[Z06] Current C5 Z06 owner - C6Z move worth it for me?
02-26-2017, 07:24 PM
#1
Racer
Thread Starter
Current C5 Z06 owner - C6Z move worth it for me?
Lots of these topics come up but I'll keep this short. I've got an '01 C5 Z06 making about 380 whp and it runs and drives great. While I do like the styling of the C5 FRC, I absolutely LOVE the C6Z styling - it's just so modern and muscular and I can stare at it for hours. With my C5, I find myself having to find the correct angle to do the same, and it always seems to be the rear 3/4 view or side view. 
Anyway I've read all the stuff about the valve guides and so forth on the LS7 and I won't lie its got me worried. I reckon a warranty (which would be a must) would mitigate that fear of mine or getting the heads done would also solve the problem. It's weird, I don't feel as connected to the C5 Z as I thought I would and I'm really kind of disappointed with the interior (above what I already knew about it). I often ask myself if the lack of connection, in part, is due to it being quicksilver and me having never owned any other color besides black. The C5's need major dropping of the suspension and are under-wheeled in my opinion. With just lowering via stock bolts, the C6Z looks f'n nasty. The C6Z also *seems* to have a much nicer interior from every picture I've seen. Unfortunately I do not know anyone with a C6Z so I can't physically touch one. Located in southern CT if anyone wants to show me theirs
This is not a track car - weekend street car only. Anyone go to a C6Z and regret it?
Anyway I've read all the stuff about the valve guides and so forth on the LS7 and I won't lie its got me worried. I reckon a warranty (which would be a must) would mitigate that fear of mine or getting the heads done would also solve the problem. It's weird, I don't feel as connected to the C5 Z as I thought I would and I'm really kind of disappointed with the interior (above what I already knew about it). I often ask myself if the lack of connection, in part, is due to it being quicksilver and me having never owned any other color besides black. The C5's need major dropping of the suspension and are under-wheeled in my opinion. With just lowering via stock bolts, the C6Z looks f'n nasty. The C6Z also *seems* to have a much nicer interior from every picture I've seen. Unfortunately I do not know anyone with a C6Z so I can't physically touch one. Located in southern CT if anyone wants to show me theirs
This is not a track car - weekend street car only. Anyone go to a C6Z and regret it?
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03-02-2017, 11:33 PM
Melting Slicks
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2018 C6 of Year Finalist
St. Jude Donor '10, '17
The issue of our heads has been discussed ad nauseum in these forums for years. About once a week, and often times once a day, a post or comment comes up regarding it. There are a few disbelievers still around - and probably always will be. Jerri is one of them. There was another poster recently that claimed that geography somehow magically played a role in premature valve guide wear. It doesn't bother me, or most of us here. Amusing at best. What bothers me and others are obvious mis-information, bizarre opinions regarding serious issues with no facts to back them, and ill-informed non-users giving poor advice regarding things they don't understand and never will.
Fact is, professional engine builders, machine shops and experts in the business almost universally agree that due to machining errors of our heads by Linamar, LS7s are prone to catastrophic failure. Some and likely many of the valve guide centerlines machined by Linimar are simply not concentric and depending on how bad will cause side loading of the valve stems. Valve seat runout in a high revving motor like the LS7 is a bad thing. The side loading (wiggling) of the valve causes wear on the guide and the seat. Eventually, the guide wears well beyond its service limit (valve-stem to guide clearance), the valve wobbles too much, the stem breaks and drops into the motor and boom goes motor. Additionally, the premature guide wear prevents the proper and efficient transfer of heat out of the stem and into the guide. Then the stem runs hot and can also cause the valve to fail. This is well documented and well understood at this point. It is not guessing, conjecture or opinion. It has actually, really happened many, many, many times. It isn't a myth. It isn't a guess. It isn't paranoia bred of contempt. It is a simple, yet very unfortunate set of verifiable, documented and proven facts. No amount of "opinion" can change this.
Some/many of the damn valve guides and seats in our heads weren't machined properly and weren't concentric. It sucks.
