[Z06] Car is Done, mods complete....
04-25-2013, 11:13 PM
#41
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Thread Starter
04-25-2013, 11:18 PM
#42
04-25-2013, 11:30 PM
#43
Instructor
[QUOTE='06 Quicksilver Z06;1583739326]You running the stock exhaust valves with the WCCH heads or solid stainless steel?[/
Richard at WCCH did his stage II with SS exhaust valves, min milling. Mike Norris added TB/160 stat and my car already has cai/headers/corsa. I told Mike to do a conservative tune ended up at 501/478 which I'm happy with. The car runs strong and most importantly it is very reliable now.
Richard at WCCH did his stage II with SS exhaust valves, min milling. Mike Norris added TB/160 stat and my car already has cai/headers/corsa. I told Mike to do a conservative tune ended up at 501/478 which I'm happy with. The car runs strong and most importantly it is very reliable now.
04-25-2013, 11:32 PM
#44
...
Richard at WCCH did his stage II with SS exhaust valves, min milling. Mike Norris added TB/160 stat and my car already has cai/headers/corsa. I told Mike to do a conservative tune ended up at 501/478 which I'm happy with. The car runs strong and most importantly it is very reliable now.
Richard at WCCH did his stage II with SS exhaust valves, min milling. Mike Norris added TB/160 stat and my car already has cai/headers/corsa. I told Mike to do a conservative tune ended up at 501/478 which I'm happy with. The car runs strong and most importantly it is very reliable now.
No doubt nice results.
04-26-2013, 06:35 AM
#45
Race Director
Thread Starter
[QUOTE=Macattack;1583739403]
that's the number I'm shooting for right at 500 rwhp
You running the stock exhaust valves with the WCCH heads or solid stainless steel?[/
Richard at WCCH did his stage II with SS exhaust valves, min milling. Mike Norris added TB/160 stat and my car already has cai/headers/corsa. I told Mike to do a conservative tune ended up at 501/478 which I'm happy with. The car runs strong and most importantly it is very reliable now.
Richard at WCCH did his stage II with SS exhaust valves, min milling. Mike Norris added TB/160 stat and my car already has cai/headers/corsa. I told Mike to do a conservative tune ended up at 501/478 which I'm happy with. The car runs strong and most importantly it is very reliable now.
that's the number I'm shooting for right at 500 rwhp
04-26-2013, 07:09 AM
#46
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whats up with guys with ( EXHAUST VALVE )??
MY Z06 2008 (STOCK) 49400 miles
AND IM PLANNING TO INSTALL HEADERS,INTAKE,160STAT AND TUNE.
but they said you must remove heads and change exhaust valve??why
im really confused i mean when you open the heads if you are going to fix something NOT FOR FUN.
MY Z06 2008 (STOCK) 49400 miles
AND IM PLANNING TO INSTALL HEADERS,INTAKE,160STAT AND TUNE.
but they said you must remove heads and change exhaust valve??why
im really confused i mean when you open the heads if you are going to fix something NOT FOR FUN.
04-26-2013, 08:37 AM
#47
whats up with guys with ( EXHAUST VALVE )??
MY Z06 2008 (STOCK) 49400 miles
AND IM PLANNING TO INSTALL HEADERS,INTAKE,160STAT AND TUNE.
but they said you must remove heads and change exhaust valve??why
im really confused i mean when you open the heads if you are going to fix something NOT FOR FUN.
MY Z06 2008 (STOCK) 49400 miles
AND IM PLANNING TO INSTALL HEADERS,INTAKE,160STAT AND TUNE.
but they said you must remove heads and change exhaust valve??why
im really confused i mean when you open the heads if you are going to fix something NOT FOR FUN.
Exhaust valve failures have also been known to occur and have been reported with disturbing frequency in here, in completely bone stock C6 Z06s.
The two piece stock exhaust valve breaking off near the exhaust valve head, and that piece falling into the combustion chamber usually results in a destroyed engine, and failures of this type have been described in here and elsewhere, for a period of years now.
