Which engine would you choose for a swap?

[varg]

Yes, the Honda B16 and B18 engines are impressive to me as well. In the '90s the m42 was comparable to other Japanese 4 cylinders in terms of power. The SR20DE found in the Sentra SE-R and NX2000 made 140 hp and that was even a 2 liter. The 1.8L in the Isuzu Impulse and Storm GSI made 140hp. Honda was on a different level back then. I would love to own an EM1 or GS-R.

Right, proving my point, the M42 compares with average late '80s/early '90s 4 cylinders, not with good ones. Ergo, it is not a good engine, it is about average. Just with some critical flaws. You know you're not in good company when you have to stoop to a Sentra or an Isuzu to compare favorably. Remember that the engine we're talking about came in a car that cost $21,000 new, and that SE-R was about half the price and... it was a Nissan :giggle: The Honda was also close to half the price, and somehow managed to be powered by an engine that was superior in every measure and revered to this day as the beginning of a legendary line.

BMW knew how to make a good engine, we all know them. M42? Not one of the hits.

Also the reason they rev like shit is the 26lb dual mass flywheel!!!

Yeah that big chunk is definitely partially responsible for its lackluster throttle response. Even with the M20 clutch setup you just won't find the M42 particularly responsive for a small I4 though.

Honda engines are transverse and have some really crappy engineering designs. I’d take a slightly less powerful BMW engine any day.

Care to elaborate? Especially in light of how many well known flaws the M42 we're discussing has it's interesting that you'd call honda engines flawed in comparison. As far as 4 cylinders go, Honda's are universally acknowledged to be among the best out there.

[Julien]

Honda engines are transverse and have some really crappy engineering designs. I’d take a slightly less powerful BMW engine any day.

expand on this, i'm curious to hear it

[Andrew325is]

Honda engines are transverse and have some really crappy engineering designs. I’d take a slightly less powerful BMW engine any day.

[Motheye99]

I put 87 in my m42. There only economical to get another used one white it eventually breaks.

Also the reason they rev like shit is the 26lb dual mass flywheel!!!

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[agent]

Why three commas? Are you a billionaire?

Would have been funnier if you didn't explain the reference. I still lol'd though.

[Codym42]

How does the handling compare after the swap? Does it feel any different?

It is VERY tail happy when driven hard. Its better now that I replaced tires but it still doesn't feel like it should. A friend of mine who has an e30 drove my car and agreed with me. I'm eventually going to do either an adjustable rear subframe or riser bushings along with new bilsteins in the rear. I was also told to remove the rear sway bar completely but haven't tried that yet.

It's pretty simple. Compare the M42 to a good little I4 from the same era, the first generation Honda B16A.

1.8L vs 1.6L
6,500rpm vs 8,000rpm
138hp vs 160hp
10:1 vs 10.2:1
$21,000 car vs $12,000 car
meh vs the start of a legend

It's not that BMW couldn't do it, it's just that they didn't. A good, fun 4 cylinder revs high to make what little power it does and is ever responsive, an M42 doesn't even like to rev. 6,500rpm is plenty of revs for a 6 cylinder designed in the 70s (M20), but even in the late '80s when the M42 was penned 6,500rpm was average at best for a 4 cylinder. Look at that B16A, 1.6L, 20 more hp than the M42, revs to 8,000 rpm. The M42 on the other hand? It's coarse and noisy, and falls flat on its face after 6,000rpm. It doesn't even respond well to mods NA, with even a mere 150hp being a rare sight on M42club. Some pretty awful issues like profile gasket failure, crank walk and snapped idler tensioner bosses have also been observed in M42s. It's an engine with a lot of flaws considering what it came from; the era of BMWs being very durable, long lasting cars.

The rally engine is kind of a non-sequitur when talking about ordinary M42s, there's nothing stock left aside from the castings and they've attempted to fix every issue they can such as getting rid of the idler sprocket and putting a 180° thrust bearing set in it. It's basically a high dollar custom build, what is there to hate about that? other than getting a mere 205hp for your $10k of course. M42s are, in stock form at least, pretty much economy car motors minus the reliability.

