Newbie with LS7 Questions - Page 6 - CorvetteForum - Chevrolet Corvette Forum Discussion



C6 Corvette ZR1 & Z06
General info about GMs Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track

Newbie with LS7 Questions

Reply
 
 
 
Thread Tools Search this Thread
Old 06-25-2017, 12:09 AM   #101
rockinSeat
CF Senior Member
 
rockinSeat's Avatar
 
Member Since: May 2008
Location: Colorado Springs Colorado
Posts: 671
Thanks: 0
Thanked 6 Times in 6 Posts
Default

I did a statistical analysis once (see my prior posts). It was something like, with 30,000 z06s as a population, to get within +/- 10% accuracy we need a sample size of like 4 or 5 hundred cars. So if you look at the out of spec registry thread below, and it's sister thread the in-spec registry, there were 200 out of spec and about 25 in spec.

So my statistics are a bit rusty, but I think I could say with about 100 percent confidence that at least half of them are f'd up.

also, there was a helpful member here who used to keep a record of all the ls7 failures, see his old posts. He had about 35 dropped valve cases documented in his spreadsheet. That was years ago.

Another statistical analysis I did was on the mileage distribution...I concluded that the z06 population was not accumulating mileage very fast, in fact we wouldn't see most failures for years.

Guess what? Gm concluded the same thing. They'll be out of warranty before they pop, so as long as nobody spins into a semi on the interstate, we don't have to do a recall. Lol there have been two fires posted due to dropped valves with pictures.

So believe it or not, 6.5 failures per thousand may have been a true statement at one point in time, say, when the vast majority of all the ls7 had less than 20k miles. But what will the failure rate be when they've all had a 100k miles?

Hopefully it will be a lot lower because of people being proactive on this forum.


https://www.corvetteforum.com/forums/c6-corvette-zr1-and-z06/3386141-the-out-of-spec-guide-wear-registry.html

https://www.corvetteforum.com/forums/c6-corvette-zr1-and-z06/3385533-the-in-spec-guide-wear-registry.html
rockinSeat is offline   Reply With Quote
The Following User Says Thank You to rockinSeat For This Useful Post:
MTPZ06 (06-26-2017)
Old 06-25-2017, 12:19 AM   #102
Dirty Howie
CF Senior Member
 
Dirty Howie's Avatar
 
Member Since: May 2004
Location: SoCal
Posts: 25,345
Thanked 107 Times in 82 Posts
Default

Quote:
Originally Posted by rockinSeat View Post
I did a statistical analysis once (see my prior posts). It was something like, with 30,000 z06s as a population, to get within +/- 10% accuracy we need a sample size of like 4 or 5 hundred cars. So if you look at the out of spec registry thread below, and it's sister thread the in-spec registry, there were 200 out of spec and about 25 in spec.

So my statistics are a bit rusty, but I think I could say with about 100 percent confidence that at least half of them are f'd up.

also, there was a helpful member here who used to keep a record of all the ls7 failures, see his old posts. He had about 35 dropped valve cases documented in his spreadsheet. That was years ago.

Another statistical analysis I did was on the mileage distribution...I concluded that the z06 population was not accumulating mileage very fast, in fact we wouldn't see most failures for years.

Guess what? Gm concluded the same thing. They'll be out of warranty before they pop, so as long as nobody spins into a semi on the interstate, we don't have to do a recall. Lol there have been two fires posted due to dropped valves with pictures.

So believe it or not, 6.5 failures per thousand may have been a true statement at one point in time, say, when the vast majority of all the ls7 had less than 20k miles. But what will the failure rate be when they've all had a 100k miles?

Hopefully it will be a lot lower because of people being proactive on this forum.


https://www.corvetteforum.com/forums...-registry.html

https://www.corvetteforum.com/forums...-registry.html
Excellent post


DH
Dirty Howie is online now   Reply With Quote
Old 06-26-2017, 01:41 PM   #103
MH663
CF Senior Member
 
MH663's Avatar
 
Member Since: Jul 2014
Location: Dayton OH
Posts: 781
Thanked 80 Times in 74 Posts
Default

Quote:
Originally Posted by rockinSeat View Post
I did a statistical analysis once (see my prior posts). It was something like, with 30,000 z06s as a population, to get within +/- 10% accuracy we need a sample size of like 4 or 5 hundred cars. So if you look at the out of spec registry thread below, and it's sister thread the in-spec registry, there were 200 out of spec and about 25 in spec.

