[Z06] GM response to LS7 valve guide issue summary confirmed
07-13-2014, 06:36 PM
#2481
OK help needed. I got an email re a post Hib posted 13/7 but forum search shows the VIN exists in this thread but searching thread says it does not exist. Did the thread get wiped for some reason and the info not completely get erased?
This was in the email plus a VIN.
odometer: 16,334-mi.
engine build date: 2/21/12
vehicle sale date: 4/20/12
Valve stem-to-guide clearance measurements with dial indicator, done per 2012 Service Manual, pg 9-882 and GM ESI. Done with heads on engine. Also, known as a "wiggle test." Performed by owner on 5/25/14. Images and video available.
Raw measurements taken 1.25-in. above top of guide, on thrust vector, with springs, retainers, locks and stem seals removed.
Image: http://cimg6.ibsrv.net/gimg/www.corv...6380ddf9ec.jpg
This was in the email plus a VIN.
odometer: 16,334-mi.
engine build date: 2/21/12
vehicle sale date: 4/20/12
Valve stem-to-guide clearance measurements with dial indicator, done per 2012 Service Manual, pg 9-882 and GM ESI. Done with heads on engine. Also, known as a "wiggle test." Performed by owner on 5/25/14. Images and video available.
Raw measurements taken 1.25-in. above top of guide, on thrust vector, with springs, retainers, locks and stem seals removed.
Image: http://cimg6.ibsrv.net/gimg/www.corv...6380ddf9ec.jpg
07-13-2014, 06:41 PM
#2482
Pro
That's an understatement judging by this recent article in Road & Track! Owning a supercar is just as expensive as you think
The few hundred dollars I spent to confirm that my LS7's valve to guide clearances are within service limits (at 62k miles) was well worth it to me for peace of mind. The crowdsourced interactive map of "wiggle testers" may be helpful to others similarly interested in knowing where things stand.
The few hundred dollars I spent to confirm that my LS7's valve to guide clearances are within service limits (at 62k miles) was well worth it to me for peace of mind. The crowdsourced interactive map of "wiggle testers" may be helpful to others similarly interested in knowing where things stand.
07-13-2014, 07:30 PM
#2483
Team Owner
OK help needed. I got an email re a post Hib posted 13/7 but forum search shows the VIN exists in this thread but searching thread says it does not exist. Did the thread get wiped for some reason and the info not completely get erased?
This was in the email plus a VIN.
odometer: 16,334-mi.
engine build date: 2/21/12
vehicle sale date: 4/20/12
Valve stem-to-guide clearance measurements with dial indicator, done per 2012 Service Manual, pg 9-882 and GM ESI. Done with heads on engine. Also, known as a "wiggle test." Performed by owner on 5/25/14. Images and video available.
Raw measurements taken 1.25-in. above top of guide, on thrust vector, with springs, retainers, locks and stem seals removed.
Image: http://cimg6.ibsrv.net/gimg/www.corv...6380ddf9ec.jpg
This was in the email plus a VIN.
odometer: 16,334-mi.
engine build date: 2/21/12
vehicle sale date: 4/20/12
Valve stem-to-guide clearance measurements with dial indicator, done per 2012 Service Manual, pg 9-882 and GM ESI. Done with heads on engine. Also, known as a "wiggle test." Performed by owner on 5/25/14. Images and video available.
Raw measurements taken 1.25-in. above top of guide, on thrust vector, with springs, retainers, locks and stem seals removed.
Image: http://cimg6.ibsrv.net/gimg/www.corv...6380ddf9ec.jpg
DH
07-13-2014, 07:31 PM
#2484
Pro Mechanic
Pro Mechanic
I'm trying to figure out how to post the data in the form I have it organized.
It's all the stem-to-guide numbers I've taken in several measuring sessions, both wiggle testing and with a Sunnen valve guide gage.
07-13-2014, 07:34 PM
#2485
Team Owner
I was testing a post I'm going to make. Unfortunately, it's got a lot of numeric data in tables and I can't post it because, when I do, all the formatting gets eliminated.
I'm trying to figure out how to post the data in the form I have it organized.
It's all the stem-to-guide numbers I've taken in several measuring sessions, both wiggle testing and with a Sunnen valve guide gage.
I'm trying to figure out how to post the data in the form I have it organized.
It's all the stem-to-guide numbers I've taken in several measuring sessions, both wiggle testing and with a Sunnen valve guide gage.
You have to save your table as a jpeg then upload it to Photo Bucket and then you can paste that link into your CF post and it will look correct.
DH
07-13-2014, 08:01 PM
#2487
Pro
I was testing a post I'm going to make. Unfortunately, it's got a lot of numeric data in tables and I can't post it because, when I do, all the formatting gets eliminated.
I'm trying to figure out how to post the data in the form I have it organized.
It's all the stem-to-guide numbers I've taken in several measuring sessions, both wiggle testing and with a Sunnen valve guide gage.
I'm trying to figure out how to post the data in the form I have it organized.
