0km 54b25, m52b20 and M40 for free.

[blackmanswilly]

Hey guys so I recently got my hands on 3 never started 0km engines.
-M54B25
-M52B20 (coffee table hah)
-M40B18

I am currently running a M54B30 in my car, its novelty has worn. What i am really wanting to know is, has anyone had success turning the 2.5 into a 3.
Any advice would be great.

[stonea]

Take the crank, rods, pistons, and cams out of the 3.0 and drop it into the 2.5

[roguetoaster]

M40 swap time.

[blackmanswilly]

Completely compatible Block/Head casting wise B25-B30? :)
If so I believe one should remain "Stock-ish" and another acquire Forced induction. However, this brings to the table another bunch of questions. At least I have a concise research plan.

[blackmanswilly]

M40 swap time.

M40 is the side girl ;)

[stonea]

Completely compatible Block/Head casting wise B25-B30? :)

Yeah

[haaken675]

So I am a bit confused. You currently have an m54 in your car, but you want to take the m54 internals and make a 3.0 m5x? Forgive my ignorance, but what is the point in that? You would be going to a heavier block and losing the double vanos.

[roguetoaster]

He wants to make the fresh M54/25 in to a 3.0 and put something else entirely in his car.

[blackmanswilly]

My car at the moment has a m54b30 with high km. I have a brand new m54b25 sitting here. Apparently 2.5-3.0 are compatable, suppose now i have to start buying turbo parts for a 3.0 je custom pistons and cant get any good info on best rod manufacture.
Its going to take some time

[keine30]

Crank, pistons, rods, cams, intake manifold, throttle body, and MAF are all different between the M54b25 and M54b30. I'm not sure what your management solution for your b30 in the e30 right now is, but a b30 engine can be run on a DME that originally came with a b25, just with a reflash. I swapped a b30 into my e46 325, so I've got a bit of experience with this.

That said, there are some glaring differences between the two engines you should be aware of. The biggest is that the b30 is inherently less balanced than the b25 is. I'm not sure if you're familiar with Vorshlag, but they had a lot of issues with the oil pump nut coming off in their b30. I'm aware that this isn't as much of an issue on the b25 engines. You should also take into account that this only happened to them because the car was built to be a track/autox machine, and spent a lot of time at very high RPMs, which may or may not describe your driving style.

So there's definitely a case to be made for keeping the 2.5L motor a 2.5L, and adding go fast parts to it instead. This makes even more sense when you take into account that the cams, crank, pistons, and rods of your 3.0L already in the car are probably worn, and would need replacement/repair.

Just something to think about.

[blackmanswilly]

Crank, pistons, rods, cams, intake manifold, throttle body, and MAF are all different between the M54b25 and M54b30. I'm not sure what your management solution for your b30 in the e30 right now is, but a b30 engine can be run on a DME that originally came with a b25, just with a reflash. I swapped a b30 into my e46 325, so I've got a bit of experience with this.

That said, there are some glaring differences between the two engines you should be aware of. The biggest is that the b30 is inherently less balanced than the b25 is. I'm not sure if you're familiar with Vorshlag, but they had a lot of issues with the oil pump nut coming off in their b30. I'm aware that this isn't as much of an issue on the b25 engines. You should also take into account that this only happened to them because the car was built to be a track/autox machine, and spent a lot of time at very high RPMs, which may or may not describe your driving style.

So there's definitely a case to be made for keeping the 2.5L motor a 2.5L, and adding go fast parts to it instead. This makes even more sense when you take into account that the cams, crank, pistons, and rods of your 3.0L already in the car are probably worn, and would need replacement/repair.

Just something to think about.

Yeah I have seen 2 in the workshop with that, I'm a BMW tech. Personally I wouldn't go as far as to say its inherent harmonic disproportion whether it be geometry of the rotating assembly or composition of the alloy its self. I mean the s63 twin turbo alloy v8 with a wack firing order seems to deal somewhat given the obstacles it has to overcome. Alot of the time phantom slackening and magical loosening can be owed to the domino effect of intolerance. Loctite and away she goes.

Trust me I don't plan on chucking old parts into a new block\head.. just wanted some opinion on new parts options if turning it into a 3.0 using new aftermarket parts maintaining b25 block and head is even possible.
The engine has been dismantled previously for tech info etc assembled at half torque so ill need to rebuild it anyway.



I run ms43?