As such, when some in here plan mods such as yours, they will change the exhaust valves to solid stainless steel in order to protect themselves from stock exhaust valve breakage and a fubarred engine.
04-26-2013, 08:53 AM
#48
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There have been several exhaust valve failures following mods such as you mention and despite the objections and railings of some during the continued reports of such failures, the stock hollow stemmed exhaust valves in the the C6 Z06, are widely regarded in here as a weak link.
Exhaust valve failures have also been known to occur and have been reported with disturbing frequency in here, in completely bone stock C6 Z06s.
The two piece stock exhaust valve breaking off near the exhaust valve head, and that piece falling into the combustion chamber usually results in a destroyed engine, and failures of this type have been described in here and elsewhere, for a period of years now.
As such, when some in here plan mods such as yours, they will change the exhaust valves to solid stainless steel in order to protect themselves from stock exhaust valve breakage and a fubarred engine.
Exhaust valve failures have also been known to occur and have been reported with disturbing frequency in here, in completely bone stock C6 Z06s.
The two piece stock exhaust valve breaking off near the exhaust valve head, and that piece falling into the combustion chamber usually results in a destroyed engine, and failures of this type have been described in here and elsewhere, for a period of years now.
As such, when some in here plan mods such as yours, they will change the exhaust valves to solid stainless steel in order to protect themselves from stock exhaust valve breakage and a fubarred engine.
How can i check the exhaust valve???
04-26-2013, 09:09 AM
#49
People sometimes check valve guide to stem clearance to try and get an idea of what is going on there instead.
The reasoning they use being, that excessively worn valve guides are contributing to the actual exhaust valve failures. Indeed, there are those who do not believe that exhaust valve failures have occurred in the absence of excessive valve guide wear.
But there is absolutely no assurance of that, because not every car in here which has dropped a valve, has even had it's guides measured after the resulting carnage. Indeed, very few do.
http://forums.corvetteforum.com/c6-z...ck-for-it.html
Checking the clearances and finding them to be bad, is of course an obvious sign that the owner needs to act to remedy the situation sooner rather than later.
Of course checking the clearances, finding them to be OK, and then going ahead with your modification plans, doesn't mean that they will stand up and continue to be OK afterwards for any length of time after your planned mods and that a valve won't drop.
The stock two piece hollow stemmed exhaust valves used in the LS7, aren't really touted, or highly regarded for their durability and stoutness in here.
Furthermore, you could end up having to check almost all of the guide clearances using the above method in the video, before you came across the bad one, which can be very time consuming and nearly as costly as actually removing the heads anyway.
In light of the numerous observed stock LS7 exhaust valve failures, both in here, and among shop owners and private owners outside of here, and over a period of several years, the approach of removing the heads and replacing the suspect valves and guides, irrespective of their current condition, is a practice utilized by many individuals in here, and in shops represented in here, as a means of preventing future valve related failure, in cars where modifications such as yours are planned, or in cars where more extensive modifications are planned, and even in otherwise stock cars.
This method has thus far been effective, and is relatively inexpensive, and as a result, many elect to go this route as opposed to chancing a broken stock exhaust valve, and the expense of a total engine replacement as a result of a failed exhaust valve.
Some of the stock hollow stemmed LS7 exhaust valves, are believed to have inconsistent wall thickness, and at least one random example in here, has been found to have inconsistent wall thickness upon sectioning and examination.
Now there are those in here, who in their arguments against solid stainless steel exhaust valves, are essentially saying that the above, is acceptable, and that the stock hollow stemmed exhaust valves are not the problem and not even part of the problem. Their arguments that the valves are not, and cannot be the problem, by extension, endorse the above. No two ways about it.
If you know that what you are seeing in the pics above of two random exhaust valves, might be the situation with some, and contributing factor of some of, these eventual valve failures, then only you can decide if you want to continue to run them in your car, especially if you are going to the trouble of modding it.