No doubt there are better 4 cylinders out there. My m42 made it to 283k before I pulled it with no major issues and regular maintenance. I liked the fact that the whole drivetrain in the 318is is lighter. I will say that those who argue the m42 is more economical are kind of wrong. I'd rather put 87 in an m20 and get 22mpg than have to put premium in an m42 and get 26mpg. Its just not worth it.

Yes, the Honda B16 and B18 engines are impressive to me as well. In the '90s the m42 was comparable to other Japanese 4 cylinders in terms of power. The SR20DE found in the Sentra SE-R and NX2000 made 140 hp and that was even a 2 liter. The 1.8L in the Isuzu Impulse and Storm GSI made 140hp. Honda was on a different level back then. I would love to own an EM1 or GS-R.

[varg]

I don't understand the hate for the m42 either. The rally engine would be an absolute riot.

It's pretty simple. Compare the M42 to a good little I4 from the same era, the first generation Honda B16A.

1.8L vs 1.6L
6,500rpm vs 8,000rpm
138hp vs 160hp
10:1 vs 10.2:1
$21,000 car vs $12,000 car
meh vs the start of a legend

It's not that BMW couldn't do it, it's just that they didn't. A good, fun 4 cylinder revs high to make what little power it does and is ever responsive, an M42 doesn't even like to rev. 6,500rpm is plenty of revs for a 6 cylinder designed in the 70s (M20), but even in the late '80s when the M42 was penned 6,500rpm was average at best for a 4 cylinder. Look at that B16A, 1.6L, 20 more hp than the M42, revs to 8,000 rpm. The M42 on the other hand? It's coarse and noisy, and falls flat on its face after 6,000rpm. It doesn't even respond well to mods NA, with even a mere 150hp being a rare sight on M42club. Some pretty awful issues like profile gasket failure, crank walk and snapped idler tensioner bosses have also been observed in M42s. It's an engine with a lot of flaws considering what it came from; the era of BMWs being very durable, long lasting cars.

The rally engine is kind of a non-sequitur when talking about ordinary M42s, there's nothing stock left aside from the castings and they've attempted to fix every issue they can such as getting rid of the idler sprocket and putting a 180° thrust bearing set in it. It's basically a high dollar custom build, what is there to hate about that? other than getting a mere 205hp for your $10k of course. M42s are, in stock form at least, pretty much economy car motors minus the reliability.

[Andrew325is]

^it sound SO good.

Stroker or not, an m20 makes nice noises for your ear holes.

m54, not so much

I think it sounds awful, at least that rasp. M54 sounds so much better than an M20... M44 sounds better too IMO. (S54 sounds the best of course, but it's not part of this discussion. Come to think of it M20 isn't either...) M20 is an interesting engine. I'd call it quirky, but it is very smooth running. Not sure I ever experienced an M20 that idled perfectly. I have service records for my car that show the owner took the car into the dealership when it still new complaining about a rough idle. The BMW dealer dismissed it as normal... It idles pretty well now, but not as well as an M54. The engine is great for people who are technology resistant (but of course it's still too modern for some people). I admit it is nice that there is basically no plastic on the thing. It's definitely old school. It's not efficient at all for the power it makes though (unless you're comparing it to an old V8) and it's so clickity clackity it sounds like it belongs in a tractor, or chitty chitty bang bang. :)

[Andrew325is]

I don't understand the hate for the m42 either. The rally engine would be an absolute riot. I had fun with my chipped m42 but got bored after a while. It was fun, but not fast if that makes any sense at all. I swapped mine to an aluminum m52 and its a blast. Now, the car just needs better suspension to match the additional power. The m54 would be very similar (since its aluminum too) and would be the most bang for your buck.

How does the handling compare after the swap? Does it feel any different?

[Codym42]

I don't understand the hate for the m42 either. The rally engine would be an absolute riot. I had fun with my chipped m42 but got bored after a while. It was fun, but not fast if that makes any sense at all. I swapped mine to an aluminum m52 and its a blast. Now, the car just needs better suspension to match the additional power. The m54 would be very similar (since its aluminum too) and would be the most bang for your buck.

[Caperix]

Isn't the s14 really a m10 with more stuff on top? Should weigh close to a n52 then. The reason people are bagging on it is it's hp/$ ratio is way worse than a m54 or n52. I think the s14 when fully built and money is no option, but for now I have to stick to cheaper ways of getting that power.

