LS3 Lifter noise or Piston Slap?

[IBLOWN]

New finding:

Makes the sound only at idle and under load.

If i hold it in a gear and roll (No throttle), the noise stops. Weird...

Again, after fully warmed up, no noise. But fully warmed up. About 10mins of driving.

 

[Redline457]

New finding:

Makes the sound only at idle and under load.

If i hold it in a gear and roll (No throttle), the noise stops. Weird...

Again, after fully warmed up, no noise. But fully warmed up. About 10mins of driving.

Classis slap conditions , slap under load when cold goes away after fully warmed up

 

[IBLOWN]

Yep, which is what ive always leant towards being the problem.

 

[Kakodaemon]

A little update on my noise (which i thought was extremely similar to @IBLOWN noise) and FYI to anyone else that has a similar noise.

Just been told it is most likely a delaminated piston. The place said they'll do a cold and hot compression test tomorrow and call with more info.
If they confirm thats it they said engine out jobby 4-5 grand

There needs to be a crying emoji.

 

[Redline457]

Sorry to hear that Kakodaemon, hope it works out okay for you, crying emoji

 

[Skylarking]

Just been told it is most likely a delaminated piston.

if pistons had layers of foil glued together in their construction such a term may be appropriate but never heard of that term being used to describe an issue on a cast or forged piston…

PS: seems a term used on diesel pistons when the top ring comes away…

Delamination Failure on High-Output Diesel Engine Thermal Barrier Coatings

An analytical mechanics model was employed to predict the delamination of several thermal-barrier-coated pistons that had been previously tested in a high-output, single-cylinder diesel engine. Some of the coatings delaminated during engine operation. Results are presented for two thicknesses of the

www.sae.org

Diesel Engine Failure Analysis ǀ DFC Diesel

There are many more potential causes for a Diesel Engine Failure but we have only listed the most common we encounter.

dfcdiesel.com

 

[Kakodaemon]

if pistons had layers of foil glued together in their construction such a term may be appropriate but never heard of that term being used to describe an issue on a cast or forged piston…

PS: seems a term used on diesel pistons when the top ring comes away…

http://[URL]https://www.sae.org/publications/technical-papers/content/2022-01-0440/

[/URL]

http://[URL]https://dfcdiesel.com/warranty-info/failure-analysis/

[/URL]

That's what the guy said. Reckons he has only heard of a few late model LS3's doing this.
I'll get more info tomorrow and pay more attention and ask exactly what he means by delamination.
I believe he means that something has happened to the piston giving to much play in the bore causing the noise, but when everything gets to temp and expands there is no play and noise disappears.

 

[Kakodaemon]

Sorry to hear that Kakodaemon, hope it works out okay for you, crying emoji

Thanks mate. Doesn't really matter what's wrong with it really as I need it fixed because i start a new job in a few weeks.
It's just really crap timing financially for me 6-9 months ago would have been no problems.

Also not knowing you bought a dud a few years ago only to surface at the wrong time is extremely frustrating

 

[Immortality]

If the engine is fucked it would be really good if the damage or wear&tear could be documented with lots of pictures and measurements. It would be good to get together an archive of faults to help others with warranty issues and court cases.

 

[Skylarking]

Thanks mate. Doesn't really matter what's wrong with it really as I need it fixed because i start a new job in a few weeks.
It's just really crap timing financially for me 6-9 months ago would have been no problems.

Also not knowing you bought a dud a few years ago only to surface at the wrong time is extremely frustrating

Stuff happens and I feel for you but you haven’t mentioned where you bought the car or whether you bought it at a dealer.

If you did buy at a dealer, then making a statutory warranty claim may still be an option.. As such, best call C.A.V. and have a chat to them about what has occurred, what has been done so far, the possibility of making a claim post repair, how best to document the damage that has occurred and the work required to rectify it, and whether changing a scored cam for a non factory cam, etc alters a statutory warranty claim. Best do that sooner than later.

And also worth reporting the defects to ACCC as having an engine failure in traffic (pistons let go at speed) is a safety issue. They have some interest documenting the product defect and may even want to helping you sort such things out (in conjunction with CAV).

In any case, please document all findings, measurements, clearances, etc and post such with lots of pictures because these things may help other who suffer such a defect (as immortality says above).