Last night I was able to get all my retainers and cotters replaced on my 2002 ap1 because all the rumors scared me and since I've only owned my S for 3 months and it having 110,000 miles when I bought it, I couldn't wait any longer to see if the previous owners might have mechanically over-revved my car.

I decided to replace the intake side with ap2 and go ahead and replace the exhaust side with a new ap1 set even though everyone said they don't fail. About half-way through of trying to sort them out, I accidently got a set of the ap1 cotters mixed in with the ap2, and I just got flustered trying to figure out which ones got mixed up where, especially not having been to sleep for 36 hours.

After trying to visually see a difference over and over and searching on s2ki I was starting to get worried. I found some threads on here but they were not really working for me exactly, but from seeing that some people say that the walls were different, and thinking visually that the ap1 cotters were a little more rounded than the ap2, I thought of this measurement.

I measured my old ap1 cotters with a pair of calipers and they were approximately 8.04mm depending on how good your machinist hand is lol. I started measuring all my new cotters and I noticed a difference that some were around the 8.04 mark and some were around the 7.64 range. From getting what I could from the picture that Carbon Blue posted in an older thread on s2ki, I took a measurement from end to end at the top part of the cotter. As you can see my measurements give me the clarification I needed when my eyes couldn't. In the end I also noticed that ap2 cotters sit nicely lower in ap2 retainers vs the ap1 cotters sitting up in the ap1 retainers as in the picture with the ap2 on the left, ap1 on the right. Sorry pictures suck, iPhone ugh.

I don't know if this would help anyone, but I thought I'd give it a shot. In the end, 2 cracked intake retainers and no cracked exhaust retainers of course, but peace of mind is priceless.

 

Thank you for the info. I'm switching my AP1 retainers and keepers out for AP2s and lost an AP2 keeper haha. Was going to just throw on an AP1 keeper but was thinking that there might be a difference. I'll have to call around and see if there are any nearby dealerships that sell keepers

 

your first picture describes the ap2 cotter as having two laser etched marks and two dimples. why didn't you just look for these?

 

with signs of an overrev, did you do a compression/leakdown test to see if any valves are bent?