better daily driver? M20b27 or M40/M42

[jasonbk]

I have M40 and I really wanna put some m20 in it...seriously.

[ScHpAnKy]

M42 is not a HP or torque monster, but I love my 318is. Its a fun, high revving engine in a light, well balanced car. I don't think the eta has that same feel. If you go from driving an inline six (in my case an e36 m3) you will feel like you are revving it out and killing your mileage, but you arent. After you realize that, you'll find yourself revving it out at every light.

this. If you're used to m20's and how they drive, you'll like the eta.

However, the m42 is a better engine.

I daily'd both, for what it's worth.

[IronJoe]

I think the M42 is a great daily and honestly feels much more peppy than the numbers would lead you to believe. The engine is a much more modern design and while it isn't perfect, the distributorless ignition is a huge leap in terms of smoothness, driveability and timing accuracy.

Simon, when Mark42 test drove the Diamondshart last Saturday he was pleasantly surprised with the power.

[Balleristic31]

I dont understand the argument that the m42 is a weak highway motor. My car with a fairly stock motor pulled on a friends b25 vert in all gears.

However, I feel like my m42 is pretty strong for one of these motors.

Weak m42s are absolute dogs. But I've driven plenty of etas an they all are dogs lol.

But I feel like if all I was doing was dailying the car, I'd take either. I love the torque of an inline 6 to drive around town with, something I severely miss in my m42.

[James Crivellone]

Yea but theres the Idler pulley, chain tensioner, and profile gasket to worry about. The M42 isn't as bulletproof as the M20

That right there is my main issue with the M42. At its 100% prime it can be a great motor, but every single one of those stupid little 16valves I have worked on has been a complete wreck. Destroyed timing systems, horrid compression, oil pan bolts in the sump, etc.

An M42 that is maintained is a good motor, however for most of us purchasing used E30's, they are not maintained.

An M20B27 can run with shit maintenance and continue running assuming the 30 dollar timing belt does not let go.

Although to be honest the M20B27 Super-ETA is the best of both worlds, modern(ish) Motronic 1.1 fuel injection..leaps and bounds ahead of Motronic 1.0.

[VinniE30]

I dont understand the argument that the m42 is a weak highway motor. My car with a fairly stock motor pulled on a friends b25 vert in all gears.

FWIW, my m20 eta pulled on a chipped m42 from ~70 to ...
That's an eta with just a chip and some "i" intake and exhaust bolt ons.
His car weighed less.

I haven't driven an m42 e30 but I will say I have been enjoying the m20b27 for years now.

[Balleristic31]

FWIW, my m20 eta pulled on a chipped m42 from ~70 to ...
That's an eta with just a chip and some "i" intake and exhaust bolt ons.
His car weighed less.

I haven't driven an m42 e30 but I will say I have been enjoying the m20b27 for years now.

And honestly I dont really think freeway pulls with random 20+ year old cars is an accurate way to determine an engines worthiness.

Both engines serve a purpose to me. It just depends on what you want.

Do you want light and peppy? M42
Or do u want smooth and torquey? Eta

[Ryann]

Yea but theres the Idler pulley, chain tensioner, and profile gasket to worry about. The M42 isn't as bulletproof as the M20

The m42 timing components have a bad rep because the original tensioner piston installed in the e30 m42 sucked. Those of us who don't have our heads up our asses either read about this or simply heard the chain slapping the cover and took the 5 minutes and $30 it takes to install the updated part. Others are ignorant or apathetic to the symptoms for 50k then cry when something gives way. Also, 99% of e30 m42's still on the road have already had their profile gaskets updated to the better version.

[Kershaw]

m20s are not smooth. what gave you that false idea?

[VinniE30]

And honestly I dont really think freeway pulls with random 20+ year old cars is an accurate way to determine an engines worthiness.

That's why I said "FWIW". I could have said the same thing about your story, since you brought it up.

Both engines serve a purpose to me. It just depends on what you want.

Do you want light and peppy? M42
Or do u want smooth and torquey? Eta

I agree with this.
But also consider other factors such as reliability, durability, and longevity.

[Balleristic31]

same thing about your story

Fair enough ;)

[Jrey]

My input on this since i do own an eta, its a great DD, however i cannot say much about an M42 because i havent even touched one yet, after reading several posts, yes i have to say the m20b27 are built like tanks, even with poor maintanence its still good, but its always the case that a good maintanence on these engines will last you forever.

I drive 30-35 miles back and forth to school total 3 times a week and even putting like $20 will last me at least 2 weeks if im not pulling 80+ on the highway, i still have yet to put up my statistics of my MPG but from what people are saying here that do own etas my gas mileage is probably worse than everyone elses, considering a Dinan chip that ive heard drops gas mileage and probably i have a bad O2 sensor idk how that effects gas but that could be the cause, but i have to say overall it is a torquey engine and smooth from my experience when driving around town

[e30austin]

I agree 100% with James and F34R. I despise the M42. Who gives a flying fuck about a 50 lb lighter motor and weight distribution? The fact of the matter is, at the end of the day, it is still a fucking 4-cylinder. I'd drive an automatic M20 car over an M42 5-speed car any day of the week.

[gearheadE30]

The only e30 I've owned is a 318is, but I'd say for strictly daily duty, the 325e is probably better. I love my M42, don't get me wrong, but if you need power, you do have to wind it out. I never felt like it didn't have enough power on the highway, but I also never felt like I had power to spare. The turbo has changed all that, though. Now it is a terrific daily and I still get 25-30 mpg (3.73 rear end).

Also, the timing case thing: the timing components wear out between 150k and 200k depending on driving habits, tensioner, etc. Mine still had some life left at 200k on the original tensioner, but I redid it as preventative maintenance. As far as I'm concerned, the only major design flaw of the motor is the 180 degree crank thrust bearing. Everything else can be fixed or updated pretty easily. For people who have heard of the timing system exploding, it is because the crank walks in and out when that bearing surface wears, which puts a fore/aft load on the idler sprocket mount and changes the angle of the chain relative to the crank and cam gears causing excessive load at odd angles resulting in accelerated wear and stress on the idler mount, which will eventually fatigue and break off. E36 M42's and M44's don't have an idler fwiw.

[Ryann]

Also, the timing case thing: the timing components wear out between 150k and 200k depending on driving habits, tensioner, etc.

My father-in-law's m42 has 270k on the clock and his original timing components look exactly like mine @ 117k.

I'd drive an automatic M20 car over an M42 5-speed car any day of the week.

That's because you're an ignorant, angry ginger.:D