote: Jan 25, 2021 7:44 PM Awsome work. Go Navy!
You're giving me motivation to change my avatar ... Anna just got her congressional nomination!

Re: Rebuilding My 1988 US-spec M5

Posted: Jan 26, 2021 9:19 PM
by knunger
Stunning Jens,
Absolutely stunning.

Can't wait to see it at the Sheraton for the next SandyEggo day!

Re: Rebuilding My 1988 US-spec M5

Posted: Feb 17, 2021 1:14 PM
by jhh925
knunger wrote: Jan 26, 2021 9:19 PM Stunning Jens,
Absolutely stunning.

Can't wait to see it at the Sheraton for the next SandyEggo day!
Yeah, I can't wait to get this thing on the road! And in that sense, having SPD '21 canceled was a blessing in disguise - no disappointment about not having this done by March.

Re: Rebuilding My 1988 US-spec M5

Posted: Feb 17, 2021 6:30 PM
by vinceg101
jhh925 wrote: Feb 17, 2021 1:14 PM
knunger wrote: Jan 26, 2021 9:19 PM Stunning Jens,
Absolutely stunning.

Can't wait to see it at the Sheraton for the next SandyEggo day!
Yeah, I can't wait to get this thing on the road! And in that sense, having SPD '21 canceled was a blessing in disguise - no disappointment about not having this done by March.
But maybe by Nov. 1 for SoCal Vintage Meet? (here in LA)

I feel the same way about not having my new interior done by March also.

Re: Rebuilding My 1988 US-spec M5

Posted: Feb 18, 2021 9:22 PM
by Karl Grau
vinceg101 wrote: Feb 17, 2021 6:30 PMI feel the same way about not having my new interior done by March also.
New interior?

Re: Rebuilding My 1988 US-spec M5

Posted: Feb 19, 2021 3:12 AM
by vinceg101
Karl Grau wrote: Feb 18, 2021 9:22 PM
vinceg101 wrote: Feb 17, 2021 6:30 PMI feel the same way about not having my new interior done by March also.
New interior?
(Shhhh...it's a secret :cool: )

Re: Rebuilding My 1988 US-spec M5

Posted: Mar 15, 2021 1:16 PM
by jhh925
vinceg101 wrote: Feb 17, 2021 6:30 PM
jhh925 wrote: Feb 17, 2021 1:14 PM
knunger wrote: Jan 26, 2021 9:19 PM Stunning Jens,
Absolutely stunning.

Can't wait to see it at the Sheraton for the next SandyEggo day!
Yeah, I can't wait to get this thing on the road! And in that sense, having SPD '21 canceled was a blessing in disguise - no disappointment about not having this done by March.
But maybe by Nov. 1 for SoCal Vintage Meet? (here in LA)

I feel the same way about not having my new interior done by March also.
Oooh ... yeah, maybe!

Re: Rebuilding My 1988 US-spec M5

Posted: Mar 15, 2021 3:21 PM
by jhh925
Overdue for an update. The rate of progress really seems to be picking up and there's lots to report.

Right now, everything I'm doing is geared at getting the motor back in ASAP. To get the motor in, I want to have all the cooling system hoses and AC lines that go through the firewall back in (once the motor is in, getting those parts installed would be near impossible). Getting all those hoses & lines back in means having to get the heater core & AC evaporator boxes back in. Getting those boxes back in means putting the carpet back in. Putting the carpet back in ... well, you get the idea. It all started to feel like a pretty long & complicated task, so to keep me on task (so to speak), I did this to-do list that was intended to be in order of what needs to get done first to last. Since doing this list, I've modified my strategy a bit, but more on that later.

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Cleaning up and checking the wiring felt like the elephant in the room for me. When I took the car apart, what I found in the electrical system was a combination of prior bad stereo installations (probably multiple), a Viper installation and incorrect connections in the fuse block. The result of that was that I had anxiety about whether the wiring in my car would match the wiring diagram, and that I'd end up with a bunch of gremlins that would be super hard to diagnose & correct once the car was back together. So my plan was to test all the fuse pin connections to as many of the "fused components" as I could; e.g., test continuity from the radio power supply fuse to the radio power supply end-point, etc. All of that seemed to check out, though I had a moment of panic when all the side make lights were indicating that they were shorted out to ground. It took me a while to figure out that the bulbs were installed in the taillights and were in fact grounding the system out.

