BK06043 - 1991 E34 M5 in Alpineweiß

[dschneider]

I figured I really ought to start a thread to document my ownership of this car. A little late, but I forgive myself because nothing's happened recently...

Introducing BK06043, a US-market E34 M5 produced 1991-02-12. Exterior: Alpineweiß II (218), Interior: Silbergrau Hell nappa leather (0438) without wood trim. Standard US delivery: heated electric front seats, sunroof, rear headrests, ski-pass, no rear spoiler/wing. Shortly after purchase:

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The story of how I acquired this car is worth recounting. After catching up on a turbo M30 E30 convertible build thread on RevLimited, I was browsing local Craigslist in the Portland, OR area for E34 stuff. Since my other car (and daily driver) is an E34, I like to keep tabs on what's for sale. Sometimes interesting things show up. There wasn't anything particularly interesting this time around, and whatever keyword combination I had just tried didn't return any listings. But wait, what's this? In the "Related listings" section below the empty search results I spotted something interesting: "1991 E-34 M-5 in Bend, OR" at an outrageous price and 26 days old. It seemed too good to be true. The listing included a correct VIN, some decent photos, and mileage: 152k. The description was simple: "For sale 1991 M-5 the good : recently rebuilt S38 engine. The bad: rusted undercarriage. $5000 OBO" I picked up my phone and called.

On the phone with the owner, I got as much information as I could. He purchased the car after finding it on eBay in late 2016. He arranged with the seller to make the transaction via a friend of his, who was a pastor, who had a connection where the car was located in North Carolina. It was then shipped to California where is was reported to have passed SMOG. He said he was going to donate it for a church raffle to raise money, but that once his connection (the pastor) took possession of the car and had it inspected they determined that its condition was not suitable for sale. He then shipped the car to Bend, OR. I was unperturbed by the reported rust, since getting just the S38 in any running condition would make it a worthwhile purchase.

About the engine rebuild, he said that the previous owner had had the engine "fully rebuilt" by an indy shop in Asheville, NC, and that he had the receipts and everything. He sent me some additional pictures, including the NC title, and insisted that I have the car trailered. If I didn't want it, he was going to sell it to a local shop. I told him I had to check a couple things and that I'd call back. Unnamed indy shop in Asheville sounded familiar—there are only so many classic BMW specialists out there. But first, past eBay listings.

I searched for the full VIN and was able to uncover an old eBay listing. Listed for $11,000 in March of 2016, and with an auto-updating vehicle history report. Originally sold and lived in NY. 10/02/15 Titled in Texas. 8/12/16 Titled in Asheville NC. 1/26/2017 passed emissions in Burlingame, CA. So far so good. Now on to the shop reported to have rebuilt the engine.

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A quick trip to Google for BMW performance shops in Asheville turned up a single hit. It was none other than the predecessor to Koppinger Performance (whose name I don't currently remember), an operation run by RevLimited user RagtopE30 (Matt Koopi). The very author of the turbo E30 build thread I had been reading earlier in the day. On their website, I found a couple pictures of an M5 and S38 during assembly (they're even still in the gallery!). "I bet it's the very same car." The website at the time was a Weebly without its own domain name, and a generic contact form. Impatient, tracked down Matt's phone number from his posts on RevLimited and called. He answered. I asked him if he'd recently rebuilt an S38. "Yes. Why do you ask?"

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After an extensive conversation with Matt, I received a handful of additional pictures of the engine, including a couple shots of the engine bay showing a distinctive wiring pigtail sticking out of the fuse box cover that matched the photos from the seller, and a bunch of information about the car. According to Matt, he had rebuilt the engine around August of 2016 for a friend. This friend had purchased the car from a seller in Texas just prior. While driving it home, an enthusiastic young companion apparently gave it the money shift doing a pull on the freeway. After pulling the engine he discovered that #2 and #5 cylinders had been slightly toasted, but the block was salvageable.

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The block was bored, decked, and rebuilt with AP Racing forged pistons.

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[dschneider]

The head was also completely rebuilt, and the secondary air pump deleted.

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Thoroughly satisfied that the engine alone was worth at least as much as the entire package, I called up the seller and arranged to meet the very next day. Although it was May, a late snow had the pass over Mt. Hood still snowed in.

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I arrived and found the car exactly as advertised. Slightly dusty but stored in a garage, it fired right up and made a beautiful sound. At some point, a Supersprint exhaust had been installed, which produces a very unfortunate resonance around 3k RPM. I exchanged cash for car, keys, and paperwork then headed to the local DMV to get a temporary operating permit. No point paying back-registration on a car that will probably be a donor.

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I then arranged a tow back to my preferred mechanic in Portland, Matrix Integrated, for a full condition assessment. Onto the trailer we go!

