[Z06] Another Valve Guide Thread
03-12-2013, 09:19 AM
#1
Drifting
Thread Starter
Another Valve Guide Thread
Did my homework and found a wealth of information on head problems with the L7. I am impressed by the number of tech heads who know every nut, bolt and quirk of Z06s. So maybe you can help me decide what to do.
I could not find a single case of a 100% stock 06 Z06 with valve guide or rocker arm issues, but I did not read every single post/thread either. It seems 2007 is the most problematic year, with 08s and 09s following closely behind and the vast majority of these cars are modded. Are stock 06/Zs for the most part immune to this problem?
I drive a 2006 Z06 with 11k miles, is 100% stock and tracked once or twice a year for some spirited driving but never abused.
Should I play it safe and have the heads done or is this a non issue for stock 06/Z06s?
Thanks in advance for your help.
I could not find a single case of a 100% stock 06 Z06 with valve guide or rocker arm issues, but I did not read every single post/thread either. It seems 2007 is the most problematic year, with 08s and 09s following closely behind and the vast majority of these cars are modded. Are stock 06/Zs for the most part immune to this problem?
I drive a 2006 Z06 with 11k miles, is 100% stock and tracked once or twice a year for some spirited driving but never abused.
Should I play it safe and have the heads done or is this a non issue for stock 06/Z06s?
Thanks in advance for your help.
03-12-2013, 09:28 AM
#2
You are going to get 15 pages of opinions, while there are a few data points we know.
- The heads never changed from 06-13, so all are at the same risk
- My guides were fine (also an '06, most others trashed - including stock '06s)
- only cars with proven out of spec guides have failed so far
- cars with WCCH bronze guides and OEM or SS valves have a 100% track record thus far
So if your guides are in spec, you're probably fine per the data. If they aren't its a matter of time from what we've seen. No magic way to know unless you check them, so that's really the answer. A few hrs of labor and chump change compared with the cost of owning equivalent performing cars, so not totally unreasonable.
- The heads never changed from 06-13, so all are at the same risk
- My guides were fine (also an '06, most others trashed - including stock '06s)
- only cars with proven out of spec guides have failed so far
- cars with WCCH bronze guides and OEM or SS valves have a 100% track record thus far
So if your guides are in spec, you're probably fine per the data. If they aren't its a matter of time from what we've seen. No magic way to know unless you check them, so that's really the answer. A few hrs of labor and chump change compared with the cost of owning equivalent performing cars, so not totally unreasonable.
03-12-2013, 09:38 AM
#3
Excellent! 
Now you have -- I have one. You should check your guide wear (that's how I discovered mine; there were/are no symptoms in my case).
Now you have -- I have one. You should check your guide wear (that's how I discovered mine; there were/are no symptoms in my case).
03-12-2013, 10:13 AM
#5
Drifting
Thread Starter
Next question......any recommendations for a shop in South East Pennsylvania to have the heads checked?
03-12-2013, 11:20 AM
#7
Race Director
You are going to get 15 pages of opinions, while there are a few data points we know.
- The heads never changed from 06-13, so all are at the same risk
- My guides were fine (also an '06, most others trashed - including stock '06s)
- only cars with proven out of spec guides have failed so far
- cars with WCCH bronze guides and OEM or SS valves have a 100% track record thus far
So if your guides are in spec, you're probably fine per the data. If they aren't its a matter of time from what we've seen. No magic way to know unless you check them, so that's really the answer. A few hrs of labor and chump change compared with the cost of owning equivalent performing cars, so not totally unreasonable.
- The heads never changed from 06-13, so all are at the same risk
- My guides were fine (also an '06, most others trashed - including stock '06s)
- only cars with proven out of spec guides have failed so far
- cars with WCCH bronze guides and OEM or SS valves have a 100% track record thus far
So if your guides are in spec, you're probably fine per the data. If they aren't its a matter of time from what we've seen. No magic way to know unless you check them, so that's really the answer. A few hrs of labor and chump change compared with the cost of owning equivalent performing cars, so not totally unreasonable.
Especially in bold. I would agree with the rest of this post, however, there are a lot of failures that have popped up here were we do not know in fact if the guides were in spec or out, Valve dropped and motor blew up, nobody took the time to have the guides checked.
