sfphinkterMC

Cracked valve retainer found under valve cover, valve dropped and motor grenaded.

46,000 miles total , 23,000 under boost, many on track.

Lightweight titanium valve retainers with double valve springs with otherwise stock valvetrain on new junkyard head.

cdelena

Bummer.. clearly bad damn luck.. speculation on cause? too many miles at redline? just an inadequate part?

Spankee

Exact same thing happened to my old turbo Integra. Retainer cracked and valve broke off putting a hole in the number four piston. Schrappnel went everywhere...re-dristributed and bent all the other valves and damaging the remaining pistons. Also tore up the internals of the turbo. Put a new engine in it, sold it.....and here I am today.

Boit

What was/is the condition of the valve keepers on that particular cylinder? One of the keepers could have cracked from stess and allowed the retainer to dip on one side followed by the catastrophic failure that you described. I'm wondering if the mechainic stopped searching for the cause once he discovered that the retainer cracked? Once you get into these components, it is very difficult to ascertain exactly what was the first failure. Something like this is a domino effect. Once something fails, it takes other components with it. Example: if a valve guide has excessive wear, it will begin to allow the valve stem to wobble, once it wobbles too much at high RPM's, then it could cause the keepers to fail which could cause the retainer to fail which could cause the head to disintegrate.So many components can de damaged and destroyed during the failure that it's nearly impossible to point to an underlying cause with any degree of accuracy. With these components, who's to say that the retainer caused the keepers to fail, or vice versa.

sfphinkterMC

i can inspect head somemore and look into it, but i've been made aware of a handful of other F20c's cracking the retainer, although some, not sure how many, may have been drag car motors with big boost,etc.,i'll try to follow up.

clarification: the valvetrain in failed motor was stock, my new motor has Ti valve retainers with double valve springs(and crazy power, that's one good reason to blow your motor, cause now you get to build a badder one).