[Z06] LS7 valve failures "post fix"?
05-18-2018, 01:29 AM
#1
LS7 valve failures "post fix"?
I'm doing my due diligence on my next car shopping effort and a C6 Z06 is on my short list.
I've read a lot of the threads on the notorious valve issue.
Would it be safe to say getting the heads fixed is a permanent solution? i.e., have there been any reports of valves going out of spec after the fix has been made? Assuming AHP head work...
From what I've read here, the answer seems to be the fix is permanent.
Post fix, do y'all still check your valves for wiggle?
Appreciate your feedback as it will help in my decision process.
Thanks!
I've read a lot of the threads on the notorious valve issue.
Would it be safe to say getting the heads fixed is a permanent solution? i.e., have there been any reports of valves going out of spec after the fix has been made? Assuming AHP head work...
From what I've read here, the answer seems to be the fix is permanent.
Post fix, do y'all still check your valves for wiggle?
Appreciate your feedback as it will help in my decision process.
Thanks!
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soundscribe (05-18-2018)
05-18-2018, 09:03 AM
#3
Team Owner
No it is not permanent, as guides are wear items, but after a good fix they should last a solid 100k+ miles like most cars.
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soundscribe (05-18-2018)
05-18-2018, 09:49 AM
#4
Drifting
Doesn't matter if you have OEM untouched heads or "fixed" heads. Like Unreal says, guides are a wear item. If you have untouched heads, get them checked right away. If you have "fixed" heads, check them at regular intervals based on your driving style. For street driving, I plan to check my AHP "fixed" heads every 15k miles.
Last edited by Must_Have_Z; 05-18-2018 at 09:49 AM.
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soundscribe (05-18-2018)
05-18-2018, 10:22 AM
#5
Team Owner
And to further expand, loose guides or dropped valves? With fixed heads, you can still drop a valve, just like in any car. F150s, Ferraris, Toyotas, Yamahas, every known combustion engine that uses a valve can and has dropped a valve so saying it is a permanent fix, even if the guides never wear. If the guides don't wear, then the valve is probably going to be wearing.
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soundscribe (05-18-2018)
05-18-2018, 10:36 AM
#6
Racer
Many threads on this issue, which it seems is not just common to LS7, bought a nice little engine for my little s10 truck. All guides offset to the seats. Seats n stems look and mic great but guides up to .0055 out of round. After new guides n everything recut n I lap should be good,
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soundscribe (05-18-2018)
05-18-2018, 01:09 PM
#7
Race Director
NemeZ claims his PRC w/ 8K had excess wear, has to be a first.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
Just turned 60K w/ an '08, first owner.
Several members have more than twice mine & still running strong.
Others, have had catastrophic failures w less mi & while many appear to happen w/ tracked Zs, there were bone stock low mile cars, too.
Mine's under the knife right now for head rebuild + a few other niceties. Even tho' covered w/ GMEPP 'til '19, just had a notion it was time.
Car's been suburb aside from a HL ballast, blown Blose speaker, various recalls addressed including new MC.
LS7's been solid.
But quoting a valued member: "They work great, until they don't". Nature of issue demands proactive action.
Post fix, do y'all still check your valves for wiggle?
Won't learn condition of mine for another week, but those heads got me a solid reliable 60K miles over 10 years in whatever condition.
Once rebuilt it'll take 20 years for me to rack-up another 60K, assuming I live long enough. So no, probably won't recheck my heads.
Heads, wear items like cam, lifters, guides down to penny ante tires & brakes are all part of LS7 ownership I find it acceptable -- given what this little BB does w/ so much ease.
A very special engine, LS7, wart & all.
G/L w/ your decision but one last thing. Have you driven a LS7, coupe or roadster?
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
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soundscribe (05-18-2018)
05-18-2018, 04:55 PM
#8
Race Director
'Permanent' in that no one's reported a failure w/ rebuilt heads.
NemeZ claims his PRC w/ 8K had excess wear, has to be a first.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
Just turned 60K w/ an '08, first owner.
Several members have more than twice mine & still running strong.
Others, have had catastrophic failures w less mi & while many appear to happen w/ tracked Zs, there were bone stock low mile cars, too.