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As reported, the chassis did have some significant rust, to the point of not being worth salvaging. It appears to be the typical sunroof drain causing rot in the side skirt, which has progressed to the complete destruction of the forward passenger jack point. There is a hole in the passenger floor pan and rust up through the panel seam at the rear and into the seat mount cross brace. Worse, however, is rust at the rear seat belt mount points. I later had that assessed by a family friend who runs a body shop in California, and his opinion was that, while that rust could be addressed, any repair represented a serious safety liability, and that the whole rust condition on the chassis was not worth repairing. Also needed: a new fuel tank, straps, and all hard lines.

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So... what's the status? Right now, the car is sitting in a garage in California waiting for me to commit to a project. I had been hoping to do a full Touring chassis swap conversion, but unfortunately don't think that's viable at this point. First, because I'd like to have the car be CA-viable in case I ever have to register it there. California engine swap restrictions and the vagaries of model year releases means that I can't legally put my '91 engine into any Touring, because the Touring didn't actually get sold in CA until '92. In theory I could make a strong case for equivalence based on the emissions control classifications (the '91 M5 is the exact same as the '93 and '93 for emissions regulation purposes), but apparently it's hard to find a CARB referee who will offer any modicum of flexibility. Second, and perhaps more significantly, because decent examples of Touring chassis have become very hard to come by.

I have enjoyed a bit of driving in the car, although every bushing in it is toast, the Bilstein shocks are way too harsh, and the spring rate is too much for my taste. The engine feels very smooth and strong. With the bore and deck, the displacement and compression have both been slightly increased. It's also fitted with a Dinan chip. Altogether, it probably makes a nice little bit over stock power. Unfortunately, the last time I had it out was over a year ago, and that ended with a tow truck ride home after the MAF gave up the ghost.

I've pulled the sport seats to use in my 535i in the mean time, and am now considering my options. The easiest thing would just be to M5-swap by 535i. That would have the benefit of leaving me with a known good condition low-mileage M30, which I could swap into my dad's beloved but currently dead E28 535is for a nice little performance bump. But if I'm making an M5 clone, I'd really want a Touring.

Thoughts?

[q20v]

Great story, thanks for sharing. I'd love to find a nice M5 engine like this for my ride. I'd vote for the swap into the 535i, and put the M30 in your dad's car. But whatever you end up doing, keep us updated!

Barry

[zubbie]

Interesting. My non runner M5 has the same sunroof, jackpoint rust issue, although not as bad (still rebuildable).

Wish my engine had been redone though. GL with whatever you do.

[Sir Montalbon]

The easiest thing would just be to M5-swap by 535i. That would have the benefit of leaving me with a known good condition low-mileage M30, which I could swap into my dad's beloved but currently dead E28 535is for a nice little performance bump. But if I'm making an M5 clone, I'd really want a Touring.

Thoughts?

Great read! I say go this route. If you find a suitable touring someday, it wouldn't be hard to find another M30 to swap back into your 535i while you put the S38 into the touring. Win win.

[Red Shirt KRT]

Find a good m5 shell maybe?

Either way you made out well, even if you just part it out and buy something else with the funds.

[zubbie]

Putting the drivetrain into a good M5 shell will yield a much more valuable car than an M5 clone despite being nearly identical chassis.

[dschneider]

Find a good m5 shell maybe?

Putting the drivetrain into a good M5 shell will yield a much more valuable car than an M5 clone despite being nearly identical chassis.

I'm aware of the collectibility value loss of making any sort of M5 clone, compared to using a chassis with an original M5 VIN (which is stupid if the only thing I'm keeping is the unibody shell, but that's collector logic for ya). However, since I don't intend to ever sell any such project car, I don't want to go to the extra trouble of finding a clean, straight, rust-free M5 shell. They only imported ~1400 to the North American market, so we're looking at a very small pool of potential donors. At this point, E34 M5s are either whole and should be kept that way, or they're not and for good reason. Mostly they've been wrecked. The remainder have been driven into the ground and parted. An empty M5 shell is worth just the same scrap value as any other sedan shell, aka not-worth-keeping-around dollars.

Unless someone on the forums happens to have one handy (preferably with the SLS system intact, even if not functional), it's just not worth it.

[de Witt]

I'm aware of the collectibility value loss of making any sort of M5 clone, compared to using a chassis with an original M5 VIN (which is stupid if the only thing I'm keeping is the unibody shell, but that's collector logic for ya). However, since I don't intend to ever sell any such project car, I don't want to go to the extra trouble of finding a clean, straight, rust-free M5 shell. They only imported ~1400 to the North American market, so we're looking at a very small pool of potential donors. At this point, E34 M5s are either whole and should be kept that way, or they're not and for good reason. Mostly they've been wrecked. The remainder have been driven into the ground and parted. An empty M5 shell is worth just the same scrap value as any other sedan shell, aka not-worth-keeping-around dollars.

