slightly off subject - how much more do the AP2 retainers weigh compared to AP1 retainers?

 

Sorry if this is a little off-topic here, but I'm having a major tune-up done at the moment, including valve adjustment. The tech said that although he's not an expert in detecting retainer problems, he didn't see any that looked low/had noticeably high keepers (a member/sponsor and fellow S2000 owner-tuner).

As part of the general checkup, they've performed a leakdown test and will be doing a compression test. Will either test indicate a problem with retainers or is it solely up to an experienced visual inspection?

I can only remember one time where there MIGHT have been an over-rev, but I'm pretty sure I caught it before it even hit 9k, and that was at least 10-15k miles ago (85k miles on the clock now, all mine).

FWIW, all of the valves were within spec (on the tight side of spec, last adjustment I did myself around 50k miles) and the leakdown indicated 3/3/3/4%

 

A leakdown or compression check will not detect a cracked retainer, unless other damage has also been done. What you're looking for is the keeper sinking down deeper within the retainer. Billman posted excellent pics, but I don't remember the exact thread.

 

You might want to try to find the pictures of good and bad retainters that Billman posted and print them out so your mechanic can see what the damage looks like. It's fairly easy to see, but not if you don't know what to look for.

 

The one on the left is serverely broken. I've found some with slight recess, that I couldn't even show in my best picture.

 

Even the worst broken retainer, one that is touching the roller and scoring the cam, will show no symptom, not even noise.

It won't show up in compression or leakdown either.

 

Billman!

So: Use the ap1 retainers because they are "lighter" and will fail before we drop a valve, split ap1/2 retainer/keeper on intake/exhaust, ap for greater strength, or go aftermarket for Ti?

Thanks

 

Bill, do you have any pictures that show what this looks like with the rocker arms in place?

 

Thanks for the info. Yeah, I've seen those pics before and so has the tech. He said he's done visual inspection for cracked retainers before, but never seen one himself. I honestly think I'm just being over-cautious. I'll see if I can schedule time with Billman next time I plan to be up in NY Thanks again!

 

Keep in mind that the supposed 8K limit doesn't exist. The rest of the world's AP2s still rev to 9K and these retainers were changed for a reason.