boy would that open up a door... Dear sirs... my motor was making a few ponies when your titanium retainer gave up the ghost and dropped a valve on my $80,000 motor, please see enclosed parts list and start sending replacements ASAP. Sincerely Joe Racer"Sorry. That would mean it's time for a timeout. If valve retainer failure is the cause you might want to present the parts back to the manufacture of those parts. Best case they might help with rebuilding costs. Worse case they will tell you to take a flying leap.