[mega_stihl]

Greetings. I am new to these forums and this is my very first post.

I've owned several older BMW's and I currently own a BMW E46 320Ci which I swapped to a 330Ci. Completely rebuilt the engine and then swapped it over, swapped the brakes, axles, ... The car is on Bilstein B12 and H&R sways. The only issue is that even after the engine swap, hp is addictive.

I was looking into E90 335i's. Why? Because a 3 liter turbo has potential to tons of hp, and the E90 is the only "recent" BMW that I still find somehow half decent. I'm a huge fan of sharknoses and I don't care about newer bimmers. The only downsides compared to my E46 are
- more expensive car
- more expensive in maintenance
- harder to work on
- more expensive in tax.
About the latter: I live in a country where we have the highest road taxes in the world. This is why I swapped the engine in my E46, so no one would notice. The swap already paid for itself.

My question: the N54 and N55 (and the car in general), are they a PITA to work on, or is it not that big of a deal after all? I do know that to reach the N54 turbo's you have to drop the subframe which is a PITA. Besides the wastegate rattle, are these engines somewhat reliable? Not really talking about things that go bad and will need replacement, but I mean: can I take it for a 1000km trip on holiday without needing the phone number of the tow truck?

Another question. I'm toying with the idea of swapping an N54 into a 323i.
6cil to 6cil swaps don't really attract that much attention, and 323i's and even 318i/320i's can be found dirt cheap. They are also a lot cheaper in tax. My question is: is doing the swap a huge amount of work? I'm not talking about pulling the engine out and in, I'm talking about programming the ECU and stuff like that. M54 to M54 in the E46 is practically plug & play. And what about everything else in the car? Is there a huge difference between lets say the 320i and the 335i besides the engine (and drivetrain, ofcourse). Just wondering if swapping is worth it. If I need €10 000 worth of parts, than I'm better off buying the 335i as it is and just accept the fact that it's higher in taxes.


Kind regards

[whyzee125]

These take a considerable amount of maintenance as you know, and are definitely a step up from an e46 in most regards. I used to be an e46 guy but I never looked back once I got my first 335i.

N54 is a great engine. They're more reliable now than they used to be as most of the main culprits have been revised (turbos, HPFP, injectors). They love to leak oil out of every orifice and they go through water pumps fast. There's not a lot of room to work on them but most of the common jobs that you'd be likely to DIY (water pump, gaskets, etc.) aren't really any harder than on an e46. Proper maintenance is key and it sounds like you're well equipped to take care of one.

N55 is not worth the hassle IMO. They like to spin rod bearings for no reason, have major PCV issues, harmonic balancer issues, and have a ton less power potential than the N54. They do sound better though.

That's my $.02

[Suvorovo]

How much are index 12 injectors going for in europe? They're like $3500 USD for a set of 6. 10k Euro will fix up a worst case scenario 335i. Turbos 6k, Injectors 3.5k, HPFP.

Don't have a 335i, but just my two cents:

1. Don't buy one that's modded, most likely driven hard to death.
2. Don't get xdrive. More parts, more problems, harder to work on, more money. I hate my xdrive. The gearing is worse (3.23 for 330xi) which makes great gas mileage, but slower acceleration
3. Try to get one with maintenance history. Most n54 probably have Index 9s,10s,11s,12s by now. You can easily check the index on the injector.
4. N54 waste gate rattle will probably be common on most high mileage n54s. I believe you can buy a waste gate rebuild kit, not too expensive.
5. You're probably ready for HPFP issues/water pump/thermostat.
6. High mileage n54s will need carbon buildup removal since direct injected.

[mega_stihl]

thank you for responding.

Suvorovo : I have no idea what "index xx" means.
1. This is something I am also aware of. This is a clear indication that their money went to mods rather than maintenance. It's common over here.
2. I want an RWD. Why else buy a BMW?

whyzee125
I am pretty well equipped. I have a lift that goes up to 1m20cm. I can't stand underneath the car but it's a HUGE upgrade coming from a jack and jackstands. I have a 20ton press, an engine hoist, Delphi laptop and standard BMW diagnostic tools, ... I used to be a mechanic for living but decided it's more fun to do for yourself/friends than as a fulltime underappreciated job.
About the N55: I thought these were better than the N54 with regards to reliability. less HPFP and WP issues. I have driven/owned/worked on neither so I can't tell and I thank you for your input.
But what I'm afraid for is this: if my CEL comes on on the E46, I know it's probably something that will cost me €100 worst case scenario. Either a failed coil pack, cam sensor or MAF sensor. If a CEL comes on on an N54, is this a scenario where I should contact my bank and ask them for a loan?

