After reading all the "speculation" re C6s, other possible defects, changing only one valve spring, etc this is not the problem with the C8, IMO.

Put a pic of three broken vales that occurred at, 150 miles below. These are unusual failures and it appears to be from what I have read and observe to be an internal metallurgical failure like a none metallic inclusion. If this were improper heat treatment that would affect large numbers of spring in a batch and probably picked up in a QA test etc.

There are very few failures reported on the forum and assuming a number more look at the potential population with vey rough numbers. GM has presented a concern over many months of production and just increased that past October. So from ~June through ~October. So using a SWAG of ~5000 cars that could have been affected that's 80,000 springs! It appears what has occurred is a very small percentage of the population. Forum members do have a way of turning anything into a Chicken Little, "The Sky's Falling" event!

As I recall GM had said, at least initially, IF a valve spring is found to be broken, replace just that one. If the engine had a CEL but a spring was not found then change all 16! Considering the percentage occurrence makes sense to me as it looks like a 99% probability the other 15 are fine. As was posted, warranty repairs occur all the time! Most spring failures reported on the forum didn't have a valve drop and hit a piston. BUT clearances are so small can see why it happened. To replace a piston they had to take the bottom end apart and would have been able to see any other defects. IMO the repair is likely to be fine.

So, your money BUT if you are getting a "good deal" I'd not have any concerns. Certainly better than "there will be others" that could be a year or more from now. You will have a 5 year warranty and it's NOT a CarFax Recordable Event. Heck I'll be looking to buy a Grand Sport before I reach 5 years!

 

How many miles do you have on your car?

 

Dealers use any of the hundreds of reasons why your trade is handicapped in some way, service record is just one of many. If you didn't have this warranty work done it would be some thing else.

 

Geez, this has me scared. At first, it was build date threw Sept 15th, but now it's threw Oct 7th. My car was built on Sept 22nd and I only got 67 miles on her...

 

My C8, delivered September 1st, was no doubt built around the same time as yours.. However it's a wide range of dates and was recently extended by GM, this is a summary of the latest I found:

"In that original TSB, General Motors stated the faulty valve springs were used in the production of the engines from June 1st – September 15th. However, more and more Corvette owners whose engine build dates were past September 15th were also experiencing broken valve springs....... The new end date for affected 6.2L engines is now October 7th, 2020."

Did not go back and try to find how many C8's were built in that 4+ month period but my prior post saying IF it were ~5000 that is ~80,000 springs in question. Although the forum is not a total answer we probably represent a sufficient number of failure reports (not many) that the odds of having one are very small.

Do what I did after passing 500 miles and hit near redline. In fact I do that often on fun 0 to 60 runs merging into traffic from a stop! I do it most days onto the 4 lane divided highway at the end of my street with traffic going 65/70 mph on the 60 mph speed limit highway. That no doubt stresses the springs the most! I've done that enough now that my concerns with >1000 miles are not an issue

Sure it can happen but so can some AH distracted looking at a text message or using their cell phone ruin my 60 year driving record of never having had an accident with another car! Much higher probability IMO

 

I am much more concerned you have driven only 67 miles in your car. Go out and enjoy it. If you are going to use it as an art piece, no need to worry over the springs, it doesn't need to run to look at it. Many show cars of the past did not run. Otherwise, go drive it. when you get past 1000 miles you will know you probably don't have a valve spring issue. I don't think I have seen a car that broke a spring past 1000 miles. I am sure someone will correct me if I am wrong.

 

As I note in the post #25, distracted drivers should scare you more! Get past 500 miles and then hit redline when your near your home so IF it fails you can get it fixed! A few 0 to 60 mph runs (no need to use launch control etc) will get it near 6500 in 1st!

 

No mention by GM of the actual Build Date of the Engine, just when the Car was Assembled.

I wonder how long it takes to build and ship the Engine to BG from the Tonawanda Plant?

 

I finally got my car on October 23 and I drove her to work since my boss wanted to see her. Got corvid 19 and was out for a few weeks. Honestly thought I was going to die as it felt so bad. Got better and took her to a car show and a nice drive down the beach. That's why there's only 67 miles on her.

 

Glad you recovered. Much more of an issue than valve springs, which if an issue can get fixed good as new.

Hope your car will be fine. Odds are in your favor.

 

OK, fair enough. Now that you are better, celebrate by driving it around to ensure you don't have the valve spring issue, so you stop worrying about. Worrying gives you wrinkles. And if a valve spring breaks, they will replace them all with new ones, and you won't have to worry about it anymore. So driving and enjoying your car is the solution either way! Plus I heard from my cousin's, brother-in-law's uncle that driving your Corvette speeds recovery from CoVid-19.

 

Thank you for your good thoughts, Jerry. Really appreciate it.

 

What I am seeing in the broken spring pictures is that the broken spring still helps to hold the valve closed. I think that is the reason the valve is not dropping, and hitting the piston. That is a good thing, as usually a dropping valve will break pistons, crack cylinders and ruin the head. If that happens, the engine is junk. Too much debris flying around inside.

 

Almost 700...

 

Things are looking up. Few have failed with that many miles, I seem to recall one. A few hundred more miles and you likely in the clear. Get driving!

 

Thanks JerryU...Yes,I picked up my car on September 2nd...I've got about 700 miles on it now.As soon as ETA blows out of SW Florida I'll take her out for a spin..We've probably gotten 5+inches of rain today already..

 

Thanks....I will as soon as this tropical storm gets out of SW Florida!!...

 

We've had a steady rain most of the day. Be heavier tomorrow. C8 should be able to go to the store Saturday!

 

Must be a hungover Bills fan assembling on a Monday morning. The engine plant is in Tonawanda, NY and the Bills are doing quite well on Sundays.

 

Hi folks,

I'm new here and I'd like to ask your help. I'd like to buy a 2021.08. C8 Lt2 but I read in a previous post that some of the 2020 C8s may have a problem with the valve springs. Is it conceivable that the 2021 models are also affected by this? My VIN number is 51222....thanks in advance for the answers