That said, OP, at a minimum I would recommend you get a competent shop to check your heads and guide wear..its going to cost some money, but the question boils down to , would you rather spend a few hundred dollars (maybe more) or spend around 15k to replace the motor if it blows.
The difficult part is nobody knows with any real degree of certainty just how widespread the problem is. Some will tell you its 1% or less cars effected, some will tell you it's like 20-30% or more!
Since there is no pattern of model year, or tracked vs street failures , or modded vs stocked failures ...its very hard to tell if not impossible which cars are suspect.
Check the heads and go from there
03-12-2013, 02:12 PM
#9
Especially in bold. I would agree with the rest of this post, however, there are a lot of failures that have popped up here were we do not know in fact if the guides were in spec or out, Valve dropped and motor blew up, nobody took the time to have the guides checked.
That said, OP, at a minimum I would recommend you get a competent shop to check your heads and guide wear..its going to cost some money, but the question boils down to , would you rather spend a few hundred dollars (maybe more) or spend around 15k to replace the motor if it blows.
The difficult part is nobody knows with any real degree of certainty just how widespread the problem is. Some will tell you its 1% or less cars effected, some will tell you it's like 20-30% or more!
Since there is no pattern of model year, or tracked vs street failures , or modded vs stocked failures ...its very hard to tell if not impossible which cars are suspect.
Check the heads and go from there
and very well put Frank. Good point about the guide wear as well.
Many strongly believe that these valve failures and guide wear always co exist.
But because very few people have their guides checked after breaking a valve, it's impossible at this point, to know if this is always the case.
Show me a case of someone dropping a valve in here, and more often than not I can show you a person who doesn't know what their guide wear measurements at three points was before, or after, the dropped valve.
Hoefi's name comes to mind, but few others.
The water becomes even murkier in that some believe that some of these failures reported as valve failures, may actually have been piston failures.
Also, I'm somewhat surprised at the results of the original posters search efforts.
Aside from Mark200x, my stock, save for MGW shifter and DRM Bilsteins 2006 had started to show guide wear at around 20,021 miles with three exhaust guides out of spec as measured at 3 points.
This was documented in the valve guide thread started by musicmankeb awhile back.
Last edited by '06 Quicksilver Z06; 03-12-2013 at 02:40 PM.
03-12-2013, 02:30 PM
#10
I've got an '06 Z06 that was at the limit (.0032) with a few exhaust valve guides at 26,000 miles. The only mod is a vararam intake (no tune, exhaust, etc).
The engine would have likely lasted quite a bit longer without problems. Though because I have no warranty and have the heads off anyway, I'm having the guides, valves and springs replaced.
The engine would have likely lasted quite a bit longer without problems. Though because I have no warranty and have the heads off anyway, I'm having the guides, valves and springs replaced.
03-12-2013, 03:33 PM
#11
Le Mans Master
Has anyone found a reliable way to check the valve guide wear with the heads on the engine - ie, remove the spring and use a dial indicator on the side-to-side play? Or at least a method that indicates there could be excessive wear and the heads should be removed for a detailed check & measurement.
03-12-2013, 04:01 PM
#12
Burning Brakes
and very well put Frank. Good point about the guide wear as well.
Many strongly believe that these valve failures and guide wear always co exist.
But because very few people have their guides checked after breaking a valve, it's impossible at this point, to know if this is always the case.
Show me a case of someone dropping a valve in here, and more often than not I can show you a person who doesn't know what their guide wear measurements at three points was before, or after, the dropped valve.
Hoefi's name comes to mind, but few others.
The water becomes even murkier in that some believe that some of these failures reported as valve failures, may actually have been piston failures.
Also, I'm somewhat surprised at the results of the original posters search efforts.
Aside from Mark200x, my stock, save for MGW shifter and DRM Bilsteins 2006 had started to show guide wear at around 20,021 miles with three exhaust guides out of spec as measured at 3 points.
This was documented in the valve guide thread started by musicmankeb awhile back.
See any correlation between "valve drop's" and guides?
Do you agree with confused garage "only cars with proven out of spec guides have failed so far" ?