So my statistics are a bit rusty, but I think I could say with about 100 percent confidence that at least half of them are f'd up.

also, there was a helpful member here who used to keep a record of all the ls7 failures, see his old posts. He had about 35 dropped valve cases documented in his spreadsheet. That was years ago.

Another statistical analysis I did was on the mileage distribution...I concluded that the z06 population was not accumulating mileage very fast, in fact we wouldn't see most failures for years.

Guess what? Gm concluded the same thing. They'll be out of warranty before they pop, so as long as nobody spins into a semi on the interstate, we don't have to do a recall. Lol there have been two fires posted due to dropped valves with pictures.

So believe it or not, 6.5 failures per thousand may have been a true statement at one point in time, say, when the vast majority of all the ls7 had less than 20k miles. But what will the failure rate be when they've all had a 100k miles?

Hopefully it will be a lot lower because of people being proactive on this forum.


https://www.corvetteforum.com/forums...-registry.html

https://www.corvetteforum.com/forums...-registry.html
Yes, nicely stated.
MH663 is offline   Reply With Quote
Old 06-26-2017, 06:02 PM   #104
MTPZ06
CF Senior Member
Support Corvetteforum!
 
MTPZ06's Avatar
 
Member Since: Dec 2008
Location: Honolulu HI
Posts: 9,057
Thanked 593 Times in 526 Posts
Default

Hard to believe in 2017 that people still drink the 1% Kool-Aid...
MTPZ06 is offline   Reply With Quote
Old 06-27-2017, 11:52 AM   #105
Michael_D
CF Senior Member
 
Michael_D's Avatar
 
Member Since: Aug 2010
Location: Alaska
Posts: 4,067
Thanked 220 Times in 178 Posts
Default

Quote:
Originally Posted by MTPZ06 View Post
Hard to believe in 2017 that people still drink the 1% Kool-Aid...
Stupidity does not have an expiration date.
Michael_D is offline   Reply With Quote
Old 06-27-2017, 10:15 PM   #106
SSmoothZ06
Junior Member
 
Member Since: Jun 2017
Location: WA
Posts: 13
Thanked 1 Time in 1 Post
Default

Ok, newbie here, but I close to buying a 2008 Z06, and I think I got my questions answered.

1. Ask for $2 to $3000 off on the Z06 because they can not verify that the valves have be done and nothing on the carfax show any valve work or replacement.

2. Don't buy the GM replacement heads they are the same.

3. Or have them check every couple of years for wear.

4. Don't argue with Notreokc or Nuke61 and Michael D.

Last edited by SSmoothZ06; 06-27-2017 at 10:50 PM.
SSmoothZ06 is offline   Reply With Quote
Old 06-27-2017, 10:27 PM   #107
Unreal
CF Senior Member
 
Unreal's Avatar
 
Member Since: Nov 2007
Location: Gilbert AZ
Posts: 18,927
Thanked 888 Times in 762 Posts
Default

Pretty close. Carfax doesn't show maintenance. Put Notreokc on ignore, so you don't have to see his stuff. Don't buy anything from GM unless you have too, and checking every couple of years just depends on setup. If it is a big cam aggressive setup, yep.
Unreal is offline   Reply With Quote
Old 06-28-2017, 11:50 AM   #108
SSmoothZ06
Junior Member
 
Member Since: Jun 2017
Location: WA
Posts: 13
Thanked 1 Time in 1 Post
Default

FYI, I've looked at a total 5 Z06's and 2 have had there motors replaced under 50,000 miles.

don't know the circumstance of what the reason was.

Here is another:

https://seattle.craigslist.org/see/cto/6176939646.html
SSmoothZ06 is offline   Reply With Quote
Old 07-07-2017, 01:56 PM   #109
NotreOkc
CF Senior Member
Support Corvetteforum!
 
NotreOkc's Avatar
 
Member Since: Jun 2009
Location: Plano TX
Posts: 226
Thanked 13 Times in 11 Posts
Default

Quote:
Originally Posted by kbreese View Post
This sadly comes down to one thing: As painstakingly as everyone has tried...Sometimes you just can't fix stupid.
As everyone has tried huh? Tried what? To prove your opinion is right and mine is wrong? If not jumping on the bandwagon is stupid I'd prefer that over joining the masses.
NotreOkc is offline   Reply With Quote
Old 07-07-2017, 02:01 PM   #110
NotreOkc
CF Senior Member
Support Corvetteforum!
 
