Author Topic: Possible M42 engine with alloy block (Read 8434 times)

ToniBmwPortugal · « **on:** May 22, 2012, 03:08:06 AM »

Hi there!
I'm doing lots of research about the the 2.1 stroker and i cam eup with an ideia and i wanna now what do you guys think i maybe give some help.

Is it possible to mate the BMW N46B20 (alloy block) to an M42 head? Anybody knows whats the bore spacing on the N46?
The ideia is to make an engine like a stroker M42 (M42B20 or S42

) but with an alloy block to reduce the weight on the front axle even more!

I'm sorry if it's a stupid ideia :p but let me now what do you guys think!

Greetz

colin86325 · « **Reply #1 on:** May 22, 2012, 07:13:46 AM »

Sounds like a cool idea! In the worst case scenario you could always get a head gasket to verify the spacing.

ToniBmwPortugal · « **Reply #2 on:** May 22, 2012, 03:39:32 PM »

Quote from: colin86325;112698

Sounds like a cool idea! In the worst case scenario you could always get a head gasket to verify the spacing.

First i wanted to know whats the bore/cylinder spacing on the N46 engine but i can't find it anywhere... Nobody knows?

doitover · « **Reply #3 on:** May 22, 2012, 04:11:06 PM »

The M42 is an aluminum block. Pretty much all metals of interests are alloys of one kind or another.

Much more than the bore spacing has to line up to allow a head swap. According to Wiki, the n46b20 has been out since 2004? If it is doable, someone has probably done it?

wazzu70 · « **Reply #4 on:** May 22, 2012, 07:23:04 PM »

Quote from: doitover;112710

The M42 is an aluminum block. Pretty much all metals of interests are alloys of one kind or another.

Much more than the bore spacing has to line up to allow a head swap. According to Wiki, the n46b20 has been out since 2004? If it is doable, someone has probably done it?

The M42 is NOT an aluminum block. The block is pearlitic cast iron. There are both aluminum alloys and steel alloys.

If the block is not open face it would be interesting to see the similarities.

Better yet, why not just swap in the new motor and run it on a standalone. Wish we got them here in the US.

doitover · « **Reply #5 on:** May 22, 2012, 07:46:36 PM »

My bad, I was thinking of all the aluminum housings I've had to fix threads on.

ToniBmwPortugal · « **Reply #6 on:** June 04, 2012, 11:26:21 AM »

Has anyone seen/knows something about this?

"Hudson,
Save yourself the mission and just swap the whole motor. I've been through this twice before. I once put a mid 80 BMW K-series bike head onto a 1140cc Mini cooper engine. Ran great with all the beemer electronics, but the oil flow (not pressure) wasn't sufficient for the head and ate up the cams in less than a year. I've also swapped a honda H22 head onto a 318is. They're always a mission to adapt and then end up with some obscure flaw no matter how meticulous I am about the build. That being said, I've also run a flat-6 Honda goldwing motor into a Devin Porsche/VW with great success aswell as a BMW R1150S motor into a BMW 700. Both of those cars turned out better than expected. " in http://www.fireblades.org/forums/honda-fireblade/86332-bore-centers.html

Is that even possible? If it worked i guess it was a hell of an engine. The only flaw i see on the design of the M42 its the lack of a variable timing cam system which allows to run agressive cams but mantain some of the driveability at lower rpm's.

danlolasdad · « **Reply #7 on:** June 04, 2012, 03:32:04 PM »

IS there a build thread for the honda h22 cyl head to m42 block?

ToniBmwPortugal · « **Reply #8 on:** June 04, 2012, 04:45:01 PM »

Quote from: danlolasdad;112984

IS there a build thread for the honda h22 cyl head to m42 block?

I've not found any, i wish i would found some... That ideia is even possible :confused:

ToniBmwPortugal · « **Reply #9 on:** June 04, 2012, 05:03:50 PM »

Bore spacing:

BMW M42: 91mm
Honda H22: 94mm
Honda B18: 90mm

ToniBmwPortugal · « **Reply #10 on:** June 04, 2012, 07:19:34 PM »

http://www.e30tech.com/forum/showthread.php?t=113374

And how about that?