Help with pistons

[33 Waka owner]

Recently pulled engine apart due to excessive smoke and found that every piston was ruined, but my front piston seemed to have different numbers to the other 5, also was curious to know how the pistons would break in this way (see last photo) bought the car with the issue, also exhaust and intake where out a tooth on timing

[GTSBoy]

The different markings are probably just binning. mass manufacturers don't blueprint engines to have matched components. They have bins of different sized pistons and just throw the appropriate sized piston into each bore to match the off-tools dimensions of the bore.

The damage is called a cracked ring-land. It is frequently caused by detonation, although there is not a lot of indication for that on the piston crowns. Anyway, it's f**ked. Needs a rebuild. Clearly the last person to have it apart was a clumsy f**k, because the cam timing was out.

[Duncan]

Hope it was a bargain if you bought it smoking.

BTW confirmed, nissan grade rb pistons and choose the closest fit for the bore. Certainly not blueprinting but it is at least better than always just using the same size. the RB26 grades are listed on EN101 of the workshop manual (they had grades for big end and main bearings too. Of course none of that matters now you are rebuilding it, just get it measured to confirm what size pistons you need (standard or oversize)

BTW you need to check the bearings and rod bolts too, detonation is hard on the whole rotating assembly. Your engine shop should be able to confirm