Aftermarket Pistons?

[M Y G O D]

I'm tearing apart my CA18DET for an inspection before swapping it into my S13 convertible, and I noticed that the pistons look quite a bit different.

I was told that the engine had a cometic headgasket (verified), ARP head studs (verified), ported and polished head (verifying), and forged pistons.
My issue is that these pistons don't look like typical forged pistons of any design that I've researched, nor do they look like stock cast pistons.







(sorry for the sub-par pictures, I couldn't get the best angle from under the crankcase.)

I just joined these forums after seeing the remarkable amount of information float and boost boy have on these engines, and I hoped that one of them or somebody equally knowledgeable could chime in. Thanks!

[themadscientist]

Difinitely not stock cast pistons. They look very typical of a forged piston.

[M Y G O D]

that's what I thought, but my friend said they look like cast forged pistons? like cast pistons that went through the forging process afterwards. he said they just look like replacements for stock pistons, and I have to agree that they look very different from any of the forged pistons I've seen for CAs (cp, wiseco, etc.) what could they be?

[themadscientist]

I think those are called hypereutectic pistons, but no, those are not that. There's no telling what they are. Other than, I think it was Wiseco not notching for the pin oilers, I haven't seen a "bad" forged CA piston. Some are noisy, but that's about it.

[biosehnsucht]

My custom order (due to overbore) CP Pistons were always nice.





Maybe if you had x-ray vision you could see if there was markings under the little end of the rod like on mine.

[float_6969]

They could be Supertech pistons. They're not well labeled. Regardless, those are definitely forged pistons.

[M Y G O D]

the guy seemed pretty straightforward with me, and I could tell he was being honest about the pistons. they just seemed odd, but definitely match the description. thanks for your input, guys.