Originally Posted by RED MX5,Nov 20 2007, 12:35 PM

Mrivera beat me to it.

Do a search on "retainers" or look at all the posts by Billman250. AP1's can crack and stretch retainers on an over rev and the damage is not apparent until their is a major engine failure, but checking for damaged retainers is very easy. When an AP2 is over reved, the damage is immediately apparent, because instead of just hammering out the retainers, the AP2's exhaust valves start hitting the pistons, and the damage is catastrophic and impossible to ignore. Apparently some prefer total distruction to having to simply replace retainers, but the best plan is to avoid over reving the car.

Just to be clear, you can only do this kind of damage with a "mechanical over rev" or "money shift." This happens when you try to shift up near redline, and shift down instead. Things start to break between 10,000 and 11,000 RPM. With any used AP1 or anytime you suspect that an AP1 has been over reved, a retainer inspeciton is in order. With an AP2 you don't need to inspect anything after a suspected over rev, because you will absolutely know instantly if the valves hit the pistons.