Here's before view under the dash:

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And here's a pic from when I was nearly done. Any harnesses I found where the tape wrap had c one loose or was disintegrating got re-wrapped with Tessa high temp tape. I've come to the conclusion that most of the gray dust & dry powdery grim in all the interior nooks & crannies is disintegrated harness wrapping. The wrap on all the big main harnesses behind the cluster all disintegrated at my touch, and in clear sunlight you can see all the dust cascading down as you remove the tape fragments.

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In that pic above, I've steam cleaned, used compressed air and vacuumed as much as I Gould get to. If nothing else, it smells so much nicer & cleaner!

I also (nearly) finished refurbishing the evap box. Before:

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After:

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The only thing I'm not happy with is that the "O" ring kit I bought didn't have a small enough one to seal the small pipe on the expansion valve, so I reused the old one. Not a day later I found a better kit and ordered it. So, unfortunately, before the evap box goes back in, I'll have to disassemble and re-do one of the connections. I also discovered that one of the new Knipex needle nose pliers (angled jaw, slightly flattened tips) worked perfectly to straighten all the bent aluminum fins.

And this one is a bit geeky, but given the amount of damage by the battery box where it looked like battery fluid had leaked out, I was particularly motivated to replace the fuel pump cover gasket on the trunk floor. That part is NLA, and my old was was ruined. So, I took two sheets of that thin foam, stuck them together, and build this round cutter:

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I cut the outside edge first, then the inside, then used Rotabroach to cut the bolt holes. Result (before the bolt holes were cut):

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New stickers arrived. Most of them were from Pukar Designs, but he sent the wrong paint code sticker, so I actually had to design my own in Adobe Illustrator and get it printed up. "But wait!" you say, "Aren't there plenty of other places to buy BMW paint code stickers?!?" Well, lots of places on eBay and Etsy appear to sell them, but they were all incorrect ... wrong size, wrong color, wrong font, wrong orientation, no part numbers, etc. I finally found one of the Etsy sellers who was fine printing up my design.

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I've no also got the doors mostly reassembled, including the trim, glass & handles. This is starting to make my collection of parts look a bit more like an actual car. Most of the trip clips are new. (For some idiotic reason, I only ordered 25 new clips when I actually needed a total of closer to 36, so I had to reuse some of the old ones.) I also used the 3M strip caulk under the aluminum trip to replace the old white putty that had been removed. The 3M stuff is a bit stickier, so removal will take a bit of care if I ever have to do that.

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And now one of the small victories that I'm particularly excited about. One challenge I knew I was going to have to deal with with how to attach the Euro M88 headers (with their 3-bolt flakes) to the US-spec cat section (with their 2-bolt flanges). As it's been explained to me, the usual solution when installing euro headers is to cut the 2-bolt flanges off of the US exhaust manifolds and then onto the euro headers. I didn't want to do that juuuuust in case I had smog emissions certification issues and had to go back to the US manifolds. Unfortunately, I couldn't find a set of aftermarket flanges that seemed to have the right specs without going to some of those klugy "universal" flanges that have the elongated bolt holes.

So, I designed my own and had it fabbed! I used a company called Oshcut.com. Design your part in AI, upload the cutting diagram, specify your material, and they'll cut it using a laser CNC machine. This service is limited to cutting out of a sheet and bending, but this was plenty for what I needed. First I drew the part on AI, printed it out in paper, confirmed that the paper part fit onto the US flanges, then had Oshcut cut the part & send them to me. This basically didn't take any longer than it would have if Summet Racing actually had the part in stock. I was pretty amazed.

