RWDlover

The block being the same and the pistons same diameter means nothings, there are many other things that i do not know if are common. Piston ring width, piston ring thickness being two. Someone mentioned that the thickness is the same, so i would still have to verify the ring width, or measure the depth and height of the piston ring channels and see if it's the same for AP1 and AP1 04+/AP2 pistons

dagle

Lol if you refer to the original post of this thread, that 'someone' was me. and yeah they're interchangeable within spec. I measured it out and fit them in, but ultimately went with an AP1 piston instead so never confirmed. If you think about it, the pistons themselves didn't change 01 to 02, but the piston rings changed. and 02-09 remained the same, so by the commutative property, the later style rings fit all pistons 00-09.

RWDlover

Well, thank you very much then, i will order the 04+ piston rings for my AP1

dagle

I actually stand corrected, the AP2 piston rings have different part numbers (04-09 has only 1 style) while the AP1 has 2 different styles. I remember the AP2 rings fitting, but I'll double check in a second if I can find my extra AP1/2 pistons.

RWDlover

No prob, at least you realized why i am looking if the rings are interchangeable. Would be great if you can take some measurements, if you do find them.

dagle

Sorry in advance, my micrometer ran out of batteries and I didn't have the mint-sized batteries handy so pictures will have to do.

AP2 left (PZX) and AP1 right (PCX) I think:


(PZX) left set of rings and (PCX) right


Top rings comparison:


Bottom rings comparison:


Oil rings were the same too, pictures weren't useful since they were so thin they blurred.

dagle

Additional detail:

The top rings for both AP1 and AP2 were etched with "R1"

One of the bottom rings were etched with R2. The other wasn't etched. I noticed it after I had mixed them up already (I think it was the AP2 with the etching, but am unsure).

Oil rings appeared to be the same measurement, but the AP2 oil ring material was substantially stiffer to bend.

RWDlover

Thank you very much for the pics mate. Are these pistons stock, both AP1 and AP2?

dagle

As far as I know, yes. You can see the part number castings (PCX and PZX) on them. The yellow tinged ones are AP1 and the gray ones are AP2 in the last picture.

RWDlover

Very very interesting, i didn't know they changed the piston coating on the AP2, hence my question if all the pistons are OEM, just wanted to confirm.