Extra M42 motor kicking around. Thoughts?

[E30King]

So when I was building my M42 on my 'vert, I had purchased a complete motor and an extra rebuilt head (part of the deal) and a bunch of other misc. bits. Anyways, plans were to replace the entire motor, but instead, we just did the head as the block was still good.

Now I have this extra motor sitting around in my storage, and I don't plan on selling it. I'd just like to gather some thoughts on what to do with it. Should I bore it out? Possibly do something with a turbo? (No expert on turbos, and not sure what are the possible kits are) Supercharger? (quite liking that more :p) I'm not exactly too sure, on what's the best route, as I don't want to spend huge amounts of cash, but I'd like to get some good power pumped out of it.

With that in mind, I've been having thoughts of pulling out the M40 out of my wagon, and sticking this built motor in. My wagon is my donkey, and I haven't been giving 'er the pampering it deserves haha. So I think this should make up for it.

[DesktopDave]

Two litre stroker.

[E30King]

Two litre stroker.

Bore out the block, eh? What else would I need to make a stroker 4-cylinder? Don't IE sell the kits?

[DesktopDave]

M42 diesel crank.  It's a Euro only model, but should only be ~$400 or so for a decent used part.  You can also bore the block, but that'd add to cost.  I think compression can also be raised by M3 pistons and M20 rods?  Solid lifters and late thin-stem valves would round out a nice muscular package without any increase in weight.

Don't quote me on that, I haven't done it myself.  An M44 crank, MarkD chip and a mild porting job would give some great gains as well for much less money.

It's doable on all OEM parts...there are a few people on here that have done it.

[clutchkick]

boost it.

[MikeDE]

If you go stroker, sell that rebuilt M42 head and get an good M44 head.  Lighter valve train, better for high revving applications.

Checkout E30zone.net.  It's a UK-Based E30 site, someone always has a Rover 75 CDT cranks for sale.  They drop right into an M42.

[DaveM-sport]

2/2.1L stroker..... AND... supercharger

Do it... You know it'll be awesome! :cool:


By the way... Sell the rebuilt M42 head and get another to build to suit your engine.
Don't get an M44 head, they're shite for building a nice revy engine due to having rockers.

[MikeDE]

2/2.1L stroker..... AND... supercharger

Do it... You know it'll be awesome! :cool:


By the way... Sell the rebuilt M42 head and get another to build to suit your engine.
Don't get an M44 head, they're shite for building a nice revy engine due to having rockers.

Stroke and SC...I like it.

I had heard that people prefer the M44 head for NA applications b/c of the less parasitic valvetrain.  Then again, I am new to the M42 but I think I like it.  I've only driven my Touring w/ M42 about 80km(50mi) and it's fun as hell.

DAVE, can you verify that the M40 block is the same as the M42 block?  If so, i'm keeping it....

[DaveM-sport]

M40 blocks are the same as the M42 if your talkiing about the bare block.

Well, any M44 I've ever driven and that includes 3 or 4 I put into E30s on both the E30 inlet and management and M44 inlet and management and they never seem to be as willing to rev to the redline as an M42b18.

As the bottom end is lighter which should help and valvetrain being abit lighter, I'm blaming the rockers. I know it should make fookall difference but thats just my experience of it anyway.


For my M42b21 which will also be on S54 throttle bodies and custom CF airbox, I'll be more or less making a 4 cylinder S52 head so should be more than capable of taking abuse all the way to a 7-8000rpm redline



A supercharged 2.1 would make an awesome engine!!! one of the guys I know over here has a rotrex on a 1.8 making nearly 300bhp. Could only imagine what it would produce in a 2.1 considering a good 2.1 bottom end with no FI with just stock intake can make 200bhp alone.

[MikeDE]

M40 blocks are the same as the M42 if your talkiing about the bare block.

Well, any M44 I've ever driven and that includes 3 or 4 I put into E30s on both the E30 inlet and management and M44 inlet and management and they never seem to be as willing to rev to the redline as an M42b18.

As the bottom end is lighter which should help and valvetrain being abit lighter, I'm blaming the rockers. I know it should make fookall difference but thats just my experience of it anyway.

Ok cool, then I will be holding onto my M40 block.

Do you have spoecs on your m42b21?? I'm tallking about crank, bore, rods, pistons, etc.

[DaveM-sport]

Ok cool, then I will be holding onto my M40 block.

Do you have spoecs on your m42b21?? I'm tallking about crank, bore, rods, pistons, etc.

I actually threw out an old M40b16 block the other day... might pull it back out of the skip now that I think of it


As for the 2.1, just going the usual route really... M47 crank, 86.4mm bore, custom rods and pistons etc with a little work on the head, few tricks on the bottom end and made look all fancy and sound nice with some S54 itbs and airbox :p

Still gathering bits for it at the moment as other things always pop up and I'm also trying to build my M52 M-tec Touring for a daily at the moment.

[MikeDE]

Nice, i'm really diggin my M42 so I already have plans for a stroker.

[DaveM-sport]

Nice, i'm really diggin my M42 so I already have plans for a stroker.

Yeah, my iS was great fun to drive by the time I took it off the road but I won't be happy unless its putting out at least 100bhp/litre next times its back in action

[MikeDE]

To tell ya the truth, I haven't had this much with a car since I bought my first(of many) Turbo Eclipses/DSM's in '99.  And since I quit DSM's in '03, i've had an '03 SVT Focus euro pkg, '90 Volvo 744T, '97 M3,  '87 325seta.  I bought the Touring 1.5 yrs ago with the intent of swapping in an M50vanos that I had sitting around.  I'm glad I went this route, it seems to have so much more spirit than a garden-variety m/s/5x swap.