Here's the new flange:

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And here's the set up to cut the euro headers. I made a jig to hold the US part correctly, with the bottom and end boards rigid so that they exactly replicate the two mating surfaces (at the head & at the input flanges to the cats). Then I remove the US manifold, bolt in the euro headers and use the vertical board to mark where to cut the euro headers.

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Under the "measure twice, cut once" principal, I haven't cut the euro headers yet.

The next step would be to cut the headers, then bolt the new flanges to the vertical board, then weld the flanges to the headers in the jig. Out of an abundance of caution and a bit of OCD, instead what I've decided to do is cut the headers, then mount the exhaust in the car, drop the engine & tranny in there, tack the flanges to the headers while their actually bolted in place to the cats, pull it all back out again and then fully weld the flanges to the headers after the motor is removed from the car. First, I have the time. Second, because there's no springy billows section in the euro headers, that whole set up will be more rigid and a proper, unstressed fit will be more important.

Re: Rebuilding My 1988 US-spec M5

Posted: Mar 22, 2021 1:43 PM
by jhh925
Headliner day at "Casa JHH925."

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Re: Rebuilding My 1988 US-spec M5

Posted: Apr 07, 2021 6:20 PM
by jhh925
Making progress on the "pre-install checklist" to install the motor:

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One note - I've ticked off the "install moonroof" item, but I didn't actually install the moonroof. I thought (naively) that because I have an original BMW moonroof that installing it would be very plug-n-play. I had previously read (though it was a long time ago and even then I hadn't read very carefully) JBORT's instructions on how to install the Saab moonroof. Well, I didn't have a Saab moonroof, did I? So naturally, the BMW version would be hella easy.

Well, based on a couple other threads here on the forum, I came to realize that I'd have to modify a couple parts. Still relatively easy, but without ready access to spares, I decided I could do without the moonroof. So, anyhow, the original sunroof is reinstalled.

On a more constructive note, I got the 2-bolt flanges welded on to the modified euro M88 headers and I'm very happy with the results!

To recap, I built a jig to hold the original manifolds, then mounted the headers in the jig to mark where to cut the pipes. I also had a pair of 2-bolt flanges fabricated in mild steel.

Next step: slide the flanges onto the headers, mount the headers on the motor, drop the motor onto the mounts in the engine bay & attach the tranny & tranny mount. With that done, the ends of the headers would be positioned under the car exactly where they will be sitting when everything gets put back together.

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Next, I installed the cat section and the resonator exhaust section. That step locates the flanges for the cat intake side. The headers lined up to the cats pretty well. Then I bolted them together, tacked the 2-bolt flanges to the headers ... and then dropped the tranny, pulled the motor, removed the headers and welded up the flanges. It actually went pretty well and took a lot less time than I was anticipating.

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While I had the cat section in there, I also repaired the tranny-to-exhaust brace. This is the plate that attaches to the underside of the tranny & bridges over to a tab on the cat section. Here's a pic of what it's supposed to look like (not my pic, this is from a BaT auction):

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In my case, the end of the tranny brace was cut off, and the tab on the cat section was likewise mostly cut off. I tabbed an "L" bracket for the tranny brace and a new tab for the cat section and tacked them in place while everything was still installed on the car. I painted all the new parts with some high-temp exhaust pipe paint. Not as elegant as the yellow zinc (hidden under the paper wrapping), but it suits me fine at this point.

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That big tear in the shroud is bugging me. Not sure yet how to address that.

Re: Rebuilding My 1988 US-spec M5

Posted: Apr 08, 2021 1:30 AM
by cek
jhh925 wrote: Apr 07, 2021 6:20 PM
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I has warm feels seeing this. Nice work buddy!

Re: Rebuilding My 1988 US-spec M5

Posted: Apr 25, 2021 1:11 PM
by jhh925
Much progress being made!

