[E91 Hoarder]

Hi Folks. I just bought a 2006 325i MT e90. The car has really bad rod bearing knock and mechanic says it needs a new engine. Reaching out to our collective wisdom for an advice.

The obvious choice is to swap it with similar engine from another 325i, but this could be an opportunity to put something more powerful. What are my options?
- will n52 from 330i work without major modifications?
- will n52 from 328i 2007-2012 years work?
Crazy ideas (probably dont have budget/expertise for these)
- m3 swap
- LS2 swap

My background is mostly in turbo n54 and n55 variant, and all of these N52 revisions are a bit confusing. The swap will be done myself on my driveway.

If you have any links to the similar swaps or useful info, please share.

[hassmaschine]

the N52 internals are all basically the same (if you're in the states). So you could use any N52B30, providing you keep your engine harness, metal valve cover, sensors, etc. Not sure if you can retrofit a plastic valve cover and PCV system on the 2006 cars, but I don't see why not.

Unless you just happen to find one you don't need a 2006 330i motor either. you can put the 3 stage on any N52, everything else about the engines are the same. The only one that isn't the same is the N51, which has a lower compression ratio and extra emissions equipment.

[whyzee125]

I'd be tempted to do an LS engine now that the kit is so easy to get. LSe90.com I think is where all the info is. I've toyed with the idea of buying one with a blown engine myself to LS swap

[E91 Hoarder]

Originally Posted by hassmaschine

the N52 internals are all basically the same (if you're in the states). So you could use any N52B30, providing you keep your engine harness, metal valve cover, sensors, etc. Not sure if you can retrofit a plastic valve cover and PCV system on the 2006 cars, but I don't see why not.

Unless you just happen to find one you don't need a 2006 330i motor either. you can put the 3 stage on any N52, everything else about the engines are the same. The only one that isn't the same is the N51, which has a lower compression ratio and extra emissions equipment.

Thanks for the info! I am US-based, N52 it is .

Originally Posted by whyzee125

I'd be tempted to do an LS engine now that the kit is so easy to get. LSe90.com I think is where all the info is. I've toyed with the idea of buying one with a blown engine myself to LS swap

it is tempting indeed


In terms of picking the replacement engine, are there any best practices? Most engines that I have come across so far, are from salvage yards, many have unknown history or have been sitting exposed for some time. Is there a way to minimize the risk (test/inspect/ask right questions) while choosing one?

[E91 Hoarder]

Another question, is there a list of parts and repairs to address while having the engine out? I came across this thread, and they reference newtis.info for the complete guide, but the site was taken down by BMW request.
This is what I discovered so far:
1. Replace valve, oil pan, oil housing gaskets
2. Replace O2 sensors
3. Some bolts need to be replaced - not sure what and where
anything else?

Again, if there is a good guide on this somewhere - please send me that way

[FiberMonkey]

Originally Posted by BMWTF?

Hi Folks. I just bought a 2006 325i MT e90. The car has really bad rod bearing knock and mechanic says it needs a new engine. Reaching out to our collective wisdom for an advice.

The obvious choice is to swap it with similar engine from another 325i, but this could be an opportunity to put something more powerful. What are my options?
- will n52 from 330i work without major modifications?
- will n52 from 328i 2007-2012 years work?
Crazy ideas (probably dont have budget/expertise for these)
- m3 swap
- LS2 swap

My background is mostly in turbo n54 and n55 variant, and all of these N52 revisions are a bit confusing. The swap will be done myself on my driveway.

If you have any links to the similar swaps or useful info, please share.

Have you completed the swap? I have an 06 that I am race prepping. Car has 172k on it. I am finding it hard to find motors from 06 with less than 150k on them.

[E91 Hoarder]

Originally Posted by FiberMonkey

Have you completed the swap? I have an 06 that I am race prepping. Car has 172k on it. I am finding it hard to find motors from 06 with less than 150k on them.

exactly. I am looking for the engine right now, and they are hard to find. As you say most of them are high mileage. My plan B is to get one N52 from 328i, but I rather have a direct swap from 325i/330i. Not in a rush, I have another car so, hope to come across something within couple of months.

Curious about what you do for the race prep? I am thinking about going to the track events this summer.

[hassmaschine]

An N52B30 is an N52B30 is an N52B30. You really don't need a motor from a specific year. The blocks, heads, and internals are all functionally the same - except for minor revisions - which are usually a good thing. The stuff that bolts to the outside - valve cover, oil pan, intake manifold, wiring, etc - is easily swapped over from your original motor.

[E91 Hoarder]

Originally Posted by hassmaschine

An N52B30 is an N52B30 is an N52B30. You really don't need a motor from a specific year. The blocks, heads, and internals are all functionally the same - except for minor revisions - which are usually a good thing. The stuff that bolts to the outside - valve cover, oil pan, intake manifold, wiring, etc - is easily swapped over from your original motor.

I have not been able to find a definitive list of what needs to be swapped over. People say sensors are different, but what sensors? I’ve seen your posts on this topic in different threads, maybe you can help? Thanks for chiming in!