Unless someone on the forums happens to have one handy (preferably with the SLS system intact, even if not functional), it's just not worth it.

You can always get an E34 M5 touring later (dont worry, prices will go down due to global recession in a few years). Just stuff it in your father's E28 or an E28/E24 of your own, you will only wonder what took you so long. As much as I love the E34, the E28 and E24 are just so visceral and enjoyable to drive. E28 for a sleeper and E24 for a BAMF cruiser.

[my540]

Do the same smog laws apply to imported vehicles that are older than 25 years? I know the federal government doesn't care if it's older than 25 years. You can import an e34 touring from Germany and swap it.

[de Witt]

Do the same smog laws apply to imported vehicles that are older than 25 years? I know the federal government doesn't care if it's older than 25 years. You can import an e34 touring from Germany and swap it.

Smog laws on motor vehicles are applied at the state level and vary. OP registers his vehicles in CA and IIRC smog check is required on gas-powered vehicles MY1976 and newer.

[dschneider]

You can always get an E34 M5 touring later (dont worry, prices will go down due to global recession in a few years). Just stuff it in your father's E28 or an E28/E24 of your own, you will only wonder what took you so long. As much as I love the E34, the E28 and E24 are just so visceral and enjoyable to drive. E28 for a sleeper and E24 for a BAMF cruiser.

The E28 unfortunately needs a bit more love than just the drivetrain swap, which I'm not prepared to invest quite yet. He's the second owner and purchased the car when it was only a couple years old ('91 or '92, I think), so it has a fair amount of sentimental value and deserves a full restoration. It S38 into E28 may be an easy swap, but going into an early model E34 chassis is practically bolt-in except for one or two accessory brackets in the engine bay. So into my current daily it'll be.

And you're right, I can import a nice M5 Touring when the economy tanks. We're due for a downturn on this cycle pretty soon, but I'm kinda hoping to take advantage of that to buy property, so we'll see if my finances work out for a car on top of that.

Thanks for the advice, it always helps to bounce these kinda of things off other people for that last confirmation.

Smog laws on motor vehicles are applied at the state level and vary. OP registers his vehicles in CA and IIRC smog check is required on gas-powered vehicles MY1976 and newer.

I'm actually in OR full time now, but odds are good I'll be back in CA in the future. I don't want to have to hassle with smog or leave my cars out of state when that happens, and I'm not banking on CA relaxing the smog laws one iota. Anything post-1976 has to conform to the smog requirements from the year it was originally sold.

[sugaki]

I forget, can they tell what model year it is from the engine--like you can't just say it's from a '92 M5?

Find a 520i Touring that somehow snuck into California and went by the noses of DMV and smog refs.

Seems like there are part-outs on occasion for the M5, maybe get a shell that way.

[BleedsBlue]

Awesome, Dakota, I didn’t know this back story or that this M5 was in your hands when you placed your order recently!

I totally get the the need to scrap the M5 chassis. We might have only received ~1400 of these, but we aren’t nearly to the point of B36 values that would make saving a car like this fiscally smart. Plus, when an M5 goes down, it typically lives on via transplant; or if parted out, it helps many other M5s stay on the road!

I won’t address the CA stuff - there are many reasons I won’t move back
However, Matty Matts (IG) and Racee78 on this board have done (or are in the process of doing) a B36 swap into a regular E34 Touring chassis, in California. There is at least precedent, Matt uses his as a daily!

I have a soft spot for Tourings, particularly with SLS, but the truth is that the S38 (B36 especially) really rewards a lighter chassis. I know Racee78 is using a non-sunroof Touring, which sheds awesome weight up top, but if you retain SLS you will still be looking at a near two ton vehicle wet. It pays to remember that factory M5 Tourings benefited from the S38B38’s extra torque and displacement.

A B36-powered Tourings is still no joke, and some strategic weight loss, bolt-ons, and a proper diff will go a long way. But I would also consider dropping the B36 in a lighter chassis.

[sugaki]

Even assuming the engine passes muster, it's still a pain to get the engine ref'ed. Doing some digging, it's possible they can trace the production date based on the engine serial, but not sure.

[T444E]

Cool story.

[dschneider]

I forget, can they tell what model year it is from the engine--like you can't just say it's from a '92 M5?

If I go through the process of getting the car CARB certified, the referee will check part numbers. An acceptable donor vehicle VIN has to be provided, but I'm not sure if they would even be able to identify the engine, DME, or other components as from that vehicle. They are probably supposed to cross-reference the engine serial number to verify that it's from an acceptable donor vehicle. Although, since it would be completely legal to swap a '93 M5 engine into a '91 M5, it seems like there shouldn't be a problem if I had a '93 M5 engine since it could have come from a CARB legal engine replacement to begin with.