Got the headers ceramic powder coated (before / after):

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Got the heater core box, A/C evaporator box, front A/C lines and carpet back in ... I like this 'natur' color more than I remember:

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Taped the trunk felt insulation pad back in. I didn't think to get pics, but I bought a roll of two-sided picture hanging tape (this stuff from Amazon) to hold the felt down. My thought is that if I don't like this felt or if the results don't last has hoped for, the tape will be a whole lot easier to remove than contact cement. I also ended up spraying a thin layer of 3M sprayable glue along the edges of the felt. This industrial felt seems to be very willing to "separate" if you fray the edges, so by spraying the glue into the edge fibers, I'm hoping to give the felt a bit more structure & protection.

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Next, I tackled the trunk lid liner. I started with the original anthracite vinyl liner (which had a very warped fiber board backing), collected a second M5 anthracite liner, and managed to fine a new OEM gray liner (wrong color, but the fiber board was in very very good condition). My plan was to pick the best anthrazit vinyl sheet, remove the gray vinyl from the new liner, then glue the anthracite liner to the good fiber board panel. So far, that seems to have worked like a charm. Starting parts:

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Stripped, cleaned fiber board, sprayed with a thin coat of polyurethane for a bit of moisture protection:

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Gluing the fiberboard:

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Result:

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I also mounted the new non-spoiler, non-M5 trunk lid with Roundel and M5 badge, and also set in the rear windshield:

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And today, I'm finally going to dive back into the engine wiring harness and finish that MF'er up so that I can drop the engine in for good.

Re: Rebuilding My 1988 US-spec M5

Posted: May 04, 2021 7:35 PM
by jhh925
What a relief ... the engine wiring harness is done and the 55-pin connector for the '179 ECU is all wired up, tested and taped clean. Final result:

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And the diagram I was using to test all the pin connections:

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I think I described some of this earlier. De-pinning the 35-pin connector was easy, and most of the components that hook up into the ECU just directly re-map from one set of pins on the 35-pin connector for Motronic 1.0, and get inserted into a new set of pins in the 55-pin connector for Motronic 1.3. There are three exceptions:
  • The logic & wiring for how you start the car is different, requiring rewiring for the ignition switch wires, main relay and the associated wires that go to the ECU. Put another way, I changed the ignition, main relay and associated wiring connections in my harness so that they now work the way they'd work in a Motronic 1.3 writing harness.
  • The old O2 sensor was 3-wire, the new one is 4-wire. There are probably multiple ways to do it, but I "orphaned" the wiring for the old 3-wire set up and installed a new shielded 4-conductor wire in parallel to the old signal wire. (That's the tan wire held in place temporarily by the blue masking tape & running along the side of the engine harness in the pics below.) That allowed me to use the new style 4-pin screw-in connector and the separate B35-style connector for the heater circuit.
  • The ever purge vale & barometric presser sensor in the M5 sit at the far front-right of the engine compartment at the end of a long section of the engine harness. The old set up (separate purge vale & purge vale relay + the barometric sensor) aren't needed, and all I wanted was a simple 2-wire set up to run to the new-style purge valve. Because that section of the harness is so long, I couldn't thread new wires inside, and I didn't want to run separate wires on the outside of the loom, so I repurposed a couple of the now unused wires in there and re-routed them so they'd work with the new purge valve. I then added a new Bosch 2-wire connector at the end of that section of the wiring harness.
Other than that, it really was basically just moving pins from one connector to the other. In a couple cases, I found it was best to add an extension to the existing wire, but mostly this is a plug-n-play swap. Mostly. Not that I didn't sit there for a few long days shuffling between four different wiring diagrams.

It felt pretty chaotic while I was actually doing the work, but I think the end result came out pretty neat & clean.

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One challenge that I'll figure out later is that the 35-pin connector comes out of the ECU with the wiring pigtail facing 180 degrees in the opposite direction from where the 55-pin connector will come out of the new ECU. I'll solve that either by mounting the ECU flipped upside down, or (more likely), by rotating the ECU a bit. We'll see.

Anyhow, the engine is ready to go in permanently! Which is exciting all by itself, but also means I'll get a bunch of room back in the garage.

Re: Rebuilding My 1988 US-spec M5

Posted: May 18, 2021 4:37 PM
by jhh925
Making progress, getting closer to that first start. Here's what I've gotten done recently:

I painted the gas tank (SprayMax 2k "Hot Rod Black" paint - hoping it's a bit harder & tougher than the SEM trim black) and then installed it.