Mine's under the knife right now for head rebuild + a few other niceties. Even tho' covered w/ GMEPP 'til '19, just had a notion it was time.
Car's been suburb aside from a HL ballast, blown Blose speaker, various recalls addressed including new MC.
LS7's been solid.
But quoting a valued member: "They work great, until they don't". Nature of issue demands proactive action.
Some do, many more w/don't.
Won't learn condition of mine for another week, but those heads got me a solid reliable 60K miles over 10 years in whatever condition.
Once rebuilt it'll take 20 years for me to rack-up another 60K, assuming I live long enough. So no, probably won't recheck my heads.
Heads, wear items like cam, lifters, guides down to penny ante tires & brakes are all part of LS7 ownership I find it acceptable -- given what this little BB does w/ so much ease.
A very special engine, LS7, wart & all.
G/L w/ your decision but one last thing. Have you driven a LS7, coupe or roadster?
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
NemeZ claims his PRC w/ 8K had excess wear, has to be a first.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
Just turned 60K w/ an '08, first owner.
Several members have more than twice mine & still running strong.
Others, have had catastrophic failures w less mi & while many appear to happen w/ tracked Zs, there were bone stock low mile cars, too.
Mine's under the knife right now for head rebuild + a few other niceties. Even tho' covered w/ GMEPP 'til '19, just had a notion it was time.
Car's been suburb aside from a HL ballast, blown Blose speaker, various recalls addressed including new MC.
LS7's been solid.
But quoting a valued member: "They work great, until they don't". Nature of issue demands proactive action.
Some do, many more w/don't.
Won't learn condition of mine for another week, but those heads got me a solid reliable 60K miles over 10 years in whatever condition.
Once rebuilt it'll take 20 years for me to rack-up another 60K, assuming I live long enough. So no, probably won't recheck my heads.
Heads, wear items like cam, lifters, guides down to penny ante tires & brakes are all part of LS7 ownership I find it acceptable -- given what this little BB does w/ so much ease.
A very special engine, LS7, wart & all.
G/L w/ your decision but one last thing. Have you driven a LS7, coupe or roadster?
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
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soundscribe (05-18-2018)
05-18-2018, 07:26 PM
#9
That is encouraging.
Sorry for my ignorance, but what is "PRC"?
[/quote]
Thanks! The selecting/shopping phase is part of the fun.
No, I've not driven an LS7 car yet. I didn't want to until closer to the buy time. Didn't want to get all excited until I completed a few things.
I'll start looking more seriously in the fall.
Thank you all for the input and putting my mind at ease. It seems like the "fix" at least gets the guide life into a more normal range.
Even checking the guides every 15K miles - I can deal with that as I work from home and don't put many miles on a car.
NemeZ claims his PRC w/ 8K had excess wear, has to be a first.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
G/L w/ your decision but one last thing. Have you driven a LS7, coupe or roadster?
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
Thanks! The selecting/shopping phase is part of the fun.
No, I've not driven an LS7 car yet. I didn't want to until closer to the buy time. Didn't want to get all excited until I completed a few things.
I'll start looking more seriously in the fall.
Thank you all for the input and putting my mind at ease. It seems like the "fix" at least gets the guide life into a more normal range.
Even checking the guides every 15K miles - I can deal with that as I work from home and don't put many miles on a car.
05-19-2018, 08:44 AM
#10
I have all Ti valves in mine now.. Instead of testing it now, I think I'm going to just pay attention to any noises, and oil use issues as my logic is that these valves should hold up to failing valve guides long enough for me to notice an issue unlike the hollow OEM exh valves..
05-19-2018, 11:35 AM
#11
Drifting
Just curious, while under the knife, did they find anything wrong with your valves?
Good luck with it after the work is done!
Justin
05-19-2018, 11:45 AM
#12
Race Director
Seriously if there've been others it was a precious few.
As a 10 yr Z owner & CF member approaching twice that time I follow this stuff almost daily.
Failed rebuilt LS7 heads is rare.
Doing due diligence w/ LS7 means, to me, being connected to the LS7 community here at CF as well as other sites.
