M42 vs M44

[tomstickland]

I'm considering buying an M44 engine to replace my high mileage M42 unit.

What is the general opinino on the difference between the two of them?
Is the M44 seen as a mild upgrade?

[TheDutch]

I asked Tim about M42/M44 interoperability a while back, I'm sure he wont mind me repeating his response:

more or less any m42s will fit, m44s a bit more work. 94+ M42 or M44 is the best drop-in engine. you can go with the m44 bottom end stuff to give you 1.9. You'll then get a lighter crank and better rods too. This is easily done. Can also do the whole engine, but as you suggest there's more work there due to dual temp switch in cyl head (not a biggy), manifolds, oil pickup, sump, upper timing case cover, all belt driven bits need to be e30. need e30 crank sensor too, I've never tried it on the later m42/44 bottom timing casing but it should be fine - teeth on the later wheels are smaller but if you run e30 crank wheel with e30 VR sensor should be fine. basically m44 engine + all m42 manifolds/sumps/ancilliaries will work. M44 head is less friction, quieter but tamer. could try to run M44 injection, that would give you MAF and OBD2 which would be pretty smart and you could pretty much just drop in the m44 then. you'd need to sort EWS though.

[tomstickland]

So, a good option is to combine the M44 bottom end with M42 top end and sump, ancilleries etc?

[jaistanley]

I think the two best options are: Use the M44 bottom end complete on an otherwise E30 M42B18 engine, or swap the complete M44 engine with E30 manifolds into the E30 and sort out the wiring (change the plub and sort the EWS).

The former will give you a 1.9 E30 318iS and the latter will give you the extra torque, slightly better fuel but more of a tame drive from the M44.

That's how I'd interpret it anyway.

Personally I'd go for the M44 1.9 bits in a M42 block (as a re-bore/hone would give you fresh cylinders), some CAT cams and a megasquirt...

[tomstickland]

Are the blocks different then? Apart from the bore?

[jaistanley]

I'm really not sure. I think they are near as dammit the same though, but thats only because I've not heard any different.

I would get the M42 block you have bored/honed/cleaned/new core-plugs/gaskets simply to make it all like new. With a new set of piston rings and new bearings (not that much money but extra) you'd have a fully re-built and as-new bottom end.

Just a thought.

[mrLEE30]

or just get a real engine with 6 cylinders, drop that in and be done with it

[tomstickland]

I want to use a real engine with 4 cylinders.

I'm interested in the differences between the 42 and 44.
From what I've read, I'd need to mix and match m42 bits onto a m44 to get it to fit into the car.
The m44 has slightly more capacity.
What are the issues with using the m44 management? Is it do with immobilisers?

[Jon_Bmw]

Seems a lot of extra hassle for very little gain to me. If you are going down engine swap routes perhaps a more powerful 4 pot could be sourced as you seem to like the balance that you perceive the 4 pot to give you?

A tuned XE engine with a rear wheel drive vauxhall box
A 200sx c18det turbo engine(260bhp is easy for these)

[GrindCulture]

or just get a real engine with 6 cylinders, drop that in and be done with it

At least they've got the right amount of valves per cylinder

From what I've heard the M42 internals are forged whereas the M44 are cast, also the M42 cams are balanced a differently I think.

I have read something on bimmerforums or somewhere similar about the differences and from what people on there were saying as that the M42 is a much better, smoother and stronger engine, all be it smaller displacement.

[tomstickland]

I Just want to keep a similar power plant and sort the oil burning. Hence not caring about more power. Fan of simple 4 pot engines.
Maybe I'll rebuild an M42 then.

[jaistanley]

I'd do that myself.. The extra 100cc isn't going to set the world on fire. You could spend the time balancing everything, fit some better cams and liberate power raising the rev limiter and mapping.. Hence the megasquirt idea.

[Jhonno]

you can go with the m44 bottom end stuff to give you 1.9. You'll then get a lighter crank and better rods too - M44 head is less friction, quieter but tamer.

Sounds like an M44 is the better lump, just wake it up with some cams/lightened fly i'd say..

[tomstickland]

I'm not interested in swapping the cams, balancing or ecu change.
There seems to be some conflict of opinions here regarding "out of the box" M42 vs M44.

The M42 was designed for compeition use, essentially the road cars have a homologation engine.
I assume that the M44 was a reengineering exercise. Capacity was slightly increased. Were there any improvements in ecu/mapping/mpg etc?

My guess is that the M42 is the sweeter unit.

[Andyboy]

The M42 was designed for compeition use, essentially the road cars have a homologation engine.

B*llocks! The M42 was designed to power an E36, no more, no less. That's why the early E36 race cars used the 2 litre S14 engine until 1994. BMW switched to the S42 when the regs changed.

[GrindCulture]

My guess is that the M42 is the sweeter unit.

I think I'd have an M42 over an M44 any day. Sure the M44 is lighter and quieter etc. but it's also not as strong and not as well balanced. But I'd love an S42 in a road car

[pacerpete]

The M42 was designed for compeition use, essentially the road cars have a homologation engine.

B*llocks! The M42 was designed to power an E36, no more, no less. That's why the early E36 race cars used the 2 litre S14 engine until 1994. BMW switched to the S42 when the regs changed.

