M42B18 (E36) swap in E30 (M40B18)

[beardass]

Hi there,

I registered to this forum because I'm parting out my old E36 with the M42 engine. I'm going to fit this engine into my E30.

I want to change al of the E30 engine parts with the parts from the E36. That wil include:
- enginge
- airflowbox
- intake manifold
- exhaust manifold
- alternator
- engine loom + DME

For this to work i know i need the E30 m42 engine brackets and that I will need to change the oil pan and oil pump from the m40.

However, I've got two concerns. Since there are no parts available from an old E30 m42 I need to use as much of my m40/m42.

So, wich exhaust am I going to need? I'm currently thinking of fitting the m40 exhaust onto the m42 manifold and leave the catalyst of of the exhaust system. I don't know if this will benefit the engine???

Then we have the wiring loom. I have already found out that the c101 connector needs to fit the x20 connector. There ar a few schemes out there on the web so that shouldn't be a problem.
But I've also read that de DME/ECU needs to be modified because they don't share the same position. But...... the e36 DME is in the engine bay and the m40 DME is in the glove box so I'm a bit confused on that part...

So to say short, how do i fit the exhaust system and the wiring loom?

[Dj Buttchug]

early model e36 harness should plug right in. Anything pre 1995. Also the e36 m42 exhaust manifold should be the same as M42 e30. I don't think you'll have any problems there.

[beardass]

I know it can fit, but it isn't just a 1 on 1 swap. bear in mind that I don't have any parts of the e30 m42...

[varg]

The block is the same so the mounts and the rest of the drivetrain should work no problem. If the wiring harness is a direct swap as stated above, it should be an easy plug-and-play swap. I know it's a fairly common swap in Europe since the M40 is a pretty terrible little lump, there should be plenty of info available if you spend some time googling it. A quick search yielded this: http://bimmersport.co.nz/topic/24259...0-project-car/

http://www.m42club.com/forum/index.php?topic=4414.0

[roguetoaster]

The M40 is a pretty terrible little lump

Have you ever driven, much less owned, an E30 with an M40? They are just fine for regular driving, very much like a base model Civic in terms of speed and efficiency. However, I can see why someone would want an upgrade.

It should also be considered that the M40 is nearly a strange hybrid between the M20 and M42 platforms, and neither of those are terrible.

[varg]

Have you ever driven, much less owned, an E30 with an M40? They are just fine for regular driving, very much like a base model Civic in terms of speed and efficiency. However, I can see why someone would want an upgrade.

It should also be considered that the M40 is nearly a strange hybrid between the M20 and M42 platforms, and neither of those are terrible.

Yep, sure have. I've known a couple of people who have imported M40 318 wagons into the US over the years and have heard enough from them and our european friends to know what's up. If you like the M40 that's fine, it doesn't change that it's the worst engine put in an E30 from the factory. The M40 doesn't have M10 stoutness and it doesn't have M42 performance, heck the performance isn't even much better than M10. The M42 isn't very good either with the timing case design, profile gasket and inadequate thrust bearing, but it's better. At least it doesn't wear camshafts like an M40, it has a good cylinder head, and it has a timing chain like the M10. The M42 also has decent performance potential if you force-feed it, have you seen the rods in an M40? They won't take abuse like an M10 or M42. To top it off, stock for stock, the performance improvement going from M40 to M42 is more going from than M10 to M40, and you gain durability to go along with that performance.

[Porthos]

I am thinking of doing the same. The M40 is garbage. The good thing is almost 95% of the M40 is compatible with the M42. Hope this helps too. I would love to follow a thread if you go through with it. http://www.e30zone.net/e30zonewiki/i...ine_Swap_-_M42

[TobyB]

...and the later E36 M42 has a better timing chain setup to boot.
But does the (massive) E36 manifold fit into the E30? I thought it didn't.

And I'd use the M42 'header'- it's excellent, really. If the M40 got the
crappy exhaust I think it did, you might want to scrap the entire M40 exhaust...
...and use what you can get away with in the Netherlands. Around here, if it
passes the sniffer, no- one physically looks at it.

t

[The White Guy]

Toby,
I think you are correct in stating that the E36 M42 intake manifold will not fit into a E30 chassis if you have a hood in place.