70thAnnvGuy

Egoncool,
New to forum, not to high performance cars and driving. Not in my case! Any help would be greatly appreciated.

smitty1966

My C6 LS7 started huffing a little blue smoke out driver side on startup at 36,000 miles. When we pulled heads found 2 exhaust valves on that side were very, very loose in the guides. Took them to a shop that specialized in LS heads and they confirmed this was a common problem (given the low production numbers of the engine), they had repaired a bunch of them. They had found brand new Z/28 LS7 heads on engines they were modifying with incorrectly machined exhaust valve guides. Most LS7 had no issues, but some ended up with incorrectly machined heads from the contractor in Canada. Chevy/GM fumbled this problem.

smajicek

Smitty1966, I believe this thread was specifically created just for the LT6 motor which is in the new 2023 Z06, why you are posting about C6 when this is about C8 gen corvette. If I am wrong I apologias..

GatorsJMC

Did you get the pico scan done?

cajunboyz

Interesting topic

GatorsJMC

Teslarosa is not following up here. Hope his issue was resolved.

Just to reiterate, my '24 LT 6 was producing a loud ticking noise, apparently from a cam follower, hot or cold, coming from the drivers side bank of cylinders/ cams. The pico scan confirmed this graphically and the TSB was performed at the Daytona, Fl dealership (I took a museum delivery).
Results were a reduction of approx 60-70% in tapping intensity to my older ears. After repair pico scan showed improvement. Without getting pissy and complaining more about it and demanding a new engine, it seems like an acceptable fix to me after putting on another 400+ miles. LT 6's do make noise, different from pushrod engines. Actually a bit of sewing machine noise I dare say . But again, my older ears are to blame here for any inaccuracies!
YRMV

sandcracker21

Have had my 24 HTC for two weeks now and just passed the 500 mile break in. No problems at all and no "ticking" noise. Fingers crossed!

Preshenne

Have New Z06 waiting at the dealers. Asked for engine run recording. I am not skilled in the dreaded "LT6 Ticking" noise. How does this one sound?

GatorsJMC

Don't notice any from your posted clip. Have to get the exhaust note as quiet as possible...

Quite a noticeable ticking noise you can easily hear from either of the rear wheel wells. GM's pico scan is an audio print out of engine "noises". Look for sharp, repetitive amplitudes on the graph. That's what will trigger the TSB routine be undertaken.
Mine didn't appear until 600-700 miles after the drive home from a museum dilevry..

smajicek

Sounds normal to me. Mine is HTC so it makes it harder to hear if I did have ticking

jkirsc1

So I have had my 2023 Z06 less than a year, and I have only about 1700 miles on due to my work schedule and travel. In any event, I can hear a clear "knocking" sound at low speeds only when the car is up to temperature. Took it to the dealership last week, service advisor and mechanic both say its not the same sound as the TSB for the camshaft caps. They sent a recording of the sound to GM. GM advised to drop the engine and perform the TSB repair anyway and see if they see anything else that needs replacing while they have the engine dropped. First issue is the parts for the TSB are backordered so they can't even do step one yet to even get to what the actual problem may be. Maryland has a 30 day lemon law within the first two years of ownership and it looks like we're headed that way. I really love this car, but with the expectation it'll be just sitting there weeks with no end in sight before they actually find the real problem is disheartening. I opened a case online with GM and the Maryland Attorney General's Office to start the process of a purchase back or replacement. Anyone know of anything I can do in the meantime or didn't do yet that I should? Wife is a lawyer so I don't need one of those.

RapidC84B

What parts are needed for the camshaft TSB? It's just backing off the bolts and retightening to spec.

SinisterC6

Does anyone have a clip of what the abnormal tick sounds like?

jkirsc1

That's what I thought too, but they told me bolts, gaskets and nuts are not reusable and had to be ordered

GatorsJMC

Had to wait approx 10 days for parts when the TSB was done. Bolts, seals, gaskets...

RapidC84B

Interesting... I wonder if it depends on if the engine has to be dropped or not. The cam cover gasket is reusable and the video I watched online they literally just back off the bolt and retighten it.

GatorsJMC

Come to think- bolts were not replaced. Seals were the back order item. Left bank only was done...

Brandon's Z

The first C8 where having problems with the transmissions and now the new hot rods are having problems with the engine. Grr GM get your act together! I am the old man that likes the old cars. They didn't break (as often) and when they did it didn't take two weeks for a record time repair.

I can't wait for the new ZR-1. I hope someone wants me to take it for a spin. Although, I hope I don't spin it! Thanks for sharing???

GatorsJMC

I seem to remember different C-series all having their respective teething issues.
C 8's are no exception, but definitely more complex!

Brandon's Z

I love all Corvettes and especially the C4 ZR-1. GM did an excellent job of testing the LT5 before it went into the new Z. Ford and GM use to do actual endurance testing with engine builders and drivers. Now we leave to the brilliant AI. Just a sign of the times. 180K price for a new hot rod and the engine blow. I hope GM gets in front of this. It been going to long. I hope to drive a ZR-1 soon!