JackD

I was going 85 mph on a freeway when I broke an exhaust valve spring on my stock 2003 Z06.

As I tried to slow down and pull over, the engine died (at 35 mph).

It have 72k miles on my Z06; my mechanic says that I don’t need compression and leak down tests after the new spring is in place.

Other than replacing the spring, is there anything else I should be concerned with? Is it possible for the valve to collide with the piston head? Is this a common failure on stock Z06s?

Any advice? Thanks in advance….

heavymetals

Don't know who your mechanic is, but I suppose he is right if there is no obvious damage when he pulls the spring.

That is, if the valve is loose and not bent after hitting the piston.

Hope you got lucky and all you broke was a spring.

This is not the first time I have heard of this.

Guess I will have to get off the dime and replace mine.

I already did it to my V, but that is my "daily driver" so I need it to be dependable.

Cobra4B

IF the valve didn't drop all you'll need is new springs. I'd replace the entire set.

These cars aren't your average toyota... you must take it easy when they're cold. The cam is rather large for a stock car and that necisitates stiffer springs. Stiffer springs are more brittle when cold.

Let your oil get up to at least 140 on the DIC before going WOT or over 3000 rpms.

redroket

Same thing happened to me! I had the dealership change the broken spring which I now wish I would have had them all changed! Its true these cars won't run with a broken valve spring!
Good Luck!

RAMMAN

I would do a quick compression test on the one cylinder that the spring broke, after it's replaced. If it checks good replace the rest of the springs for the added insurance.

vettesrnice

I had a broken spring on my Ls1 in my 72 Chevelle and it ran great but the spring only lost one twist on it.
Don't think you need a leak down test for the rings but the test will let him see if the valve is seating in the head.

Z06_Bob

At 72K miles and a broken spring, I can't believe your mechanic is only going to replace the broken spring?! The stock springs on the '03 Z06 aren't that strong to start with... I would upgrade to a set of Comp. 918's for added insurance and dependability.

Z06_Bob

MVR 155

DO NOT just change the one spring.... do the whole set, the comp 918's are a good replacement, cheap insurance in my opinion.

mr-z

Is your Z stock.

heavymetals

Replace all the springs.

zulatr

If you change to the 918s, which many people swear by, can you raise the safe rev limit on the car? Seems like valve train is the current limiting factor for rpm in the LS6. What can you rev that spring to with the stock cam?

mk

Z06_Bob

I would bump it 200 rmp's to 6800 with the stock cam, but that's about it to be safe. You should still be shifting just before hitting the rev limiter.

Z06_Bob

Diamond

I had two break sitting at an idle. GM warranty would only replace the broken ones, I wanted them all replaced. No go. Soon after I switched camshafts and went with all new springs.

bluestreak63

I don't start getting on it and keep it below 3000 rpms until oil temp is at least 165-170 degrees. Probably overkill, but I'm in no hurry...well maybe sometimes...