03-12-2013, 04:31 PM
#13
Think about it. If we were seeing numerous cars drop exhaust valves, with the majority having guides in spec, but some not in spec, the data would indicate the valves are the issue. Now, what we actually see, is most cars have guide wear, some of those actually fail, and of those, all have had guide wear. That's the data, take it how you will. Just don't spin it.
Everything after this is based upon assumptions, which are impacted by opinions.
Last edited by ConfusedGarage; 03-12-2013 at 04:34 PM.
03-12-2013, 04:43 PM
#14
I suggest you contact one and ask them.
Aside from the suspected correlation often cited in here, and elsewhere, none.
There have been several cars in here to fail, "so far" where it was not determined one way or another what shape the guides were in when they failed.
In fact, in only a few cases, or even a couple of cases of valve failure reported in here, do I recall any attempt to measure the guides "post mortem".
03-12-2013, 04:53 PM
#16
Burning Brakes
No, but theories among professionals on this very thing abound.
I suggest you contact one and ask them.
Aside from the suspected correlation often cited in here, and elsewhere, none.
No, I don't agree with that, and would really need to check and see if those are his exact words.
There have been several cars in here to fail, "so far" where it was not determined one way or another what shape the guides were in when they failed.
In fact, in only a few cases, or even a couple of cases of valve failure reported in here, do I recall any attempt to measure the guides "post mortem".
I suggest you contact one and ask them.
Aside from the suspected correlation often cited in here, and elsewhere, none.
No, I don't agree with that, and would really need to check and see if those are his exact words.
There have been several cars in here to fail, "so far" where it was not determined one way or another what shape the guides were in when they failed.
In fact, in only a few cases, or even a couple of cases of valve failure reported in here, do I recall any attempt to measure the guides "post mortem".
03-12-2013, 04:55 PM
#17
Burning Brakes
This isn't my opinion, it's a description of the data we have available. Of course I realize not everyone who pops a motor checks their guides. However, many have, and every documented case here had guides outside the service limits.
Think about it. If we were seeing numerous cars drop exhaust valves, with the majority having guides in spec, but some not in spec, the data would indicate the valves are the issue. Now, what we actually see, is most cars have guide wear, some of those actually fail, and of those, all have had guide wear. That's the data, take it how you will. Just don't spin it.
Everything after this is based upon assumptions, which are impacted by opinions.
Think about it. If we were seeing numerous cars drop exhaust valves, with the majority having guides in spec, but some not in spec, the data would indicate the valves are the issue. Now, what we actually see, is most cars have guide wear, some of those actually fail, and of those, all have had guide wear. That's the data, take it how you will. Just don't spin it.
Everything after this is based upon assumptions, which are impacted by opinions.
03-12-2013, 05:06 PM
#18
However my "recommendation" is to talk to cylinder head professionals, and other professionals with experience in the LS7 valve train issue, and more than one, such as Richard at WCCH, Charlie at RPM, Ryne Cunningham at CMS, the people at Vengeance Racing, and Texas Speed, Darin Morgan at Darin Morgan Cylinder heads, the people at Advanced Induction, for you best "recommendations" on how to manage this matter. Ask them what they would do in their own cars, .....and why.
See which ones are saying the same thing, and which have some consistency in how they approach this matter, the number of cases they have done using their methods, and their degree of success.
It would also be worth it to see which ones seem to march to the beat of a different drummer, and how many cars they have done and their successes or failures describe here and elsewhere, and make your selection as to whose advice among any group of professionals that you are going to follow.
Oh, and BTW, with regard to your prior question and your quote
Many cars have failed in here and the condition of the guides after they failed, never reported.
Below is a listing of said to be stock cars in here which have failed.
Many of them dropped valves.
If "only cars with proven out of spec guides have failed so far", then where are the guide to stem measurements for the cars in the following list which have failed?
List of Claimed Stock LS7 engine failures reported on CF
Charles Scavone 2006 Model Dropped Valve Street cruising.
Whitjo 2006 Model Dropped Valve Street cruising
66L72 2006 Model Oil Starvation Track,
Ruf-Racer 2006 Model *Two* LS7 engines replaced under warranty. Causes of failures unknown
Raceguy 2006 Model Spun Bearing Track
dg144 2006 Model Oil Starvation
Sprite2005 2006 Model Valve
Mr-Z 2006 Model Valve Street
fastbluels6 2006 Model Dropped Valve, street.
