Someone talk me into m42!

[dooodstevenn]

My heart wants a e30 318i...but my wallet and brain tell me to get the 325i.  Here is my rational:

M20 may be heavier...but I can set up suspension to counteract the slightly heavier front.

there are more parts available, and cheaper too!

makes more power, and all the benefits of bigger displacement.

But, from all the reading i've done the general idea is to get the m42 since it's rev happy, turns in nicely, and geared lower will be just as torquey as the m20, but i'm very discouraged by the limited parts, and the expensive price of them.  I want this to be a nice, fun car that I can take to meets and track/auto-x and I do have a reliable DD.

How I like to drive:

I'm not into straight line speed or what not, I like to rev high and turn fast.

---------

I'm know this topic of m20 vs m42 has been beat to death on almost every forum, but i'm having a real hard time deciding.

also some other questions:

1. For those who have driven both, are the extra 200 lbs in the front really that noticeable, and does it effect any of it's other characteristics?

2. Are replacement parts to be had? If so where? I can't seem to find them either...

3. I keep hearing the m42 is more reliable than the m20 can someone explain to me what's more reliable about it? (I do know about the valves ticking on the m20)

[Jason@TMS]

M42 is great but little performance parts available. Great balance. Not a huge difference as I currently own both. 318is's are harder to find. M20's require more maintenance.... valve adjustments and timing belts. Both rev. IMO 318's are usually taken care of better (different type of owner). My advice, find a nice e30 with good service history and buy it regardless of engine. Harder to find one that hasn't been destroyed than one with the engine you want.

[dooodstevenn]

M42 is great but little performance parts available. Great balance. Not a huge difference as I currently own both. 318is's are harder to find. M20's require more maintenance.... valve adjustments and timing belts. Both rev. IMO 318's are usually taken care of better (different type of owner). My advice, find a nice e30 with good service history and buy it regardless of engine. Harder to find one that hasn't been destroyed than one with the engine you want.

You make a good point of buying a good e30 without regard to engine. Thanks!

[DesktopDave]

I'd suggest the M42, but I'd snap up any cheap E30 that isn't half rust and bondo.  The weight penalty of an M20 is difficult to notice when hooning, especially given the 25% advantage in torque.

The M42 I bought was just a lucky break - I'd been looking for any decent E30 - but it's been a great all-round car.  It just feels "right" for me somehow.  I've owned maybe six E30s in various states of decay...all have had their charms.  Even my least favorite E30 (a diving board Eta automatic sedan with the vinyl comfort seats) wasn't all that bad of a car, believe it or not.

Try out a bunch of them, you never know what will 'click.'  To tell you the honest truth, my favorite BMW so far was my 633CSi 5-speed.  She had her ugly side...I didn't trust her as far as I could roll her, parts are laughably expensive, and that big M30 gas hog isn't "quick" in any sense of the word...but she felt good and sounded right.  The E24 is gigantic compared to an E30 (at least on the outside)...but the M30's effortless torque matches so well with an E24's long wheelbase and heft.  The 6'er is ponderous in the city, but on the open road she had a silky grace that no E30 can match.

Jason brings up a good point about rarity - I looked for an M42 for a long time once I'd decided to get one.  I got lucky as the car had been very well maintained.  Came with a folder of records dating back to when the car was sold.  That had never happened to me before!

I've had a bunch of BMWs - I'd say you basically can't go wrong with an E30.  Even if you find a neglected one, they can usually be brought back.  The E36 is nice too - and both offer a lot of bang for the buck these days.

[dooodstevenn]

Thanks for the replies! Speaking of the rarity of m42's I just did a quick craigslist search and found 3 of them, pictures look good and all.  Is this just in southern california? Or are they pretty much gone everywhere?

[keflaman]

Normally after you purchase one a dozen come up for sale in better condition and for less than what you paid.

[Nelson_40]

1. For those who have driven both, are the extra 200 lbs in the front really that noticeable, and does it effect any of it's other characteristics?

2. Are replacement parts to be had? If so where? I can't seem to find them either...

3. I keep hearing the m42 is more reliable than the m20 can someone explain to me what's more reliable about it? (I do know about the valves ticking on the m20)

1. It's more like ~40 in the front (two extra cylinders), 20 in the middle (transmission, extra interior options), and maybe 10 in the rear (medium case diff). It does not really impact the performance, especially since there is ~30 extra HP on tap. But it really drives differently due to the differences in power band/torque and the way it revs.

2. Replacement parts are just as readily available as for any E30, at least online. I wouldn't trust (or pay more) for in stock auto store parts. As far as engine performance (especially internals) there is less to be had vs. the M20, but there is more than enough to choose from.

3. Much more reliable, maybe not on the street as there are so many variables, but certainly on the track. Our Chump Car has maybe 70 hours track time on a non rebuilt 100k+ mile engine and has not failed. I cannot say the same for the M20 cars which are forever breaking rocker arms and having distributor issues.

In summary, buy the M42 if you like the concept of a peppy, spirited and split personality (in a good way) (in the way it can poke around town or fly to redline) car, or buy the M20 if you want to be like everyone else and kneel down at the altar of power. Whatever you do, don't buy an M42 and M50 swap it, know in advance if you can live with 136 stock (~155-60 with basic mods) HP.

The reasonable fuel mileage does not hurt either.