The machining errors of the heads by Linamar and GMs lack of quality control contribute to a measurable, beyond acceptable failure rate of our motors, and GM themselves have reluctantly acknowledged it right here on these forums. Katech, who developed, built and supplied the C5-R motors to Corvette racing for over 10 years, and who assisted in the development of the LS7 has documented and acknowledged the issue. American Heritage Performance, a well respected and full-on cylinder head machine shop has documented and verified the issue. Vengeance Racing, pretty much a master in modifying GM cars, especially LS motors and most especially LS7s has documented, verified and posted the data online. East Coast Supercharging, another top-notch shop has documented and verified the issue, and even posted a youtube video of it. I can go on and on here. So if you choose to believe or even consider "Jerri in New Jersey's" opinion over those of the above - well then we are wasting our time with the discussion.
In addition, experienced home mechanics, who wrench their own cars up to and including complete engine replacement have demonstrated and documented the issue. Even lacking the expert evidence mentioned above, I trust a guy like outhouse, who wrenches his own car over a random non-user who likely doesn't even change his own oil. I wrench my own car as well, I know my limits and I know my engine. I love the LS7. It is an engineering marvel and a miraculous accomplishment. There is nothing like it. Not even my C7 Z06 compares to my much beloved but always angry LS7 that howls and screams raw, unfettered power. It just needs a little love.
These are the facts.
Fact is, professional engine builders, machine shops and experts in the business almost universally agree that due to machining errors of our heads by Linamar, LS7s are prone to catastrophic failure. Some and likely many of the valve guide centerlines machined by Linimar are simply not concentric and depending on how bad will cause side loading of the valve stems. Valve seat runout in a high revving motor like the LS7 is a bad thing. The side loading (wiggling) of the valve causes wear on the guide and the seat. Eventually, the guide wears well beyond its service limit (valve-stem to guide clearance), the valve wobbles too much, the stem breaks and drops into the motor and boom goes motor. Additionally, the premature guide wear prevents the proper and efficient transfer of heat out of the stem and into the guide. Then the stem runs hot and can also cause the valve to fail. This is well documented and well understood at this point. It is not guessing, conjecture or opinion. It has actually, really happened many, many, many times. It isn't a myth. It isn't a guess. It isn't paranoia bred of contempt. It is a simple, yet very unfortunate set of verifiable, documented and proven facts. No amount of "opinion" can change this.
Some/many of the damn valve guides and seats in our heads weren't machined properly and weren't concentric. It sucks.
The machining errors of the heads by Linamar and GMs lack of quality control contribute to a measurable, beyond acceptable failure rate of our motors, and GM themselves have reluctantly acknowledged it right here on these forums. Katech, who developed, built and supplied the C5-R motors to Corvette racing for over 10 years, and who assisted in the development of the LS7 has documented and acknowledged the issue. American Heritage Performance, a well respected and full-on cylinder head machine shop has documented and verified the issue. Vengeance Racing, pretty much a master in modifying GM cars, especially LS motors and most especially LS7s has documented, verified and posted the data online. East Coast Supercharging, another top-notch shop has documented and verified the issue, and even posted a youtube video of it. I can go on and on here. So if you choose to believe or even consider "Jerri in New Jersey's" opinion over those of the above - well then we are wasting our time with the discussion.
In addition, experienced home mechanics, who wrench their own cars up to and including complete engine replacement have demonstrated and documented the issue. Even lacking the expert evidence mentioned above, I trust a guy like outhouse, who wrenches his own car over a random non-user who likely doesn't even change his own oil. I wrench my own car as well, I know my limits and I know my engine. I love the LS7. It is an engineering marvel and a miraculous accomplishment. There is nothing like it. Not even my C7 Z06 compares to my much beloved but always angry LS7 that howls and screams raw, unfettered power. It just needs a little love.
These are the facts.
02-26-2017, 07:34 PM
#2
Safety Car
I had two C5 Z06s. One was highly modified and one was stock. Great cars. I've had a C6 Z06 since 2007. I did have the LS7 replaced under warranty. I now have 70,000 miles on it, 50+ track days that include over 1000 laps exceeding 150 mph. Still on original clutch, trans, diff. Other than the LS7, the car has been perfect.
