LS3 cold start Slap is driving me crazy!

[Anthony121]

You will only her piston slap under load. My Redline has been making this sound when cold since about 18,000kms. It now has 58,000 and right now as I've done about 6,000 kms on this oil, it is noisier than fresh oil.

All it is with an aluminum piston in a round hole. The piston is not exactly round when cold so that why it makes a bit of a thud when cold. Don't push the engine until it has warmed up and you will be right. I have driven a VF redline with very bad piston slap but as I said mine is a dull sound when cold. My other V8 hasn't made any noises yet but I'm only at 3.000 kms.

 

[Immortality]

That is all well and good but there are plenty of documented cases where these engines are out of spec and are destroying themselves. Yes it is a very basic old design but the lack of over head cams does not excuse poor build quality elsewhere in the engine, piston to bore clearances been the main culprit. It seems clear that quality control on the last of the LS3's used in the VF run is definitely worse than earlier models. Generally speaking, with each engine iteration it should be an improvement and the issues of the earlier designs should be ironed out. Clearly something has gone wrong....

 

[Subju]

a

 

[07GTS]

most of the LS3 in the HSV's seemed good its just when they started to use them in the holden range they prob got a good bulk deal on the rubbish that was left over

 

[lmoengnr]

The LS3's in the VF were the last 'production' engines built in Mexico...
Current LS3's are built in the US, by the crate engine section of GM Powertrains, in much smaller batches.
HSV did get a bad batch in 2010/11, they had soft cam lobes.

 

[Immortality]

Probably at some stage the LS production moved to the Mexican plant but unfortunately it seems it was more of a mexican't problem....

In the early days the LS3 was a performance model of the LS1 and build in lower numbers, by the time they ended up in the VF the performance engines been used in the Corvette and Camaro had already moved in the LT series motors and the LS3 were now the bargain basement mass produced model....

edit:lol, beat me to it ^^^^

 

[Skylarking]

Lack of refinement yes, but what do you expect from essentially an engine configuration from the 60's and 70's that's been refined over the years....

Doesn’t matter when the pushrod engine was first designed, they’ve had forever to sort out all the issues and they’ve had forever to modernise their production facilities and improve quality control.

The fact it’s pushrod doesn’t mean tolerances should be crap, the engine shouldn’t sound like someone has left a few bolts in the combustion chamber while it warms up (not the case for me... yet) or the component properties of some parts leads to potentially early failure (pushrods, lifters, cams, chains?)...

What did I expect... a reasonably quiet powerful engine with reliability and long life... maybe it is the case and it’s just the fact one reads of all the problems on forums... but whatever the case, it’s not confidence inspiring

 

[Smashfist]

Yes some engines are out of spec and need work but on the whole it's a compromise. You want quiet, go back to an iron block with steel pistons and then wonder why it's heavy and doesn't make as much power - LS engines are noisy and they have been since they were new. The alloy pistons to the iron liner means that somewhere in the cold/hot/warmup process there's going to be some clearance somewhere given the metals heat and expand at different rates - that's physics at work and you can't do squat about it.

 

[Immortality]

Yes some engines are out of spec and need work but on the whole it's a compromise. You want quiet, go back to an iron block with steel pistons and then wonder why it's heavy and doesn't make as much power - LS engines are noisy and they have been since they were new. The alloy pistons to the iron liner means that somewhere in the cold/hot/warmup process there's going to be some clearance somewhere given the metals heat and expand at different rates - that's physics at work and you can't do squat about it.

I disagree, modern alloys (used to make pistons) expand less with heat so need less piston to bore clearances than older engines so there is no excuse for it. sure if you run forged pistons and heavy springs and solid lifters would I expect mechanical noises from the engine but for a stock factory engine you really shouldn't be hearing mechanical sounds.

LS motors have had issues with pistons/rings and oil usage from day zip because GM decided to make design compromises to try to increase efficiency. The fact that some people with VF/LS3's have whisper quiet engines and others have sowing machines clearly demonstrate that quality control was rather lacking at the engine production plant and then GM saying that excessive oil consumption/engine noise is acceptable is just pure horse ****.

Modern production techniques are supposed to improve quality and reliability, not make it worse.

 

[abuch47]

you all using anecdotes as statistics. got a friend with a ve gts had piston slap.

its a common fault of LS going back to holden recognising it with the first iteration, VT.

yes its annoying its not fully removed through QC but this is an american car company lmao.