I do have 1 final issue, which is something I probably won't find an answer to because petrol in the US and A is a lot cheaper than in Europe. I do love LPG and have LPG fuel injection in all of my petrol fueled cars. The price is 1/3 of petrol. The M54 engine runs great on LPG, but since the N54 is direct injection (and LPG is port-injection), we don't have many people running LPG on these engines over here because these systems are more complicated, so no one can chip in with regards to how well these engines take LPG.

I know the "true" petrolheads will tell me: "you don't buy this car only to while about its fuel consumption". Well, that might be true, but driving on LPG saves me around €1300 a year. So call me what you want, it's still a nice amount of money in my pocket at the end of the year

Kind regards

[neilvan]

Originally Posted by mega_stihl

I do know that to reach the N54 turbo's you have to drop the subframe which is a PITA.
Kind regards

Not true; I've done turbos multiple times on different cars, all on jack stands and without dropping or touching the subframe. Can be done in a day but that being said all were rwd cars (x-drive i'm sure youd have to)

My n54 cars have been very reliable but parts do wear out over years and have to be replaced. that's just regular maintenance. Just buy a decently maintained, lower mileage and non abused one

N54 and N55 have the same waterpump & HPFP issues (same parts) as well as both get carbon build up. the N54 has wastegate and injector issues (both can be fixed with a new turbo or Index 12s) whereas the N55 has rod bearings(more common to happen during a OFH gasket change)

The idea of a drivetrain swap is doable for sure but its way more involved than a larger M54 swap as all the drivetrain and engine ecu/harness should be changed over

[oVeRdOsE.]

I lot of people ask me about my bmw s , I have the 3 big N : N52-54-55.

I always ask them what is their mechanics skill level. Since those cars got a lot more failure point than a corolla, but 90% of the time it's easy , somewhat cheap and won't required a towing.

aka many stuff can fails, but no major stuff, this is why people who doesn't know those engine will say that they are not reliable (kind of true) , but on a enthusiast point of view they are reliable, because nothing big will fail VS the power it can take.

The moment you go to the dealer or indy to get your aged bmw to be fixed, this will kill the vibe.
I.e water pump is easy to do, pumps are around 200-300$, but can take up to 4-5 hours.
Same for the valve cover gasket, it's a 50$ part but a 3-4 hours job, easy but time consuming.

One pros, is common failure means common parts and might also means that those stuff are already done on the car.

Simply wait for it.

I don't need a 335xi 6mt, but when I saw one online with 9k$ of repair bill and asking for 8k$, this car was like new and jumped on it.

issue you might deal with if 100% OEM :
- water pump and thermostat.
- coil packs
- injector
- High pressure fuel pump
- seals (all of them : cover, oil pan, oil filter housing, misc sensors)
- vacuum line (in fact most plastic lines will cracks)
- Charge pipe (plastic)
- waste gate rattle
- vanos solenoid ( 90% of the tiem they simply need a clean up)


I didn't read much about rod bearing, but mine were done at 100k km. Don't know why, but car runs great , now at 115k km)

Also don't swap a N54 in a sedan E90. The hassle won't worth it, just get a 335.
The only ''valuable'' N54 swap is in a E91

[whyzee125]

whyzee125
I am pretty well equipped. I have a lift that goes up to 1m20cm. I can't stand underneath the car but it's a HUGE upgrade coming from a jack and jackstands. I have a 20ton press, an engine hoist, Delphi laptop and standard BMW diagnostic tools, ... I used to be a mechanic for living but decided it's more fun to do for yourself/friends than as a fulltime underappreciated job.
About the N55: I thought these were better than the N54 with regards to reliability. less HPFP and WP issues. I have driven/owned/worked on neither so I can't tell and I thank you for your input.
But what I'm afraid for is this: if my CEL comes on on the E46, I know it's probably something that will cost me €100 worst case scenario. Either a failed coil pack, cam sensor or MAF sensor. If a CEL comes on on an N54, is this a scenario where I should contact my bank and ask them for a loan?

