What happens when you drop a valve on the Norschliefe

You know, the thing is this is down to a component failure - either a failed retainer or valve spring. It's not the tuners/builders fault - it's down to the manufacturer of the failed component. It wouldn't of mattered who built it, the outcome would of been the same....

Regardless of the builder/tuner. I feel not enough r&d has gone into aftermarket products.

It doesn't, it's not like OEM where they have teams of engineers with countless money. You're always taking a risk when going aftermarket...

When buying aftermarket valves and retainers i would suggest replacing them every now and then or at least pull the engine apart once a year...like me, depending on the level of abuse on the engine of course. I recently pulled off my ported b16 head with Ferrea valves, guides, supertech 85lbs springs, Skunk2 pro2 cams and and noticed that a valve was pretty worn on the contact area/seat and was about to fail... lucky me.

I had some skunk2 retainers (<-old version) in a previous build which several of them was worn on the bottom (where the spring is in contact with the top retainer).

OEM