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[Z06] ***Build Date/VIN Analysis of LS6 Valve Spring Failures***

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[Z06] ***Build Date/VIN Analysis of LS6 Valve Spring Failures***

Old 03-30-2018, 11:09 AM
  #521  
mad.Z06
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Originally Posted by clemson3 View Post
It sounds like you won't have peace of mind unless you swap them out, so I vote you just go ahead and do that.
Agreed and that's the direction this is heading. Was being optimistic that someone "in the know" could point out a sure fire way to tell. Without a lick of yellow I'm fairly certain they've been replaced - especially if the part for that year was always yellow. That's the detail I can't confirm.
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Old 03-30-2018, 01:12 PM
  #522  
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Default Go Ahead - Change 'Em!!

Originally Posted by clemson3 View Post
It sounds like you won't have peace of mind unless you swap them out, so I vote you just go ahead and do that.
I agree with Clemson3. We had a hard saying in the Navy about documentation of work. Not documented? Not done. If you don't have the documentation, either through a service invoice or a searchable cloud record by a dealer who did the work, then I would get the springs replaced. I had mine replaced with OEM Chevy catalogue official part number springs and the work was done by my local dealer. There are other aftermarket springs out there that are allegedly as good or better. Just do your homework.

According the the anecdotal stuff out there, you can break a spring at your current low mileage, or it might wait until 95,000 miles. But the point is that this engine and certain VIN Lots have already DEMONSTRATED breaks, and those broken springs can result in a ventilated block and total loss of the engine if it occurs at high RPM.

Chevrolet should pay for all those disasters and pay warranty on all the fixes. But it'll never happen.

Pay possibly $8000+ later or spend the roughly $800-$1000 and get new springs and get it done right. This car is too nice and superb driving and fun to worry about such things.

Of course, you could always swap out for a nice new crate LS3 525 motor, add some nice Kook long tube headers as part of the swap, and have a rubber-shredding engine with a factory warranty. That thought is often on my mind. But your miles are too low. Get the new springs!!

Good luck,
Mike

Last edited by TomcatMike; 03-30-2018 at 01:13 PM. Reason: Forgot the sig
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Old 03-30-2018, 01:22 PM
  #523  
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Originally Posted by TomcatMike View Post
I agree with Clemson3. We had a hard saying in the Navy about documentation of work. Not documented? Not done. If you don't have the documentation, either through a service invoice or a searchable cloud record by a dealer who did the work, then I would get the springs replaced. I had mine replaced with OEM Chevy catalogue official part number springs and the work was done by my local dealer. There are other aftermarket springs out there that are allegedly as good or better. Just do your homework.

According the the anecdotal stuff out there, you can break a spring at your current low mileage, or it might wait until 95,000 miles. But the point is that this engine and certain VIN Lots have already DEMONSTRATED breaks, and those broken springs can result in a ventilated block and total loss of the engine if it occurs at high RPM.

Chevrolet should pay for all those disasters and pay warranty on all the fixes. But it'll never happen.

Pay possibly $8000+ later or spend the roughly $800-$1000 and get new springs and get it done right. This car is too nice and superb driving and fun to worry about such things.

Of course, you could always swap out for a nice new crate LS3 525 motor, add some nice Kook long tube headers as part of the swap, and have a rubber-shredding engine with a factory warranty. That thought is often on my mind. But your miles are too low. Get the new springs!!

Good luck,
Mike
Great advice, thanks Mike. Was going to replace them as part of a Cam install because there's no sense paying the $800 - $1,000 now and then removing them and and throwing them in the trash as part of a Cam install. Not to mention paying X2 the labor since, quite literally, the same steps need to be taken .
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Old 03-30-2018, 01:42 PM
  #524  
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Default New Cam

Originally Posted by mad.Z06 View Post
Great advice, thanks Mike. Was going to replace them as part of a Cam install because there's no sense paying the $800 - $1,000 now and then removing them and and throwing them in the trash as part of a Cam install. Not to mention paying X2 the labor since, quite literally, the same steps need to be taken .

Just a quick note on a new cam. I was all hot-to-trot to get a new cam. I plan to have new Kook long-tube headers, new CATS, and new O2 sensors installed, possibly add a Corsa exhaust, in the next couple of months. Already have it budgeted with a quote from the shop.

I was told, candidly, by the shop, that a new cam is not a drop-in plug-and-play deal. The cam swap needs to be thoughtfully and logically engineered and installed and dyno'd. Probably needs to be dialed in and degreed professionally, depending on your requirements. You're talking a lot of money, so make sure that the headers and cam swap are worth the mere 40 to 50+ HP increase. He'll be glad to take my money, but we're talking $3500 for just the cam work alone.