I do have 1 final issue, which is something I probably won't find an answer to because petrol in the US and A is a lot cheaper than in Europe. I do love LPG and have LPG fuel injection in all of my petrol fueled cars. The price is 1/3 of petrol. The M54 engine runs great on LPG, but since the N54 is direct injection (and LPG is port-injection), we don't have many people running LPG on these engines over here because these systems are more complicated, so no one can chip in with regards to how well these engines take LPG.

I know the "true" petrolheads will tell me: "you don't buy this car only to while about its fuel consumption". Well, that might be true, but driving on LPG saves me around €1300 a year. So call me what you want, it's still a nice amount of money in my pocket at the end of the year

Kind regards[/QUOTE]

IMO you'll be just fine--the people with horror stories about N54's are not the people who have been in the BMW game and have a lift in their garage. They're the people who liked the BMW name or wanted something fast and cheap and aren't prepared to maintain it. You won't need a loan for every CEL if you keep your car maintained.

I've almost exclusively driven an N54 car since 2013 and I've never once been burned. I maintain my stuff, take care of issues as soon as or before they arise and have never had problems. All my N54's have been modified too. I've been stranded exactly once and it was due to a leaking water pump.

Unfortunately have no idea about LPG but I would guess that's not commonly done on these cars. I know all the UK guys with range rovers do it but that's the extent of my knowledge lol.

The N55 was claimed to be more reliable when it came out and at the time it may have been but the N54's HPFP, injectors, and all the ancillary components that fail have been revised. They now use the same HPFP and they've always used the same water pump. The N54 index 12 injectors are very reliable. Worst case, N54's have worse ancillary components but the engine itself is way more reliable.

[mega_stihl]

Originally Posted by oVeRdOsE.

I lot of people ask me about my bmw s , I have the 3 big N : N52-54-55.

I always ask them what is their mechanics skill level. Since those cars got a lot more failure point than a corolla, but 90% of the time it's easy , somewhat cheap and won't required a towing.

aka many stuff can fails, but no major stuff, this is why people who doesn't know those engine will say that they are not reliable (kind of true) , but on a enthusiast point of view they are reliable, because nothing big will fail VS the power it can take.

The moment you go to the dealer or indy to get your aged bmw to be fixed, this will kill the vibe.
I.e water pump is easy to do, pumps are around 200-300$, but can take up to 4-5 hours.
Same for the valve cover gasket, it's a 50$ part but a 3-4 hours job, easy but time consuming.

One pros, is common failure means common parts and might also means that those stuff are already done on the car.

Simply wait for it.

I don't need a 335xi 6mt, but when I saw one online with 9k$ of repair bill and asking for 8k$, this car was like new and jumped on it.

issue you might deal with if 100% OEM :
- water pump and thermostat.
- coil packs
- injector
- High pressure fuel pump
- seals (all of them : cover, oil pan, oil filter housing, misc sensors)
- vacuum line (in fact most plastic lines will cracks)
- Charge pipe (plastic)
- waste gate rattle
- vanos solenoid ( 90% of the tiem they simply need a clean up)


I didn't read much about rod bearing, but mine were done at 100k km. Don't know why, but car runs great , now at 115k km)

Also don't swap a N54 in a sedan E90. The hassle won't worth it, just get a 335.
The only ''valuable'' N54 swap is in a E91

Thank you for your input.

The main reason for a N54 swap rather than just buy a 335i, is the €600 of difference in annual tax.

5 hours of work for a waterpump and valve cover gasket is an insane amount of work compared to the E46 where the waterpump is in and out in literally 25 minutes.
Can I get away with aftermarket parts like lets say Bosch injectors (or whatever the OE brand is) or any reputable aftermarket brand, or should I stick to strictly OEM? Also a huge factor in costs
What you said about doing it yourself because if you have to take it to the dealer, the fun is gone ... That goes for any car nowadays. I used to work at a VAG dealer, and I still have my "connections" there, and I ask my former co-worked for parts numbers when I'm working on a VW/Audi at home, so I can cross-reference that part number. The cost of VAG (actually this goes for any brand nowadays) parts nowadays, even without labour, is simply ridiculous. If I had to reach out to the dealer for maintenance and repairs, I wouldn't even be able to afford a Skoda Fabia or VW Polo.

Back to the E90: What I might do is rather than buy a low mileage one, I buy a cheaper high mileage and change out most of these parts myself, so I know it's done the correct way and they can last a while from there. An example is my sharknoses. I rather buy a higher mileage than a very expensive low mileage one. They are 30 years old so the suspension is gone regardless of the mileage.

