C8Z Valve Tick
Thread Starter
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
C8Z Valve Tick
Currently 850 miles and have developed a noticeable valve tap at idle. Can't hear it above idle,- exhaust drownes it out.
NCM delivery and almost afraid to have a local dealer's tech address the issue and "learn" on my car.
Open to solutions before any component damage...
NCM delivery and almost afraid to have a local dealer's tech address the issue and "learn" on my car.
Open to solutions before any component damage...
Thread Starter
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,402
From: Bethesda MD
There are a couple big threads in the Z06/ZR-1 forum on this issue. Search for ticking.
Put your car exhaust in stealth and see if you hear it in the higher rpms. Finally there is a TSB on this. They do a picoscope recording to determine if the problem is there. If they determine there is a problem, you decide whether you want to fix it or leave it as is.
These cars do have a lot of mechanical noise; much more than the stingray and the C7.
Put your car exhaust in stealth and see if you hear it in the higher rpms. Finally there is a TSB on this. They do a picoscope recording to determine if the problem is there. If they determine there is a problem, you decide whether you want to fix it or leave it as is.
These cars do have a lot of mechanical noise; much more than the stingray and the C7.
Thread Starter
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
So, had the local dealer do the TSB work for a minimal improvement in the cam/ follower/ valve tick, coming from the left bank. Before & after pico scope prints did show an improvement, but not much. Looks like it's there to stay, just not as pronounced as before.
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Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,402
From: Bethesda MD
That's disappointing to hear for all that work, the improvement was minimal.
Heel & Toe
Joined: Jun 2011
Posts: 24
Likes: 0
From: Choctaw OK
Mine has been at the dealership for a few days with a ticking noise issue, and a couple fault codes. ECM and Knock Sensor.
The service manager called me today and said GM told him to pull the motor. They will be tearing into it Monday. It’s a 2023 with 6500 miles on it.
I’ll post what they figure out when I get it back.
The service manager called me today and said GM told him to pull the motor. They will be tearing into it Monday. It’s a 2023 with 6500 miles on it.
I’ll post what they figure out when I get it back.
Drifting
Joined: Feb 2023
Posts: 1,353
Likes: 1,115
Mine has been at the dealership for a few days with a ticking noise issue, and a couple fault codes. ECM and Knock Sensor.
The service manager called me today and said GM told him to pull the motor. They will be tearing into it Monday. It’s a 2023 with 6500 miles on it.
I’ll post what they figure out when I get it back.
The service manager called me today and said GM told him to pull the motor. They will be tearing into it Monday. It’s a 2023 with 6500 miles on it.
I’ll post what they figure out when I get it back.
Thread Starter
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Drifting
Joined: Feb 2023
Posts: 1,353
Likes: 1,115
Be aware going into this that GM does not want take apart any engines to 'fix' them because attempting this has, in the past, resulted in snapped cam tower bolts which further complicated the repair. Since then, most/all the pico tests have come back 'satisfactory' meaning - your car is okay.
Thread Starter
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
That's an irregular tapping and this is symptomatic of a problem engine.
Be aware going into this that GM does not want take apart any engines to 'fix' them because attempting this has, in the past, resulted in snapped cam tower bolts which further complicated the repair. Since then, most/all the pico tests have come back 'satisfactory' meaning - your car is okay.
Be aware going into this that GM does not want take apart any engines to 'fix' them because attempting this has, in the past, resulted in snapped cam tower bolts which further complicated the repair. Since then, most/all the pico tests have come back 'satisfactory' meaning - your car is okay.
Coming from a mechanical lifter- tappet background from years ago, too much valve/ rocker clearance meant too much wear. Fast forward to todays LT6 cam follower set up, my thoughts were the same- too much noise meant too much wear in the cam-follower arrangement. Have you seen how low the torque settings are for the cam cap bolts? I was surprised, myself...
Last edited by GatorsJMC; Jan 10, 2024 at 11:40 AM.
Drifting
Joined: Feb 2023
Posts: 1,353
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[QUOTE=GatorsJMC;1607412960]I'm curious where your information comes from within GM. My "repair" was just done in December and I saw two Pico Scan graphs of the before and after the TSB was done. It clearly depicted less amplitude in the display and the sound was less pronounced after the TSB work./QUOTE]
The engine still had the valvetrain/tick after the repair, it was just less pronounced, but still there - you are saying?
The engine still had the valvetrain/tick after the repair, it was just less pronounced, but still there - you are saying?
Thread Starter
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
[QUOTE=Mitchell_B;1607413008]
Affirmative, my friend 
I'm curious where your information comes from within GM. My "repair" was just done in December and I saw two Pico Scan graphs of the before and after the TSB was done. It clearly depicted less amplitude in the display and the sound was less pronounced after the TSB work./QUOTE]
The engine still had the valvetrain/tick after the repair, it was just less pronounced, but still there - you are saying?
The engine still had the valvetrain/tick after the repair, it was just less pronounced, but still there - you are saying?