Crazy to do the M54 as my first ever build/swap? (87 325es)

[jc1000]

Hello! Noob here.

I just bought an 87 325es (M20B27) and want to do an engine swap. I am mechanically inclined and enjoy working on cars, but have yet to do something as big as a full engine build or swap (this will be my first). For instance, I have not welded before or done any wiring, but am interested in learning.

I plan on keeping this car forever, and want it to be fast! I want to be somewhat responsible financially, but do have some money to spend on it. I also have a place to work on it and am willing to spend some good time on it (I am not in a rush). I realize I have a lot of options. The main ones I am considering are to build an M50/M52 (with possible future turbo), build an M52B30 stroker, or go with the M54. I could also rebuild my current engine and turbo it, but I like the idea of a newer, more powerful engine.

Of the options, I am most excited by what the M54 has to offer - power, torque, newer technology. I would also be able to follow common engine build videos and threads for this engine since I won't be modifying much of the internals (as opposed to the M52B30 stroker, for instance). Of course, this comes at the cost of more fabrication/"figuring out" and a less well-worn path as far as the actual swap has to go. I guess what I am trying to gauge is if the M54 option is "hard-but-doable" or just way over my head.

Would love to hear any and all arguments as to what I should do. Is the added performance/HP of the M54 over the M50/M52 worth the added complexity? Anything else I should be considering when making this decision? As long as it will be sporty and quick, I am pretty open.

[AceAndrew777]

The M52 is a waste of time, just do a proper M20 if that's the option. A 2.9L M20 with ITB's is so fun it's ridiculous.

Picture this .... but with a chunk more power.
🐒 BETTER THAN AN M3 - CRAZY 327i BMW E30! - YouTube


That being said, if you're strictly comparing the 24v's then opt for the M54.

.... my worthless two cents. Arguing over swaps is a tale as old as time.

[jc1000]

The M52 is a waste of time, just do a proper M20 if that's the option. A 2.9L M20 with ITB's is so fun it's ridiculous.

Picture this .... but with a chunk more power.
🐒 BETTER THAN AN M3 - CRAZY 327i BMW E30! - YouTube


That being said, if you're strictly comparing the 24v's then opt for the M54.

.... my worthless two cents. Arguing over swaps is a tale as old as time.

Thanks! How do you get the M20 to 2.9? Could I do it with my M20B27?

[TobyB]

If you want powr and modrn, N52 is probably a better bet.
The M54 is getting a bit long in the tooth.
That said, if you can find a good donor, do it.

t

[digger]

if you want the car fast and be based on a BMW inline 6 then you're going to need a turbo in there, so an m52 turbo is a well trodden path

[MrBurgundy]

The M52 is a waste of time, just do a proper M20 if that's the option. A 2.9L M20 with ITB's is so fun it's ridiculous.

Picture this .... but with a chunk more power.
🐒 BETTER THAN AN M3 - CRAZY 327i BMW E30! - YouTube


That being said, if you're strictly comparing the 24v's then opt for the M54.

.... my worthless two cents. Arguing over swaps is a tale as old as time.

M20 is life.

[It's Soda Not Pop]

The M52 is a waste of time, just do a proper M20 if that's the option. A 2.9L M20 with ITB's is so fun it's ridiculous.

Picture this .... but with a chunk more power.
🐒 BETTER THAN AN M3 - CRAZY 327i BMW E30! - YouTube


That being said, if you're strictly comparing the 24v's then opt for the M54.

.... my worthless two cents. Arguing over swaps is a tale as old as time.

That video and Kamron Baker's videos are the reason I'm going ITBs. Sooooooo Sexy

[e30davie]

first google result gives this guide,

https://www.r3vlimited.com/board/forum/e30-technical-forums/24v-engine-swaps/m54-s54/351110-e30-m54-swap-guide

well documented, but there are a few items in there that i wouldnt consider basic mechanical work. ie, welding oil pickups. and some of those bits must be hard and expensive to get by now.

[Panici]

The M52 is a waste of time, just do a proper M20 if that's the option. A 2.9L M20 with ITB's is so fun it's ridiculous.

Curious as to why you say the M52 is a waste of time?
I was pleased with my M52B28 even naturally aspirated. It made my E30 feel like a different car compared to the M20B25.
It was a great match with the stock 14" wheels/tires and a riot to drive (aka tail happy) with a mildly-upgraded suspension setup.


It's a well-documented swap and able to make good power as an unopened stock unit when boost is added.

It was also the first engine I opened up to refresh, and it was simple enough. Even the single vanos wasn't too difficult to rebuild. It all went back together without issue and runs strong.


All that said, I do have a spare M52 waiting in the wings that I pulled from a parts car. They are becoming harder to find in my area. And that's a big point for the M54/newer engines.

[TobyB]

The M20 makes approximately the same torque as the M52, and it's only a 40 hp bump on a good day.

The M54 is lighter (aluminum block) and the B30 makes a real bump in torque AND horsepower. That said,
it's not night and day, just a 'good bit' better.
The N52 is darned close to double the horsepower, and close to that in torque. THAT will wake things up, if tuned.

but yeah, not bolt- in.

t

[digger]

Not sure what numbers you're comparing to m20b27 either way numbers seem a extremely suss.

It comes down to how fast you want the car to be or whether its more about doing a project, any project for the experience/enjoyment/tears

[varg]

If you do 24V in the E30 make sure it's an aluminum block engine, whatever it is. You can feel the difference in feel between an M42 and an M20 (I've done it), it doesn't need the extra weight of an iron block 24V. Yes, they're heavier than an M20, the head is huge in comparison even if the blocks are similar in weight. I've considered the 24V NA builds, it's just hard to get a enough power to satisfy my fun car wants; better than 10lb/hp.

[KI4UJO]

I currently have a m54b30 in one of my e30s, it is where I ended up after a string of 24v powerplants (m50, m50tu, m52b28). Overall, it feels like the correct engine for the car - not overpowered, but the right amount of power and torque.

With that in mind, it was not the most straightforward swap. Standouts include having a custom P/S pressure hose fabricated as well as the wiring (this part really isn't documented very well, service data is your friend). M54s are also approaching 20yrs old at this point - I'm doing a rebuild on a b25 for a customer currently. If I was installing one today, it would get a full overhaul before going back in..... but that applies to really any engine IMO. Doing anything twice sucks.

As noted above, the weight difference is noticeable. That is one of the main reasons I went m54 - my car started life with an m10, and the cast iron 24v engines left some to be desired in the handling department. While this still isn't as light, its a big improvement (-60lbs?)

It is worth asking - what is your goal for the car? I built mine to be able to drive every day if I want, with an emphasis on highway (2.79 lsd ftw!). With that in mind, it still performs quite well on backroad stuff, with the soft suspension (and driver in the seat) being the real limiting factor. I mention this as m54b30s can have issues with harmonic vibrations at high RPM. If you want a track car, I'd probably stay with a cast block engine.

Overall, would I do it again? Absolutely! I'd definitely recommend it, just be sure to go through the engine before dropping it in (and change to a better oil ring design... they're good at using oil with stock style rings)

N52 is also something to consider now. 6 speed gearboxes are a bit easier to come by for them.... but there is a lot more fabrication involved. You'll be building most everything to fit it

[digger]

if all you want is m54 power then rebuild the m20 into a nice stroker..........

[McGyver]

What is "fast" for you?

Building an m20 stroker has some real benefits. It'll be a fresh engine, is relatively cheap to build on the side as a spare, and would be plug-and-play with your current setup.