Do the springs, mebbe the Kook headers, and have someone do a good dyno job with appropriate chip update so that the car remains driveable on the street and you can live with it long term everyday. That's far cheaper than adding the cam and new springs (and rocker arms) too.

Just a thought . . . . .

Good luck,
Mike
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Old 09-20-2018, 10:40 PM
  #525  
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if my last digits on my 2003 z are 30034 I should be in pretty good shape?
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Old 09-21-2018, 12:03 AM
  #526  
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Originally Posted by joesephus View Post
if my last digits on my 2003 z are 30034 I should be in pretty good shape?
Likely not. It appears daunting at first, but is doable at home. Get the dual valve spring compressor tool and it goes twice as fast.
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Old 09-21-2018, 08:42 AM
  #527  
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Default C5 Z06 Valve Springs

Originally Posted by Trash View Post
Likely not. It appears daunting at first, but is doable at home. Get the dual valve spring compressor tool and it goes twice as fast.
Yes, it can be done at home. But ensure you have the spark plug hole adapter and compressed air to keep the valves closed and seated anytime the spring keepers are off. This is ABSOLUTELY CRITICAL!!

Back to your VIN - mine was in the moderate risk category, so it was a no-brainer to replace the springs. Look at it this way - regardless if it's Low, Medium, or High Risk, the Impact if you drop a valve at 4000 RPM will be very HIGH, and you are looking at a new motor if the piston, rod, crank, block are all boogered up. Parts and Labor will run you the south side of $1000, depending on where you go. I bought my own Chevy OEM springs out of the catalogue, and my local Chevy dealer, who has a Corvette expert, charged about $700 for the labor. Cheaper than $6000+ for a new or used motor.

Since then, I have added new Kook Long-Tube headers and Kook Hi-Flo CAT-back X-Pipes. It was dyno'd with three runs to redline and pulled 383 RWHP, which equates roughly to 440-450 HP at the crank.

Go ahead - replace them. It's the right thing to do.

Best of luck to you.
Mike
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Old 09-21-2018, 03:59 PM
  #528  
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Originally Posted by TomcatMike View Post
Yes, it can be done at home. But ensure you have the spark plug hole adapter and compressed air to keep the valves closed and seated anytime the spring keepers are off. This is ABSOLUTELY CRITICAL!!

Back to your VIN - mine was in the moderate risk category, so it was a no-brainer to replace the springs. Look at it this way - regardless if it's Low, Medium, or High Risk, the Impact if you drop a valve at 4000 RPM will be very HIGH, and you are looking at a new motor if the piston, rod, crank, block are all boogered up. Parts and Labor will run you the south side of $1000, depending on where you go. I bought my own Chevy OEM springs out of the catalogue, and my local Chevy dealer, who has a Corvette expert, charged about $700 for the labor. Cheaper than $6000+ for a new or used motor.

Since then, I have added new Kook Long-Tube headers and Kook Hi-Flo CAT-back X-Pipes. It was dyno'd with three runs to redline and pulled 383 RWHP, which equates roughly to 440-450 HP at the crank.

Go ahead - replace them. It's the right thing to do.

Best of luck to you.
Mike
Quick caveat. To address the response from Trash, he provided me a very detailed way back in early 2015 how to do the valve springs without using compressed air. One has to rotate the crankshaft to TDC for the applicable cylinder. This allows the valves to drop only a very short distance onto the piston. This method can be time consuming. I got started, found I needed 3.6 hands, had no help, and aborted. It's tedious but doable.

Best thing is to get the plug hole adapter and compressed air - should work well regardless of the piston position.

Cheers,
Mike
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Old 10-11-2018, 09:27 PM
  #529  
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Does anyone know if this VIN of my buddy’s 03’ is affected?

1g1yy12s535132686
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Old 10-14-2018, 05:50 PM
  #530  
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Never too late to join this club I guess. 2003 Z06 with 36,500 miles and cylinder #3 has a broken valve spring. Looks like I got really lucky and the valve didn't drop and still holds compression but will be digging deeper for the inspection just to be sure. I'll get the car's build date number when I get the car back.

Add me to the statistics and please change your valve springs to those who have not


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Old 10-15-2018, 09:54 PM
  #531  
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what springs would be best to go with, my 03 was built in april, is it in the range most dangerous or least or somewhere in the middle.Either way I am gonna swap em, was quoted 600 and parts. Just want to make sure I get good springs from gm, thanks jy
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