Worst kind of noise?
 

Hi all,

I need some help figuring out what to do next with my '15 BRZ...

Last weekend, just as I was on my way home, pulling over at a light, I heard a knock as I clutched in. Alerted by that, I started paying attention to all the noises.
I was less than a mile from home, so I decided to baby it until I park up.
No lights on the dash, temps were OK, but the noise kept getting worse, more and more knocking.

As I was driving into the garage, the engine stalled. No CEL or codes when I connected an OBDII scanner. Unfortunately, it sounds to me like rod knock :/

Backstory about the car:
It was imported privately from the US, bought at an auction, running and driving but a salvage title due to damage to the front of the car.
When it finally arrived it needed some new parts(hood, bumper, headlamp, fender, radiator and fans), but the suspension was straight, the impact did not go past the front crash bar structure.
It also got a full service with fluids and was never turned on before that to make sure it has oil etc.

The car was at 35k miles when I got it earlier this year.
I was running ENEOS 0w20 since I read some recommendations. Level was fine, it has done a total of 400 miles since I got it!

It is not my first Subaru, so I knew the engines are let's say delicate, so I checked oil ever fill up and let it properly heat up and cool down each time.
I'd say it was driven like it was meant to but without abuse. I did not get to try it on track yet :(

Here is a pic from the day it was all fixed up and ready for registration:
https://i.ibb.co/grp5WV0/1657566201964.jpg

It's been a dream car of mine ever since I heard the first rumors of Toyota/Subaru bringing back the 86 as an affordable sporty RWD platform.
I had to wait 10 years to finally be in a position to get one, so you can imagine, I am a bit heartbroken at the minute.

I am considering a couple of options:
a) Swap a complete used engine.
+ least labour-intensive
- 86/BRZs are very rare where I live so finding it locally is almost impossible. I'd have to import it again from the US but this seems risky(what if it happens again?) and expensive in the end.
b) Buy a built IAG shortblock
+ long term fix (hopefully), ready for boost
- Very expensive taking into account shipping and all associated costs. Never intended to go FI, since there is still a lot for me to learn and enjoy in NA form.
c) K24 SWAP
+ fixes the main weak point of the car
- again, expensive with the whole kit. Plus, the whole car is very clean so it would almost be a shame to make it a 'project'.
d) Buy an OE shortblock and rebuild to stock
+ parts are available
- how can I be sure this does not happen again? Is it possible to still enjoy and really drive the car without constantly worrying about the engine?

I am leaning to option d) but with that said, I don't know if I should keep it or sell it off...

What are your thoughts?

Failures of these engines beyond the early 13s is pretty rare actually. There are far far far more 14+ cars out there that have never had a single engine issue than ones that blew u. You just don't hear about those ones.
Since you only have 400 miles since the rebuild I would guess that the engine took a harder knock in the crash than the body damage appeared. One good smack to the crank pully is all it would take. Bet if you pull it apart you find a bent rod or even a smashed main bearing.
If in your position I would try to find a 14+ block that was NOT in a front end damage crash and just stay stock.

@hu60 my guess would be something wrong with the ground strap / grounding on the car. Next would be fuel pump malfunction.

Looks like you are in Poland. Why import a car / engine from the states, if that's what has gone wrong. You can get salvage reconditioned engines from the UK ( or even Ireland) and should work out cheaper.

Sent from my SM-G781B using Tapatalk

Thanks for the input guys!

It is clear now that a stock engine has to go back in. I will try and source a 14+ like you suggested, otherwise get an OE shortblock for a rebuild.
@radroach any tips on how to diagnose the possible causes you mentioned?
Is it possible to check for a lean condition without taking the engine apart? Would a mechanic be able to tell by looking at spark plugs for example?

Other than that, it really might have been just caused by the original impact. However, it is almost hard to believe looking at the very limited damage to the body (no airbag was even deployed).

It is somewhat comforting that it is not a common occurrence with such a low mileage examples, so it makes me consider keeping it for a while after it's rebuilt...

A short update.
Engine is out and it is indeed a spun bearing.
There is even play on cylinder 3 rod. My mechanic is saying that it must have been abused and that I should run a thicker oil.

Since I cannot find a reasonable used motor, I will order an OEM short blok.

Question, should I also replace the oil pump, or is it ok just to clean the old one?
If so, looking at the schematics, it looks like it is integrated with the timing chain cover?
That again would be very expensive to replace...

Completely disassemble everything and take the castings to a shop for professional cleaning. Residue from the spun bearing is everywhere inside.