MIKER

The number 6 intake valve spring broke on my 2002 Z06. There was no valve to piston contact. I replaced all of the springs and all is well. I was one of the lucky ones who got off cheap.

Like many others who have suffered with broken LS6 valve springs it happened under a low to no load situation. I had lifted throttle in 6th gear while approaching a reduced speed zone from 70 mph. It started ticking and the check engine light flashed on a couple of times (P0300). I immediately killed the engine and coasted into the first available parking lot. I never attempted to restart the engine based on the horror stories I've read here on the forum about the valve dropping after restart.

I have been aware of this possiblility for a long time and even somewhat expected it. I had even purchased all new springs, retainers, keepers, and seals from forum member mitymikec two years ago but never got around to replacing them until now. I was glad to have had them on hand but I should have replaced them sooner.

I'm posting this in hopes that other 2002 Z06 owners will take heed and change their springs before possibly loosing an engine.

P.S. For reference my Z06 has 76,000 miles on it but from what I've read about it here on the forum, spring failure doesn't really correllate with any certain mileage.

Z06SRUL

That's a real bummer. Another reason to buy the 2001.

Kurtomac

ya...good reason to buy a 01 so you can have oil consuption and not have to spend 150 bux on better replacement valve springs that take an hour to put on...good one....oh yea you can have less power and worse resale

Tech

W
O
W

BTW, they are $50 from Lingenfelter.

~Josh

Smart you killed it right when you saw the signs.. Most wouldn't.

Are you guessing there was no ptv contact? That ticking sound was the piston slapping the valve upwards.

If the valve still spins freely in the guide I'd suppose it's fine not to pull the head, but I'm sure the piston and valve touched.

LS6Beachbum

Glad to hear you avoided the restart.


I personally had my valve springs replaced around 50,000 miles by CJ at cunningham motorsports and have slept well since then. Well worth the $$$.

81c3

Youre making me nervous..... my 02 Z has 79k on it.

MIKER

I suppose my stating, "There was no valve to piston contact.", may have been a bold statement. I did not visually verify that no contact had been made by using a borescope or pull the head to inspect the internals.
However, the post spring replacement compression test yielded the same values I had noted from an earlier compression test. (~175 psi)
Even if there has been piston to valve contact it is running perfectly now and I'm not curious enough to look into it any further.

Is that correct? I assumed the "ticking" was due to the clearance between the valve stem and rocker arm caused by the broken spring. I would guess that the valve would no longer seal after being spanked by the piston at least several hundred times before I killed the engine.

As a side note, I also found it interesting that once 125 psi of compressed air was applied to the cylinders, to hold the valves in place during the spring change, I was unable to press down hard enough on the valve stems, with my thumb, to break the seal.

Atok

I think you're correct on that. If the cylinder holds pressure (leak down test) then you're fine.

ZO6ME

Upgraded valve train is probably the smartest mod I did. It just sounds like good insurance if nothing else.

Z06_BluByU

when was your car manufactured (its on the driver side door label)?

mooty1

Some people are talking about changing to 04 springs,but aren't the specs the same on the 01,02,03&04's ?

z060-0

My 02 has 20,000 miles. Should I be worried. Never heard of this problem before.

mooty1

Sorry,yes

mooty1

I think the springs for 50.00 from lingenfelter are same as stock and are the ones that are breaking

~Josh

The '01 springs are only rated for .525 lift of the '01 cam.

You can add Comp 918 springs which cost about $190 and look identical to stock (you can reuse the oem retainers and locks) and they are rated up to .600 lift.

Years ago there was a bad run of 918 springs. They were on my Firehawk. Under very light load there was a tapping sound for about 3 seconds and then the motor blew. The tapping was the valve hitting the piston. On the motor teardown, piston #3 was GONE.

striper

Is this problem common to only '02 Z's? I've heard of the problem before but have never given it much thought. I have an '03 Z06 with 73k miles on it. It runs perfectly, but should I be concerned? I'd rather fix it before I blow an engine. What are reasonably priced springs to use with totally stock heads? I've got a Honker intake, 160 thermostat, LG street exhaust system, Magnaflow catback and an ECS tune. It runs great and more power than I can use in NJ driving conditions. If I change the springs is it worthwhile doing better hi-lift rockers at the same time if I don't intend to change the cam and heads in the future? Recommended rocker arms?

bumble-z

I believe the early run of 03 Z's had the same bad batch of valve springs too. I'll be changing mine out soon.

mooty1

I broke one last spring.Only changed the one that failed.Can't take the risk any longer.I believe more and more 02,03 &04's will begin to break with age.I believe all are the same spring. I am going to contact comp cam & Lingenfelter tomorrow and see what they recomend. GM should correct it but i'am sure they think there is no problem

MIKER

09/2001