This thread really derailed, but OP you should be the first to do a N20 swap, that's a light motor.

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N20's are cheap even new from BMW now, that is due to timing chain issues. They are light & 240 hp is good, but they are done at 100k. N52 is a good choice but it will need a custom oil pan & pick up or a custom subframe, plus only a few have cracked the ECU. The m54 would also be my choice, they are affordable, will make good power & last forever. I have 320k on my e46.

[pandaboo911]

M54 is the obvious choice. Cheapest option, most reliable, most power. Dunno why anyone would choose any other unless they’re racing in a class that limits by displacement or some shit

[Julien]

I wouldn't call the S14 mediocre. If they were that bad they wouldn't be worth thousands of dollars. N52s are worth peanuts, less than M54 for some reason. Not sure why. Bargain if you can get one running in an E30.

Speaking of bargains, here's an S14 at auction in the UK someone might be able to a get a deal on. Doesn't say how many miles and no info as far as health of the engine like compression, so assume it needs a rebuild I guess. Doesn't say which variant, but maybe S14b20? I messaged the seller yesterday and haven't got a response. Might be a scam, but they've been a member since 2015, so who knows. Current bid is $2k with 2 days to go.

https://www.ebay.com/itm/complete-en...e/133107436596

S14s are only worth $$texas because of the e30 m3 bubble. They are great 80 tech, but things have changed greatly in 20+years. I'm honestly just trying to push people's buttons when I say they are mediocre. Truth is, they're great on track, I just find them annoying in a driver. But with their cost, it's just not worth it.

My bad on the N52, I thought all N motors had turbos.

I'd love a Mag /Alu block for an S14,,, but not interested in the size and the added weight of an N52.

I can lift an S14 block w/ crank, pistons, rods from the floor to my bench. They dont weigh much at all and they are a small package.

If you think the S14 is mediocre, carry on with your grocery getter engines.
I'll take 'em all.
Most of the people that bag on S14s, know really nothing about S14s.

S14B20 is a 2.0 litre version

Why three commas? Are you a billionaire?

Shortblock? Because I don't believe for a second than an S14 is over 100lbs lighter than an M42.



Engine weight figures are completely meaningless without information about the state of the motor when weighed.

100% agreed

Having run a pretty well-built M44 in my e30 for years now, I’d say it’s not a bad choice. Only 2 things I would change about my build tho. 86.5 or 87mm Je pistons with rings are only around $800 and it yields nearly 2.0L. Second, they do fall flat at 6,500 and it really needs an intake cam to make it rev to 7k and make power there. Aside from that, it’s a delightful, if slightly underpowered swap, and it returns 30+ mpg with my foot buried in it all the time. It’s not that slow however, it’s slightly faster than my workmate’s 86 325i. It’s a pretty cost-effective way to have a 170hp ( or more) 4cyl. Definitely go with all the late ECU and harness, it’s worth the trouble for the improvement in throttle response alone. And get a flash on it. That woke it up also. There are cheaper ways to make more power for sure. But I can roll into any CA smog station and pass without anyone ever asking a question.

Nice, I loved my m42 in my 89 318is! I wouldn't swap one into a car though. Unless it had an m40.

My point is that this context of its state and weight relative to another engine in similar state is critical to that weight meaning anything at all and should be mentioned when quoting the figure. Hence my comment asking if that's a short block weight because it's so much lighter than expected.

Yep

[JimmyP]

yeah, but come on man....you bought the car already built for pennies on the dollar of what it would cost today. lets be realistic.

i know this because you beat me to this car by about 2 days

Well, part of it was that I knew Tim built the car from when he started building it. He was posting about it on the SIG as he was doing it because the wiring was slightly different.
I loved the whole concept. I wanted to do one myself, I had all the parts.

I didnt even know he had it for sale untl I heard someone say something about Tim's cabrio for sale..
They day I heard he was selling it I emailed him and bought it.
If I hadn't bought it, I would have ended up doing one myself, it was that or an M2, I still want an M2, I still have all the parts to build one LOL.

[Motheye99]

M20 and its SOHC brethren makes some of the best noise you can get out of a BMW the modern M cars doesn't even come close.