I listen to feedback/experiences from other Z06 owners, why I said & know issue is across the spectrum from low to high mile cars.
However, once heads are cleaned-up statistically LS7 is as solid as it can be. Statistically.
Even tho' my GMEPP would replace entire engine if it fragged?
I like my present LS7, its been good to me providing 60K thoroughly enjoyable miles & more smiles/satisfaction over 10 years than could ever be counted.
Not only does my LS7's longevity mandate proactive action, it deserves it.
With additional upgrades bill for my Z is at $7K.
Where on God's green earth c/would a vehicle w/ 75% of C6 Z06's performance & styling be had for $7 large?
05-19-2018, 12:08 PM
#13
Race Director
Great meeting another original '08 owner w/ the same fabulous experience.
Just curious, while under the knife, did they find anything wrong with your valves?
Heads removed/shipped to builder yesterday (Friday).
Anxious to hear what builder, who does check, has to say.
I'm told builder does heads for certain NASCAR teams, don't know who, just that they build heads for race engines.
Good luck with it after the work is done!
Probably because I live in BF'd Egypt, WI, labor was a good deal higher than what I've often read cited here. FWIW.
Well known shop in these parts, beaucoup experience w/ all manner of builds but most important to me, LS platform experts.
They're doing a custom ground 'baby cam' while it's apart also, "For drivability and performance."
'News' so far positive, they did the baseline dyno run. Didn't blow.
Unfortunately been away, only got a phone message or I'd have asked what it made. Probably call, Monday.
05-19-2018, 12:27 PM
#14
Race Director
Head builder: https://www.texas-speed.com/t-prcheads.aspx
OK, but do test drive one. IMO try LS7 first, then LS3/2/1.
Only real way to put LS7 in perspective.
Read so many guys who bemoan not finding a Z in their choice of color.
Color's important, no doubt, but it's the LS7 one wants under the paint too.
It'd seem.
As I told another member statistically, based on current reviews, odds increase dramatically for LS7 durability, reliability and most important longevity once heads are addressed.
You're in better shape than I if skilled enough to get into a LS7 w/o wrecking it.
Even though not ready to buy now do not pass a chance to drive a Z06, if one presents itself.
Heck if you lived in E/C WI I'd allow you seat time in mine.
For one reason or another w/ every passing year we see less & less of these unique cars and remember, prod #s for '11-'12-'13 were pitifully small to start so they're simply not there to be had.
No, I've not driven an LS7 car yet. I didn't want to until closer to the buy time. Didn't want to get all excited until I completed a few things. I'll start looking more seriously in the fall.
Only real way to put LS7 in perspective.
Read so many guys who bemoan not finding a Z in their choice of color.
Color's important, no doubt, but it's the LS7 one wants under the paint too.
It seems like the "fix" at least gets the guide life into a more normal range.
As I told another member statistically, based on current reviews, odds increase dramatically for LS7 durability, reliability and most important longevity once heads are addressed.
Even checking the guides every 15K miles - I can deal with that as I work from home and don't put many miles on a car.
Even though not ready to buy now do not pass a chance to drive a Z06, if one presents itself.
Heck if you lived in E/C WI I'd allow you seat time in mine.
For one reason or another w/ every passing year we see less & less of these unique cars and remember, prod #s for '11-'12-'13 were pitifully small to start so they're simply not there to be had.
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soundscribe (05-24-2018)
05-19-2018, 07:47 PM
#15
Pro
'Permanent' in that no one's reported a failure w/ rebuilt heads.
NemeZ claims his PRC w/ 8K had excess wear, has to be a first.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
Just turned 60K w/ an '08, first owner.
Several members have more than twice mine & still running strong.
Others, have had catastrophic failures w less mi & while many appear to happen w/ tracked Zs, there were bone stock low mile cars, too.
Mine's under the knife right now for head rebuild + a few other niceties. Even tho' covered w/ GMEPP 'til '19, just had a notion it was time.
Car's been suburb aside from a HL ballast, blown Blose speaker, various recalls addressed including new MC.
LS7's been solid.
