skeet

I am new to Z06 ownership ( car is still on the transport from Ohio) and worried about what I hear about valve springs breaking. How many actually had this happen? Is it connected to any Vin number run or build date? Thanks

zo6vetteman2003

There is nothing wrong with the ZO6 stock valvesprings as long as you know the do's and don'ts. The issues are and have been if you leave the car for a long time parked with compressed valvesprings this may cause a valvespring to break, so run the engine to operating temperature and drive it as much as possible if stored. Raising your rev. limiter well beyond the springs ability at 6600rpm where spring frequency starts to deteriorate (harmonics) and valvefloat ensues. The other issues are Cams. If you swap your cam for a cam with higher lift, replace the valvesprings with springs rated for the amount of new lift. The stock valvesprings are a beehive design rated at 271lb./in. The springs are good quality, but can only handle up to .570" of lift max.

Wolf Dog

What year is it Skeet? Someone either here or on the road racing forum did a post, several in fact last month after doing a lot of research on the issue. What started him was breaking two springs on separate occasions on his '02. My '02 broke one with about 9000 miles on it. At the time I broke mine several other members broke springs on thier '02's. There indeed seem to be an issue with that model year. GM admits an issue with that year but won't say whether it was just a bad batch or if it was a design issue. Most of the guys had their springs replaced by GM. In my case the valve broke and went flying through the engine then finally getting stuck in the opening to the starboard cat. GM replaced the entire engine. I've since replaced the whole valve train as the car is just a track car now and I wanted the reliability of roller rockers.

Do a search and you might be able to find the posts I am referring to..or better yet he will read your post and chime in.

Good luck.
Steve

skeet

Wolf Dog - I think I remember the thread but I thought he was talking about a bad batch of springs and not a design problem. What is your build date and vin number? Maybe other people who have had this problem can send their vin number in also to see if their car was made close to the other cars having a problem.By the number of replies here to this topic it does not sound like it is too common.
I bought an 85 Ford tempo to do chores and for rain/snow days (instead of driving my mint 88 and 95 Vettes) and found it had a problem with a distributor module. One day I saw in a newspaper that there was a class action suit because so many people were having the same problem. I sent in my receipt for work done and about 5 months later I got a check in the mail for $350.
Anyone else have this problem?

skeet

Guess it is not common. That's nice to know.

Jedster

I broke my valve springs, 2002 Z06,

It had something to do with MISSING 3rd gear, and banging the rev limiter!!!!

Be careful in your shifts, and 90% of the time, its the driver not the car!


HAVE FUN

Diamond

Yeah, I had one break. Stalled while idling. GM wouldnt replace them all, so I did myself.

skeet

Diamond What year is your Z and what is the vin or build date?

24hr Z06

My #8 cyl. spring broke a little after passing the 15,000 mile marker on my 2004 Z16..

Almost always warmup the oil temp to 170 before getting on the car (have been a few times where I went above 4k but not past 5800)..

Rev limiter was set to 6900rpms, never missed a shift, nor have I ever hit the limiter.. Maybe went past 6700rpms once before this happened..

Day the #8 went, I was chasing down 2 bikes for about 10mins, and driving the car pretty hard.. Started to slow down, and about 5mins later it broke..

Mods.. Tune, intake, t-stat, and headers.. Good excuse to upgrade the springs, so now the car is ready for a cam..

LTC Z06

Added this to post 17 of the FAQ.

zo6vetteman2003

This is a very important point, even with a heavy duty aftermarket valvetrain. Although your coolant temperature may be over 176 degrees, your oil temperature will be alot cooler during the first few minutes. It is important to get your oil temperature well over 150 degrees before visiting higher rpms. This is one of the reasons why some valvetrains get damaged in addition to my #2 post above. I always let my engine warm to where I am satisfied that the chances of breaking something are remote. Even in the dead of summer, it doesn't matter, only that you will not have to wait as long.
Excellent point 24hr ZO6!