Whosurdaddy 2006 model Dropped Valve street
capitalpiggy 2006 Model Dropped Valve Street
kennyC6 2006 Model Dropped Valve street
Larry T 2006 Model Spun Bearing
Blemley 2006 Model Rod Bearing
Wesh60 2006 Model Unknown cause. Failed at 581 miles..
TFAST4U 2006 Model Street. Oil pump failure.
upsetatchevy 2006 Model Bearing Failure
euro749 2006 Model Valve Street
TheJimer's Report 2006?? Model See post
The "breakdown":
20 reports of failed stock motors in 2006 models.
9 valve related
4 bearings
3 oil starvation
4 unknown
**************************************** **********************************
Bmore30 2007 Model "Seized" on Street
Pistol Champ 2007 Model Dropped Valve, street
GMautotech description 2007?? Model See post. Valve
Cor Dame 2007 Model Valve
Cobraq8 2007 Model Dropped Valve
Hoefi 2007 Model Dropped Valve
UR2SLO 2007 Model Dropped Valve
CodeBlack 2007 Model Stock street.
BLKLS7 2007 Model stock Valve.
tjwong 2007? Describes a failure in a car belonging to a customer of his. Valve
The "breakdown":
10 reports of failed stock motors in 2007 models.
8 valve related
1 "seized"
1 unknown
**************************************** **************************************** *******
ctdeng0 2008 Model *Two* LS7 engines to fail under warranty. 1st failure rod bearing 2nd failure "rod bearing"
snapsZ06 2008 Model Oil pump failure, street.
Joe_Planet 2008 Model Track, possible valve
07C6Z 2008 Model Dropped Valve
elh0102 2008 Model Track Oil Related Failure Bearing?
Pro531cad 2008 model cracked piston, street.
DoctorV 2008 Model Broken valve spring, valve likely contacted pistons, street.
Darius 2008 Valve failure, track
RedSSR 2008 Model "Seized"
DirtyHowie 2008 Model Dropped Valve
Tailwag 2008 Model Piston
blue 85 2008 Model Spun Bearing
MarkusWelby 2008 Model Second of two LS7 engine failures. First LS7 failed. Then replacement LS7 engine failed after approx. 3500 miles.
Marcosis 2008 Model Oil Starvation
Hulksdaddy 2008 Model Bearing Failure
rikhek 2008 Valve, Street
Bill Dearborn 2008 Model Broken Valve, track
The "breakdown":
19 reports of failed stock motors in 2008 models.
7 valve related
5 bearings
2 oil pump related
2 unknown
2 pistons
1 "seized"
**************************************** *****
Mrimpala02 2009 Model Crank Bearing Failure
1 report of failed stock motors in 2009 models
Charles Scavone 2006 Model Dropped Valve Street cruising.
Whitjo 2006 Model Dropped Valve Street cruising
66L72 2006 Model Oil Starvation Track,
Ruf-Racer 2006 Model *Two* LS7 engines replaced under warranty. Causes of failures unknown
Raceguy 2006 Model Spun Bearing Track
dg144 2006 Model Oil Starvation
Sprite2005 2006 Model Valve
Mr-Z 2006 Model Valve Street
fastbluels6 2006 Model Dropped Valve, street.
Whosurdaddy 2006 model Dropped Valve street
capitalpiggy 2006 Model Dropped Valve Street
kennyC6 2006 Model Dropped Valve street
Larry T 2006 Model Spun Bearing
Blemley 2006 Model Rod Bearing
Wesh60 2006 Model Unknown cause. Failed at 581 miles..
TFAST4U 2006 Model Street. Oil pump failure.
upsetatchevy 2006 Model Bearing Failure
euro749 2006 Model Valve Street
TheJimer's Report 2006?? Model See post
The "breakdown":
20 reports of failed stock motors in 2006 models.