But judge for yourself from the above, if they well could be the problem with manufacturing like that. The above photo shows you a stock exhaust valve with inconsistent wall thickness. Some of us, do not wish to run the risk of having something like this fail in our cars.
Others though, will tell you that this is nothing to be concerned about, as the valves aren't the problem they say. Despite the above photos and the prospect that this is probably not the only LS7 exhaust valve out there with inconsistent wall thickness.
Good luck though with whatever you decide.
The reasoning they use being, that excessively worn valve guides are contributing to the actual exhaust valve failures. Indeed, there are those who do not believe that exhaust valve failures have occurred in the absence of excessive valve guide wear.
But there is absolutely no assurance of that, because not every car in here which has dropped a valve, has even had it's guides measured after the resulting carnage. Indeed, very few do.
http://forums.corvetteforum.com/c6-z...ck-for-it.html
Checking the clearances and finding them to be bad, is of course an obvious sign that the owner needs to act to remedy the situation sooner rather than later.
Of course checking the clearances, finding them to be OK, and then going ahead with your modification plans, doesn't mean that they will stand up and continue to be OK afterwards for any length of time after your planned mods and that a valve won't drop.
The stock two piece hollow stemmed exhaust valves used in the LS7, aren't really touted, or highly regarded for their durability and stoutness in here.
Furthermore, you could end up having to check almost all of the guide clearances using the above method in the video, before you came across the bad one, which can be very time consuming and nearly as costly as actually removing the heads anyway.
In light of the numerous observed stock LS7 exhaust valve failures, both in here, and among shop owners and private owners outside of here, and over a period of several years, the approach of removing the heads and replacing the suspect valves and guides, irrespective of their current condition, is a practice utilized by many individuals in here, and in shops represented in here, as a means of preventing future valve related failure, in cars where modifications such as yours are planned, or in cars where more extensive modifications are planned, and even in otherwise stock cars.
This method has thus far been effective, and is relatively inexpensive, and as a result, many elect to go this route as opposed to chancing a broken stock exhaust valve, and the expense of a total engine replacement as a result of a failed exhaust valve.
Some of the stock hollow stemmed LS7 exhaust valves, are believed to have inconsistent wall thickness, and at least one random example in here, has been found to have inconsistent wall thickness upon sectioning and examination.
Just finished sectioning a valve guys, figured i would show you what i found.
The sodium is pretty cool, i definitely played with it in water haha. Anyways, i found the wall of the stem to be pretty uneven which i would not have expected. .029" at the thinnest and .039" at the thickest. A 25% shift in wall thickness is pretty extreme in my mind, not saying that is the cause dont get all twisted up yet and say .029" is plenty of steel given the spring weight and modulus of 420SS. But i do think that could cause uneven thermal distribution, just some food for thought. Also i found some helical mill lines from when they drilled the stock, and they were right at the intersection of the weld joint. These interest me quite a bit, this is a big no-no in a fatigue environment. The nature of these lines is to create hi stress nodes which lead to crack propagation. but again just food for thought. I will get this thing under an SEM and poke around.
sectioned valve by DSeddon1, on Flickr
The sodium is pretty cool, i definitely played with it in water haha. Anyways, i found the wall of the stem to be pretty uneven which i would not have expected. .029" at the thinnest and .039" at the thickest. A 25% shift in wall thickness is pretty extreme in my mind, not saying that is the cause dont get all twisted up yet and say .029" is plenty of steel given the spring weight and modulus of 420SS. But i do think that could cause uneven thermal distribution, just some food for thought. Also i found some helical mill lines from when they drilled the stock, and they were right at the intersection of the weld joint. These interest me quite a bit, this is a big no-no in a fatigue environment. The nature of these lines is to create hi stress nodes which lead to crack propagation. but again just food for thought. I will get this thing under an SEM and poke around.
sectioned valve by DSeddon1, on Flickr
Some new info here with another sectioned valve. One, the wall was very even on this one....which may seem good; however, you would assume the wall would be around .035 all evened up right?? Nope... .0315 -.032 but still the same .313 OD again quite interesting. And I sectioned the rear of the valve because I wanted to see the construction back there as well, another peculiar part to the puzzle. It had some nipple shaped inner piece (sodium fill port, or is the slug of sodium contained in there until it is ready to have the tip drilled out??). But the peculiar part is the fact some sodium was trapped up towards the top of the shaft hmm..i know the melting point if sodium is around 200f so why was it trapped up there?? Any thoughts??
