Excessive Lifter Noise???
Thread Starter
Instructor
Joined: Dec 2016
Posts: 245
Likes: 132
From: Port Coquitlam BC
Excessive Lifter Noise???
I originally posted this in the General Discussion section, however, did not get many replies, so thought i would ask here as well.
Asking to see if this is normal, or not...and specifically asking those that have a HTC.
Have a 2023 Z51 HTC, which now has about 475 miles on it. Have totally babied it during the break-in period, making sure not to over-rev, or load it up too much.
Starting at around the 300 mile mark, I noticed, what I think is excessive lifter noise under part throttle,, and deceleration. Between 1,700-3,000 RPM. Very noticeable with the rear window down, and in particular when in "Z" mode, when at a constant RPM, increasing RPM slowly, or decelerating. I have heard some describe the LT2 as sounding like a sewing machine. This sound is not the injectors, but most definitely valvetrain.
When the car returns to idle - no lifter noise. And this occurs when it is in V8 mode.
I have read about the collapsed lifters on the AFM cylinders, but would that not happen all of the time? It does sound like it would be more than 1 lifter, but not all of them
I also have a 2020 ZL1, and it has no lifter noise at all. Yes, I am aware of the LT2 vs. LT4 but the architecture is the same.
Is this normal or common for the LT2's to have lifter noise, or is it time for a visit to the dealer?
Asking to see if this is normal, or not...and specifically asking those that have a HTC.
Have a 2023 Z51 HTC, which now has about 475 miles on it. Have totally babied it during the break-in period, making sure not to over-rev, or load it up too much.
Starting at around the 300 mile mark, I noticed, what I think is excessive lifter noise under part throttle,, and deceleration. Between 1,700-3,000 RPM. Very noticeable with the rear window down, and in particular when in "Z" mode, when at a constant RPM, increasing RPM slowly, or decelerating. I have heard some describe the LT2 as sounding like a sewing machine. This sound is not the injectors, but most definitely valvetrain.
When the car returns to idle - no lifter noise. And this occurs when it is in V8 mode.
I have read about the collapsed lifters on the AFM cylinders, but would that not happen all of the time? It does sound like it would be more than 1 lifter, but not all of them
I also have a 2020 ZL1, and it has no lifter noise at all. Yes, I am aware of the LT2 vs. LT4 but the architecture is the same.
Is this normal or common for the LT2's to have lifter noise, or is it time for a visit to the dealer?
Burning Brakes
Joined: Feb 2013
Posts: 904
Likes: 296
From: Sacramento, California
Injectors? They are very loud on DI engines and with the engine right behind you it's more noticeable than engines up front. Maybe a ride in another C8 would help put your mind to ease or bring it in to your dealership and let them hear it.
Race Director
Joined: Mar 2007
Posts: 11,328
Likes: 8,483
I originally posted this in the General Discussion section, however, did not get many replies, so thought i would ask here as well.
Asking to see if this is normal, or not...and specifically asking those that have a HTC.
Have a 2023 Z51 HTC, which now has about 475 miles on it. Have totally babied it during the break-in period, making sure not to over-rev, or load it up too much.
Starting at around the 300 mile mark, I noticed, what I think is excessive lifter noise under part throttle,, and deceleration. Between 1,700-3,000 RPM. Very noticeable with the rear window down, and in particular when in "Z" mode, when at a constant RPM, increasing RPM slowly, or decelerating. I have heard some describe the LT2 as sounding like a sewing machine. This sound is not the injectors, but most definitely valvetrain.
When the car returns to idle - no lifter noise. And this occurs when it is in V8 mode.
....................
Asking to see if this is normal, or not...and specifically asking those that have a HTC.
Have a 2023 Z51 HTC, which now has about 475 miles on it. Have totally babied it during the break-in period, making sure not to over-rev, or load it up too much.
Starting at around the 300 mile mark, I noticed, what I think is excessive lifter noise under part throttle,, and deceleration. Between 1,700-3,000 RPM. Very noticeable with the rear window down, and in particular when in "Z" mode, when at a constant RPM, increasing RPM slowly, or decelerating. I have heard some describe the LT2 as sounding like a sewing machine. This sound is not the injectors, but most definitely valvetrain.
When the car returns to idle - no lifter noise. And this occurs when it is in V8 mode.
....................
Thread Starter
Instructor
Joined: Dec 2016
Posts: 245
Likes: 132
From: Port Coquitlam BC
In Z mode, the settings are all customizable. What settings in Z mode? The ones that might affect engine noise are "engine/shift" and "engine sound". With the NPP exhaust, engine sound will change the points at which the exhaust tail pipe flow control valves open and close, which will affect exhaust sound - and if set to "track" those valve will be open nearly all the time. The engine/shift setting will affect throttle response, gear shifting and engine performance. And if set to Track, it will prevent V4 mode. So it can affect engine sound as well. I do not hear anything on mine that sounds like valve train noise ever. With the HTC, I have never heard the ticking noise from the injectors either - I believe there is more noise isolation between the engine and cabin on the HTC than the Coupe. But if really are hearing a valve train noise then yes, dealer trip.
Really don't think it is injectors, but could be wrong.
Thread Starter
Instructor
Joined: Dec 2016
Posts: 245
Likes: 132
From: Port Coquitlam BC
Burning Brakes
Joined: Dec 2007
Posts: 761
Likes: 335
From: Charlotte NC
These engines are inherently noisy so it's probably not an actual issue. Make sure the rubber access panel over the oil cap/dipstick on the engine cover is snapped into place. I accidently left that open once after checking the oil and the engine noises were significantly louder in the cabin. It's amazing how much that cover insulates sound.
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Thread Starter
Instructor
Joined: Dec 2016
Posts: 245
Likes: 132
From: Port Coquitlam BC
These engines are inherently noisy so it's probably not an actual issue. Make sure the rubber access panel over the oil cap/dipstick on the engine cover is snapped into place. I accidently left that open once after checking the oil and the engine noises were significantly louder in the cabin. It's amazing how much that cover insulates sound.
Yes, the two access hatches are both fully closed, but thank you for the suggestion.
Rob
Melting Slicks
Joined: Apr 2021
Posts: 2,755
Likes: 2,323
From: Simi Valley, CA
2022 C8 of the Year Finalist - Modified
Hey folks, take a look at YouTube, C8 Corvette, Rick Conti Tech Tuesday for today (6/6). They talk about a GM document about excessive engine noise caused by collapsed lifters on 2023 GM products (not just Corvettes) and the procedures the dealer is supposed to go through for this problem, including lifter replacement. It seemed to fit right in with this topic.
Chuck, the mechanic, was quick to point out that this is a different problem from the standard high-pressure fuel pump/injector noise that we all know and love.
Chuck, the mechanic, was quick to point out that this is a different problem from the standard high-pressure fuel pump/injector noise that we all know and love.
Race Director
Joined: Mar 2007
Posts: 11,328
Likes: 8,483
Hey folks, take a look at YouTube, C8 Corvette, Rick Conti Tech Tuesday for today (6/6). They talk about a GM document about excessive engine noise caused by collapsed lifters on 2023 GM products (not just Corvettes) and the procedures the dealer is supposed to go through for this problem, including lifter replacement. It seemed to fit right in with this topic.
Chuck, the mechanic, was quick to point out that this is a different problem from the standard high-pressure fuel pump/injector noise that we all know and love.
Chuck, the mechanic, was quick to point out that this is a different problem from the standard high-pressure fuel pump/injector noise that we all know and love.
Last edited by Andybump; Jun 7, 2023 at 08:54 AM. Reason: found a later version