If anyone knows a CARB referee who actually has some technical knowledge, I would love to talk to them. The over-the-phone "ask a ref" experience is rather poor, since they want to discourage people from doing engine replacements that they won't then validate.

This all basically boils down to the fact that the E34 M5 was a single CARB certified engine combination throughout its entire lifetime, so IMO it shouldn't matter exactly what year the vehicle was produced in because it's literally the same engine every year.

Matty Matts (IG) and Racee78 on this board have done (or are in the process of doing) a B36 swap into a regular E34 Touring chassis, in California. There is at least precedent, Matt uses his as a daily!

It's totally possible. There are model year overlapping examples to be found, making it a straightforward CARB engine change. Just swap in all the emissions controlled components from the donor and it's an easy pass with a CARB ref. It's just challenging because the majority of M5s were sold in the first year of availability, '91. So I have to figure out if I can get around that by model year equivalency argument for the M5.

Thanks for the kind words, Brent. You'll probably be hearing from me as soon as you get the oil cooler and radiator package up for sale.

Edit: just looked up Matty Matts on IG, and dang you didn't mention he's got an E28 535is too. He's got my dream garage going on.

[sugaki]

This all basically boils down to the fact that the E34 M5 was a single CARB certified engine combination throughout its entire lifetime, so IMO it shouldn't matter exactly what year the vehicle was produced in because it's literally the same engine every year.

California unfortunately doesn't work on common sense, but tries to make car modders and importers miserable. When I checked the law, it's based on model year, not production range. That said, digging into it, it seems like the ref would need to have documentation of the corresponding VIN and 8-digit engine serial to figure out the date of production, since the serial number itself doesn't have the date of production. Kinda doubtful refs would have that kind of access, since they'd need to get the archives from BMW Classic, or have the BTX build sheet handy.

[dschneider]

Long overdue update! I have a number of things to share.

I have recently moved (back) to Oregon, where sanity prevails. Even in the most-restrictive Portland Metro region, 1995 and earlier cars are exempt from emissions control restrictions, which significantly simplifies my project prospects.

It took a while, but I moved the M5 up from CA. Borrowed a friend's truck and trailer (after making some much-needed repairs on the trailer) and stashed the car at a second friend's house while I searched for a workspace.

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I eventually rented an industrial studio across town to store the M5, but didn't get much work done on it. Mostly because...

I acquired a Touring!

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It ran (poorly) and drove (poorly) at time of purchase, which was convenient for moving it. Seems to have suffered a head gasket failure, since it drank coolant and produced a white cloud. No water in the oil, though, just sucking coolant into one or more of the cylinders. The paint is OK (better than my sedan) and overall condition is suitable. It's even the perfect color combination! Granitesilber Metallic over Silbergrau Hell, which means my M5 interior bits will match perfectly. And I've always wanted a Granitesilber E34 after seeing some pics on here a while back. For reference, this is VIN ~GD24968.

Last year I bought a house with a 2.5 car deep garage. With the help of the same friend, moved the M5 over and cleared out the workshop.

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[dschneider]

I got some QuickJacks (considering MaxJax for this space as well, since it has a low ceiling height).

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And got the M5 to fire up on MegaSquirt!

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Having sat for multiple years, I took some precautions before spinning it over. I pulled the spark plugs and oiled lightly inside the cylinders. The fuel was stabilized, and when it was parked it had a very full tank of >100 octane. I checked and topped up the coolant, checked the oil, and spun it over dry for a few seconds before firing.

It fired right up on the base/startup map provided by DIYAutoTune. It even idled, kinda poorly. I only let it run for a few seconds, just long enough to determine that it did run adequately and on all cylinders, then shut it back down.

This was an important milestone for the car, since last time it was running it died out on a maintenance drive (which was years ago . Diagnosis was a dead MAF, and as the Angry Ass gents know that's a NLA part where remanufactured units are >$1000 at this point if you can even find one. Swapping the S38 to MegaSquirt is a cheaper alternative, in terms of parts cost, and will allow me to get a better tune given the engine's overbore.

So I know the S38 runs as-is, and I can feel much safer pulling it out knowing that it worked before I start messing with it.

In the mean time, the Touring is getting stripped so I can prep the engine bay. It's filthy! I have never seen so much oil buildup embedded with road grit.

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Unfortunately, it looks like someone used the core support as a jacking point, or maybe ran over a tall curb, because it's kinked on the passenger side. I'll pull a replacement off the M5. Having the cross braces on the front removed will be helpful for simplifying the swap, since my workspace has limited height.

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That's how things sit for now. The greasy gunk on the Touring engine bay is unpleasant to work with, and I've been busy working on my sedan to prep for AX this season. I actually don't have a thread for that car (yet!), but it's my first E34 and the reason I'm into this chassis. I'll put together a full writeup on that car and get it posted over the weekend.

Cheers!