Full sectioning by DSeddon1, on Flickr
Full sectioning by DSeddon1, on Flickr
Now there are those in here, who in their arguments against solid stainless steel exhaust valves, are essentially saying that the above, is acceptable, and that the stock hollow stemmed exhaust valves are not the problem and not even part of the problem. Their arguments that the valves are not, and cannot be the problem, by extension, endorse the above. No two ways about it.
If you know that what you are seeing in the pics above of two random exhaust valves, might be the situation with some, and contributing factor of some of, these eventual valve failures, then only you can decide if you want to continue to run them in your car, especially if you are going to the trouble of modding it.
But judge for yourself from the above, if they well could be the problem with manufacturing like that. The above photo shows you a stock exhaust valve with inconsistent wall thickness. Some of us, do not wish to run the risk of having something like this fail in our cars.
Others though, will tell you that this is nothing to be concerned about, as the valves aren't the problem they say. Despite the above photos and the prospect that this is probably not the only LS7 exhaust valve out there with inconsistent wall thickness.
Good luck though with whatever you decide.
Last edited by '06 Quicksilver Z06; 04-26-2013 at 09:46 AM.
04-26-2013, 10:10 AM
#50
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People sometimes check valve guide to stem clearance to try and get an idea of what is going on there instead.
The reasoning they use being, that excessively worn valve guides are contributing to the actual exhaust valve failures. Indeed, there are those who do not believe that exhaust valve failures have occurred in the absence of excessive valve guide wear.
But there is absolutely no assurance of that, because not every car in here which has dropped a valve, has even had it's guides measured after the resulting carnage. Indeed, very few do.
http://forums.corvetteforum.com/c6-z...ck-for-it.html
Checking the clearances and finding them to be bad, is of course an obvious sign that the owner needs to act to remedy the situation sooner rather than later.
Of course checking the clearances, finding them to be OK, and then going ahead with your modification plans, doesn't mean that they will stand up and continue to be OK afterwards for any length of time after your planned mods and that a valve won't drop.
The stock two piece hollow stemmed exhaust valves used in the LS7, aren't really touted, or highly regarded for their durability and stoutness in here.
Furthermore, you could end up having to check almost all of the guide clearances using the above method in the video, before you came across the bad one, which can be very time consuming and nearly as costly as actually removing the heads anyway.
In light of the numerous observed stock LS7 exhaust valve failures, both in here, and among shop owners and private owners outside of here, and over a period of several years, the approach of removing the heads and replacing the suspect valves and guides, irrespective of their current condition, is a practice utilized by many individuals in here, and in shops represented in here, as a means of preventing future valve related failure, in cars where modifications such as yours are planned, or in cars where more extensive modifications are planned, and even in otherwise stock cars.
This method has thus far been effective, and is relatively inexpensive, and as a result, many elect to go this route as opposed to chancing a broken stock exhaust valve, and the expense of a total engine replacement as a result of a failed exhaust valve.
Some of the stock hollow stemmed LS7 exhaust valves, are believed to have inconsistent wall thickness, and at least one random example in here, has been found to have inconsistent wall thickness upon sectioning and examination.
Now there are those in here, who in their arguments against solid stainless steel exhaust valves, are essentially saying that the above, is acceptable, and that the stock hollow stemmed exhaust valves are not the problem and not even part of the problem. Their arguments that the valves are not, and cannot be the problem, by extension, endorse the above. No two ways about it.
