ETA vs M42 Daily Hoonmobile

[DER E30]

Overall, if you want a car to hoon in, and by my recokoning that means a car to run up to redline and throw around like a bag in the wind, the M42 wins. You drive it and the overall feeling it gives is that it wants you to drive the piss out of it. No, it is not the fastest E30 but it FEELS like it. The M42 just wants you to beat the fuck out of it***remember the general faults I mentioned above and keep on top of them.

+1.

I've never driven an m20 or anything else in an e30 but the m42 wants to be popping the revlimiter!

[James Crivellone]

ETA all day.

You want a daily, the M20B27 has a few benefits

1) It does not spin fast enough to break anything, rockers, etc
2) They pretty much never wear out (see point 1)
3) You feed them seals from time to time, timing belts, and waterpumps.. simple

The M42, between the timing system, 180degree thrust bearing (7200rpm all day..hahaha.. yeah look at the crank afterward), yadda yadda.

Yes, I realize you can replace the thrust bearing (if the crank is any good) and the timing gears, chains, profile, etc.

The M42 is a pile of crap, sorry.. I've worked on enough to hate those awful motors. I know you can put money into them to last, but the M20B27 is one of the best inexpensive I-don't-care-about-maintenance motors BMW ever built.

[DER E30]

LS swap

[roguetoaster]

ETA all day.

You want a daily, the M20B27 has a few benefits

1) It does not spin fast enough to break anything, rockers, etc
2) They pretty much never wear out (see point 1)
3) You feed them seals from time to time, timing belts, and waterpumps.. simple

The M42, between the timing system, 180degree thrust bearing (7200rpm all day..hahaha.. yeah look at the crank afterward), yadda yadda.

Yes, I realize you can replace the thrust bearing (if the crank is any good) and the timing gears, chains, profile, etc.

The M42 is a pile of crap, sorry.. I've worked on enough to hate those awful motors. I know you can put money into them to last, but the M20B27 is one of the best inexpensive I-don't-care-about-maintenance motors BMW ever built.

That's a bit of hatchet job James, the M42 is just as reliable or unreliable as any M20 or M10 if they are maintained on an equal level. I'd go in to how my daily M42 has been as reliable as I could want, leaving me stranded but twice in four years but that's not the point. To be fair, no 20+ year old engine with lots of miles on the clock is going to make for a good daily without addressing up front maintenance needs.

That said, if you neglect upkeep on an M20B27 it will probably run poorly for a long, long time. Does that make it a good engine? I don't think so, it just makes it under stressed. On the other hand, does the M42 being an engine you have to rev to get power from make it good? Not really, something in between would be better.

Both engines initially seem difficult to work on, both have overly complex and failure prone vacuum hoses and cooling systems; the M42 requires occasional tensioner changes, the M20 takes the occasional timing belt; the M42 requires regular replacement of the coolant pipe, the M20 takes regular valve adjustments. I could go on, but my point is that both are about even in terms of hours you will have to devote to maintenance. Does the M42 have an idiotic half lubricated crank bearing, yes. Does this make it unreliable? Not in my experience with on and off track M42s.

As far as performance the M42 is fun to rev, if you like that sort of thing; if not powerful, the B27 is not rev happy, but has good low end torque; the M42 gets good mileage if you control yourself, likewise for the B27; a stock 318 feels slow, a stock 325e feels slow; the M42 is about at the end of it's reasonable naturally aspirated tuning limits, the B27 has a good way to go for not too much money. Neither are great choices to install if starting from scratch unless you already have one of them on hand, or lots of experience with one of the engines, or a stockpile of spares. If I were starting from the ground up the best period correct engine for an E30 is simply an M30, preferably a B35.

[James Crivellone]

That's a bit of hatchet job James, the M42 is just as reliable or unreliable as any M20 or M10 if they are maintained on an equal level. I'd go in to how my daily M42 has been as reliable as I could want, leaving me stranded but twice in four years but that's not the point. To be fair, no 20+ year old engine with lots of miles on the clock is going to make for a good daily without addressing up front maintenance needs.

That said, if you neglect upkeep on an M20B27 it will probably run poorly for a long, long time. Does that make it a good engine? I don't think so, it just makes it under stressed. On the other hand, does the M42 being an engine you have to rev to get power from make it good? Not really, something in between would be better.

Both engines initially seem difficult to work on, both have overly complex and failure prone vacuum hoses and cooling systems; the M42 requires occasional tensioner changes, the M20 takes the occasional timing belt; the M42 requires regular replacement of the coolant pipe, the M20 takes regular valve adjustments. I could go on, but my point is that both are about even in terms of hours you will have to devote to maintenance. Does the M42 have an idiotic half lubricated crank bearing, yes. Does this make it unreliable? Not in my experience with on and off track M42s.

As far as performance the M42 is fun to rev, if you like that sort of thing; if not powerful, the B27 is not rev happy, but has good low end torque; the M42 gets good mileage if you control yourself, likewise for the B27; a stock 318 feels slow, a stock 325e feels slow; the M42 is about at the end of it's reasonable naturally aspirated tuning limits, the B27 has a good way to go for not too much money. Neither are great choices to install if starting from scratch unless you already have one of them on hand, or lots of experience with one of the engines, or a stockpile of spares. If I were starting from the ground up the best period correct engine for an E30 is simply an M30, preferably a B35.

I don't completely disagree with you, but to be honest its hard for me to like them, even after all that work getting them back to a solid point they are still an anemic zero torque little engine.

I've seen both M42's and B27's come in with random issues, 90% of the time the B27 goes away with a cheaper fix.

Hell, every M42 I've seen has something stupid wrong with it, usually timing, chattery chain (yes, poor maint.), the stupid vacuum hoses under the intake, the fact that most I've taken apart have a toasted thrust bearing (with a scored crank in the process).. Hell tons of M42's with shit compression (I sold one on here a year or so ago for 200 bucks because I wanted nothing to do with the darn thing)

Out of say 100+ M42's I've touched (we don't really get THAT many) most have stupid expensive problems.. some don't, good for the owner / previous owner.

B27's however.. Heck aside from the timing belt, most I see still running along, the lower ends are solid, bearings are typically good, they just...work

Although I will admit the 88 SuperETA was the best version, with the newer Motronic 1.1 dumping 1.0.

I will admit i'm biased.. I've just seen so many bad M42's, and for the cost I honestly see ZERO point in keeping them going, just like the M40.

On the M30 point, I will respect that, our chumpcar has one of those engines (B35) and it has never given us a lick of problems, including 24+ hours running, several 8 hour races, etc.. no issues.

With that being said, I ran an M50NV in my racecar for a full season, including 6 / 8 hour endurance races and that is one of the best engines I have tossed into a racecar.. good god that thing just worked.. only thing I did was Locktite the oil pump nut, and tossed it into the car.

I knew I'd stir the pot with this, but thats okay, we all have our opinions, and in many ways we are right, just like in many ways we are wrong... just like when I see an S52 in an E30 M3.. that is the antichrist to me :)