LS3 Lifter noise or Piston Slap?

[Immortality]

If the tolerances are correct at op temp how is it excessive?

It's literally the definition of durability dude. It's damage that had no bearing on the life of the engine or the extra abuse I gave it with boost and why it still runs like a dream today after nearly 20 years and 320k. Any engine that runs is being 'damaged' with every stroke and every rotation. That's why all things eventually degrade and wear out. It's how that degradation relates to operation that defines durability

But are they?

LS motors use hypereutectic alloy pistons, an alloy that expands less with heat than a normal alloy and considerably less than a forged alloy piston. These engines should have less piston to bore clearance than an older style motor with cast alloy pistons and shouldn't make any noise at all. It's a sad state of affairs that Holden/GM has people believing that their lack of quality control leading to some engines slapping like a bitch and others not is acceptable. If it was a true characteristic of these motors than ALL would do it but that is certainly not the case.

My 340,000km V6 engine with failed head gasket that was probably pinged to death on LPG has no marks in the bore like your LS. Just because it runs doesn't mean it's right.

The thing with mechanical items is they can be out of tolerance and still run for years. At my old work there was one part that would wear out reasonably quick, if you replaced the worn component early then you would only need to replace that one part, you could run it for a lot longer on the fucked part (many millions of cycles) and then you would end up replacing much more of the assembly as more parts got damaged. It ran but it doesn't mean it's right.

Piston slap is the domain of high performance engines with forged pistons that require the extra piston to bore clearance for thermal expansion. The stock LS motor is not that even if GM market it as such.

That's why it's called a phenomenon I guess. I mean size and geometry is an obvious influence and we're talking in thousandths, I can't see that lubrication would have any influence. The piston rocks and the skirt bumps the bore. Once expansion occurs tolerances are spot on and it stops. When you compare my stroker to a stock piston it's very obvious why they slap

I personally think all LS slap, it's more a question of if it's audible. I've seen oodles of LS blocks and the majority of bores had the right marks in the right places

So why is it than that your built motor has closer tolerances if the wider tolerances on the factory motor is acceptable?

I suspect you are correct, most of these motors probably have some form of piston slap than isn't auditable but again, just because it does, does that make it right or just poor quality control? The guy that built your stroker would probably agree the factory LS motors have excessive tolerances.

 

[IBLOWN]

Heres an in-car video i just made. Stone cold.

 

[VCoz]

ACCC Review -
Holden undertakes to comply with consumer guarantees
3 August 2017
The ACCC investigated Holden following consumer complaints about its response to a manufacturing fault.
“Holden acknowledged that it misrepresented to some consumers that it had discretion to decide whether the vehicle owner would be offered a refund, repair or replacement for a car with a manufacturing fault, and that any remedy was a goodwill gesture,” ACCC Chairman Rod Sims said. “In 2021 the ACCC will be looking to improve industry compliance with consumer guarantees across a range of high value goods, particularly motor vehicles and caravans,” Mr Sims said. “Despite the pandemic, the ACCC received a high volume of complaints about motor vehicles consumer guarantee issues in 2020.” “Enforcement action against a number of motor vehicle dealers and then leveraging these enforcement outcomes to achieve broader industry behavioural change continues to be a key project for the ACCC,” Mr Sims said.
What has changed?
A GM Holden Engineer acknowledged re LS3 factory assembly the piston and bores are not matched - so if tolerances of a piston and a bore (one small and one large) then the clearance becomes cumulative. If it is supposed to be 2 thou but is 6 thou on one cylinder and by chance within tolerances in others then is that resulting Piston Slap a design characteristic or a manufacturing error. The focus on piston skirt design rather than manufacturing tolerances diverts complainants attention from why some new engines have piston slap but others don't. Look at Australian Consumer Law (ACL), and recognise that many other factors also apply to what is acceptable under ACL including '‘substantially unfit for their common purpose’ and ‘not fixed in a reasonable time’ and are ‘unsafe’, would have ‘stopped someone from buying the vehicle if they’d known about the problems.’ That is why ACL applies after warranty has ended - suggest look at the New Zealand Case: 'NZ Consumer Protection findings came to conclusions noises of the types described in an LS3 6.2l engine, at the kilometres ours has travelled ‘failed to meet the acceptable quality guarantee in the Consumer Guarantees Act.’ (NZ) http://www.nzlii.org/nz/cases/NZMVDT/2019/266.html - Expert Mr Mulholland said re that 2015 VF2 LS3 6.2l engine: ‘in a vehicle of the age of Mr Wilson’s, and with its relatively low odometer reading of 42,000 km, he would not expect to hear any piston slap noise whatsoever. Mr Mulholland said that the noise in Mr Wilson’s vehicle lasts much longer after start-up than would be expected in a vehicle of this age and mileage.’ GMANZ/Dealer apply similar rhetoric here as seen in this NZ case. Who do you trust = Holden name is dead - the same push rod design is used in GM's latest LT Corvette V8 engines - do your own US searches on all these LS#/LT# engines and form your own opinion if what is categorised as normal and a design characteristic or an abnormal noise due to a manufacturing fault. Durability - when damage is caused prematurely or impacts on the engine operation does that make the engine less durable. Would it have ‘stopped someone from buying the vehicle if they’d known about the problems’ certainly devalues the vehicle re resale.

 

[Banjo79]

Heres an in-car video i just made. Stone cold.