Gas tank installed:

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I also really wanted to replace that rubber "floor" by the gas cap, but the correct E28 part is long since NLA, so I modified the version for the E24 (which is still available). It's not perfect, but it's pretty close! Three rubber seals for the gas filler neck (from L to R): unmodified E24, modified E24, my original E28.

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And here's the final fit in the car:

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I also jumped ahead a bit and put my tools back - blue rag courtesy of Ivo:

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I dropped the engine in and mounted the re-finished flywheel & a new Sachs clutch assembly:

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Due to the wider S38 head, the M88 headers & the M5-specific aluminum shield (hard to see, but I'm talking about the red circle at lower right), after the engine was dropped onto the front mounts, it didn't tip back as far as a regular M30 motor would have, so getting the tranny bolts all back in & torqued was a royal pain. That bolt at the very top of the bell housing took me hours. That was in part my own damn fault ... once I pulled that aluminum shield off, the motor-tranny would tip down another few mm and I was able to snake my extensions up to get to the bolt.

I also moved the vent parts from the original uncracked dash (which will stay in storage) to my newly recovered leather dash. I had to re-create one of the felt insulation pads - the original was ruined by a PO in a prior botched gluing job.

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And here's the current state:

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I'm now working up a checklist of the things I need to get done to let me do a first crank on the motor. My goal there is to reattach / reinstall as few parts as possible so that if (or more likely when) I need to dig back into stuff I will be minimizing how much stuff will need to come back off.

Re: Rebuilding My 1988 US-spec M5

Posted: May 18, 2021 7:21 PM
by Tiit
Thanks for sharing.

Re: Rebuilding My 1988 US-spec M5

Posted: May 18, 2021 10:40 PM
by Adam W in MN
Jeez this thread is so informative and inspiring.

Re: Rebuilding My 1988 US-spec M5

Posted: May 18, 2021 10:52 PM
by Kapt
Your attention to detail is inspiring. Fantastic work.
Thanks for the tip on the e24 gas cap rubber.

Re: Rebuilding My 1988 US-spec M5

Posted: May 19, 2021 11:48 AM
by jhh925
Kapt wrote: May 18, 2021 10:52 PM Your attention to detail is inspiring. Fantastic work.
Thanks for the tip on the e24 gas cap rubber.
Thanks ... also, in case it's helpful, I was reminded recently that there are probably a few different PNs for those gas cap rubber parts. The specific one I started with is PN 16111119235. RealOEM says that part will fit in an E28 up through a production date of 12/1987 ... but my experience is that it won't fit without modifying the "throat" so that it will fit onto the top of the E28 gas filler neck.

Re: Rebuilding My 1988 US-spec M5

Posted: May 19, 2021 10:21 PM
by Ricky535
Which pulse generator bracket are you going to use for the 179 ECU, B34 or B35?

Re: Rebuilding My 1988 US-spec M5

Posted: Jun 30, 2021 5:14 PM
by Kapt
What method did you use to install the rear glass?

As always, great work.

Re: Rebuilding My 1988 US-spec M5

Posted: Jul 02, 2021 5:37 PM
by jhh925
Ricky535 wrote: May 19, 2021 10:21 PM Which pulse generator bracket are you going to use for the 179 ECU, B34 or B35?
Stay tuned ... I'll do my update today or tomorrow and (assuming I understand your question correctly) I'll show you what I did.

Re: Rebuilding My 1988 US-spec M5

Posted: Jul 02, 2021 5:41 PM
by jhh925
Kapt wrote: Jun 30, 2021 5:14 PM What method did you use to install the rear glass?

As always, great work.
Put glass into the rubber gasket first, thread some nylon rope into the notch in the gasket where the body pinch weld will end up (making sure that the rope ends overlap and exit the gasket midway along the bottom edge), set the gasket+glass+rope into the body opening, and then start pulling the rope out so that it pulls the gasket up & over the pinch weld.