You are wrong Andyboy. During the late 80s there was a race series involving stock milkfloats and 'competion' prepared ISs . It only ran for a season due to blown profile gaskets, cracked heads and lack of interest !

[tim_s]

The M42 was designed for compeition use, essentially the road cars have a homologation engine.

B*llocks! The M42 was designed to power an E36, no more, no less. That's why the early E36 race cars used the 2 litre S14 engine until 1994. BMW switched to the S42 when the regs changed.

of course it was designed as a road going e36 engine, but the motorsport stuff here is kind of misleading.
The 2l S42 made more hp and was lighter and smaller for the same capacity than the S14. The reason the S42 wasn't used before 1994 is because it didn't exist (and it wouldn't have been viable, only the BTCC used the 2l format, BMW didn't even enter a works car in '93). Techspeed did however choose to run an e30 318is up against the destroked e30 m3s in 1990. afaik there aren't any regs that would have prevented running an S14 in a supertouring car after the S42 was developed. Using an older production engine hasn't been an issue in supertouring regulations, in fact iirc some schnitzer '94 STW cars ran the S14. Basically the S42 was an improvement in 2l form. The S14 was the only BMW motorsport developed 2l engine until BMW made the s42, a more powerful and lighter unit.

[Andyboy]

The S42 gave marginally more power because the design of the head was better - well, the S14 was a very old engine by 1993/4. BMW had no choice anyway because the S14 homologation expired in 1995. It was the S42 or nothing.

But to say the M42 was designed as a competition engine is just daft - a bit like all that 'baby M3' crap. It's just one of a number of 16 valve engines around in the early nineties.

[tomstickland]

It was just something I read somewhere. I'll see if I can dig it out. It mentioned things like hollow cam shafts.

[tomstickland]

Not on topic, but:
Just randomly looking around on the net, and saw this.
http://bmwnut.blogspot.com/2006/04/1991 ... -mods.html

Adjust the cam timing - You know how on the E30 M3 you have to buy a $300 kit with adjustable cam sprockets to tune your cam timing? Not on the 318iS! The M42 is equipped with tunable cam sprockets from the factory. So pull your Cosmoline covered valve cover off and with the proper tools you can tweak your intake and exhaust cams up to 6 degrees +/- to provide more top end horsepower or more low end torque. See, you don't have to blow a grand on a set of Schrick cams to make your M42's cams a little hotter. The best setup is to adjust the intake cam to 5 degrees (advanced) and leave the exhaust cam alone. I would recommend having a shop do this work.

[neilofla]

the m42 has hollow cams, sodium filled exhaust valves, all 16 valves double sprung, adjustable cams, stainless steel header, (and a dual mass flywheel to negate a lot of that) but it was still designed as a road going engine.

it was mildly impressive in 1990 all right, but as andyboy says, just one of many 16 valvers, Honda and VW had nice 16V engines around then too. (i know, used two swear words just then...)

I still prefer to my iS to any other coupe from around then though!

Re original topic question - i think the m42 has forged crank + beefier con rods giving a lot of bottom end strength, (not that the M44 aren't long lived), so maybe just replacing things like gaskets, piston rings, and timing chain in your m42 will see it right for another 50k.

[tomstickland]

I'm thinking of buying another M42 engine and doing a rebuild.
Rebore, new rings, near bearing shells, oil pump, seals, water pump, chain etc etc.

[jaistanley]

PM me then dude.. I have one that could do with all that sat here...

[tomstickland]

What are the differences between the E30 M42 and E36 M42?
From the photos I've seen on Ebay the inlet manifold is different.

[GrindCulture]

The inlet manifold is different, the belts are different too I think, there are a few other differences but I can't quite recall them off the top of my head.

[neilofla]

the E36 inlet manifold is different (variable length inlet tract i think), the sump is different, exhaust manifold is cast not stainless, (I used to think it was dimensionally the same as E30 item, but i'm not so sure now, so the e36 manifold might not clear steering column) E36 crank is cast not forged,
I think the ancillery belts were the same up to '96.

I'm not so sure when knock sensors + the immobiliser business arrived, but i think it was post '96, someone correct me on this

If you've found a good E36 M42, and swap over sump + exhaust / inlet manifold, it should slip into the E30 OK

[tomstickland]

So....
M42 1.8 16v in E30
M42 1.8 16v in E36, different manifolds, cast crank etc
M44 1.9 16v in E36

[neilofla]

So....
M42 1.8 16v in E30
M42 1.8 16v in E36, different manifolds, cast crank etc
M44 1.9 16v in E36

yep. i think the change from m42 to m44 was 1996
i don't know much about the leccy side of things though, so i'm no use to you on the ecu / loom info

[odbod]

I used an E36 M42 engine, there is another thread recently on this, worth reading, there were a few variations on the installation in the E36 in terms of belt layout, I just changed the sump and manifolds and went for it!

http://www.e30zone.net/modules.php?name ... highlight=

[tomstickland]

Since I'm going to rebuild a 2nd engine then I've got plenty of time to check all the options. I'm going to get on with it.

[Dave_M3]

Build it as a 2.1 screamer, lol