[oVeRdOsE.]

from what I can tell, no alternative yet for injectors.

However, those car getting older, and some folks before scrapping their car will remove the index 12 injectors and flip it around 1000 $ usd used on FB market.

DIY is not that bad when you do the maintenance at the due date and not waiting last minute and had to wrench 4 days on this car.

You have a point on the 600euro difference, but honestly I didn't even look at this at all, since at the beginning a 335 n54 is not a rational buy.

The fuel might be an other factor for you then.
My E91 and E90 has the same fuel gauge right? So Im driving way more my N52 and I know when Im around 1/4 I can do a full week going to work.
Then jumped on my N54 and I did the same thinking, to find out I had only 2 days left. So yes , it pump way more gas, especially if its modded to beat the f out of it

[mega_stihl]

yes I just looked into this. The N55 injectors can be found for €100 a piece from Bosch. OEM N54 injectors are probably what will make me wanna cry when these wear out. A set of 6 is about half what my car is worth right now.

Many thanks for the input you guys!

[fastboatster]

Did they ban diesels from the city centers in your country or it was in Germany or somewhere else or did not happen? I’d think that you have more used diesel engines available to you, and perhaps an m57 swap would be a better option. I don’t know if it will be saving you money on fuel, though - you seem to want to run the lpg and that may or may not be cheaper than diesel where you live.
As for the n54 vs n55 swap, hard to talk about those 2 in general. The n55, even in the e chassis, had some variations, that includes the hpfp, for example. Early build dates have the same style hpfp as the n54, later build dates have an hpfp just like many other direct injected cars. This pump is way cheaper but seems to be less capable. I don’t believe it’s a good idea to retrofit this new style pump to the n55 with old style hpfp as the vacuum pump/hpfp chain is tensioned by “leaf spring” chain tensioners which some people reported is not sufficient to provide proper tension which leads to the chain stretching very quickly - and there’s no provision to mount the newer style hydraulic chain tensioner.
Rod bearings - this one is a hit or miss with n55. Mine were decent when I pulled them at 108kmiles, and some posts showed pretty major wear at 75kmiles. However, my car wasn’t tuned and I suspect that tuning (how quickly the tune allows to build up the boost in the low rpm range) and how hard it was driven determines the rod bearings condition. I also saw plenty of posts and videos with the n54 rod bearings, and if that engine had a lot of boost and in general driven hard and/or beat on, they won’t be much better than the n55 bearings. So idk, perhaps you can change the rod bearings if you decide you want an n55, it’s not that difficult to diy and not that much extra money and hardware compared to just replacing the oil pan gasket.
As for the power potential - both make plenty, just need to realistically decide what your goals are. Anyway, both n54 and n55 are good, but I’d say I’d go for the late e chassis n55 engine. Or, do the m57 swap instead

[mega_stihl]

They did ban diesels from our cities with the exception of the newest diesel engines. Diesel & petrol are around €1,60-1,70 per liter, while LPG is around 65c per liter. It even used to be around 40c per liter. It's basically fuel without tax. Nuff said about how much tax we pay over here ...

To register a 3 liter diesel over here you must be crazy as the rules have changed with regards to annual tax. In 2010 we would receive tax reduction and bonusses if we register a new diesel. Few years later we realized these diesels were bad for the environment instead of good. (nice one politicians! Act first, do research later), so then they started to ban diesels from the streets, meaning that if you register a diesel now, you'll pay lots of taxes. If you would register an M57 they will publically crusify you.

But besides that I've always been a petrol (or LPG) man. Loved petrol more than diesel because of it's simplicity, driveability and because it doesn't pollute like crazy, and last but not least, before 2014 literaly EVERYONE had a diesel, and I didn't like to follow the trend. But the M57 is a very nice engine regardless.

[oVeRdOsE.]

For rod bearing, I'm touching wood, but the N55 I own it since a while and now on 150k km, still super fine,

- and day one Ive used liqui molly with 1/3 lucas oil stabiliser snake oil.

- oil change every 10k km.

- Also, using mahle filter to avoid collapse paper filter.

- Magnetic oil drain plug. And I do remember the 1st oil change I got metal filings on it ! (I dont know if it was from factory or my 2 previous collapsed mann filter that didn't filter properly by making the bypass valve open. )

- disable the shutoff engine function.

[Xalithar]

FCP Euro has good videos on N55 and N54 Engines, specifically for cons and pros and certain things to look out for on these engines. Not only that Youtube university is always good.