Project BMW 318is: Building A Stroker

While we had the engine out of our 318is, we decided to take the opportunity to rebuild it for more power and torque–because more is always better, right? And there’s still no replacement for displacement. Like our earlier engine work, these modifications were done at Metric Mechanic, where owner Jim Rowe and his gang have figured out a way to …

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Yep, awesome!

This is the internet, so, I'll pick at details in a good natured way, this time.

Wouldn't you call the new con-rods H-beam, compared to the old I-beam? Maybe I'm confused.

This is a sweet build.

What kind of power potential does this all translate to? I've been considering going this route VS the m47 crank.

wheelsmithy,

I do not consider myself an engine builder, although I have built an engine or two. I'll ask Jim Rowe, but this is what he called these connecting rods

And Captainawesome, the builder said I could expect 160-170 hp, but that is with the restrictive stock fuel injection with only a chip and larger injectors changed. With a stand-alone FI system,  there may be even more horsepower available.

I think I am going to be happy with the simplicity and reliability of the stock stuff for now!

awesome!  I hope Metric Mechanic is still doing this when my M42 eventually wears out....

Tom, 

   I was being that nit-picking guy on the internet. Not important. I love this, and all the builds. Carry on in good health.

Looking good! You all should put that supercharged 318i article back up so we can compare!

FYI for anyone interested, the red one is for sale if you're willing to spend the dough...

https://raleigh.craigslist.org/cto/d/youngsville-1991-bmw-318is-coupe/6780041200.html

So what is the price tag for building a similar stroker motor to this?

All in, it is about $7500 to build this engine. And while that might sound a little steep, everyone who has driven the car so far has said that at that price, it is a bargain, as this is a very, very sweet E30 and when we run it against an M3, i have no doubt it will not only fare well, but embarrass it.

What are the advantages to rebuilding a M42 like this vs doing some upgrades to a M44?

With the price of E30 M3's, something like this does seem like a good way to get a car that performs like an M3 at less cost, if not "cheap".

Tim Suddard said:

All in, it is about $7500 to build this engine. And while that might sound a little steep, everyone who has driven the car so far has said that at that price, it is a bargain, as this is a very, very sweet E30 and when we run it against an M3, i have no doubt it will not only fare well, but embarrass it.

Heady praise!

I can't wait to see perhaps a better intake, header, injectors, Megasquirt and E85. I suspect that would it have it up near 200 at the crank.

I have driven many E30s in varying configurations and can attest, a 318is with a 1.9L 11.5:1 build (stock crank, max bore) pulls noticeably harder than a stock M3.

Also, if anyone wants to build a more budget friendly 2.0 M42, here's my recipe:

• M44 crank
• 140mm M42 rods
• S52 pistons with 1.5mm decked off the top and valve reliefs recut (I was a machinist at the time, so why not)

According to my calcs this should have resulted in a 2.0L displacement and ~11:1 compression.  Unfortunately I built the bottom end just before my car was totalled, and I have never had the chance to put it in anything else.

2002maniac said:

I have driven many E30s in varying configurations and can attest, a 318is with a 1.9L 11.5:1 build (stock crank, max bore) pulls noticeably harder than a stock M3.

Also, if anyone wants to build a more budget friendly 2.0 M42, here's my recipe:

• M44 crank
• 140mm M42 rods
• S52 pistons with 1.5mm decked off the top and valve reliefs recut (I was a machinist at the time, so why not)

According to my calcs this should have resulted in a 2.0L displacement and ~11:1 compression.  Unfortunately I built the bottom end just before my car was totalled, and I have never had the chance to put it in anything else.

This sounds like something I'm interested in for both my m42s. Finding a machinist that will touch or machine pistons locally like I would need ends up being the biggest issue though. If there's an off the shelf piston option to combine with the m44 crank and m42 rods for a similar setup I'm all ears. If it's a few hundred more for that I'm cool with it.

Just put a Toyota 3SGE BEAMS engine in it and be done

In reply to ErikTheSwede :

As cool as that sounds, the exhaust and intake are on the wrong side making the swap difficult. Tuning can be pretty tough with them as well. Then the resale value of a 318is with a Toyota motor would be laughable. A nice 318is can fetch 8k and up these days.

captainawesome said:

In reply to ErikTheSwede :

As cool as that sounds, the exhaust and intake are on the wrong side making the swap difficult. Tuning can be pretty tough with them as well. Then the resale value of a 318is with a Toyota motor would be laughable. A nice 318is can fetch 8k and up these days.

I know. I'm just running my trap. I genuinely hate BMW engines but love their chassis and suspension. I am guilty of looking at more than 1 E36 318TI and having visions of the 9000 rpm Toyota 4 cylinder swapped in there

I have to say this motor in an E36 is what interests me. I can pick up E36 for $2500 all day. They don’t have the E30 tax. But they do have, what a 200 - 300 lbs penalty over an E30?

This would also be a good time to make a shortened oil pan or a budget built dry sump kit so you can lower the car without worrying about damaging the oil pan.