M52B28 or M54B30, Similar difficulty?

[Whiskey98]

Hello everyone, first post so apologies if this has been done to death already!

I have owned my 1990 320i 2 door for almost a year now as my daily car and absolutely love it. It's got the original M20B20 engine, 5 speed Getrag 240 box, and modifications include professionally done carbon fibre roof skin, Bilstein B12 lowering kit, and I believe it has had an LSD fitted (unsure of ratio at this moment). I feel as though this car is crying out for a 24v engine conversion and I'm in a pretty good position to consider giving it a go in the near future. I'm from the UK and my car is RHD.

Here's the thing that's puzzling me, there seems to be loads of info out there on swapping in M(S)50 and M(S)52 engines, but considerably less on swapping in an M54. By all accounts it looks like the M54 is the superior engine compared with the M52:
- Larger max displacement
- Better performing ECU
- Superior inlet manifold
- Wider power band
- Better fuel economy
- Newer so parts more readily available
- Engines in greater supply

On top of this, 90% of the swap looks to be the same as the M52 and M50, you still need the E34 oil pan, E36 arms, E28 mounts etc.

So my question is, is there something I've overlooked here? Is there something about the M54 engine that despite all its benefits over the earlier engines, is a deal breaker when it comes to deciding whether to fit that, or an M50/52?

The modifications to the oil pickup and throttle pedal bracket seem simple enough, even things like dual VANOS and the DISA system don't seem off-putting since this engine is hailed as one of BMWs most reliable ever, and rebuild kits for these systems are readily available.
I'm an electrical engineer by trade so the wiring doesn't bother me.

So help me out here! Is there a genuine reason why M54 swaps are so much rarer than M52?

I have a few more questions regarding M54 swaps, specifically for RHD E30s so I will stay engaged with this thread.

Cheers!
Peter

[MrBurgundy]

I don't have a swapped e30 but have lots of exp with m54, m52 and m20s

The m20 is just so good in an e30.. Specifically the m20b25, when it comes to stock power plants. I know it may not be as powerful as the others, but if you put the money you would need to do a clean swap, you can put together an m20b28 ITBs and a good standalone, I promise you will be way more happy w the results.

The m54 is a good DD motor- arguable one of the best. Especially the b30 variant. If you're about taking the engine up to redline often, you're gonna be disappointed w the m54

If you did an m50 swap yeah you're gonna get a power boost, but lets say you had the b25, I wouldn't even consider that unless you wanted to boost it.

The best configuration IMO, i'm sure some will disagree. An m52b28 w s52 cams is a lot of engine for the money it would take to slap that together. Especially if you get an aluminum block variant.

I haven't looked at m50/m52 prices in a while but they used to be dirt cheap compared to m54s.

That might be why.

Anyways, to boil down what I said. What are you going to use the car primarily for?

[DesertBMW]

I don't have a swapped e30 but have lots of exp with m54, m52 and m20s
The best configuration IMO, i'm sure some will disagree. An m52b28 w s52 cams is a lot of engine for the money it would take to slap that together. Especially if you get an aluminum block variant.
I haven't looked at m50/m52 prices in a while but they used to be dirt cheap compared to m54s.

Why post then if you don't have experience with these swaps? You sure do have lots of posts on this forum and lots of them are nonsense. Guy is in UK there engines are rarer and more expensive, they don't have S52 stuff, you are giving wrong information.

So my question is, is there something I've overlooked here? Is there something about the M54 engine that despite all its benefits over the earlier engines, is a deal breaker when it comes to deciding whether to fit that, or an M50/52?

Gas pedal is a deal breaker on M54, oil pickup screen is a deal breaker, more wiring, water hear piping, radiator connections. That is one of the reasons why people tend to go with M52B28

[digger]

if swapping on a budget i would transfers the majority of gizzards from M54 (crank mainly) into a good condition alloy block m52 and use the M50 manifold, S52 cams or whatever the hotness is these days

[hoveringuy]

M54 is the better swap and only marginally more difficult. Most of the "standard" DOHC stuff works fine. You can run the G260 transmission, which means same driveshaft. Same radiator, exhaust, etc.

You can also run a 6 speed which is a little more difficult but so, so nice, particularly having the bigger clutch.

I think I needed to add a bung for a coolant sensor dedicated to the E30 cluster and obviously the gas pedal.

