Mr. Jean

Ouch, sorry guy.

'06 Quicksilver Z06

I'm also wondering if it ran lean and detonation lead to the failed piston.

68Stang

Previous tune was in kr. Current tune was much safer. Timing and a/f were good. Car made 565 rwhp. Has just over 30k miles.

Undy

The head of the valve pops and leaves the stem/spring in place, as viewed with the valve covers off. Your symptoms are text book for a dropped valve, FWIW.

mtomlin1

Doesn't he have one piece stainless valves?

Wouldn't this prevent this happening or is this another case of wcch heads failing

LFZ

Just because you have a solid valve...doesn't mean it won't snap.

*FYI..I have dropped a SS valve in my other vette (non LS7 so calm down )

TXGS507

That SUX Bro....Couldn't have happened to a better guy... Look at the bright side though Ryan. Now you can build a new engine and "maybe" keep up with me.

Vette @ 71

Don't remember anyone who dropped a valve saying it followed by a large back fire.

mtomlin1

Oh ok I wasn't sure , I knew the two piece had a tendency to snap off but thought a stainless solid one stopped this.

JoesC5

I've never dropped a valve(thus I haven't ever broken off the head) in any car I've had and that goes back to 1959 when I had a 1953 Ford with a small block Chevy bored to 301 cu in, turning 8,500 RPM(no misprint) with 1/8" oversize valves. In fact the 427 big block(from a wrecked Corvette) that I had in my 1964 Malibu SS never dropped a valve and it had HUGE stainless steel valves(re: heavy) that saw 7,000 RPM quite often.

I'm comfortable with the solid stem stainless steel exhaust valves I have in my C6 Z06. In fact, at all RPM's up 6,800 RPM, I have less valve bounce than the stock OEM exhaust valve, according to Katech's spintron testing(stock cam with dual valve springs).

Since I don't like accidently hitting the rev limiter, I shift at 6,800 RPM instead of the factory redline of 7,000 RPM, so I haven't lost anything but 200 RPM.

Bill Dearborn

Hate to tell you this but looking at the stems from the top doesn't tell much. Most LS7 valve drops involve the head of the valve breaking off and banging around in the cylinder not a complete swallowing of the valve like might happen if a valve spring broke and the valve fell into the cylinder. From the top of the engine with the valve covers off all the valves look good from the bottom not so good. You will have to pull the heads to know for sure but piston parts inside the intake indicate a valve was involved in some form or fashion since the parts would have to get past an intake valve to get into the manifold.

Bill

mtomlin1

I redline the **** out of mine , track it regularly and change at 7200 no issues never hit the limiter though or Mis shift if i loose a valve I'll just upgrade to a full mast block , gives me a reason to buy it that way - or at least justify it to the wife!!

JetBlue427

sorry to hear about your engine...but off topic i noticed your screen name...do you still have a stang? I have a 67 fastback pro-touring modded

LFZ

Good for you Joe. Lets hope you never do.

Tigershark3

I'm in...

Blackonblacksls

there has to be valve heads missing.

That's how that metal ended up in the manifold..

Also looks like the block is trashed too as that's where all the coolant came from..

Looks like that's likely going to be a total loss on the motor..

Sorry to hear your bad luck

Josh B.

Makes sense. Sorry about your engine. Please keep us updated on the diagnosis.

ram360

So just to be clear.... Is the failure believed to be the same valve issues with the ls7 even with the aftermarket heads on the car or is it attributed to something else?

stefuel

Well, the heads have to come off anyways youze looks at it. The intake is off so he should be able to see the intake valve through the port. Pull the header off and look into the effected port to see if the exhaust valve head is still there. I'm guessing it's MIA.

Dan_the_C5_Man

Do you know the specific target AFR?