9 valve related
4 bearings
3 oil starvation
4 unknown
**************************************** **********************************
Bmore30 2007 Model "Seized" on Street
Pistol Champ 2007 Model Dropped Valve, street
GMautotech description 2007?? Model See post. Valve
Cor Dame 2007 Model Valve
Cobraq8 2007 Model Dropped Valve
Hoefi 2007 Model Dropped Valve
UR2SLO 2007 Model Dropped Valve
CodeBlack 2007 Model Stock street.
BLKLS7 2007 Model stock Valve.
tjwong 2007? Describes a failure in a car belonging to a customer of his. Valve
The "breakdown":
10 reports of failed stock motors in 2007 models.
8 valve related
1 "seized"
1 unknown
**************************************** **************************************** *******
ctdeng0 2008 Model *Two* LS7 engines to fail under warranty. 1st failure rod bearing 2nd failure "rod bearing"
snapsZ06 2008 Model Oil pump failure, street.
Joe_Planet 2008 Model Track, possible valve
07C6Z 2008 Model Dropped Valve
elh0102 2008 Model Track Oil Related Failure Bearing?
Pro531cad 2008 model cracked piston, street.
DoctorV 2008 Model Broken valve spring, valve likely contacted pistons, street.
Darius 2008 Valve failure, track
RedSSR 2008 Model "Seized"
DirtyHowie 2008 Model Dropped Valve
Tailwag 2008 Model Piston
blue 85 2008 Model Spun Bearing
MarkusWelby 2008 Model Second of two LS7 engine failures. First LS7 failed. Then replacement LS7 engine failed after approx. 3500 miles.
Marcosis 2008 Model Oil Starvation
Hulksdaddy 2008 Model Bearing Failure
rikhek 2008 Valve, Street
Bill Dearborn 2008 Model Broken Valve, track
The "breakdown":
19 reports of failed stock motors in 2008 models.
7 valve related
5 bearings
2 oil pump related
2 unknown
2 pistons
1 "seized"
**************************************** *****
Mrimpala02 2009 Model Crank Bearing Failure
1 report of failed stock motors in 2009 models
In the cases where the reports are second hand, I point to the member's tenure here, so as to give the reader an idea of the poster's reliability in that report.
The count stands at 12 failed motors, which have been reported in here, due to valve trouble and have failed a stock exhaust valve, since back on 9/28/12
1. CGZ06 2009 stock 34,670 miles
2. Cyclone09Z06 2009 stock 18,200 miles
3. Jackal 2006 56,000 miles cam only
4. jmurf28 Stock 2006, 13,555 miles[/B]
5. fmcockc 39,000 miles failed on track
6. Gary Glasser 2006 Z06, dropped a valve at 40k miles
7. jad568 2007 45,000 miles failed while being backed out of parking lot
8. AreOhBeeC6Z 29,000 miles, bolt ons
9. Corvette0096, 10 year member, report of a case of a 2008
10. z51Vett, 9 year member, report of a case 2007, 33,000 miles
11. Daniel Hoffele 2007 49K miles CAI, Catback, stock tune.
12. philpacs 2006, 30K miles
The truth is, we don't know just what shape the guides were in in these cars.
All we know is that they failed a stock exhaust valve.
So I cannot agree with the approach ""only cars with proven out of spec guides have failed so far".
We don't know that.
As much as we want to say that "bad guides" are what cause this, we don't know for certain. Just as we don't know that bad valves cause it either.
But both are implicated.
And so as a result, many in here elect to replace both.
Finally, with respect to the stock guides and the stock guide material, I found it interesting what WhiteDiamond reported that the pro fixing his heads, told him.
http://forums.corvetteforum.com/c6-z...post1583272660
In my professional opinion LS7 heads need bronze guides. Actually, I feel all LS engine need bronze guides. The LS series engines are a great feet of engineering but they blew it when they used the cast “alloy” guides in conjunction with non roller tip rockers and Titanium valves....
Last edited by '06 Quicksilver Z06; 03-12-2013 at 05:31 PM.
03-12-2013, 05:11 PM
#19
This link will show you PA vendors: http://forums.corvetteforum.com/vend...p?location=170
There may be some closer not far from your state line. ECS is in NJ, I think Franz is down in MD/DE(?), both participate in the forums here and could be closer than some PA vendors.
03-12-2013, 06:19 PM
#20
Burning Brakes