NotreOkc's Avatar
 
Member Since: Jun 2009
Location: Plano TX
Posts: 226
Thanked 13 Times in 11 Posts
Default

Quote:
Originally Posted by MTPZ06 View Post
Hard to believe in 2017 that people still drink the 1% Kool-Aid...
So you want to tell me your stats? I would love to hear them. With roughly 7K Z's made a year for 8 years, give or take each model year that is about ~56K LS7's made.
How many needed to be replaced? How many blew up? If it is not 1%, what is it? 2%? 5%
Please enlighten me. Because that is still 95% that had zero issues. Including mine. Do you not like those odds?

Last edited by NotreOkc; 07-07-2017 at 02:19 PM.
NotreOkc is offline   Reply With Quote
Old 07-07-2017, 02:03 PM   #111
NotreOkc
CF Senior Member
Support Corvetteforum!
 
NotreOkc's Avatar
 
Member Since: Jun 2009
Location: Plano TX
Posts: 226
Thanked 13 Times in 11 Posts
Default

Quote:
Originally Posted by Michael_D View Post
Stupidity does not have an expiration date.
Jumping on that bandwagon is pretty easy huh? Some might call that stupid or simple minded.
I'll reside with the ~95% (give or take, since my 1% is apparently ludacris) that never had an issue including me.
That 2-3K you are going to spend on fixing this HUGE issue, I put in the bank and towards my ZR1. Thanks.
NotreOkc is offline   Reply With Quote
Old 07-07-2017, 02:17 PM   #112
MTPZ06
CF Senior Member
Support Corvetteforum!
 
MTPZ06's Avatar
 
Member Since: Dec 2008
Location: Honolulu HI
Posts: 9,057
Thanked 593 Times in 526 Posts
Default

Quote:
Originally Posted by NotreOkc View Post
So you want to tell me your stats? I would love to hear them. With roughly 7K Z's made a year for 8 years, give or take each model year that is about 57K LS7's made.
How many needed to be replaced? How many blew up? If it is not 1%, what is it? 2%? 5%
Please enlighten me. Because that is still 95% that had zero issues. Including mine. Do you not like those odds?
Once again, proving you need to go back and do some homework...because your production numbers are WAY off. The information is out there and easily accessible...you just appear to be unwilling to do any sort of fact checking.

I don't wish to enlighten you on anything; go on believing what you want...matters little to me.
MTPZ06 is offline   Reply With Quote
Old 07-07-2017, 02:27 PM   #113
NotreOkc
CF Senior Member
Support Corvetteforum!
 
NotreOkc's Avatar
 
Member Since: Jun 2009
Location: Plano TX
Posts: 226
Thanked 13 Times in 11 Posts
Default

Quote:
Originally Posted by MTPZ06 View Post
Once again, proving you need to go back and do some homework...because your production numbers are WAY off. The information is out there and easily accessible...you just appear to be unwilling to do any sort of fact checking.

I don't wish to enlighten you on anything; go on believing what you want...matters little to me.
Ok, I can admit my first search gave me some bad data. How's ~28K produced. Either way, my opinion stands. Take whatever % you want. 90%, 95%.....no issues. Including me. I pocketed the 2-3K and left my engine alone. I'll take those percentages. Have a good one.
NotreOkc is offline   Reply With Quote
Go Back   CorvetteForum - Chevrolet Corvette Forum Discussion >
Reload this Page
  • Newbie with LS7 Questions
  •  
     
    Reply

    Related Topics
    Thread Thread Starter Forum Replies Last Post
    New member. Premier Edition C7 Blu-rayZ51 Intros 9 05-31-2017 09:07 PM
    [Z06] C6zo6 Bandairas C6 Corvette ZR1 & Z06 12 02-21-2017 02:44 PM
    Valve guide problems - LS3 vs LS7 pmt67usa C6 Tech/Performance 3 12-22-2016 12:02 PM
    Set of 8 factory del west ls7 titanium intake valves 5.0 mustang man C6 Parts for Sale/Wanted 0 04-19-2016 02:36 AM


    Thread Tools Search this Thread
    Search this Thread:

    Click for Advanced Search

    Posting Rules
    You may not post new threads
    You may not post replies
    You may not post attachments
    You may not edit your posts

    BB code is On
    Smilies are On
    [IMG] code is On
    HTML code is Off
    Trackbacks are Off
    Pingbacks are Off
    Refbacks are Off

    Forum Jump


    All times are GMT -4. The time now is 12:38 AM.


     
    • Ask a Question
      Get answers from community experts
    Question Title:
    Description:
    Your question will be posted in: