Wholly impossible

 

Someone did damage in the first 3 miles Probley driving hard over the rev limit befor the first 500miles I’m guessing lol

 

I wonder how much of that 50 miles the engine was pegged to the rev limiter...

 

"Blue smoke means it spun a bearing and bent a rod" 🤦🏻‍♂️🤣

Really? Three completely unrelated events and yet somehow you've deduced just from listening that both of these things happened, A truly "spun" bearing makes a terrible racket because the crank journals are now hitting the ID of the main bore or the big end of the rod. Spun bearing means LITERALLY that: the bearing has grabbed the journal and literally "spun" in its housing. Most of the time that doesn't happen. A bent rod is a completely different event and only happens from overloading the engine at low rpm (excess boost at say 2500 rpm) or something in the chamber that prevents the piston/rod assembly from completing its rotation--there by bending or even breaking the rod.

Blue smoke is from a compromised oil ring and/or valve guide issue. It can happen from a cracked piston from physical contact (valve float which caused piston/valve contact) A pinched ring land from too many detonation events and/or overheating which prevents the second compression ring (which functions as an oul SCRAPER) from doing its job, or pre-ignition which is different than detonation and often FAR MORE destructive.

My point was that the 3 issues you mentioned do not necessarily go together. It could be a number of events happened or one event snowballed causing others.

GM took a big risk in making a 5.5 l FPC STREET car. No one has ever made an FPC V8 that large in a warrantied street car (Ford tried to stretch it to 5.2 litres in GT350 and that wound up being a disaster) The engine basically functions as (2) 2.75 liter 4 cylinder engines and every 4 cylinder I can remember that was over 2.3 liters, had balance shafts, otherwise they would shake themselves to death. It looks like GM mitigated most of the in cabin vibration by installing very soft engine mounts (you can see the engine/trans unit severely tilting on its axis in the Throttle House Z06 videos.

Regardless, people are SO QUICK to jump on the negative band wagon as soon as you get one report of a possible problem. My thought was a possible balance issue creating harmonics which is playing havoc with havoc the valve train at high rpm? Perhaps some of the engines are close to perfect and some are slightly off, and all that inertia at 8500 rpm creates a resonance which is floating valves a lot earlier than intended.

 

Bozos are all you can expect for testing the C8.
https://www.freep.com/story/news/202...ys/4450339002/
They should send them over to a local Toyota factory for QC.

 

Geez, this guy is definitely a "glass half empty" type of person

 

Several thoughts:
1. Break in protocol is there for a reason. Follow it.
2. Abusing any mechanical object beyond its designed capabilities often leads to failure.
3. While having a warranty is great, do you want your car sitting at a dealership for an extended time period and likely coming out with a variety of cosmetic issues that were not there before?
4. It is unrealistic to think that a mass-produced car will be extensively road tested before delivery. Cost prohibitive.

 

And these points illustrate the potential that GM denies the warranty. The first thing they're going to do is claim abuse and not following the outlined break in procedure. I've been through it with GM, the owner may have quite the fight on his hands.

 

Pretty sure the cars are actually rev-limited prior to the break-in mileage. My '23 Stingray had a 4K hard rev limit.

 

They're not actually limited, just visually it makes it appear so.

 

I dont think the owner revved the car and even if he did, the engine should not really detonate like this.

 

No need to be one of the first thousand or so.

 

3rd year in (or is it 4th?)

 

Not a new concept. Ferrari has been doing it for at least 60 plus years. It is a gradual process not straight to maximum revs. Better to detect an issue before installation in the car. Ferrari also uses it to document that the requisite power numbers are made by the engine.

 

In gear, yes, but park/neutral has a soft limiter to prevent free revving.

 

I'm going to take a couple of minutes to defend the OP. He will probably be our only link to finding out what happened to this motor, and he reached out to the forum early. Once GM gets hold of the car, we probably won't hear much. I actually watched his whole video, and unlike the keyboard warriors who formed their condescending opinions based on a few seconds of uninformed viewing, there was a lot of good information. First, it is pretty obvious that the motor has problems - harsh mechanical sound and probably oil in a combustion chamber (right bank). The OP seemed genuinely concerned and knew enough about cars to suspect a problem early on. He owns 2 other C-8s, and from the video views of one of them, his comments about the car, and even the way he parks them in the video, he takes excellent care of his vehicles. He even had a dealership salesman following him when he first heard the "ticking". My concern would be how a dealer stock car was treated before he drove it off. I believe he commented the car had 3 miles on it when he picked up, but my concerns are the idiots that have access to the car before the sale and who want to rev a cold motor to show off the unique sound. Revving a cold, new motor with no load on it is a very bad idea. You see that happen all the time on YouTube videos. When I picked up my first C6 Z06 in 2016 (I was at the dealer for the unload), there was another new, undelivered customer car with a broken valve spring - employee revving a cold engine hard and developed a ticking sound. i am hoping this is an isolated component material failure (or cold, no-miles motor abuse) and not something we are going to have to deal with on a larger scale. I went through the era of the early C6 Z06 broken valve springs, spitting needle bearings from the rocker arms, and eventually dropped valves due to improperly machined heads. Luckily I was not impacted. I am not totally risk averse, but I just want the facts from credible sources so I can weigh risk versus reward regarding a purchase.

 

8.5mpg over 50 miles tells me the engine was not handled gently

 

"and developed a ticking sound"
A little bit of tick is normal right? Now I'm paranoid about Z06. It definitely has a tiny bit of a ticking sound, but I'm pretty sure I have heard a similar noise from my Cadillac.

 

Listen to the change in sound at 10:30 on the video. I am afraid that is a little bit more than a ticking sound. Sounds valve train to me, but I'm not there or qualified to offer an authoritative opinion without proper diagnosis.

Missileer quote: 8.5mpg over 50 miles tells me the engine was not handled gently

The 18.7 mph average speed might also indicate a lot of idle time driving the mpg average down and not really that much abuse in those 50 miles.

 

Not really..But ok

Plenty if other inconsistencies in the story