I'm not a fan of the E34 oil pans in general (hang too low). Check out Harper Fabrication. https://harperfab.com/products/e30-24v-oil-sump-v3 This is a BARGAIN for what you're getting!

[Whiskey98]

Thanks for the replies and advice. My E30 is my daily car for everyday commuting, and driving on weekends. I won't ever be taking this car to the track, my end goal is an E30 for everyday driving but will take off if you put your foot down.

So from what I'm hearing there isn't anything else that sets the M52 and M54 swaps apart that I'm not already aware of. More or less made my mind up that I will go down the M54 route then.

In the UK, M20B25 engines are hard to come across, but M52B28 and M54B30 engines are still very plentiful on Ebay and Facebook marketplace and a decent one costs around £800-1000 for M52, and £1000-1200 for M54.

For the gearbox, a 6 speed sounds very tempting but I would also be very happy with a Getrag 260 from a 325i, I've currently got a Getrag 240.
The fabricated oil pan looks good too, however if I just use an E34 oil pan I'll be sure to use a good skid plate to protect it.

I've noticed that M54s have cats after the exhaust manifolds, these can be deleted and programmed out of the ECU, right? Are the exhaust ports the same as the M52 so I can use similar manifolds to an M52 for clearing the RHD steering linkage?

[MrBurgundy]

Why post then if you don't have experience with these swaps? You sure do have lots of posts on this forum and lots of them are nonsense. Guy is in UK there engines are rarer and more expensive, they don't have S52 stuff, you are giving wrong information.



Gas pedal is a deal breaker on M54, oil pickup screen is a deal breaker, more wiring, water hear piping, radiator connections. That is one of the reasons why people tend to go with M52B28

Fuck off lmao

You say their engine options are harder to source, yet the OP says they're plentiful.

Yet you're saying I'm giving the wrong info. Jesus

You say the wiring for the pedal is a deal breaker for you ect ect ect, but your incapacities are not actually deal breakers for competent people. You're saying this m54 swap essentially is impossible because of a few extra steps... lol

A euro s50 cams wont even fit in an m52 swap, retard. He can buy s5x US cams on same shit this forum is on.... The internet.

Talk about posting nonsense... you're an idiot brother.

[DesertBMW]

You say their engine options are harder to source, yet the OP says they're plentiful.

Yet you're saying I'm giving the wrong info. Jesus

You say the wiring for the pedal is a deal breaker for you ect ect ect, but your incapacities are not actually deal breakers for competent people. You're saying this m54 swap essentially is impossible because of a few extra steps... lol

A euro s50 cams wont even fit in an m52 swap, retard. He can buy s5x US cams on same shit this forum is on.... The internet.

Talk about posting nonsense... you're an idiot brother.

I am the first person to do M54 swap on this forum and even wrote instructional post about it. I am the most qualified to speak on it. You are not because you never did the swap because you lack the skills. All you do is post low quality posts here calling people names, shame on you.

[MrBurgundy]

I am the first person to do M54 swap on this forum and even wrote instructional post about it. I am the most qualified to speak on it. You are not because you never did the swap because you lack the skills. All you do is post low quality posts here calling people names, shame on you.

Don't take yourself too seriously. Everything I said is valid, yet you had to say something, for some reason. I even mentioned I don't own a swapped e30 for a reason.

If you come shit on what I have to say, I'm not going to sit there and just take it. Anyways not to derail the thread....

Carry on

Cheers

[Whiskey98]

Cheers, my plan will be to have the car off the road for the shortest time possible, although I'll definitely be expecting there to be setbacks. For that I'll be gathering all the parts beforehand and doing jobs like the steering linkage, steering rack upgrade, brakes etc, one at a time while the B20 is still in the car and running. Meanwhile I'll get the water pump, thermostat, spark plugs etc sorted on the engine while it's out of the car.
As for the gearbox, I think I'll go for the Getrag 260 for now since it will be more than ideal for what I need the car for, and is much cheaper than a ZF 6 speed. Won't keep it fully off the cards though.
I've a few more questions regarding the swap:
What would the best diff ratio be for an engine and gearbox combination like this?
Is the oil pump nut locking wire mod needed for an M54?
If I used an E30 Getrag 260 gearbox, can I reuse my current propshaft, or does the gearbox have to move back a bit?
I'm wanting to go for a twin pipe exhaust system like I currently have, what is an ideal diameter for each pipe? Thinking 2"
Cheers!

