Z28 valve guides LS7 issue? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

highrevving · 03-10-2022, 07:58 PM

Is this still an issue with Z28 dropping a valve?

I searched and not seen any latest info reported.

HoodCheck · 03-10-2022, 08:43 PM

Yea...you'll hear both ways, but the fact is, Chevy said that heads after 2011 (when they found a "busted machine") no longer had the issues, but PLENTY of people have found brand new heads out of spec before even being ran.

Z28WANNAB · 03-11-2022, 01:42 PM

I agree w Hoodcheck. There is definate evidence there is a potential issue w all of our engines. I have to say, based on may posts over time on this, you have a higher probablilty of it happening if you spend more of your time in the high rpm arena. Anyting over 6500 rpm is the red zone, it seems. I have only 6000 miles on my 2014, no issues yet. At minimum, I'm eventually going to send my heads out and get the necessary valve guide upgrade to prevent this for the long run. I understand, it's generally about $1000 per head. Texas Speed and one other (I cant remeber now) are common places to get this done. Go to the top of page 2 and read all the posts on this issue. Title is "Valve drop issue".

highrevving · 03-11-2022, 02:38 PM

Thanks y'all!

WVracer · 03-11-2022, 04:36 PM

Yeah, don’t buy into GMs excuse. All the LS7s have the issue. WCCH used to be a good choice for LS7s heads. Back in the C6 Z06 days guys were reporting less than 10k miles and still were dropping valves. For me I would be getting my heads done ASAP just for the peace of mind. However, it seems most of the motors dropping valves were cammed. When you look at the valve train geometry of the LS7 you’ll see that the valve stem is not supported very much. So using a high lift cam and factory rockers will place more lateral load on that unsupported stem creating failure. Extended and better material valve guides, and roller rockers are the typical fix.

highrevving · 03-17-2022, 03:12 PM

Thanks.

I searched on this forum for owners that experienced this issue but nothing reported yet.

ariZona28 · 03-18-2022, 08:41 PM

If you continue your search you'll discover that member 4 FN 27 (probably the coolest username and license plate) had a failure, luckily still under warranty.

69L48Z27 · 03-18-2022, 09:14 PM

Quote:

Originally Posted by ariZona28

If you continue your search you'll discover that member 4 FN 27 (probably the coolest username and license plate) had a failure, luckily still under warranty.

I can’t find any either.

Here was the quote from 4FN27:

The story...of Unscheduled High Speed Disassembly...

https://www.camaro5.com/forums/showthread.php?t=419077

Nothing conclusive to say it was the Valve Issue and nothing to say it wasn't.

All I know is my Dealer and GM took care of me 100% with no hassle.

4 FN 27 · 03-19-2022, 07:54 AM

Quote:

Originally Posted by ariZona28

If you continue your search you'll discover that member 4 FN 27 (probably the coolest username and license plate) had a failure, luckily still under warranty.

Yep it was my Z. But I cannot conclusively say it was a dropped valve. We were not allowed to open the motor up. Had to go back as it was taken out.

Some evidence does point in that direction thou.

I wouldn't let an issue like that scare me out of owning an LS7. They are bolted together so we can fix them. Otherwise God would have had them welded.

Quote:

Originally Posted by ariZona28

4 FN 27 (probably the coolest username and license plate)

Thank you...

Hunt-man · 03-19-2022, 01:24 PM

It seems there have been no confirmed failures in the 2014 / 15 Z28's.
It appears there is no reason to spend several thousand to fix a problem that hasn't been occurring.
If I'm missing something please let me know.
My 2015 has about 6,000 miles on it. No issues so far.

HoodCheck · 03-19-2022, 05:31 PM

I have heard of and talked to a few people with the issue (or at least, thats what they say it was). New heads out of the box, manufactured after the supposed problem was found, have even been found out of spec. I want to say a couple are in the Z/28 owners group (Camaro 5th gen Z/28) on facebook too (or at least there were at one point; don't know if they still are).
I have also spoken with Z06 owners with the issue who owned post 2011 models; in fact, 1 guy owned 3 C6 Z06s, ALL of them had the problem, and even after the head "fix", he still had to have them fixed again (at least 1 of his was post-2011). I think he was chocking it up to the 12 degree angle, which iirc, GPI also said was the likely culprit....but then again, I do remember him saying he tracked his, so they were run hard too.

This is the problem with this question; you get opinions from various people, many of who didn't do any real research into the matter (not saying thats the case here) or go with a "well I haven't had the problem yet"...in reality, some basically new engines had the issue, and some last literally 75k+ miles and never have the issue. If you aren't beating the shit out of your car at the track, I'm sure there is less of a chance of a problem.

To me, it seems more sensible to head off the problem. If there's a concern of staying stock, well buy aftermarket and keep the stock.