But quoting a valued member: "They work great, until they don't". Nature of issue demands proactive action.
Some do, many more w/don't.
Won't learn condition of mine for another week, but those heads got me a solid reliable 60K miles over 10 years in whatever condition.
Once rebuilt it'll take 20 years for me to rack-up another 60K, assuming I live long enough. So no, probably won't recheck my heads.
Heads, wear items like cam, lifters, guides down to penny ante tires & brakes are all part of LS7 ownership I find it acceptable -- given what this little BB does w/ so much ease.
A very special engine, LS7, wart & all.
G/L w/ your decision but one last thing. Have you driven a LS7, coupe or roadster?
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
NemeZ claims his PRC w/ 8K had excess wear, has to be a first.
Must be a rational story explaining NZ because can't recall any other valve/guide failures reported, otherwise. Regardless who rebuilt heads.
Just turned 60K w/ an '08, first owner.
Several members have more than twice mine & still running strong.
Others, have had catastrophic failures w less mi & while many appear to happen w/ tracked Zs, there were bone stock low mile cars, too.
Mine's under the knife right now for head rebuild + a few other niceties. Even tho' covered w/ GMEPP 'til '19, just had a notion it was time.
Car's been suburb aside from a HL ballast, blown Blose speaker, various recalls addressed including new MC.
LS7's been solid.
But quoting a valued member: "They work great, until they don't". Nature of issue demands proactive action.
Some do, many more w/don't.
Won't learn condition of mine for another week, but those heads got me a solid reliable 60K miles over 10 years in whatever condition.
Once rebuilt it'll take 20 years for me to rack-up another 60K, assuming I live long enough. So no, probably won't recheck my heads.
Heads, wear items like cam, lifters, guides down to penny ante tires & brakes are all part of LS7 ownership I find it acceptable -- given what this little BB does w/ so much ease.
A very special engine, LS7, wart & all.
G/L w/ your decision but one last thing. Have you driven a LS7, coupe or roadster?
If not go get a taste of what you're dealing with, now.
Decisions get a lot easier after a test drive.
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Landru (05-20-2018)
05-20-2018, 11:28 AM
#16
Race Director
Expecting >8K on rebuilt heads is a gimme, has to be twice if not three times that.
Why I believe there's something w/ what PRC's doing, or not.
They originally replaced one valve and guide but left the rest completely worn.
I STH wouldn't have been comfortable w/ their solution and you weren't satisfied, either.
BTW upon reflection I now recall your experience.
Truth is there're a LOT of rebuilt LS7 heads out there, done by a variety of competent builders. At this time there simply isn't any hard data which w/could say how long rebuilds will last w/ any certainty.
I fully expect my newly rebuilt heads to last at least 60K, not kidding myself though. My expectation(s) vs reality do vary.
I sent the heads to Mamo Motorsports and he found the rest of they guides worn. I’m glad I sent them otherwise it could’ve got ugly. I’m sure they will last much longer with Tony’s work. Tony’s work is phenomenal and his customer service is incredible.
In any event can't recall anyone testing their rebuilt heads (by any one of more well known rebuilders) w/ say 10-15K. Hasn't happened, yet.
Might hear of this more as time goes on & owners recheck.
Last edited by Landru; 05-20-2018 at 11:29 AM.
05-21-2018, 11:41 AM
#17
Instructor
Member Since: Sep 2013
Location: Arizona
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I have a 2006 Z06 with 76,000 miles. I don't know if the heads have been worked on or not, and it had two owners before me. It runs like a top and I drive it like it should be driven.
I've got to say, constantly reading about the valve issues really gets to you after a while.
My son, a lead Nissan mechanic who works on GTRs, told me he's never worked on any Nissan engines with valve issues, including GTRs that have been tracked. He said they rarely have engines issues of any kind if the regular maintenance has been done.
I really like my car and I'm not thinking of selling it, but if I had waited for the right GTR I wouldn't have had to read about the valve issues every time I get on the forum, and would be in a much better frame of mind after.
I've got to say, constantly reading about the valve issues really gets to you after a while.
