LS3 Lifter noise or Piston Slap?

[Pollushon]

I watched a youtube of a crate LS3 being stroked a while back, I was surprised to see the OEM piston had a Teflon skirt pad, it didn't seem to be a coating. Make of that what you will

 

[vc commodore]

I watched a youtube of a crate LS3 being stroked a while back, I was surprised to see the OEM piston had a Teflon skirt pad, it didn't seem to be a coating. Make of that what you will

Seeing as though another member wanted to see an OEM piston, would you be able to post a link to that video? Might help with this thread....

I also know, sometimes remembering the name of the creator of these videos can be difficult too so posting it might be out of the question too...

 

[RevNev]

I watched a youtube of a crate LS3 being stroked a while back, I was surprised to see the OEM piston had a Teflon skirt pad, it didn't seem to be a coating. Make of that what you will

If the stock pistons have a Teflon skirt pad, could be the reason piston slap begins or gets worse at higher km's as the Teflon pad wears. We know the stock pistons can handle serious engine mods and a good thrash that an older engine with cast pistons wouldn't sustain, the stock LS3 pistons may be a better piston than we think and subject to greater heat distortion more like a forged race piston.

Teflon coated pistons covers the entire piston but a Teflon skirt pad is solely on the skirt with an alloy border (original piston alloy) around the pad that's a few thou thick.

 

[Martbar]

My suggestion is don’t wait until the repair is done. I’d first call CAV, now, and discuss it with them else you may shoot yourself in the foot and not be able to claim repair costs. After talking to CAV I’d call ACCC and get their take on the issue of Holden sitting on known defective engines..

Do it,

So the shop i took my car to said that there is a Teflon coating on the sidewall of the piston which has worn off causing the piston head to not move straight up and down but tilt and move side to side which causes the knocking noise. They tested all lifters, valve springs and oil pressure and everything was ok. Will talk to him on Tuesday regarding time and price to fix it.

Mate you've had it in the shop and compression and oil pressure's ok
I would disagree with their opinion about the pistons wearing off the teflon coating. If your engine had anything drastically wrong with it, the noises wouldn't go away after a couple of minutes.
If you're really that worried about the slap noise take it to a specialist tuner and get them to adjust the tune, to mitigate the problem. As @Skylarking has said get in touch with the dealer and see what their take on it is. Then if that's unsuccessful go to the relevant consumer protection agency. If all else fails a bit of slaps not the end of the world. Again good luck mate you've got plenty of options.

 

[Martbar]

If the stock pistons have a Teflon skirt pad, could be the reason piston slap begins or gets worse at higher km's as the Teflon pad wears. We know the stock pistons can handle serious engine mods and a good thrash that an older engine with cast pistons wouldn't sustain, the stock LS3 pistons may be a better piston than we think and subject to greater heat distortion more like a forged race piston.

Teflon coated pistons covers the entire piston but a Teflon skirt pad is solely on the skirt with an alloy border (original piston alloy) around the pad that's a few thou thick.

Mate when I was talking to one of the Holden mechanics he said that most of the earlier aluminium motors were noisy. They tried pistons with longer skirts, to fix some of the louder motors, with limited success. With the modern computer technology and precise methods of production, why it would affect some engines more than others is
puzzling. I could understand it to some extent if the problems were only with the high performance motors, but ours is a standard 6 litre.

 

[Immortality]

Mate when I was talking to one of the Holden mechanics he said that most of the earlier aluminium motors were noisy. They tried pistons with longer skirts, to fix some of the louder motors, with limited success. With the modern computer technology and precise methods of production, why it would affect some engines more than others is
puzzling. I could understand it to some extent if the problems were only with the high performance motors, but ours is a standard 6 litre.

By now it has become apparent that GM had quality control issues and excessive piston to bore clearance are the result, or worse, they simply did not care (it's a "performance engine" after all and they are noisy right?).

A quick online search says the LS3 motors use a Hypereutectic Cast Aluminum Alloy piston. The whole point of using this specific material is that it expands less with heat allowing closer piston to bore clearances and quieter engines.

LS motors were also really bad for burning oil in the early days ( and didn't really ever fix that problem either). Short piston skirts, low tension rings (to reduce friction and improve economy) and it all adds up to a recipe for disaster.

I know an ex Holden tech who used to do the rebuilds on LS motors for cars that came in for warranty work for burning excessive amounts of oil. Rip **** and bust, get it done and then take it out and run in the new rings

Other manufacturers can build quiet alloy engines so GM is just full of ****.

 

[Skylarking]

Yes, other manufacturers can build quiet and powerful petrol engines (max effective power or bhp/ltr) that don’t clatter like a diesel.

Manufacturers are simply deaf dumb and blind when it suits them… In this case Holden is deaf to piston slap so they simply consider it normal and not an issue… Just like diff whine which is so bad it scares cats, but their deaf mechanics can’t hear it so it’s normal…

GM/Holden have always been full of it… just look at the shitfuckery that GM has done over the years and it’s clear they simply don’t care about the law or how to behave in a decent way towards their customers.. Been spanked repeatedly via class actions in the USA and only their bankruptcy and restructure save them from having to fork out millions upon millions more... And a fish rots from the head so Holden wasn’t immune to repeating such shitfuckery.

Sadly many other manufacturers are the same…

Toyota is now appealing the $2B compensation bill because they say not all customers experienced the DPF issue. But Toyota conveniently ignore that those customers car’s value’s were deflated because of this problem… something that was actually supposed to be part of the compensation which was why it was set so high and wide… About $8k per person who bought one of those problematic diesels…

As an example, $8k for rebuilding one‘s LS3 would be nice but it wouldn’t do the job fully or to a good standard. And a new create engine is, what, $16-18k these days? Really, there needs to be a class action against GM/Holden down under…

 

[Pollushon]

Seeing as though another member wanted to see an OEM piston, would you be able to post a link to that video? Might help with this thread....

I also know, sometimes remembering the name of the creator of these videos can be difficult too so posting it might be out of the question too...

Quick google, ask and ye shall receive

Seems to me it's more a geometry issue, Teflon or none, the LS3 especially is prone to slap. The question is as annoying as a sound may be what are the numbers on catastrophic failure because of it? Most of us accept LS are just a noisy bag of bolts for one reason or another regardless

 

[Immortality]

You have to wonder about the factory piston design too, a short skirt piston is already going to be a lot less stable in the bore. The stock piston has the ring pack very close to the piston crown.

(random interweb pic)

Now if you have a look at a quality aftermarket piston, the ring pack is further down the piston so much so that the oil rings actually cross the piston pin bore.

 

[RevNev]

Now if you have a look at a quality aftermarket piston, the ring pack is further down the piston so much so that the oil rings actually cross the piston pin bore.

Lowering the ring pack reduces piston ring heat and lowers the compression ratio. Not a great idea unless ring fatigue from excessive heat is an issue in a particular engine combination.