M-Technic II slow restomod

[P.Kelly]

I'm finally getting around to starting on my restomod. I picked up a 1991 M-Technic II (full 771 package last October) from a kid in Santa Cruz who owned the car for less than a year. Prior to him it was briefly owned by DG Films on this board. I believe it had two long-time owners prior to him; likely making me the fifth owner based upon DMV records.

The car is a Northern California car. From purchase to today its home has been in about a 100 mile radius. It seems to have been relatively well taken care of and has logged a respectable ~140,000 miles in the last 21 years.

My goal is to bring it back to what it was in 1991 and then some. It will be a weekend car for me and the family.

Here are some pictures the DG took while he owned the car to start this thread off with a little eye candy.


DG Films bringing the car home from the previous owner (115,000 miles on the ODO in September of 2010).

The craigslist ad read, ""I have a 1990 BMW 325i convertible, M series, factory lowered, red and black convertibel. I bought the car for my daughter. She drove it for a few months and decided she did not like convertibles. The top is an original and will need a new one. The interior is in great condition. It has 115K miles and the timing belt was replaced at 105K. It also has an awesome radio system. I am looking to trrade for any motorcycle with the same value but please NO project bikes. Honda, Suzuki, Ymaha, Vespa, Sportster, Kawasaki, BMW. Let me know what you have. I am in the process of moving and no pix at this time. Call me and I will send you via cell phone. Thank you for looking."

I think DG picked it up for $3000-4000. Nice price.



A few days later. The car looks nice at 10 feet for sure.



You can see the original M-Technic badge has been replaced an ///M Badge. Still need to rectify that. Also, the kid I bought the car from sold the factory wheels just before I rescued the car.






Sometime in December Daryl picked up a hardtop (from Ryan G, I think) and a set of BBS LM reps. No complaints on my part.






The front lip needs a bit of work here. It was resprayed before I got it, but still has some touch-up needs.






You can't quite make it out here, but the trunk lid has a nasty gash and needs some work. Also, the pin-stripe is still on the side in this picture. Someone removed it before I got it.









It has new plates on it now...


8mm front, 15mm rear spacers here















Not that I would have ever used it, but the bra went missing before I got the car.

[P.Kelly]

Things on my to-do list (in no particular order):

- Refresh the suspension
- Replace the M20 with an S5X (and have it BAR'd)
- Replace the soft top
- Replace the hardtop headliner
- Touch-up paint
- Various odds and ends

To those ends I have all the parts for the soft top, I have an H&R Touring Cup Kit, I have a set of Euro Smileys and HID kit, I also have an OBDI S5X motor and ZF trans.

[reelizmpro]

Ahhh so you got one of DG Film's cars...cool. There's something you should consider before changing your soft top. BMW does not recommend you stow the top for prolonged periods of time because the window creases and rubs against itself (if you didn't insert a towel) and you risk cracking it when you do pull the soft top out. So if your running a hardtop this presents a problem because unless you are taking it on and off...you may not want to install a fresh soft top. Then again, a fresh rear window will be more flexible than an older one but you're still taking a chance leaving it stowed. This is one of the reasons I'm not too crazy about hardtops like most people and I like the ability to drop the top when I want and put it up when I want. Just something to be aware of.

[P.Kelly]

There's something you should consider before changing your soft top. BMW does not recommend you stow the top for prolonged periods of time because the window creases and rubs against itself (if you didn't insert a towel) and you risk cracking it when you do pull the soft top out. So if your running a hardtop this presents a problem because unless you are taking it on and off...you may not want to install a fresh soft top.

Good point. I had planned to build a lift for the hardtop, that way I can store the car with the soft top up for prolonged periods.

[P.Kelly]

I ordered a Z3 differential today off EBAY out of a 2000 2.5L which means it should be a 3.15 ratio Torsen differential. Given that the car will be a cruiser and never see track duty a torsen diff will do just fine for me and the donor car only had 25K miles.

