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2003 325ci MT
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41 Posts
Discussion Starter · #1 ·
Hello all,
I purchased an almost flawless imported manual 325ci coupe that has a blown engine. I would like to swap the 330 engine into it. from what I have read, it seems like a reasonable swap. Does anyone know what engine accessories I will have to get for the 330 engine that are different than my 325 engine? And another question, what preventative maintenance should I do to the engine before swapping it in.
Thanks!
 

· Administrator
2013 X1 M-sport
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22,476 Posts
This gets asked about every week, so be sure to first search and read up on here.

Production dates of your E46 and donor B30 engine?
There’s a break at 03/2003 where some peripheral parts changed.
Use realoem.com to look up and compare part numbers.

Get a complete B30 engine. The B30 airbox, MAF, boots, TB, are all larger, so you will need those.
The rest is the same.

The B30 will start and run using the B25 DME software.
AFTER all swap-related issues are solved, flash the DME with B30 software.
 

· Registered
2003 325ci MT
Joined
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41 Posts
Discussion Starter · #3 ·
This gets asked about every week, so be sure to first search and read up on here.

Production dates of your E46 and donor B30 engine?
There’s a break at 03/2003 where some peripheral parts changed.
Use realoem.com to look up and compare part numbers.

Get a complete B30 engine. The B30 airbox, MAF, boots, TB, are all larger, so you will need those.
The rest is the same.

The B30 will start and run using the B25 DME software.
AFTER all swap-related issues are solved, flash the DME with B30 software.
Ok, thanks for the advice! This will be my first major engine job. Is it worth it to buy the Bentley 3 series service manual?
 

· Registered
2003 325ci MT
Joined
·
41 Posts
Discussion Starter · #4 ·
This gets asked about every week, so be sure to first search and read up on here.

Production dates of your E46 and donor B30 engine?
There’s a break at 03/2003 where some peripheral parts changed.
Use realoem.com to look up and compare part numbers.

Get a complete B30 engine. The B30 airbox, MAF, boots, TB, are all larger, so you will need those.
The rest is the same.

The B30 will start and run using the B25 DME software.
AFTER all swap-related issues are solved, flash the DME with B30 software.
I'm still sourcing an engine as I would prefer to have on under 100,000 miles. Let me check the production date on my car.
 

· Registered
2003 325ci MT
Joined
·
41 Posts
Discussion Starter · #5 ·
This gets asked about every week, so be sure to first search and read up on here.

Production dates of your E46 and donor B30 engine?
There’s a break at 03/2003 where some peripheral parts changed.
Use realoem.com to look up and compare part numbers.

Get a complete B30 engine. The B30 airbox, MAF, boots, TB, are all larger, so you will need those.
The rest is the same.

The B30 will start and run using the B25 DME software.
AFTER all swap-related issues are solved, flash the DME with B30 software.
Apparently my car was manufactured 12/02.
 

· Administrator
2013 X1 M-sport
Joined
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22,476 Posts
Apparently my car was manufactured 12/02.
Pre-03/2003 has the bolt-in style coils and valve cover. If you get a newer B30 donor engine (with the pencil style coils) just swap those parts over from your B25.
Most people doing the swap need to buy the B30 airbox, MAF, boots separately as they don’t usually come with a complete engine.
 

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3,111 Posts
I'm still sourcing an engine as I would prefer to have on under 100,000 miles. Let me check the production date on my car.
You do what you want to do...But these engines are good to 400k miles if you keep oil and coolant in them.. I daily drive an '03 530i (E39) with 418k miles on its M54B30.

100k miles means very little to these engines...other than a good interval to change a bunch of things on an preventative basis...cooling system, CCV, gaskets, Etc.
 

· Registered
Orient Blue Metallic 2/2001 build 330ci coupe
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250 Posts
You do what you want to do...But these engines are good to 400k miles if you keep oil and coolant in them.. I daily drive an '03 530i (E39) with 418k miles on its M54B30.

100k miles means very little to these engines...other than a good interval to change a bunch of things on an preventative basis...cooling system, CCV, gaskets, Etc.
Yeah, this is the first car I've ever owned besides my MR2 that I am not at all worried about having more than 100k miles.
 

· Registered
2003 325ci MT
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41 Posts
Discussion Starter · #9 ·
You do what you want to do...But these engines are good to 400k miles if you keep oil and coolant in them.. I daily drive an '03 530i (E39) with 418k miles on its M54B30.

100k miles means very little to these engines...other than a good interval to change a bunch of things on an preventative basis...cooling system, CCV, gaskets, Etc.
I wouldn't worry about it if I was going to keep it stock but I was thinking I would lower the compression, change the fuel system, run e85 and turbo it. I have my old Subaru to daily if I have issues but I would like it to be semi reliable after all of that.
 