AER86 · 03-23-2022, 02:56 PM

Quote:

Originally Posted by Hunt-man

It seems there have been no confirmed failures in the 2014 / 15 Z28's.
It appears there is no reason to spend several thousand to fix a problem that hasn't been occurring.
If I'm missing something please let me know.
My 2015 has about 6,000 miles on it. No issues so far.

I polled people on one of my posts to find out if anybody would confirm they had dropped a valve and the only responses i got were from people who either hadnt had an issue at all or people who had done a preventative fix by working their heads, granted I didnt get a huge number of responses, but im inclined to agree that there are no first hand confirmed cases on the forum of a valve drop (4 FN 27 included as he can neither confirm nor deny).

HoodCheck · 03-23-2022, 04:49 PM

I just hunted down a post of 1 of the people who had the issue with dropping a valve in the Z/28 group on facebook. They had to have a head and #4 piston replaced from it...so, there ya go, 1 example. I could try hunting the others down I talked to in the past, but that sounds like a LOT of work since it would be over a period of about 3-4 years, so, forget that.

FASTFATBOY · 03-23-2022, 05:43 PM

The reason you can't find anything on this forum is the Z28 carries a very small fraction of the 427's.

Want to learn about the valve issues? Go read on Corvetteforum.com

03-10-2022, 07:58 PM	#1
highrevving Drives: Z/28 Join Date: Feb 2022 Location: Orange County CA Posts: 297	Z28 valve guides LS7 issue? Is this still an issue with Z28 dropping a valve? I searched and not seen any latest info reported.

03-10-2022, 08:43 PM	#2
HoodCheck Drives: 2018 ZLE (M6/hyper blue) Join Date: Nov 2015 Location: Lithia, FL Posts: 762	Yea...you'll hear both ways, but the fact is, Chevy said that heads after 2011 (when they found a "busted machine") no longer had the issues, but PLENTY of people have found brand new heads out of spec before even being ran. __________________ Current: 2018 ZLE (M6/hyper blue) Former: 2014 Z/28 (red hot); 2017 ZL1 (auto/white); 2015 Z/28 (black); 2016 2SS (auto/hyper blue); 2012 2SS (45th anniversary/auto); 1994 Firehawk (auto/dark green); 2005 GTO (M6/blue on blue); 1999 Camaro SS (M6/pewter); 1994 Z/28 (auto/blue); 1991 Firebird (auto/red); 1988 IROC (auto/copper metallic); 1983 Camaro (auto/blue); 1981 Firebird (auto/maroon/350 Olds swap)....the list goes on...

03-11-2022, 01:42 PM	#3
Z28WANNAB Drives: 2014 Z28 CTF AGM Join Date: Jul 2020 Location: Minneapolis, MN Posts: 46	I agree w Hoodcheck. There is definate evidence there is a potential issue w all of our engines. I have to say, based on may posts over time on this, you have a higher probablilty of it happening if you spend more of your time in the high rpm arena. Anyting over 6500 rpm is the red zone, it seems. I have only 6000 miles on my 2014, no issues yet. At minimum, I'm eventually going to send my heads out and get the necessary valve guide upgrade to prevent this for the long run. I understand, it's generally about $1000 per head. Texas Speed and one other (I cant remeber now) are common places to get this done. Go to the top of page 2 and read all the posts on this issue. Title is "Valve drop issue". __________________ 2014 Z28 CTF AGM #99066 69 Z11 Convertable 4 spd - now has 496 w 6 spd, other minor suspension upgrades Owned since '78 Formerly owned 2013 ZL1, miss it 2000 XKR Last edited by Z28WANNAB; 03-11-2022 at 01:54 PM.

03-11-2022, 04:36 PM	#5
WVracer Drives: '11 2SS/RS LS3 M6 (Sold) Join Date: Dec 2015 Location: VA Posts: 200	Yeah, don’t buy into GMs excuse. All the LS7s have the issue. WCCH used to be a good choice for LS7s heads. Back in the C6 Z06 days guys were reporting less than 10k miles and still were dropping valves. For me I would be getting my heads done ASAP just for the peace of mind. However, it seems most of the motors dropping valves were cammed. When you look at the valve train geometry of the LS7 you’ll see that the valve stem is not supported very much. So using a high lift cam and factory rockers will place more lateral load on that unsupported stem creating failure. Extended and better material valve guides, and roller rockers are the typical fix. __________________ 2011 IOM 2SS/RS LS3 M6- Injen CAI, TSP 1 7/8” headers, PTB, Hurst short throw, Corsa catback exhaust, 20" TSW Nurburgrings, BMR lower control arms, BMR tunnel brace, Hotchkis lowering springs. 3660lbs. Tuned by me (sold) 2010 RJT 1SS/RS LS3 M6- CAI, TSP 2” headers, TSP F-35 cam, PTB, Hurst short throw, Dronemaster catback, BMR lowering springs, Kirkey seats, 20”/18” Weld Belmonts, 3550lbs.