For those that haven't done the math, with a ZF320, the final drive on a 3.07 diff is closest to the final drive of a Getrag 260 with 3.73 of 3.02. A 2.93 would provide a bit better fuel economy and the 3.15 will provide a little more speed, but the difference will be minimal.

[bubbajan21]

I ordered a Z3 differential today off EBAY out of a 3001 2.5L which means it should be a 3.15 ratio Torsen differential. Given that the car will be a cruiser and never see track duty a torsen diff will do just fine for me and the donor car only had 25K miles.

For those that haven't done the math, with a ZF320, the final drive on a 3.07 diff is closest to the final drive of a Getrag 260 with 3.73 of 3.02. A 2.93 would provide a bit better fuel economy and the 3.15 will provide a little more speed, but the difference will be minimal.

The Torsens only came in the coupes so I hope it was out of a coupe.

Great looking car btw!!

[P.Kelly]

The Torsens only came in the coupes so I hope it was out of a coupe.

Hmm. Everything I have read suggests that every z3 from 99 on had at least a torsen LSD, and the M models plus those with optioned upgrades had a clutch pack version. I have personally dismantled a diff from a 99 autotragic with a 3.46 torsen, thinking it was from a manual trans car. I let the yard keep that one.

I think the confusion here is that a torsen LSD will act like an open diff during the "free wheel" test. Since I'm not tracking the car, I don't need a clutch pack LSD.

Anyway, I went to the BMW site and checked the WebETK list for the car. It shows a 25% LSD as standard equipment.

01 - LIMITED SLIP DIFF.UNIT - 25% - 33 14 1 428 350

So, here's to hoping.

Great looking car btw!!

Thank you!

[robrez]

As a Z3 coupe owner who's been around a while and had a few diffs., I'm 99.9% sure it's a Torsen. I run a 4.27 torsen in my m-tech II vert (auto m20), and a 4.10 torsen in my 318i (m42). Ironically, the only car I don't run a torsen in is my Z3 coupe, which has a Dinan 3.38 clutch-pack. One day, I'll get wanganstyle to rebuild the 3.38 into a torsen as well.

Looking forward to the progress.

[P.Kelly]

Thanks, the diff should be here on Friday. We'll see then. I've got a trip to the junk yard lined up to pickup a number of items I still need for the swap and some fiddly bits for other restoration activities:

- DME holder
- throttle cable
- firewall cable management
- diff output flanges
- plastic convertible flap
- etc

[JinormusJ]

I must say. This is one sexy MTII

Can't wait to see it at the meet
Definitely sub'd; love keeping in touch with local builds. Let me know if you ever need help with anything

[P.Kelly]

I must say. This is one sexy MTII

Thanks man. It is nice in person, but the pictures are dead sexy for sure.

Can't wait to see it at the meet
Definitely sub'd; love keeping in touch with local builds. Let me know if you ever need help with anything

I am sure that I will. The motor swap is going to be the biggest automotive project I've ever undertaken.

[P.Kelly]

Well, the diff arrived today. It was packed horribly, but I think the damage to diff cover fins was previous damage because there were no parts in the box. The diff also had a big white R stamped where you normally see an S on an E30 diff case.



But that looks like a Torsen to me. Anyone know how to verify the gear ratio by the stamped marking on the ring gear?

[P.Kelly]

Today we hacked up a good chunk of the donor car. It was a 95 e36 convertible (and not the car the new motor originally came from). It is now a smart car (or what's let of it is about the same size.

I learned that windshields are a pain in the ass to remove (click the pic for funny video content):



And here is the car with the front half missing:

[P.Kelly]

And then I took a long hot shower and hit up the Weaves and Fries meet in Natomas tonight. There was some cool stuff there and someone with way better photography skills then me snapped these shots:







Some time in the next week or so the car will begin its restomod.

[P.Kelly]

Sometime next week turned into this week, as I spent 4 weeks in the UK and Germany in between, including a trip to the BMW Welt.

I pulled the gauge cluster last night, as after 140k miles and 23 years the batteries finally started to go. I had to cut the safety wire on the cluster, so I know that no one has ever touched the cluster before.