Cobra4B

When? 60k, 75k, 100k?

I have 55,xxx miles on my car w/ 6 HPDEs on it, probably 10 auto-x events, and a few 1/4 mile blasts. I daily drive the car in decent weather and probably see redline at least once everytime I drive it.

I remember reading that GM engineered the car to go over 100k on stock valve springs.

I had always figured I'd be doing a cam upgrade and it'd get taken care of then. However, after driving a few cammed out cars I've decided that I like my car's manners now and the fact that I can easily drive it to work or 12 hrs to BG kentucky when needed. Plus my 384 rwhp with the aluminum flywheel is honestly enough for now... the car is fast

jasonberkeley

It depends what you have your rev limiter set at, and how often you take it there.

In SCCA T1, many of us (with LS6s) have our rev-limiters set at 7100 rpms, and regularly shift just below 7000, and occasionally getting into the rev limiter.

Replacing valve springs with that kind of duty cycle is recommended by the folks at Phoenix every 10-11 race weekends.

If your not revving that high, you are probably fine leaving them alone.

Cobra4B

I generally shift at 6000 during HPDE events, sometimes take it to 6500 if someone is keeping close or I'm playing catchup.

John Shiels

My motor went 55,000 before it popped I had many more track events than you have on yours I believe. I had a LS1. Pull one and test it. I wouldn't bother if I wasn't dumping a cam in it. CAM 423/385 Springs should be cheap to install if you would feel better. 300-400 I think I dumped mine once in my LS6 after 2,000 miles but they never tested them like I ask to see how much they fatigued. Springs cheap new motor Cam and good tune is easily driveable.

Falcon

No wonder I had a helluva time staying with you on VIR Grand last June!
Hell, I thought my car was just slow.

Cobra4B

^ No... you're just smarter than all of us modding our cars for a few more ponies.

You did the important stuff first =)

Wolf Dog

Cobra, you didn't mention what year your Z is, unless I missed it. The '02 was problematic and there was a very long thread last year in the Z06 forum about it. I have an '02 and was a victim at 20k miles. Came to a stop sign, the car died, restarted it and it sounded like it literally blew up. I knew something was out of norm long before it happened(another story). The big Corvette center here in No. Cal. replaced the entire engine with no hassle. They took the passenger side head off even though they were supposed to return it to the home office untouched. Obviously one of the springs broke as did the valve and other parts. Half of the broken valve was found jammed into the entrance of the right cat!

Later that year I took the opportunity to modify the engine, cam heads etc. and part of the upgrade included new springs and Crane roller rockers. I wasn't going for HP necessairly, rather reliability for the track and it was a great move. Anway, it appears that the general spring problem was limited to '02's but, if you are thinking about a prophylactic upgrade, I would certainly consider it. Steve

Cobra4B

Mine's an '01

0Randy@DRM

I have seen stock valve springs get weak before, but never broke (with a stock cam). I would change them out. Race tracks hate valve springs and valve springs hate race tracks. For every mile on the track is like a 1000 miles in 6th gear cruising. The only thing to rember is either put in stock springs or something better (many aftermarket springs are not better).

Randy

Cobra4B

^ Thanks randy... I may consider an eventual spring swap this year.

95jersey

With my new G5X3, I am told once every 2 seasons, and this cam is harsh on springs (so I'm told). I figure at 150 miles per track day, with 8 track days a season (1200) x 2 seasons = 2400 track miles. LG recommended 30k miles for standard street driving.

Makes you realize how hard these cams must be on springs! And it's not like you can buy the cheaper springs like 918. You need 921's or equivalent double springs which are $550+. So every two years if ALL GOES WELL, at minimum, I have a $750 (w/labor) spring job.

I guess that 423rwhp comes at a cost.

0Randy@DRM

"With great power comes great respondsablity" Said by the old timer in the movie "Spider Man". This statment is very true in racing also.

Randy

sleeper02Z06

Don't feel bad Jody, the yellow hot rod put the hurt on my pile even when I had some nice runs on him coming out of Oak tree! Thank god for hog pen where I redeemed myself!

Timz06

I would think your springs would be fine until at least 100k, you are only doing 2 de's per year.

Tim

tedster

My 02 Z06 is stock, with 107,000mi. It is my daily driver. From April thru October, I swap to Hoosiers and go hunting for cones to kill each weekend. About once per month during that period, I'll swap out the brake pads for Hawk Blues as well as the tires, and do either a high speed autox or track event.

I popped my first valve spring at 82,000 mi. Being the lazy SOB that I am, I only replaced the broken one at the time, promising myself that I'd do the whole set over the winter.

I popped the 2nd spring at 101,000 mi. Both times I was commuting to/from work, cruising along 13 mile Rd at about 40 mph in 4th gear.

This time I replaced the entire set. Let it be known that GM no longer produces the springs from 01-03 LS6 engines (P/N 12565315). For 04, the LS6 springs were upgraded and given a new P/N (don't have it handy). Same part is the service replacement part for all LS6s. Dimensionally identical, but with slightly revised metallurgy and treatment, to yield "a more robust" part, in the words of a GM Powertrain employee working on high performance V8 valve trains.

Maybe the new "bee-hive" springs will be more likely to live for 100k. I would have gone to an aftermarket twin spring had such a change let me continue to run in NCCC Group II.

Tedster

PS: No complaints here....I beat this car hard and she just keeps kickin' butt, with nary a problem. Swapping springs on a pushrod engine is a breeze...took us a few hours for the whole set...compared to the complexity of dealing with 32 springs, 4 camshafts, 2 timing chains/belts....I'm gettin' tired just thinkin' about it!<g>

RAFTRACER

My car has only 2600 miles and I have already replaced them once, and about to do it again. I do run my car to 7300 rpm though on occassions. Car is only driven on Sundays by mature adult

Tedster, I think I know you------I didn't realize that GM had superceeded a new valve spring part #, I guess straight to the parts counter for me tomorrow..........................

I have known of 4 different cars that broke valve springs way before 82k. Yeah, you should have replaced them all. One SS gentleman thought that I put a camshaft in his car , his car ran so much better after the new set of springs. I replace mine often since I am so hard on them and have also noticed reduced upper-end power with "killed" springs. Reasons enough for me

tedster

Yup, it's me....Don't get down to Morraine Assembly too much these days, or I'd drop by. New platform....new plant.

Shoulda called you for advice before replacing my compressor. That was a "2 skinned knuckle & a scraped arm" job getting the damned thing out once everything was loose!

At least the ABS module was easy to swap, but my wallet is a lot lighter. No more "failed attempts" at threshhold braking.<g> BTW, your fix on my control arm bushings is still holding up!

Should be ready to rock once the weather cooperates. Hope to see you at Kilkare or Grissom later this year.

gmblack3

My 01 broke a stock spring at 65k miles and 25-30 trackdays.

Car was 383/382 at the wheels.

I installed a nice crane dual setup plus 1.8 gold race rockers and Ti retainers.

About $1000 for all that. I never had a retune after the install, but the new owner did and it was 393RWHP.

I would wait another year like Tim said you only do 2 events a year.

VetteDrmr

Ok, I'm convinced I need to change mine. So, for a stock '00 LS-1, what do you go back with? GM parts? Aftermarket? No internal mods in this engine's future, stock rev limiter, etc.

TIA, and have a good one,
Mike

Allthrottleandsomebottle

A nice new set of PP Golds for less than $300...........buy a $125 double spring remover and have it done in a few hours with a good piece of mind