02-26-2017, 07:37 PM
#3
Drifting
I do not believe you will be disappointed if you make the switch. If you have the funds to get a new enough car with warranty and will make you feel safer, do that. If not just address the head issue and enjoy the car. You can find many for sale that have already been "fixed".
Good luck.
Good luck.
02-27-2017, 12:51 AM
#4
Team Owner
Had my 03 C5Z for years...absolutely loved it, fixed a few of the shortcomings you mentioned, but I never considered selling it. Wound up buying a 09 C6Z, and loved looking at both parked in my garage. 
Having said that, the C5Z sat for months without moving because the C6Z was easily the car I naturally gravitated to when I wanted to take one out. Sold the C5Z to a buddy, and while I missed it...I didn't miss it that much. I seriously have no plans to part with my C6Z for the foreseeable future. 
Having said that, the C5Z sat for months without moving because the C6Z was easily the car I naturally gravitated to when I wanted to take one out. Sold the C5Z to a buddy, and while I missed it...I didn't miss it that much. I seriously have no plans to part with my C6Z for the foreseeable future.
Last edited by MTPZ06; 02-27-2017 at 12:51 AM.
02-27-2017, 09:26 AM
#6
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I recently made the switch... I owned an 01 C5Z fully built 414ci stroker w Nitrous... It was a beast! Owned it about 8 yrs. Picked up an 08 C6Z w 3LZ and Linen interior. although I loved the raw feeling of the C5Z it doesn't compare to my C6Z in terms of comfort, drivability,and overall potential once i begin to mod. Truly, I don't even miss my C5Z.. Its been about 3 weeks.
02-27-2017, 09:37 AM
#7
Safety Car
I'll add my two cents....bought an 06 Z and drove it 108K miles, it was bone stock until 86k miles when I went with headers, cam, CAI., no head work. That thing was a beast...traded it for an 11 Carbon Edition. Still have the Carbon, with 40k miles, stock, no head work. I absolutely love the car, but don't drive it near enough now, and am thinking about selling. I just can't justify it sitting in my garage all the time.
But to answer your question, you will be amazed at the C6Z...
But to answer your question, you will be amazed at the C6Z...
02-27-2017, 09:55 AM
#8
Team Owner
Interior is a step up but not that great. Definitely needs some work. With new steering wheel showing up today, I officially have more into the interior than new aftermarket heads. Heads cost $800-3000 to fix depending on what you do and who does it. A decent set of tires is $1600-2000. A clutch is $1500+. Quality brake job with good pads is $750-800 or more. These are not cheap cars to maintain, so the don't let $1500 head job turn you away, even if it is done every 30k miles.
02-27-2017, 10:18 AM
#9
Race Director
So will I: drive one.
Pity you're not in e-central WI, would gladly give you some seat time.
Only danger, getting you out.
Didn't own a C5Z, only a '03 AE, but went to a '06 w/ Z51...pretty close to C5Z performance-wise. LS7's a different animal from 'em all.
Good advise by all, particularly C6 Zs aren't inexpensive to own/maintain. But oh boy if you can, what a car and compared to P/F/L cars? C6Z is downright cheap & runs with the best imports.
Drive one, G/L
Pity you're not in e-central WI, would gladly give you some seat time.
Only danger, getting you out.
Didn't own a C5Z, only a '03 AE, but went to a '06 w/ Z51...pretty close to C5Z performance-wise. LS7's a different animal from 'em all.
Good advise by all, particularly C6 Zs aren't inexpensive to own/maintain. But oh boy if you can, what a car and compared to P/F/L cars? C6Z is downright cheap & runs with the best imports.
Drive one, G/L
02-28-2017, 04:19 AM
#10
Instructor
I have an 04 z06 and an 09 z06 with the dark titanium dash. I like the interior of the 09z. The body lines of the exterior of the c6z are pretty amazing. The c6z is more refined when driving. The engine has more power but less lopey. I'm debating tossing a mild cam in to make it a bit more raw like the c5z. I actually really like the c5z due to the shorter gearing. It feels like something you really push and are rewarded. The capabilities of the c6 in the twisties are mind bending. The c6 is going to be expensive in operating cost from gas, to tires, to brakes....
