LS3 Lifter noise or Piston Slap?

[Immortality]

What I hear in the video acoustics that may vary if heard in real time....

Which is why online diagnostics is such a hit and miss affair.

 

[lmoengnr]

I think you're right too! Piston slap seems the diagnosis Holden claims is normal for any cold start engine noise that disappears at operating temperature. In 30+ years of listening to race and performance engines with severe cold start piston slap with forged pistons at a minimum of 5 thou clearance, it's too noisy for a road car engine but not that loud really spark your attention. Mechanical roller cam and tie bar lifter noise is louder than piston slap in most cases. Gear roll over at idle with straight cut dog engagement gearboxes (Holinger etc) is the loudest of all race engine noises and sounds like the engine has no big end shells until you push the clutch in!

Being a fire marshall, standing next to a Pratt & Whitney 1830 radial after an overnight cold soak is an 'interesting' experience.
Just winding the engine over with the starter, it sounds like a box of rocks in a tumbler, then gets worse when the magneto's are switched on...
These engines have pistons with full skirts, and oil control rings at the top and bottom of the skirts.

 

[RevNev]

Which is why online diagnostics is such a hit and miss affair.

Diagnosing any abnormal noise without examining, measuring and remedying the issue is a hit and miss affair. I remember a bloke gave me 4 speed single rail gearbox to overhaul that I couldn't find anything wrong with and he complained like hell that his "gearbox noise" wasn't fixed. We fixed his "gearbox noise" in the end with a set of diff pinion bearings!

 

[Immortality]

@IBLOWN, I remember you mentioned fitting new lifters the first time you had issues, I don't suppose you remember or know how much pre-load they have?

Being a fire marshall, standing next to a Pratt & Whitney 1830 radial after an overnight cold soak is an 'interesting' experience.
Just winding the engine over with the starter, it sounds like a box of rocks in a tumbler, then gets worse when the magneto's are switched on...
These engines have pistons with full skirts, and oil control rings at the top and bottom of the skirts.

I do love old WW2 era engines.

 

[RevNev]

@IBLOWN, I remember you mentioned fitting new lifters the first time you had issues, I don't suppose you remember or know how much pre-load they have?

Our Ecotec V6 race engines use LS lifters and the best durability lifters I've used by a country mile are Johnson LS7 Hi RPM that are extremely resistant to bleed down and pump up fast on cold starts even with a 20w60 mineral based oil. Pre-load on the Ecotec and LS V8 engines is good from 1/4 to 3/4 of turn down on the rocker trunnion bolt from zero rocker to valve tip clearance.

There's no magical pre-load amount that I've ever discovered with any hydraulic lifter despite painfully shimming individual rockers chasing a couple of theoretic horsepower to no avail whatsoever. The job of a hydraulic lifter is simply maintaining zero valve tip to rocker clearance at all RPM the engine's intended to operate.

 

[Immortality]

Yup, well aware of how the lifters work, just wondering if the OP knows what the pre-load was when he changed the lifters.

 

[Kakodaemon]

Question for the knowledgeable ones..... can piston slap get "better" or "change" over time?

Reason being.... i started a new job on Monday, I currently live up in the hills of Melbourne where it has been fairly chilly in the early morning. Since the manual states that these engines do not require warming before driving, and, Holden stating that my noise is "normal" and "not a durability concern," i start her up and a minute later I drive off. I leave between 7:25 and 7:30 am. So Monday, Tuesday and Wednesday morning my car slapped its arse off (as usual) and in the afternoons did the same, but, i guess heat soak of driving to work keeps the bowels of the block warm enough that it gets to operating temps quickly and the noise goes away sooner in the arvo.

Thursday morning I started her up, she turned over and the revs dropped to idle, for a second or 2 at idle revs there was no ticking/slap, then it slowly made the knocking noise, BUT, it was absolutely nowhere near as loud as it has been the last few months. Barely noticeable inside the cabin, and outside was just a slight tick/knock. Thursday afternoon 5pm she did the same, took a few seconds for the tick to kick in, and wasn't even close to as loud as it used to be. Friday morning was a slight noise, and my roommate who was outside playing with his dog even noticed that he could barely hear it. Friday arvo at startup the noise was inconsistent, instead of the usual rhythmic tapping you could use as a metronome, it would tick a few times, miss a beat or two, tick 4 or 5 times then miss one then tick once miss 2 or 3.... then sooner than usual the noise basically went away.

I asked my room mate to record a video today of it but something went wrong and didn't record, but, it was a really quiet noise that went away really quickly, it was actually gone while the temp gauge was still at starting temp! i revved it a few times and at the last split second before hitting idle revs, it did a few quick ticks, then ticked 2 or 3 times before fading to almost nothing.
I don't understand how this can be possible?
How can it go from the neighbours walking to the top of their driveways to see what is making the horrible noise, to some thing that just sounds a bit annoying then fairly quickly going away?

I'll try with my crappy phone tomorrow to capture the noise and how soon it goes away, but i am just so perplexed by all the varying opinions between people online hearing the noise, and people in actual person hearing/inspecting the car......

 

[RevNev]

Question for the knowledgeable ones..... can piston slap get "better" or "change" over time?

Piston slap noise is the sound of a piston rocking in the bore and can only get worse as the piston and bore wears and the piston to bore clearance increases. Only lifter noise can change dramatically as you've described and reinforces my online diagnose from your video acoustics that lifter noise is the dominant issue with your engine, not piston slap.

We know Holden's intention is to avoid warranty claims with cold start engine noises and I agree with the idea someone else posted they're likely to diagnose all engine noises as piston slap and claim it's normal. If your boot hinge squeaked when cold, they'd likely diagnose that as piston slap too to avoid spraying a bit of CRC on it for you!

 

[Kakodaemon]

Piston slap noise is the sound of a piston rocking in the bore and can only get worse as the piston and bore wears and the piston to bore clearance increases. Only lifter noise can change dramatically as you've described and reinforces my online diagnose from your video acoustics that lifter noise is the dominant issue with your engine, not piston slap.

We know Holden's intention is to avoid warranty claims with cold start engine noises and I agree with the idea someone else posted they're likely to diagnose all engine noises as piston slap and claim it's normal. If your boot hinge squeaked when cold, they'd likely diagnose that as piston slap too to avoid spraying a bit of CRC on it for you!

maybe i need a 3rd opinion as to what the noise is

 

[Martbar]

maybe i need a 3rd opinion as to what the noise is

The slap noise in ours doesn't go away, it's always there. With the noise in yours not always evident,
it could be something else. When ours was diagnosed, l left it at the dealership overnight so they could hear it from startup. They put the engine through various loadings and did other tests on it.
As l didn't buy the car off them, l believe that the opinion they gave me was honest and factual. This opinion was further endorsed by the former dealer's that l brought the car off and had serviced it from new. Again the noise that yours makes mimics ours, but because you can't hear yours at every startup, if you get another opinion mention that to them. Slap is always there, sometimes its louder, but its always there to varying degrees. Good luck mate.