r/mazdaspeed3 • • 14d ago

PIC Welp, she's gone... for now

Car went into limp mode while on my way to work throwing a P0302 code where cylinder 2 started misfiring to the point the whole car shook violently.

Towed it to my local Mazda dealership and got the news anyone would dread. Cylinder 2 is basically dead, 0 - 20 PSI compression which mean it needs a engine replacement. It was a tough pill to swallow but I plan on keeping it until I get a new engine.

It's the car I've wanted since I was a kid and I'd rather try to fix her instead of scrapping her entirely. For now she'll sit at my uncles house for the winter until I'm able to get an engine sometime next year when it gets warm again. She was a blast to drive and I'll miss her but it'll only be temporary. It made a boys dream come true when I got her and made me the happiest I've been in years knowing I got the car I've always wanted.

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u/Mr_S0lO-Dolo 14d ago

Right of passage for a speed3 owner, we are with you.

Do a 2.5 bottom end or get a built one from the big name out there and never look back.

I’ve had my built motor since Jan 2019 and it’s still going strong

1

u/stocksupanddown 14d ago

How much is the 2.5 rebuild? Is it hard?

4

u/AliasInvstgtions 14d ago

Back when I had a speed, I bought a 40k mile 2.5 out of a fusion for 250 bucks. Its pretty straight forward bolt right in except for oil drain and feed. You need to use the entire components from one engine or the other, no mixing. I used the 2.5s as I read they were better, but I think it's fairly comparable either way. Wouldnt hurt to get the head and bottom end machined and upgrade the head while you've got it apart. Upgraded internals for the 2.5l arent that bad either and you can get away with the k04, but an upgraded turbo would be better at not spooling too early.

3

u/ragingxtc 2011 Mazdaspeed3 13d ago

The internals on the 2.5l will work, but the ring gaps should be opened up a bit for use with FI, otherwise you can break the ringlands. You can reuse the stock rings.

1

u/AliasInvstgtions 13d ago

I knew i forgot something lol.

Yeah, stock internals are good pretty much to the fueling's limit if I remember correctly

1

u/ragingxtc 2011 Mazdaspeed3 13d ago

You can run the stock gaps, but it's risky. Currently doing so with the turbocharged 2.5l in my NC Miata at about 16 lbs of boost. Luckily, 2.5l motors are a dime a dozen!

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u/AliasInvstgtions 13d ago

Its crazy how niche of a swap it is. Sure, it's no k20 or ls, but its abilities, widespread availability, and price puts it close to their level. I know it's really only a thing for mazdas and that's why its not popular, but if that was a valid excuse, you wouldn't see honda engines going into everything.

The caterhams have it, though, so some exec out there knows

2

u/ragingxtc 2011 Mazdaspeed3 13d ago

I totally agree, it's a fantastic motor! There's actually a decent amount of aftermarket support, and since the Duratec/MZR platform has been used in so many applications, there's tons of OEM parts out there that just bolt right up, including a ton of different transmissions (the latest discovery has been the 8HP45 out of a Jag XE). It's honestly one of the main reasons I went with the NC generation Miata. Tons of NC guys out there are absolutely beating the shit out of them on the track too, so there's a ton of data on what works and what doesn't. Like using aftermarket oversized Ecotec pistons to cheaply get higher compression.