[romkasponka]

Does not worth to play with m20. If you want more HP go for M50B28 or M54B30 . M20 would be the worst choice in this case. If you looking for good performance and handling you can go on diet and replace front hood to composite, replace heavy front bumper frame to custom steel, remove A/C and P/S. Instal medium differential in the rear and you will have not bad balance. Battery relocation to boot will make the balance same like with m42.
M50B25 136kg would the easiest to swap.
M54B30 120-130kg
M52B28 115-120kg
M42b18 102 kg
or if dare go for S54b32 147kg

[keflaman]

There is a nice little article comparing the 318is to the 325is in April's issue of "Bimmer" magazine. The author spoke on many of the same points addressed in this thread.

I tend to agree with Dave and the poster above. My first E30 was a 320i and I've never had the desire to own another M20.

I'm not into forced induction, I enjoy the sound after ~4300 RPM, and I'm quite happy to tweak the suspension just a bit to improve the handling and not be pissing blood when I arrive at my destination.

I think in the end you will be happy with whatever you chose.

[dooodstevenn]

1. It's more like ~40 in the front (two extra cylinders), 20 in the middle (transmission, extra interior options), and maybe 10 in the rear (medium case diff). It does not really impact the performance, especially since there is ~30 extra HP on tap. But it really drives differently due to the differences in power band/torque and the way it revs.

2. Replacement parts are just as readily available as for any E30, at least online. I wouldn't trust (or pay more) for in stock auto store parts. As far as engine performance (especially internals) there is less to be had vs. the M20, but there is more than enough to choose from.

3. Much more reliable, maybe not on the street as there are so many variables, but certainly on the track. Our Chump Car has maybe 70 hours track time on a non rebuilt 100k+ mile engine and has not failed. I cannot say the same for the M20 cars which are forever breaking rocker arms and having distributor issues.

In summary, buy the M42 if you like the concept of a peppy, spirited and split personality (in a good way) (in the way it can poke around town or fly to redline) car, or buy the M20 if you want to be like everyone else and kneel down at the altar of power. Whatever you do, don't buy an M42 and M50 swap it, know in advance if you can live with 136 stock (~155-60 with basic mods) HP.

The reasonable fuel mileage does not hurt either.

Are the rocker arms and distributor as bad as forums make it seem?  I take care of my cars, and are these things still present then? Or do they just happen to those who neglect their cars for hundreds and thousands of miles?  And if needed, do you have an estimate of how long it is until the rocker arms and distributor go bad?

[romkasponka]

m20 engine uses older technologies in all places: cylinder head, injection and ignition systems. If you want to have old classic look engine go for m20 but it is not as good as m50/m42 for every day use mileage or performance. It is just 10 years older technologies....

[sfinsf]

I'd like to chime in on this one....
Currently own two E30's, 318is and 325i auto
The 325 is new to me and the suspension needs to be replaced, it's original.
However, based on what you said and how you like to drive, the M42 is a no-brainer. That little tank can out maneuver anything! My suspension has been modified like many out there and I still have the orig open 4:10.
Even at this level, the car feels amazing all the time. I drive very aggressively, all the time and every light and stop sign is a opportunity to hear that amazing little 4 cyl come to life.
I have never found parts hard to find and I have done a lot of work to the 318
The weight is noticeable, and don't forget that stupid trunk tar and the sound deadening under the rear seat.
I get most of my parts from pelican, and used parts are often available in Calif because of all the dorks who are getting rid of the "4 cyl" in favor of the "more powerful 6" LOL.
Last but not least, the 318is was what the germans created after 10 yrs of learning, trial and error and engineering excellence. I'd say that is one of the reliability factors summed up. It is the best of all the e30's
Let me know if you want to hear more.... I could go on all day about that engine and it's chassis package.
Get the 318!
Besides, we are a special group of E30 owners....

[wazzu70]

Are the rocker arms and distributor as bad as forums make it seem?  I take care of my cars, and are these things still present then? Or do they just happen to those who neglect their cars for hundreds and thousands of miles?  And if needed, do you have an estimate of how long it is until the rocker arms and distributor go bad?

No its not really that bad. People just get paranoid.

A timing belt is cheap and easy to replace, timing chain needs maintenance and is super expensive to replace the guide rails.

The weight of the M20 is noticible upfront. I swapped my M20 in the car for M42 the M42 on the track is a lot of fun!

M20 is a nice and cheap engine to turbo, but I think the M42 is more fun on the track.

For a street car, M20 is probably a better option due to more torque.


Both engines have their strong point, it all depends on what you want.

[dooodstevenn]

As far as performance goes, what can be done? I think FI on it's high compression would be too much trouble.  So n/a: cams, chip? What else is there available?

[romkasponka]

As far as performance goes, what can be done? I think FI on it's high compression would be too much trouble.  So n/a: cams, chip? What else is there available?

What do you mean by saying high compression? If you would check you would see what today turbocharged engines are with same compression ratio like ours in 90ies. In your case I would go for M42 or M5x series engine which are pretty much the same just 4 or 6 cylinders. My friend turbocharged m50b25 up to ~600hp (with E85 fuel) with stock internals, aftermarket head gasket and head studs. No any problem in drag race competition and sometimes used like weekend car.

http://www.youtube.com/watch?v=yHbwPYnUpnU
http://www.youtube.com/watch?v=v1v2zQHit-I
and video with dyno and engine specs
http://www.youtube.com/watch?v=sptsXGSRkDY