I finally received all the parts I need to rebuild my motor after a 6-week wait on bearings that were backordered. I was planning on taking the head down to a local shop today to get it checked out and rebuilt with new valve seats, retainers and keepers. I planned on putting in AP2 retainers and keepers, although I do not have any evidence of cracked retainers at this point (83k on the motor when it was starved of oil). When I was double-checking my parts last night, I realized that I have the AP2 retainers that I ordered, but I apparently did not order any keepers. I happen to have a complete set of new AP1 retainers and keepers in my parts bin in the garage. Are the AP1 keepers compatible with the AP2 retainers? Should I even bother with the AP2 retainers, or should I just put the stock AP1 parts on?

 

Billman, if Im not mistaken, always replaces these with AP2s

as for compatibility - hopefully he'll see the title and Chime in.

GL

 

I think that if the AP1 retainers were uncracked, I would have just put them back on the car.

I did, in fact, put dual-spring Ti retainers on my car, but it's not going to see enough miles to make galling a big issue for many years to come.

IMO, with AP2 retainers you are basically trading a silent failure mechanism for a noisy failure mechanism. I think the real solution to the problem is to just not overrev.

 

I agree with Mike, and unless I'm mistaken, Billman doesn't exactly disagree. Anyone can blow a shift, and when/if my time comes around I'd rather stretch retainers that can be replaced easily and cheaply, than have the exhaust valves come into contact with the pistons. Yea, the latter is easier to detect, but it's a lot more expensive to fix.

As far as the question about the keepers goes, I can't help. We'll have to wait for Billman or someone else who'd done the retainer swap to chime in.

 

[QUOTE=RED MX5,Oct 10 2007, 01:45 PM] I agree with Mike, and unless I'm mistaken, Billman doesn't exactly disagree.

 

Yes.

No, due to the fact that the AP2 retainers are heavier. They are designed for a 8K redline (plus margin) not a 9K redline (plus margin).

 

That makes sense, so ideally, for an AP1 or AP2, you would keep the AP1 exhaust retainers, and run AP2 intake retainers. Or thats the ideal situation, from a reliability standpoint, not performance.

 

If you use AP2 retainers, you should use AP2 keepers.

I only use them on the intake side. On the s2k engine, the exhaust valves will always be the first to contact the piston.

The AP2 retainers will raise the over-rev RPM that causes undetected damage. This way, if you over-rev, you won't be driving around with unknown damage.

I just pulled my valve cover at 81k miles, and retainers are still perfect. They will stay AP1 forever until they start to crack, if that ever happens.

I run my car very hard all the time, it's been a good basis that retainers crack from mechanical over rev.

 

Thanks! I took the head and my new AP1 parts over to shop this afternoon. I figured that they were good enough, since they lasted 83k of hard use with no signs of trouble. The shop is going to call me if they find one that's cracked, but I didn't see any sunken keepers. I'll save the AP2 parts for my racecar.

 

[QUOTE=SC_Highlander,Oct 10 2007, 06:13 PM]Thanks!