For the front windshield, I set the gasket in first, then put the glass into the gasket starting at the bottom edge, then used plastic trim tools to pull the gasket up & over the glass. At one point I saw a video of BMW workers in the factory setting the front glass in in about 5-10 seconds using that method. Can't remember where I got the link to that vid.

Re: Rebuilding My 1988 US-spec M5

Posted: Jul 02, 2021 6:18 PM
by jhh925
jhh925 wrote: Jul 02, 2021 5:37 PM
Ricky535 wrote: May 19, 2021 10:21 PM Which pulse generator bracket are you going to use for the 179 ECU, B34 or B35?
Stay tuned ... I'll do my update today or tomorrow and (assuming I understand your question correctly) I'll show you what I did.
Actually, I don't trust myself to get my ass in gear and post an update here, and I want to be responsive.

So, as you know, the S38B35 uses Motronic 1.1, which gets crankshaft speed & position data from two sensors mounted to the transmission bell housing. In the M5, the leads for those two sensors come up inside the transmission tunnel, up along the firewall, and then plug into female connectors that are held in place by a small bracket that's mounted onto the cowl cover right up behind the ITB for cyl #6. In my mind, those connectors mounted up on the cowl wall are pretty distinctive in the M5 and I wanted to keep that look.

The M30B35 on the other hand gets crankshaft speed & position data from the single hall-effect sensor that's mounted to the timing chain cover low and on the right side of the engine. The CPS sensors for an M30B35 are readily available, but when mounted to the engine in the right spot will only reach to about ITB #1.

So, here's what I did:
- The M30B35 CPS sensor bracket mounts to the S38 timing chain cover as a direct plug-n-play. That is, the S38 lower timing chain cover is nearly identical to one off an M30B35, and any sensor mount bracket off of an M30B35 will mount directly to an S38 in the same spot.
- Obviously, if you mount the CPS from an M30B35 to the S38, you also need to swap in a vibration dampener from an M30B35, which I did.
- I then cut the CPS sensor plug off the end of the lead, and replaced it with a German audio connector (2-wire, shielded, threaded connection; if anyone's interested, I can post info about the part).
- At the other end, I bought two cheap M30B34 sensors from Rock Auto in order to get new female sensor ends and so that I'd have some additional wire lead to try to get from the cowl wall to the front of the engine. For those new sensors, I cut off the sensor-end, leaving me with a long lead & a female connector on one end.
- I'd hoped that would be enough to then just add the other half of the audio connector to the Rock Auto sensors, but I was still short. In anticipation of this, I'd already bought some 2-conductor shielded cable (20awg). I spliced some of that onto the end of the Rock Auto sensors, put the audio connector onto the end of that extension, and then plugged my new extension onto the end of the CPS.
- I did basically the same thing for the Cyl #6 sensor that's used in the M1.3 setup.
- So I ended up with the two M1.3 sensors in the proper spots and with the wiring mimicking the placement in a standard S38.

Here are pics:

CPS mounted to the front of the motor with the M30B35 vibration dampener in place:

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Top of motor showing the Cyl #6 sensor in place and both sensor wires held in place at the front of the motor using the original S38 wiring bracket:

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Audio connector between sensor and cable extension:

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Shitty pic showing where the sensor wires are going along the block underneath the ITBs:

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Sensor connectors hooked up & mounted on the cowl wall exactly as is done in a stock S38:

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Re: Rebuilding My 1988 US-spec M5

Posted: Jul 02, 2021 8:03 PM
by vinceg101
jhh925 wrote: Jul 02, 2021 5:41 PMFor the front windshield, I set the gasket in first, then put the glass into the gasket starting at the bottom edge, then used plastic trim tools to pull the gasket up & over the glass. At one point I saw a video of BMW workers in the factory setting the front glass in in about 5-10 seconds using that method. Can't remember where I got the link to that vid.
This is the method my installer used when he did mine; worked well. He had it in before I could more than a few photos of the process.
His only difficultly was with the getting the trim locked in, especially the lower passenger corner.
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