It's all the stem-to-guide numbers I've taken in several measuring sessions, both wiggle testing and with a Sunnen valve guide gage.
Code:
CYL INT EXH #1 .0028 .0030 #3 .0030 .0026 #5 .0027 .0031 #7 .0030 .0030 #2 .0025 .0028 #4 .0030 .0028 #6 .0027 .0030 #8 .0030 .0029
07-13-2014, 09:01 PM
#2488
Race Director
for those that lost an engine im sorry. then we have guys that are not even sure if they have a problem and do nothing but worry and complain.
I get it, but its not the end of the world and it can be easily taken care of for the same cost as a good set of tires!!! if it worries you that bad, sell it and move on so somebody else can enjoy it. if you cant afford to fix it for approx. 2500 bucks this car isn't for you. that means when u need tires youll have to sell it anyway...............higher end cars cost money, some more than others, its a chance we take.
I get it, but its not the end of the world and it can be easily taken care of for the same cost as a good set of tires!!! if it worries you that bad, sell it and move on so somebody else can enjoy it. if you cant afford to fix it for approx. 2500 bucks this car isn't for you. that means when u need tires youll have to sell it anyway...............higher end cars cost money, some more than others, its a chance we take.well-stated.
07-14-2014, 11:00 AM
#2489
Melting Slicks
I had a 02 m3 BMW sent out a bunch of motors with bad con rod bearings. They sent me a letter stating what the problem was and because it was their fault my car would have the bearings replaced and have a 10 year 100 k warranty on the motor. Solved the problem with the owners and with the company. GM should get ahead of this and just fix it and put it to rest. But gm will spend thousands to save hundreds.
07-14-2014, 12:15 PM
#2490
Pro Mechanic
Pro Mechanic
If the format isn't too complex, you might get away with using the code tag, like this (my measurements):
Code:
CYL INT EXH #1 .0028 .0030 #3 .0030 .0026 #5 .0027 .0031 #7 .0030 .0030 #2 .0025 .0028 #4 .0030 .0028 #6 .0027 .0030 #8 .0030 .0029
Are you saying I just use this "code" tag like you have done?
07-14-2014, 12:31 PM
#2491
Safety Car
I had a 02 m3 BMW sent out a bunch of motors with bad con rod bearings. They sent me a letter stating what the problem was and because it was their fault my car would have the bearings replaced and have a 10 year 100 k warranty on the motor. Solved the problem with the owners and with the company. GM should get ahead of this and just fix it and put it to rest. But gm will spend thousands to save hundreds.
07-14-2014, 07:06 PM
#2492
Pro
I also have an 08 with 9k purchased new. She has never seen more than 1500 between oil changes; And she is stock and not tracked, (summer only) after reading all the scary stories I took my Corvette to my dealer. The master mechanic who only works Corvettes, listened and said, "Don't worry about it, you are still on extended warranty. So my question is what caused you to have the wiggle test preformed. (strange noises, excessive oil consumption)...?
07-15-2014, 01:30 AM
#2493
Racer
Member Since: Apr 2014
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Before I took my 08Z to Abel Chevrolet I had 2 other dealers listen to it and both said all is fine and not to worry. My warranty was running out in 2 weeks and I did not like the way the motor sounded at 2k rpm. After talking to Abel they performed the wiggle test and said that if it passed the charge would be around $320.00 if not Gm would cover it under warranty, in which it failed big time. I just hope that I am not re-winding the clock !!
07-15-2014, 09:37 AM
#2494
Barely, considering the only 500 Z28 Camaros produced for 2014. Reportedly they will build 2,500 for 2015, so that should keep the LS7 alive (rather than gobbling up spares, which is what I first feared when I heard about the new Camaro).
I would be interested to know if Linamar is still supplying the cylinder head machine work and if any production changes to them have been made.
I would be interested to know if Linamar is still supplying the cylinder head machine work and if any production changes to them have been made.
07-24-2014, 01:10 AM
#2495
I am always worrying about this issue as well, but I am going to get the GMPP this week as I am down to my last 1k miles, and at the end of my 3 year warranty... most likely trade it in towards the new c7 z06, which will give me enough time to research and watch the first year problems go away.
08-04-2014, 04:40 PM
#2497
Drifting
I did a search...
That said, does this affect/apply to the LS7's built in 2012-2013's too?
That said, does this affect/apply to the LS7's built in 2012-2013's too?
08-04-2014, 04:46 PM
#2498
Melting Slicks
Unfortunately, I think that is still to be answered and only time will tell.
08-04-2014, 05:15 PM
#2499
Drifting
08-04-2014, 06:42 PM
#2500
Race Director
One alternative is using stock polished intake and exhaust valves (replace any valves that the guide clearance is near or out of spec) and do bronze guides with the heads reworked by a competent vendor. IMHO the stock exhaust valves break because of excess guide clearance from GM's vendor. The factory valves should be fine if the guides are correct to begin with. There are other opinions on this.