Also I feel as though this thread has answered my original question so I will probably start another regarding my swap once it gets underway

[hoveringuy]

Cheers, my plan will be to have the car off the road for the shortest time possible, although I'll definitely be expecting there to be setbacks. For that I'll be gathering all the parts beforehand and doing jobs like the steering linkage, steering rack upgrade, brakes etc, one at a time while the B20 is still in the car and running. Meanwhile I'll get the water pump, thermostat, spark plugs etc sorted on the engine while it's out of the car.
As for the gearbox, I think I'll go for the Getrag 260 for now since it will be more than ideal for what I need the car for, and is much cheaper than a ZF 6 speed. Won't keep it fully off the cards though.
I've a few more questions regarding the swap:
What would the best diff ratio be for an engine and gearbox combination like this?
Is the oil pump nut locking wire mod needed for an M54?
If I used an E30 Getrag 260 gearbox, can I reuse my current propshaft, or does the gearbox have to move back a bit?
I'm wanting to go for a twin pipe exhaust system like I currently have, what is an ideal diameter for each pipe? Thinking 2"
Cheers!

Also I feel as though this thread has answered my original question so I will probably start another regarding my swap once it gets underway

I don't know what your current diff ratio on the 320i is, and whether it's a small case diff or medium, but the M54 generally likes taller gears because it has so much torque. I found the 3.73 too short and a 3.25 was much better.

A G260 will bolt directly to the M54 using an M20 clutch. The minor issue is that the transmission will be tilted 10 degrees which means you need to cut and rotate the shift rod. No bigee. Use a standard M20 with G260 driveshaft (I don't know what the G240 uses).

The oil pump is still an issue on the M54 and possibly more so because the aluminum block doesn't dampen vibrations well. There are kits that just replace the entire oil pump shaft with a hardened one.

As far as exhaust single 2.5" is fine and twin 2.0" is good.

[Whiskey98]

I've began accumulating the hard to find parts for my M54B30 swap such as E34 sump, dipstick, E38 pickup, M52TU fuel rail, E36 engine arms.
Been giving a 6 speed ZF trans some more thought, they are more available than I originally anticipated. The thing that's confusing me a bit is if I did go for a ZF GS6-37BZ from an E46, would I be able to use a single mass flywheel? A lot of the ones I see specify 5 speed. Something to do with the pilot bearing? Is it even worth going single mass flywheel?

[TobyB]

The single mass is only worth the effort if it's lighter- we have one of each in E46's, and there's not really any difference.
I don't like the self- adjusting clutch with the DMF, so I prefer the single, but it's not a huge difference.

There is a spline change in the BMW range in 9-02, so the 6- speed got 20 spline input shafts, and the pilot
rides in the flywheel. The previous 5- speed has a 10- spline and the pilot's in the crank nose.
Confusingly, the later 5- speeds ALSO went to 20 spline, but the pilot's still in the crank nose.

The 6- speed allows you to run a shorter diff- the 3L cars with a 5 got a 2.93, and that made them hard to get off the line.
The lighter E30 won't have as much trouble with that. But a 6- speed with something like a 3.15 would be about ideal-
quick off the line, long- legged for the motorway.

There are lots of incremental improvements to the M54: aluminum block, the 3L makes significant torque (for a small 6),
MS43 is open AND pretty tunable, yadda yadda yadda. I have a 91 shell and an M54B30 sitting in the barn waiting for
me to get the rest of life done so I can assemble it. The M54B30 in my E46 DOES pull pretty nicely over 4k-
but it's also got the torque to get there without fuss.

I think the M52 gets more press because it was first, and when it was popular there were lots of $500 E30s with broken
timing belts (I got a couple of those, way back when) and then the E36 aged out pretty quickly, so the engine supply
was there. You could get an entire e36 for less than the head work to fix the broken timing belt's damage...
so lots of people did it.
By the time the M54 got cheap, the E30 was starting to get expensive and hard to find. Plus, the E46s and E39s held
up better than their predecessors, so in 2015, there was real pressure to 'keep the E30 original'
'respect your elders' (ha, said he, who had a 2002 )whereas in 2005, it was a cheap rat,
do what you want to and have fun.

edit: now, the N52 has gotten fun- Hovering has made it plausible, and the transmission
options are interesting for that engine. Especially if one wants an 8HP and a custom controller...
So the M54 really has lost its new engine luster, as well.

So here in 2025, do what you want to, and have fun! I need to get on that, myself.

t
getting off the couch and heading out to work on the house.