03-18-2022, 08:41 PM	#7
ariZona28 Give speed a chance Drives: 2015 Camaro 2LS, 2015 Camaro Z/28 Join Date: Nov 2019 Location: Mesa, Az Posts: 2,228	If you continue your search you'll discover that member 4 FN 27 (probably the coolest username and license plate) had a failure, luckily still under warranty. __________________ 2LS: a TREMENDOUS machine. Z/28: it's a BIT MORE POWERFUL, of course.

03-11-2022, 02:38 PM	#4
highrevving Drives: Z/28 Join Date: Feb 2022 Location: Orange County CA Posts: 297	Thanks y'all!

03-17-2022, 03:12 PM	#6
highrevving Drives: Z/28 Join Date: Feb 2022 Location: Orange County CA Posts: 297	Thanks. I searched on this forum for owners that experienced this issue but nothing reported yet.

03-19-2022, 01:24 PM	#10
Hunt-man Drives: 2015 Z28 + Piper Comanche Join Date: Nov 2015 Location: PDX Posts: 227	It seems there have been no confirmed failures in the 2014 / 15 Z28's. It appears there is no reason to spend several thousand to fix a problem that hasn't been occurring. If I'm missing something please let me know. My 2015 has about 6,000 miles on it. No issues so far.

03-19-2022, 05:31 PM	#11
HoodCheck Drives: 2018 ZLE (M6/hyper blue) Join Date: Nov 2015 Location: Lithia, FL Posts: 762	I have heard of and talked to a few people with the issue (or at least, thats what they say it was). New heads out of the box, manufactured after the supposed problem was found, have even been found out of spec. I want to say a couple are in the Z/28 owners group (Camaro 5th gen Z/28) on facebook too (or at least there were at one point; don't know if they still are). I have also spoken with Z06 owners with the issue who owned post 2011 models; in fact, 1 guy owned 3 C6 Z06s, ALL of them had the problem, and even after the head "fix", he still had to have them fixed again (at least 1 of his was post-2011). I think he was chocking it up to the 12 degree angle, which iirc, GPI also said was the likely culprit....but then again, I do remember him saying he tracked his, so they were run hard too. This is the problem with this question; you get opinions from various people, many of who didn't do any real research into the matter (not saying thats the case here) or go with a "well I haven't had the problem yet"...in reality, some basically new engines had the issue, and some last literally 75k+ miles and never have the issue. If you aren't beating the shit out of your car at the track, I'm sure there is less of a chance of a problem. To me, it seems more sensible to head off the problem. If there's a concern of staying stock, well buy aftermarket and keep the stock. __________________ Current: 2018 ZLE (M6/hyper blue) Former: 2014 Z/28 (red hot); 2017 ZL1 (auto/white); 2015 Z/28 (black); 2016 2SS (auto/hyper blue); 2012 2SS (45th anniversary/auto); 1994 Firehawk (auto/dark green); 2005 GTO (M6/blue on blue); 1999 Camaro SS (M6/pewter); 1994 Z/28 (auto/blue); 1991 Firebird (auto/red); 1988 IROC (auto/copper metallic); 1983 Camaro (auto/blue); 1981 Firebird (auto/maroon/350 Olds swap)....the list goes on... Last edited by HoodCheck; 03-19-2022 at 09:22 PM.

03-23-2022, 04:49 PM	#13
HoodCheck Drives: 2018 ZLE (M6/hyper blue) Join Date: Nov 2015 Location: Lithia, FL Posts: 762	I just hunted down a post of 1 of the people who had the issue with dropping a valve in the Z/28 group on facebook. They had to have a head and #4 piston replaced from it...so, there ya go, 1 example. I could try hunting the others down I talked to in the past, but that sounds like a LOT of work since it would be over a period of about 3-4 years, so, forget that. __________________ Current: 2018 ZLE (M6/hyper blue) Former: 2014 Z/28 (red hot); 2017 ZL1 (auto/white); 2015 Z/28 (black); 2016 2SS (auto/hyper blue); 2012 2SS (45th anniversary/auto); 1994 Firehawk (auto/dark green); 2005 GTO (M6/blue on blue); 1999 Camaro SS (M6/pewter); 1994 Z/28 (auto/blue); 1991 Firebird (auto/red); 1988 IROC (auto/copper metallic); 1983 Camaro (auto/blue); 1981 Firebird (auto/maroon/350 Olds swap)....the list goes on...

03-23-2022, 05:43 PM	#14
FASTFATBOY Drives: 2013 ZL1 Join Date: Nov 2018 Location: Mobile Al Posts: 301	The reason you can't find anything on this forum is the Z28 carries a very small fraction of the 427's. Want to learn about the valve issues? Go read on Corvetteforum.com __________________ 2013 ZL1 M6, 2.4 pulley and a few bolt ons. 590 wheel and 11.70@122 on a hard tire.