92 Mtech vert LS daily driver swap

[jon volk]

Just pulled the motor so I guess it's time for a build thread. Car is a 92 325i Mtech convertible. It's been my daily driver for 3 years and will continue to serve as such once the swap is done.







The motor is nothing extraordinary. Just an 01 4.8L with a plate kit for good measure. The stock M20 would be lucky to make 140whp on its best day so it's still a massive boost in power. Engine management is an MS3 gold box. Oil pan is a modified GTO piece.







I'm using mounts from Garagistic since the intro price of $300 was more attractive than pulling the motor in and out a bunch of times. I immediately thought something was wrong as the mounts did not line up side to side with the holes in the subframe. Turns out they chose to utilize the rearward mounting bosses that are only present on aluminum blocks. So within the first day one was cut up to. The trans crossmember also needed some trimming to sit flush against the body. The holes for the trans mount are also at a spacing that doesn't line up with either the rubber or poly mounts I have. I'll most likely just punch a single center hole in and use that.









Im fucking done with T56s so the trans is a TH400 that I hope to source another gear vendors overdrive one day, as I really like the one in my M3. I'll be swapping to 2.79 gears to make highway driving livable with the 24" tall tires on the car. Fitting the trans took some massaging with a 10lb sledge but it'll go.



That's about all for now. I've got some fairly minor rust repair to take care of before dropping the motor in. Luckily this panel is still available new from BMW for $90.

[TimeMachinE30]

Wow. Nice!!!!

[M-technik-3]

Wow that battery tray is toast! Hope the rot did not spread into the firewall. Did you have this car up for sale a few times?

Nice shop space your working with makes life so much easier.

[jon volk]

Wow that battery tray is toast! Hope the rot did not spread into the firewall. Did you have this car up for sale a few times?

Nice shop space your working with makes life so much easier.

Firewall is solid. One spot has some surface rust but it passed the stab it with a screwdriver test. It'll be a simple matter of drilling out a dozen spot welds and tacking in the new tray.


Got some more basics done today. Removed the brake booster and installed a 944 master cylinder with a plate from Massive Brakes. Removed the ABS pump and trimmed/reflared the existing lines. Also installed a vette fuel filter/regulator.



Started scrubbing 25 years of grime and whatever the yellow shit is that BMW liberally applied to the engine bay. Still got a ways to go before it's ready to start dropping the motor in.

[TimeMachinE30]

Cosmoline. Used in the storage of armory items, too.

I has good luck with purple power sprayed on liberally, a soft, long reach brush and a pressure washer.

You realraying the bay to match that purty paint on the outside?

[M-technik-3]

Used to prevent rust from starting in areas that are not commonly washed. Kinda like an improvement on rusty jones or waxoily. it;s paraffin based if I remember correctly

[jon volk]

Got it clean enough for the intent and purpose of the car. I can always touch it up a bit more later. Next up is drilling out the spot welds for the rusty battery tray...or whats left of it and put some new sheetmetal on order. Going to apply some phosphoric acid on the few spots that have surface rust to neutralize it, then treat it with POR15. Since those spots are low and out of sight, Ill just hit it with some Duplicolor Arctic White, since its a close enough match for Alpine white. Then its time to drop the motor in.

[flyboyx]

due to there rarity of Mtech 2's i elected to leave my drivetrain stock and do all the crazy stuff to a more common model. its going to be a cool car, but in some ways its a shame to modify this one to the point of no return.

[Nick's e30]

Whats the P/N on that battery tray for the engine bay? I think I should replace mine. Looks like a badass build. Why no T56?

[jon volk]

due to there rarity of Mtech 2's i elected to leave my drivetrain stock and do all the crazy stuff to a more common model. its going to be a cool car, but in some ways its a shame to modify this one to the point of no return.

I would have done it to an E30 M3 if I had the money.....



I've broken two T56s so far. One the synchros started going to shit, but it had unknown history. The other was a built trans in my M3 and overheated the cluster gear/input gear before installing a fluid pump. For my needs, it's just not worth spending $1500 on what amounts to a crap shoot core, then another 600-1500 (depending what's worn) in parts just to get a decent trans. If I did road course stuff all the time it would make sense, but I just commute to work in my cars and do stupid high gear highway pulls or rolling burnouts wherever possible. A stock th400 with fresh clutches and a manual shift kit will last longer than this motor for $450 total investment. It doesn't completely suck to drive either since it no longer does any automatic functions other than not needing a clutch pedal. It's also the same mounting position as a t56 so it's a bolt in ordeal with a normal crossmember.

Battery tray is part number 41111929429

Just about ready to weld the replacement in. Just need to make a small patch panel for the fenderwell section under the battery tray where there was some rot under the undercoating. It's only about 2"x2" so nothing terrible.

[White325is]

Love this build. Ive been following it on IG for a big. Im doing an LS swap as well. Just need to get back into it.

[lemansguy]

nice work so far. im very interested in seeing how that TH400 works for you. never seen one used in an e30 before

[jon volk]

Dropped the motor in. I'm gong to need to shim the mounts a bit to make the modified GTO pan work. While the mounts have two position "options", there's really only one. The further back choice and even that seems like it could go rearward a bit more. Modified ebay header cleared the steering shaft so that's a positive. Going to cut about a 1/4" off the water pump about for additional radiator clearance. I'll probably get the trans bolted up before attempting any more mock up.

[Pootis]

Do you have a link for those headers?

[jon volk]

Any of the "ls1 block hugger" headers on ebay. The passenger side wont work with these mounts but one of the generic truck header ones should on that side since the cast iron truck manifold fits. The block hugger I made a cut on the underside of each tube and angled it closer to the block. Took all of 15 minutes but probably not something the average swapper is going to do. Cost will end up being a little less than $300 for both sets so its not really a cost savings over the Sanderson. I just cant deal with mild steel exhaust components.