Customer C8 Z06 engine issue
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
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.
And to me, this engine is making "a terrible racket".
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.
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
Instructor
Joined: Oct 2021
Posts: 129
Likes: 53
From: Sonoma County, CA
I'm no mechanic. I really don't know myself. But I heard someone say dealers revving a new FPC engine right after cold start could cause damage as well. Is this true?
Le Mans Master
Joined: Jul 2007
Posts: 5,509
Likes: 1,819
From: Arkansas
St. Jude Donor '09 thru '17,'22 thru '26
That is true with any engine, the higher the revs and the colder the temps, the worse it is. IMO, it's never advisable until the oil has got some heat in it.
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
Another thing is that valve springs can be more brittle at cold temperatures.
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Racer
Joined: Dec 2015
Posts: 314
Likes: 154
when I picked up my c7z the salesman and I took a short test drive. When we got off the lot the oil and engine temps were under 100 and the salesman told me to “stomp on it and see what she can do”. I just cringed. Ppl do all kinds of stupid with things that aren’t theirs.
Race Director
Joined: Nov 2017
Posts: 12,759
Likes: 10,657
From: Prosper TX/Austin TX
2020 C6 of the Year Winner - Modified
I've had an engine replaced by GM under warranty only after the State Attorney became involved. I had a second on its way out and sold the car before dealing with the same nonsense again.
Advanced
Joined: Dec 2022
Posts: 89
Likes: 67
If the engine is designed with the right tolerances and has the right oiling system, there is no way it should blow like this in 52 miles. But then we need to stop assuming someone cold revved the engine. it could be an assembly issue or a parts issue.
Burning Brakes
Joined: Nov 2021
Posts: 1,198
Likes: 1,009
From: TDot
How many miles between failures? Reason for failures?
With full warranty granted on two separate occasions, is this an indication of a weakness in the LT2 - IRT track usage?
Safety Car
Joined: Sep 2004
Posts: 4,486
Likes: 5,536
From: Western Chicago Suburbs
I’ve always preferred a 3rd MY Z06 (and that looks like what I’ll end up with). If there are actual issues, hopefully they are addressed by then. At the very least we should all know what we are getting ourselves into by that point. For those of us who plan to keep this car for the long haul, this is more of a concern than those who are ok with relying on the warrantee and don’t plan to keep the car long term.
Drifting
Joined: Oct 2006
Posts: 1,372
Likes: 311
From: Bristol, VT
Race Director
Joined: Nov 2017
Posts: 12,759
Likes: 10,657
From: Prosper TX/Austin TX
2020 C6 of the Year Winner - Modified
Team Owner
Joined: Jul 2004
Posts: 40,422
Likes: 792
From: Redondo Beach, California
The engine builder's name is on a plaque on the engine. Wonder what the guy that built the engine has to say? Yep, in the future, maybe the name of the engine builder will be a factor in the resale price of the car.