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2002 BMW E46 330i
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752 Posts
I wouldn't worry about it if I was going to keep it stock but I was thinking I would lower the compression, change the fuel system, run e85 and turbo it. I have my old Subaru to daily if I have issues but I would like it to be semi reliable after all of that.
an unopened b30 can take up to roughly 600whp on corn juice. if you still wanna open the motor up, might as well upgrade rods and pistons and shoot for 800+whp
 

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1,835 Posts
You do what you want to do...But these engines are good to 400k miles if you keep oil and coolant in them.. I daily drive an '03 530i (E39) with 418k miles on its M54B30.

100k miles means very little to these engines...other than a good interval to change a bunch of things on an preventative basis...cooling system, CCV, gaskets, Etc.
that HIGHLY depends on maintenance. I've done an engine swap and before I swapped it, I opened and rebuilt the engine. It had 200k miles on it, but by the looks of it, the last oil change was about 70k miles ago.
 

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2003 325ci MT
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41 Posts
Discussion Starter · #12 ·
Pre-03/2003 has the bolt-in style coils and valve cover. If you get a newer B30 donor engine (with the pencil style coils) just swap those parts over from your B25.
Most people doing the swap need to buy the B30 airbox, MAF, boots separately as they don’t usually come with a complete engine.
Do you know any good sources to find an engine? I've looked through Craigslist, Facebook and Ebay.
 

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I have done this. I have "upgraded" a 2001 325xi to a 330xi using an M54B30 from a 2004 vehicle. The M54 engines are robust despite the E46 cooling system design shortcomings. I present some caveats:

1) Yes, you have to reflash the DME after you get the car started. Be careful. There is a limit on the number of times you can do that.
2) You will need to replace all of the air intake including the box and hoses, throttle body, injectors, intake manifold, DISA Valve, and maybe even the coils. Use this time to replace your fuel filter if you haven't already. The tank-mounted fuel pump will thank you. There are two vacuum-related components mounted on the rear of the engine/intake manifold. One is a small pump and the other a sensor I believe. I replaced them just in case.
3) Depending on the donor car, you may need to modify your engine harness so you don't throw misfire codes. This involves adding a resistor in the ground circuit of the injector wiring.
4) Plan on replacing all gaskets (intake manifold, oil pan, valve cover, exhaust, oil dipstick tube, oil filter housing), all vacuum lines (suggest going silicone with those)
5) You'll need to consider your engine extraction and transmission strategy. Some take everything out without removing the front of the car. Great if you have high ceilings where you're working and goes faster. Some take the tranny with the engine and remove the entire front end of the vehicle. I did this since I wanted to inspect the torque converter and I needed to replace the flywheel with the 3.0 liter version. CAUTION: I re-used the 2.5l auto transmission. It will work with the 3.0l engine but your shift points will be slightly off. If you're a highway driver, you'll hardly notice. If you are trying to create a performance car, you'll need to upgrade your tranny to the 3.0l GM auto or the 5- or 6-speed manual while you have everything apart. 50s Kid on YouTube in my opinion has the best auto to manual E46 swap video out there. 2nd place goes to Jason at Shoplife TV.
6) Now's a good time to consider replacing your starter, alternator, water pump, A/C compressor, and power steering pump while everything is out. If nothing else consider the starter motor strongly. It's notoriously complex to get out of an E46 chassis (one of the bolts is a bear to access).
7) DO NOT re-use torque-to-yield bolts when you remove the subframe, engine mounts, or transmission from the engine. Basically be suspect of anything M8 and larger and verify the type and follow the torque specifications when re-assembling your car. There are probably other components/fasteners I'm omitting so if in doubt use RealOEM or a Bentley manual to guide you. Some of the bolts/fasteners are only available as BMW-spec. You'll have to bite the bullet on those but know that in doing so your car is less likely to fall apart under "spirited driving." Boltdepot.com is another great source. I purchased high temp stainless steel fasteners for the exhaust that way. No way I was going to spend $70 for the exhaust pipe to cat interface bolts again.
8) REPLACE all the plastic cooling components and lines, especially those that are hidden up underneath the intake manifold. These are notorious for slow leaks that lead to overheating and head gasket failure. REPLACE your crankcase vent valve and the associated hoses. Use new O-rings and lubricate before installing them. Clean the ports on the engine prior to installation. Use Pentofrost NF or BMW OEM blue coolant when you re-fill the system and follow the cumbersome bleed process for the E46 to get all the air out of the system.
9) Consider changing out your engine and transmissions mounts (plus differential mount if it's an XI).
10) Same for the VANOS oil lines depending on their age
11) Somewhere along the line of the E46's life the A/C compressor went from a 3-bolt mount to a 4-bolt mount. You'll need that adapter plus the hardware depending on the year of the donor engine.
12) I did the manual transmission electric fan swap conversion when I did the engine swap. It's really convenient to service the car this way but bear in mind that the DME will NOT WARN YOU if this fan fails. This is why the automatic cars had both an electrically- and a a belt-driven fan. I test the fan after every oil change and swap it every 45,000 miles just in case.

I'm attaching the parts list I created when I did the swap. You don't have to do everything I did. The car had 183k miles on it when the head gasket blew. I just replaced every major component that I hadn't already because I'm keeping the car for another 15+ years. But don't skimp on seals and gaskets. Replace those regardless of how old they are or the last time you replaced them. One of the reasons I shop at FCP Euro. Lifetime parts guarantee. Use RealOEM.com or another parts finder to make sure you're verifying fitment based on your replacement engine.

