Rattle Sound Or Ping At WOT 08 Z06

[Torched]

Just broke in the car and now have over 500 miles on the ODO. I'm now taking the car past 4000RPM to redline and now notice more while adding throttle into a right turn I get a rattle or ping sound and the oil over 160. It sometimes does this going straight but it is much more noticeable during a long right turn on the gas. I thought it was the gas and have tried both Chevron 91 and Shell 91 here in CA but it made no difference. Car seems very very strong and does not appear to be loosing any power.Could this be the dreaded dry sump oiling system making noise? I know a screen has been loose in some tanks making lots of clatter. It's more annoying than anything else. What do you think maybe coming from the sump system? If i drive the car civil no noise at all it's high RPM that brings the noise on. Just had the oil changed and no sign of needle bearings which is good. Greg

[c4c5specialist]

HI there,
At higher rpm, the scavenging pump may be creating the noise.
This is normal, based on location of the oil lines and sump in relation to the engine.
I have heard this on 2 other LS7, but NOT ALL of them make this noise.
There is no PI or TSB for this condition and personally, i have not been able to find a negative performance issue with it.
Allthebest, c4c5

[Torched]

Originally Posted by c4c5specialist

HI there,
At higher rpm, the scavenging pump may be creating the noise.
This is normal, based on location of the oil lines and sump in relation to the engine.
I have heard this on 2 other LS7, but NOT ALL of them make this noise.
There is no PI or TSB for this condition and personally, i have not been able to find a negative performance issue with it.
Allthebest, c4c5

Paul, Thanks for your help. Could you be so kind to provide a more accurate description of where it is located? So you think this is not coming from the sump tank?

[c4c5specialist]

Hi there,
See, the scavenging pump pulls oil from the crankcase and sends it to the tank.
Now, this is what could create the nose. As the oil flows into the tank, it cavitates or turbulates, which ever you would like to call it.
That is why you never see your oil pressure drop, but it is completely oil pressure dependant.
The screen may have come loose, but once again, will not create a reliability condition.
I usually will use my Tech 2 to monitor knock retard to make sure its not that.
Then, using chassis ears to localize the noise.
I have had one with noise at the tank and one with noise through the hoses.
Allthebest, c4c5

[Torched]

Originally Posted by c4c5specialist

Hi there,
See, the scavenging pump pulls oil from the crankcase and sends it to the tank.
Now, this is what could create the nose. As the oil flows into the tank, it cavitates or turbulates, which ever you would like to call it.
That is why you never see your oil pressure drop, but it is completely oil pressure dependant.
The screen may have come loose, but once again, will not create a reliability condition.
I usually will use my Tech 2 to monitor knock retard to make sure its not that.
Then, using chassis ears to localize the noise.
I have had one with noise at the tank and one with noise through the hoses.
Allthebest, c4c5

Paul, This makes total sense being oil pressure dependant. As RPM'S rise so does the oil pressure causing the noise. Could you please be so kind to be more specific about the cars you have discovered the noise in. Do you or can you provide some information internally in the tank and hoses that would create such a annoying rattle. What would be wrong inside the tank and hoses that would cause this?

[Torched]

Paul could you please be so kind to address my previous question as I'm in a quandary over this to pursue a fix or leave it alone but it sure is annoying.

[c4c5specialist]

HI there,
Sorry, after doing a bunch of research, fact is sometimes its classified as normal.
It really depends on HOW LOUD the noise is.
The key thing is correct oil level.
Make sure its right where it should be by following the bulletin in our TSB section.
If the level is correct, its truly your own judgement.
Allthebest, c4c5

[markw8]

Liquid under pressure, especially if there's air too, can make a lot of noise. The tank is probably single layer alum. and that doesn't help. Mark.

[Torched]

Originally Posted by c4c5specialist

HI there,
Sorry, after doing a bunch of research, fact is sometimes its classified as normal.
It really depends on HOW LOUD the noise is.
The key thing is correct oil level.
Make sure its right where it should be by following the bulletin in our TSB section.
If the level is correct, its truly your own judgement.
Allthebest, c4c5

Paul, thanks for looking into it. My oil level is correct after a recent change. I'm hoping it does not get worse. I have a local dealer who are very good Corvette people and would address my concerns under warranty. In your best judgment what would you have to replace since some cars do this and others do not? Replace the sump tank and two lower hoses would that fix it? How can I nail this one once and for all as I would much prefer to silence it. Greg