If you know that what you are seeing in the pics above of two random exhaust valves, might be the situation with some, and contributing factor of some of, these eventual valve failures, then only you can decide if you want to continue to run them in your car, especially if you are going to the trouble of modding it.
But judge for yourself from the above, if they well could be the problem with manufacturing like that. The above photo shows you a stock exhaust valve with inconsistent wall thickness. Some of us, do not wish to run the risk of having something like this fail in our cars.
Others though, will tell you that this is nothing to be concerned about, as the valves aren't the problem they say. Despite the above photos and the prospect that this is probably not the only LS7 exhaust valve out there with inconsistent wall thickness.
Good luck though with whatever you decide.
The reasoning they use being, that excessively worn valve guides are contributing to the actual exhaust valve failures. Indeed, there are those who do not believe that exhaust valve failures have occurred in the absence of excessive valve guide wear.
But there is absolutely no assurance of that, because not every car in here which has dropped a valve, has even had it's guides measured after the resulting carnage. Indeed, very few do.
http://forums.corvetteforum.com/c6-z...ck-for-it.html
Checking the clearances and finding them to be bad, is of course an obvious sign that the owner needs to act to remedy the situation sooner rather than later.
Of course checking the clearances, finding them to be OK, and then going ahead with your modification plans, doesn't mean that they will stand up and continue to be OK afterwards for any length of time after your planned mods and that a valve won't drop.
The stock two piece hollow stemmed exhaust valves used in the LS7, aren't really touted, or highly regarded for their durability and stoutness in here.
Furthermore, you could end up having to check almost all of the guide clearances using the above method in the video, before you came across the bad one, which can be very time consuming and nearly as costly as actually removing the heads anyway.
In light of the numerous observed stock LS7 exhaust valve failures, both in here, and among shop owners and private owners outside of here, and over a period of several years, the approach of removing the heads and replacing the suspect valves and guides, irrespective of their current condition, is a practice utilized by many individuals in here, and in shops represented in here, as a means of preventing future valve related failure, in cars where modifications such as yours are planned, or in cars where more extensive modifications are planned, and even in otherwise stock cars.
This method has thus far been effective, and is relatively inexpensive, and as a result, many elect to go this route as opposed to chancing a broken stock exhaust valve, and the expense of a total engine replacement as a result of a failed exhaust valve.
Some of the stock hollow stemmed LS7 exhaust valves, are believed to have inconsistent wall thickness, and at least one random example in here, has been found to have inconsistent wall thickness upon sectioning and examination.
Now there are those in here, who in their arguments against solid stainless steel exhaust valves, are essentially saying that the above, is acceptable, and that the stock hollow stemmed exhaust valves are not the problem and not even part of the problem. Their arguments that the valves are not, and cannot be the problem, by extension, endorse the above. No two ways about it.
If you know that what you are seeing in the pics above of two random exhaust valves, might be the situation with some, and contributing factor of some of, these eventual valve failures, then only you can decide if you want to continue to run them in your car, especially if you are going to the trouble of modding it.
But judge for yourself from the above, if they well could be the problem with manufacturing like that. The above photo shows you a stock exhaust valve with inconsistent wall thickness. Some of us, do not wish to run the risk of having something like this fail in our cars.
Others though, will tell you that this is nothing to be concerned about, as the valves aren't the problem they say. Despite the above photos and the prospect that this is probably not the only LS7 exhaust valve out there with inconsistent wall thickness.
Good luck though with whatever you decide.
I hear the lifter sound at idle but they told me its totally normal. My car is z06 2008 stock.
04-26-2013, 10:18 AM
#51
Race Director
Thread Starter
At a minimum, I would have the shop check your Exhaust and Intake Valve Guides to check for wear, and make sure they are in spec, if they are close to out of spec, or out of spec, you will want to address the problem ASAP. This is actually the reason I did the mods I did.