Good luck and let us know if we can help you!
 

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· Registered
2003 325ci MT
Joined
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41 Posts
Discussion Starter · #15 ·
I have done this. I have "upgraded" a 2001 325xi to a 330xi using an M54B30 from a 2004 vehicle. The M54 engines are robust despite the E46 cooling system design shortcomings. I present some caveats:

1) Yes, you have to reflash the DME after you get the car started. Be careful. There is a limit on the number of times you can do that.
2) You will need to replace all of the air intake including the box and hoses, throttle body, injectors, intake manifold, DISA Valve, and maybe even the coils. Use this time to replace your fuel filter if you haven't already. The tank-mounted fuel pump will thank you. There are two vacuum-related components mounted on the rear of the engine/intake manifold. One is a small pump and the other a sensor I believe. I replaced them just in case.
3) Depending on the donor car, you may need to modify your engine harness so you don't throw misfire codes. This involves adding a resistor in the ground circuit of the injector wiring.
4) Plan on replacing all gaskets (intake manifold, oil pan, valve cover, exhaust, oil dipstick tube, oil filter housing), all vacuum lines (suggest going silicone with those)
5) You'll need to consider your engine extraction and transmission strategy. Some take everything out without removing the front of the car. Great if you have high ceilings where you're working and goes faster. Some take the tranny with the engine and remove the entire front end of the vehicle. I did this since I wanted to inspect the torque converter and I needed to replace the flywheel with the 3.0 liter version. CAUTION: I re-used the 2.5l auto transmission. It will work with the 3.0l engine but your shift points will be slightly off. If you're a highway driver, you'll hardly notice. If you are trying to create a performance car, you'll need to upgrade your tranny to the 3.0l GM auto or the 5- or 6-speed manual while you have everything apart. 50s Kid on YouTube in my opinion has the best auto to manual E46 swap video out there. 2nd place goes to Jason at Shoplife TV.
6) Now's a good time to consider replacing your starter, alternator, water pump, A/C compressor, and power steering pump while everything is out. If nothing else consider the starter motor strongly. It's notoriously complex to get out of an E46 chassis (one of the bolts is a bear to access).
7) DO NOT re-use torque-to-yield bolts when you remove the subframe, engine mounts, or transmission from the engine. Basically be suspect of anything M8 and larger and verify the type and follow the torque specifications when re-assembling your car. There are probably other components/fasteners I'm omitting so if in doubt use RealOEM or a Bentley manual to guide you. Some of the bolts/fasteners are only available as BMW-spec. You'll have to bite the bullet on those but know that in doing so your car is less likely to fall apart under "spirited driving." Boltdepot.com is another great source. I purchased high temp stainless steel fasteners for the exhaust that way. No way I was going to spend $70 for the exhaust pipe to cat interface bolts again.
8) REPLACE all the plastic cooling components and lines, especially those that are hidden up underneath the intake manifold. These are notorious for slow leaks that lead to overheating and head gasket failure. REPLACE your crankcase vent valve and the associated hoses. Use new O-rings and lubricate before installing them. Clean the ports on the engine prior to installation. Use Pentofrost NF or BMW OEM blue coolant when you re-fill the system and follow the cumbersome bleed process for the E46 to get all the air out of the system.
9) Consider changing out your engine and transmissions mounts (plus differential mount if it's an XI).
10) Same for the VANOS oil lines depending on their age
11) Somewhere along the line of the E46's life the A/C compressor went from a 3-bolt mount to a 4-bolt mount. You'll need that adapter plus the hardware depending on the year of the donor engine.
12) I did the manual transmission electric fan swap conversion when I did the engine swap. It's really convenient to service the car this way but bear in mind that the DME will NOT WARN YOU if this fan fails. This is why the automatic cars had both an electrically- and a a belt-driven fan. I test the fan after every oil change and swap it every 45,000 miles just in case.

I'm attaching the parts list I created when I did the swap. You don't have to do everything I did. The car had 183k miles on it when the head gasket blew. I just replaced every major component that I hadn't already because I'm keeping the car for another 15+ years. But don't skimp on seals and gaskets. Replace those regardless of how old they are or the last time you replaced them. One of the reasons I shop at FCP Euro. Lifetime parts guarantee. Use RealOEM.com or another parts finder to make sure you're verifying fitment based on your replacement engine.

Good luck and let us know if we can help you!
Thank you so much for all of this useful information, you are amazing. This will come in so useful. As of right now I will probably have enough money to order everything late November. This will be my first major mechanical job on a car so I'm excited to get started. I believe that my original car had 103k miles on it before it blew so hopefully everything is relatively fresh. My car has the 5 speed manual so I think that I'll be ok in that department. I think that I might possibly want to redo the fuel system somewhere down the line so that I can run e85, do you know if I could tune the car for that after the dme flash? I'm sure that I will have a lot of questions when the time comes so I will ask away.
 
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