I appreciate different things from each of them.
I appreciate different things from each of them.
02-28-2017, 04:36 AM
#11
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You will love it. Many have had the heads fixed/replaced......so find one w them corrected or make sure you buy it w room in the price so you can have them repaired. It's a great vette and will put a smile on your face!
03-01-2017, 10:31 AM
#12
Burning Brakes
Best all around car GM ever produced in my very biased opinion. LS7 is an absolute animal and loves to be pushed. The torque down low will leave you giggling like an imbecile every time you mash the gas pedal and you will have to fight the urge to not drive like an A Hole whenever you hit the streets. A very rewarding driving experience every time you drive it. I love mine and couldn't be happier with it. If the heads cause you concern, simply do your research and find out what the fix is, (yes, they can be fixed easy enough) and get them addressed. Not much to do after that but enjoy the heck out of it.
03-01-2017, 06:16 PM
#13
Team Owner
I owned an 02 Z06 for 4 years, H/C/I and made 457rwhp/400rwtq. I loved that car but not as much as I loved the 06 Z06 I sold it for.
03-01-2017, 09:44 PM
#14
Melting Slicks
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2018 C6 of Year Finalist
St. Jude Donor '10, '17
I owned a 2003 Electron Blue Z06. Now I own a C6 Z06 and C7 Z06. I regret ever selling my C5, but only because I love Corvettes. No regrets at all in buying the C6. It is my favorite, by a long shot. Vast, significant improvement over the C5 in most categories. And when you hear an LS7 sing at WOT, you will understand.
03-01-2017, 10:11 PM
#15
Race Director
I believe most tests of the ls7 heads were done incorrectly so don't think you have to do the heads. If your in southern conn. And want the real scoop call up and make an appointment to go see Paul Koerner at Jackson chevy in Middletown Ct. He does the corvette seminars at bowling green, carlisle, Bloomington gold, mid America. He is pretty knowledgeable on the c6 z06 head issue. The percentage of c6 z06 s that really had head issues was very very small. The internet and vendors who profited off of replacing heads blew that whole scenario into a full blown issue when in fact it was quite small.
As far as test driving a c6 z06 find one at a local dealer over the internet or autotrader or Craigslist etc...in the preowned inventory and make an appointment to test drive one.
Then you ll know if you want one. That's what I would do.
I had a c5 z06 with 385 rwhp and it was awesome. The c6 z06 is a better drive as long as you don't want roof off motoring. I like the roof off driving experience so years back I bought a c6 z51 coupe. Great car but I wouldn't call the interior that much better. I put in a dsv d shaped steering wheel and it helped.
Good luck deciding..I believe the c6 z06 is just about at the bottom of its pricing curve. I don't think you would loose any on depreciation over the ownership experience.
I'm guessing 17 grand for your car and 32 grand for a c6 z06... give or take a few grand either way...
So it's probably a 17 to 20 grand upgrade out of your pocket...
Is it worth it? Only you can decide....
Have fun.
As far as test driving a c6 z06 find one at a local dealer over the internet or autotrader or Craigslist etc...in the preowned inventory and make an appointment to test drive one.
Then you ll know if you want one. That's what I would do.
I had a c5 z06 with 385 rwhp and it was awesome. The c6 z06 is a better drive as long as you don't want roof off motoring. I like the roof off driving experience so years back I bought a c6 z51 coupe. Great car but I wouldn't call the interior that much better. I put in a dsv d shaped steering wheel and it helped.
Good luck deciding..I believe the c6 z06 is just about at the bottom of its pricing curve. I don't think you would loose any on depreciation over the ownership experience.
I'm guessing 17 grand for your car and 32 grand for a c6 z06... give or take a few grand either way...
So it's probably a 17 to 20 grand upgrade out of your pocket...
Is it worth it? Only you can decide....
Have fun.
Last edited by JerriVette; 03-01-2017 at 10:14 PM.
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03-02-2017, 11:34 AM
#18
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Wow... a bit harsh...