Not pleasant listening. Admittedly, my L77 makes a mild grinding sound, only audible at about 2100-2500rpm, which is similar to I think what RevNev described his being like. It's been there from about 20k km's and has gotten slightly worse (<10%) over the next 200k km's. At least I can and do stay below those revs for 5-10mins, always have. To those that can't and are slapping off idle for 5 mins every cold start, without trying to sound dramatic, do that twice daily for 10 years and that's 25 days continuous running whilst slapping like a mofo. That would be 25 days too many for my liking.

 

[VS 5.0]

So apparently it is normal for some LS3's to do this 'normal' noisy characteristic and that others don't? You wrote 'GM regarding piston slap, but said i couldn't take it with me.' (The likely standard document was DL 65/16 (attached as posted by another member) - GM Australia have made the claim/and not denied that DL 64/16 exists? - I have seen no evidence to believe it does!)
So who decided that 'It said piston slap was normal and in bold lettering said "Do not replace engine." - first question here is was an engine replacement under Good Will made to GM Australia/asking for the engine to be replaced? 'It was only half a page and looked like the bottom half had been covered over when photocopied' - what needed to be hidden from the owner of the vehicle? (Note the $Billions compensation that Toyota is currently facing within Australia re Diesel Filters on 3 of its post 2015> diesel vehicles.)
Re GM Australia's LS3 cold start engine noise claims and diagnostic approach - I hope to have a lot more to share after my Australian Consumer Law (ACL) legal process ends - both in evidence obtained and ultimately what Consumer Guarantee under ACL means for Holden LS3 owners in practice.
To my understanding - key statements you were given 'assumed written by the dealer' in your post (or influenced) include - 'ACCORDING TO GM/HOLDEN THIS IS NOT A DURIBILITY CONCERN.' So if GM/HOLDEN 'categorise' this cold start engine noise as a normal characteristic? then how many others have the same level and type of cold start engine noise? and then how many abnormal engines don't make that noise (never or until Xkms)? Yes, so then what does durability mean for YOUR engine and KM driven (and for those without that experience what IS being claimed to be 'normal' noise)? So how was this noise limited to 'piston slap' and not include other manufacturing faults. Quality control appears more relevant to current LS3 owners than past durability (or is it continued running) because of the simple design of an LS3 engine. As stated if the consumer would not buy a vehicle, if aware it made a loud cold start racket, then how long it keeps running is not the only issue under ACL (please read your State or Territories legislation re vehicles and why so called 'lemon laws' were created). ACCC is Federal and focuses primarily on Manufacturer and Dealer practices which impact on Consumers.

Question: What does engine internal damage look like to an independent LS3 repairer/engine rebuilder and what heard/visual internal damage would be ignored by an independent engine builder if an LS3 engine was reconditioned to be back within normal specifications (i.e. what would be independently 'categorised' as normal variations from engine specifications/tolerances re YOUR engine if independently disassembled for repair? As stated in an earlier post if you go down the repair path get any out of specification readings and lots of photos - and keep all key parts replaced.

So, now are LS3 owners expected to accepted that GM/HOLDEN (with a $$$ conflict of interest) can without transparency re the diagnostic assessment information, blindly accept claimed Knocking/tapping sound that GOES AWAY AFTER 4-5 MINUTES' under 'some' GM Australia set test circumstances satisfies some hidden GM standard, or is it that at any unspecified noise level is OK today during GM Australia LS3 tests. Where is that GM/Holden claim verified within some alleged or 'proprietary' hidden GM specification? What has been claimed above does not to my understanding fit with GM (US) Technical Bulletins that I have seen re Piston Slap (suggest LS3 owners do their own US searches to form an informed decision rather than just say some engines last hundreds of thousands of Kms (you will find that some don't and some 'normal piston slap' claims are found not to be correct and some after disassembly to be lifters (which cause internal engine damage))).

FACTs I have experienced to date: Manufacturer pre-determined/self review is very different to independent review made prior to GM Australia's influence.
I understand your urgency and position but, 'If I was you" I would register your matter/GM Australia's response with the ACCC as soon as possible and also ask the dealer to put in writing just how that GM Australia's diagnosis was formulated/tests conducted (and did the Dealer agree or just accept GM Australia's opinion as over-riding their factory trained technicians experience/diagnosis).

 

[IBLOWN]

Im going to take my car to holden and ask if they want to buy it. When they say no because of the knocking, i'll show them that.

My motor sounds fkd. Theres no way anyone will buy it. Even if i warmed it up before they bought it, they'll be knocking on my door the next morning. This aint no SS...

 

[VS 5.0]

Im going to take my car to holden and ask if they want to buy it. When they say no because of the knocking, i'll show them that.

My motor sounds fkd. Theres no way anyone will buy it. Even if i warmed it up before they bought it, they'll be knocking on my door the next morning. This aint no SS...

Let's hope they "ensure" your "customer satisfaction".

 

[Kakodaemon]

Heres an in-car video i just made. Stone cold.

That sounds worse than mine, at least mine goes away at certain revs while driving, but i think mine is louder at idle.
Either way its BS and a terrible noise that ISN'T normal or acceptable.

 

[Kakodaemon]

Im going to take my car to holden and ask if they want to buy it. When they say no because of the knocking, i'll show them that.

My motor sounds fkd. Theres no way anyone will buy it. Even if i warmed it up before they bought it, they'll be knocking on my door the next morning. This aint no SS...

I reckon this should be enforced. Holden should be forced to buy back cars with "piston slap" at their current inflated prices if a customer isn't happy with it. They can then in their own time, rip each engine out, repair it, and re-sell it. No VF LS3 should make this noise regardless.

 

[Martbar]

Same as the one that they gave me. I wonder how many owners of noisy motors, have had their concerns about slap, diminished by that piece of paper.