My son, a lead Nissan mechanic who works on GTRs, told me he's never worked on any Nissan engines with valve issues, including GTRs that have been tracked. He said they rarely have engines issues of any kind if the regular maintenance has been done.
I really like my car and I'm not thinking of selling it, but if I had waited for the right GTR I wouldn't have had to read about the valve issues every time I get on the forum, and would be in a much better frame of mind after.
05-21-2018, 01:43 PM
#18
Drifting
In 10 years of ownership I’ve never spent a second thinking about valves but now that I’m thinking about selling, I see all the hysteria on the forums and think “well, if I’m going to sell it to these guys, I better get it checked.”
05-21-2018, 05:49 PM
#19
Race Director
G/L w/ the memory thing Tony, I tried mine to no avail.
Seriously if there've been others it was a precious few.
As a 10 yr Z owner & CF member approaching twice that time I follow this stuff almost daily.
Failed rebuilt LS7 heads is rare.
Doing due diligence w/ LS7 means, to me, being connected to the LS7 community here at CF as well as other sites.
I listen to feedback/experiences from other Z06 owners, why I said & know issue is across the spectrum from low to high mile cars.
However, once heads are cleaned-up statistically LS7 is as solid as it can be. Statistically.
Even tho' my GMEPP would replace entire engine if it fragged?
I like my present LS7, its been good to me providing 60K thoroughly enjoyable miles & more smiles/satisfaction over 10 years than could ever be counted.
Not only does my LS7's longevity mandate proactive action, it deserves it.
With additional upgrades bill for my Z is at $7K.
Where on God's green earth c/would a vehicle w/ 75% of C6 Z06's performance & styling be had for $7 large?
Seriously if there've been others it was a precious few.
As a 10 yr Z owner & CF member approaching twice that time I follow this stuff almost daily.
Failed rebuilt LS7 heads is rare.
Doing due diligence w/ LS7 means, to me, being connected to the LS7 community here at CF as well as other sites.
I listen to feedback/experiences from other Z06 owners, why I said & know issue is across the spectrum from low to high mile cars.
However, once heads are cleaned-up statistically LS7 is as solid as it can be. Statistically.
Even tho' my GMEPP would replace entire engine if it fragged?
I like my present LS7, its been good to me providing 60K thoroughly enjoyable miles & more smiles/satisfaction over 10 years than could ever be counted.
Not only does my LS7's longevity mandate proactive action, it deserves it.
With additional upgrades bill for my Z is at $7K.
Where on God's green earth c/would a vehicle w/ 75% of C6 Z06's performance & styling be had for $7 large?
https://www.corvetteforum.com/forums...ed-advice.html
https://www.corvetteforum.com/forums...out-heads.html
https://www.corvetteforum.com/forums...-are-shot.html
https://www.corvetteforum.com/forums...-a-sudden.html
https://www.corvetteforum.com/forums...17k-miles.html
https://www.corvetteforum.com/forums...prc-heads.html
https://www.corvetteforum.com/forums...after-fix.html
So if a small percentage of heads/engines fail, and if a small percentage of owners "fix" their heads, then of course not many of the fixed ones will fail, either. Are the fixed heads better? I sure hope so, but I have no way of knowing.
It would be good to see wiggle tests from owners who have "fixed" their heads.
05-22-2018, 09:05 AM
#20
Race Director
So if a small percentage of heads/engines fail, and if a small percentage of owners "fix" their heads, then of course not many of the fixed ones will fail, either. Are the fixed heads better? I sure hope so, but I have no way of knowing. It would be good to see wiggle tests from owners who have "fixed" their heads.
Rebuilds have been out long enough owners need to do a cursory inspection including a wiggle. Should. If they did the results would make for the most interesting read on the topic ever posted.
Thanks for the links, my friend.
Only had time to read 1st for now, pulled this quote which couldn't be truer for any LS7 owner: "It is good to take care of your car, including "fixing" the heads if you want. But that is still no guarantee against failure. Don't stress over it." Tonym
Simply isn't enough data justifying stress, some concern OTOH not unwarranted.
Rebuilt heads supposedly assure odds of failure are statistically minimized, not eliminated. Taking proactive action w/ this issue can never hurt, though.