So, because this guy has an opposing opinion, he's a troll, and pitiful to boot? What makes you the expert on this subject matter to call this guy out. You have been on this forum for what.... a year? Are you a GM tech? Or do you work with these cars for a living? Talk about credibility issues. In other posts you "seem" to have all of the answers. What qualifies you specifically over this other guy who simply shared his opinion, experience.
To be clear... I am not taking sides nor do I know this jerrivette fella... Just trying to understand your rational. Please, enlighten me.
For the record... I will be doing heads on my 08Z in April..
(LG Motorsports) as I am not willing to take chances. Not that I support either yours or the other guys theories on the head issues for the LS7's... Mine is a proactive approach just in case.
So, because this guy has an opposing opinion, he's a troll, and pitiful to boot? What makes you the expert on this subject matter to call this guy out. You have been on this forum for what.... a year? Are you a GM tech? Or do you work with these cars for a living? Talk about credibility issues. In other posts you "seem" to have all of the answers. What qualifies you specifically over this other guy who simply shared his opinion, experience.
To be clear... I am not taking sides nor do I know this jerrivette fella... Just trying to understand your rational. Please, enlighten me.
For the record... I will be doing heads on my 08Z in April..
(LG Motorsports) as I am not willing to take chances. Not that I support either yours or the other guys theories on the head issues for the LS7's... Mine is a proactive approach just in case.
03-02-2017, 12:44 PM
#19
Safety Car
No, it is not about opposite to my opinion.
He is a troll because he constantly trolls his pitiful opinion. There is a complete consensus here about the guide issues that is the complete opposite as his bad advise.
ANYONE who tells people to ignore the consensus is doing so from stupidity. And certainly will not replace a guys motor after giving him bad advise, and the guy who does listen to Jerri, looses his motor.
When he tells us in his post above ""I believe most tests of the ls7 heads were done incorrectly"" he is telling everyone who tested they were idiots and have done it incorrectly.
So WHY are you sticking up for a guy telling people to ignore a problem GM admitted to?????
03-02-2017, 12:58 PM
#20
Team Owner
^^ Dude, that Jerri guy regularly comes in here and states that the LS7 head thing is blown way out of proportion, and that less than 1% of these cars were affected. That 99.9% of us were lied to by our shops that we needed to address the heads, etc. So we're all morons that were sold a bill of goods? All the supporting shops (Like AHP, LG, CMS, Katech, etc.) are liars? His post above is most certainly toned down compared to his usual comments. But as far as experience goes, he has none...never owned a C6Z, never wants to own a C6Z, never inspected a set of LS7 heads, never examined the wear characteristics on a set of worn out heads, etc...the list goes on.
The vast majority of us in here knows he's talking out his *** on his less that 1% stuff, because an actual number will never be known for either side...but common sense has shown its a far bigger issue than that.
What most of us take issue with, is that he targets the new/prospective owner threads...and his comments can be very reckless to that new crop of owners that come in here. Those new owners can unfortunately hope/believe they have less than 1% chance of being affected, and that any sort of inspection is totally inaccurate and unnecessary. Is this Jerri guy going to step up and buy that guy (who now has a false sense of security) a new motor if and when his pops? All the majority of us try to do in here is educate people to have their car inspected, and take action based on the results if need be. He undermines that premise, and is doing the LS7 community a tremendous disservice. Is he entitled to his opinion...sure, we all are. But as far as the "facts" and statistics he typically states...he truly has none.
I'll get off my soap box and end my rant now...
The vast majority of us in here knows he's talking out his *** on his less that 1% stuff, because an actual number will never be known for either side...but common sense has shown its a far bigger issue than that.
What most of us take issue with, is that he targets the new/prospective owner threads...and his comments can be very reckless to that new crop of owners that come in here. Those new owners can unfortunately hope/believe they have less than 1% chance of being affected, and that any sort of inspection is totally inaccurate and unnecessary. Is this Jerri guy going to step up and buy that guy (who now has a false sense of security) a new motor if and when his pops? All the majority of us try to do in here is educate people to have their car inspected, and take action based on the results if need be. He undermines that premise, and is doing the LS7 community a tremendous disservice. Is he entitled to his opinion...sure, we all are. But as far as the "facts" and statistics he typically states...he truly has none.
I'll get off my soap box and end my rant now...
