Blown engine

So I bought a blown speed 3 to part out, I never started it battery was dead and PO told me it was fucked so I didn’t start it

cylinder 2 looks like it kissed the head cause carbon was knocked off the piston and head, also looks like there’s no bearing anyone have any idea what coulda happened?

 

Tough to tell, could have run it out of oil, or did a 6th gear WOT.

 

And the bearing disintegrated? I didn’t take a picture of the crank before I put it back together to store it but there’s no bearing in the crank either. The Rod also doesn’t connect evenly to the rod cap, like the break between the 2 has uneven edges isn’t it supposed to be flat on both sides of the rod and rod cap

It was definitely low on oil and he had some bullshit local tuner tune the car.

 

They could have run it without oil for a long time, and just worn down the bearing. I would be surprised if you don't find any pieces inside the engine as you continue dismantling it.

Keep in mind that the previous owner may have done some funny shit to the car that he didn't tell you. If there is no bearing, that rod might have enough slack in the stroke to get closer to the head than normal.

As for the rod caps, that is 100% factory on Gen2. Mazda used some kind of fracture flange, I forget the name, to keep the rod caps from getting mixed up. The caps should bolt back on to the corresponding rod, but just one way, they can't be flipped or swapped.

 

oh okay thats an interesting thing to do for the rod caps, definitely some sketchy shit the way they modded the car, I bolted it back together for now gonna disassemble it completely in the spring. thanks for the reply

 

As I found this in mine. No big end rod bearing, rod had large amount of rod and crankshaft journal destruction. Of course the bearing shells don't dissolve, just become things found in bottom of oil pan. This was supposed to have been a short run with low oil. Nothing to trust once you find damage like this. Great engine now, complete rebuild. Not cheap!

 

Dayumn thats a lot of sparkles, ill be doing that in the spring. Definitely expensive I know lol.