[beedo]

Help please, 2019 AT4 6.2, buddies changed his oil 3 days prior to this and all was fine before. I was a heavy line tech for a local dealer for about 5 years 23 years ago.... but this has me stumped. No metal in the filter, scoped the pan and nothing there either, pulled valve train and everything is fine, nothing bent and moving good. Cylinder 2 Is dead, has spark but missing and no change in noise or rpm when coil is unplugged ( working). Cylinder has 175 psi of compression no marks on Cylinder or piston top from scope. Engine start and knocks for a second and then a loud what sounds to be a hammer hitting something engine jolt a bit and knocks harder. Im trying to do what I can before major tear down but sounds like a rod hammering, but the miss has me confused. Could this be a spun lifter? Not a camaro but its a 6.2 and Im not on the truck forums. Any direction will help thanks
https://youtu.be/l930GJARKTA?feature=shared

[Joshinator99]

Originally Posted by beedo

Help please, 2019 AT4 6.2, buddies changed his oil 3 days prior to this and all was fine before. I was a heavy line tech for a local dealer for about 5 years 23 years ago.... but this has me stumped. No metal in the filter, scoped the pan and nothing there either, pulled valve train and everything is fine, nothing bent and moving good. Cylinder 2 Is dead, has spark but missing and no change in noise or rpm when coil is unplugged ( working). Cylinder has 175 psi of compression no marks on Cylinder or piston top from scope. Engine start and knocks for a second and then a loud what sounds to be a hammer hitting something engine jolt a bit and knocks harder. Im trying to do what I can before major tear down but sounds like a rod hammering, but the miss has me confused. Could this be a spun lifter? Not a camaro but its a 6.2 and Im not on the truck forums. Any direction will help thanks
https://youtu.be/l930GJARKTA?feature=shared

Bad direct injector would cause a miss.

EDIT: Just heard the video… that’s not an injector lmao…

[beedo]

Originally Posted by Joshinator99

Bad direct injector would cause a miss.

EDIT: Just heard the video… that’s not an injector lmao…

Agreed, im leaning towards either the bottom end or a spun lifter, had plastic pieces in the filter media but zero metal anywhere in the pan, heads, or filter. Buddie it has maybe 45 seconds of run time since it started hammering, stopped at the store and on restart it was doing this, towed it home.

[beedo]

Originally Posted by Joshinator99

Bad direct injector would cause a miss.

EDIT: Just heard the video… that’s not an injector lmao…

Agreed, im leaning towards either the bottom end or a spun lifter, had plastic pieces in the filter media but zero metal anywhere in the pan, heads, or filter. Buddie said it has maybe 45 seconds of run time since it started hammering, stopped at the store and on restart it was doing this, towed it home.

[Joshinator99]

Originally Posted by beedo

Agreed, im leaning towards either the bottom end or a spun lifter, had plastic pieces in the filter media but zero metal anywhere in the pan, heads, or filter. Buddie it has maybe 45 seconds of run time since it started hammering, stopped at the store and on restart it was doing this, towed it home.

Hmmm…I wonder if that engine has plastic lifter trays like the LT1…? Not sure what else is plastic inside the engine.

[bishopts]

Its hard to tell in videos for me but it sounds like a double tap like a rod bearing. Sounds too heavy to be a wristpin. But again it's hard for me on videos.
Pulling the valve covers and pushrods should be pretty quick. It would give you the ability to determine a spun lifter.