Is there something catastrophically wrong with the LT6 design?
Photo by "JockItch" at Petersen Museum reveal
Did GM bite off more than their engineers could handle with the high-revving dual overhead cam flat-plane crank LT6? The design certainly was a deviation from their gold-standard norm, the tried and true pushrod V8, and while GM has received a fair amount of criticism for not updating all Corvette trims to a dual overhead cam design, the LS and LT engines sure have been reliable.
I’ve curated all the videos and stories of C8 Z06 engine issues I could find on Youtube. Are these just anomalies, perhaps due to improper break-in periods or a sloppy engine technician, or a sign of things to come? As you may recall, these LT6s are hand built and each Z06 buyer gets a special plaque on the engine from the person who assembled the engine.
As they say, a picture is worth a thousand words, but I think this first video below may leave you speechless.
Yikes, that sounds depressingly horrible.
And a second engine surfacing recently with the same sound.
The response from GM:
“At this time the concern is under engineering investigation, once a repair has been established, this PI (preliminary information) will be updated or changed to a bulletin.”
“No durability issues have been identified with this concern and customer can drive the vehicle until a repair is available.”
This beautiful Amplify Orange example was finally broken in as the owner gleefully nailed the throttle for this video. Fast forward to about 40 seconds and turn up the volume.
Here is another painful one to listen to.
Click here for a story we did on this Z06 with only 52 miles.
Vette Titans has some interesting theories.
One of the Youtubers I showcase regularly, Austin with Speed Phenom, has some ideas on why this is happening. And since he has the “highest-mileage hardest-driven” C8 Z06 out there (at 6000 miles and counting), I figured his opinion might be worth hearing. Especially given that a lot of those trouble-free miles are on the track. The engine discussion starts at 2:50.
First, he admits this is a “touchy subject”, but then goes on the say most of what you see out there is just for clicks. After that, he blames the failures that have occurred on improper break-ins and remarks that GM doesn’t have a problem. He notes this high-strung engine was designed to be “bedded in” gently from the factory. So, nothing to see here.
Just like with the LS7 valve guide-related engine failures, there is nothing that stirs up more controversy and spawns more heated debate in the Corvette community than failing engines. With the LT6, is it “nothing to see here” or “oh boy sh*it’s gonna hit the fan for GM”? We have an active community on our Facebook page, I would love to hear what you think. Douglas B.
I’ll leave you with this break-in resource directly from Chevrolet.