[Z06] Solid stainless valves - any failures?
06-16-2012, 08:33 AM
#61
Burning Brakes
I'm sure it does. And hopefully the valvetrain is still stable but behind the wheel you likely wouldn't notice. And anyone who has every driven a Z has also over reved one. Most will agree right? Hopefully that 'window' of safety of valvetrain stability over 7200 rpm is still available with the heavier valvetrain.
So, all this brings back memories to good ole LS1 days. The LS1 pistons didn't have valve reliefs and guys were smacking them left and right and bending push rods. They would swap them out with aftermarket hardened push rods because the 'stock' push rods were weak and caused failures. Oh so much fun reading... haha later so many photos of 'notched' pistons, bent valves, busted motors from failed valves, etc. Different time, different forum, gotta love history.
While I will eventually have my LS7 heads modified, it won't be by ADDING valvetrain weight. (At least I am not convinced by these non technical buyerner threads at this time.) ESPECIALLY on an awesome motor like the LS7 with a factory 7200rpm rev range. In every LS engine I've had, I've done what I could to REDUCE weight in the valvetrain, etc.
I'm more interested in what the vendors have to say about piston to valve clearances, the stock LS7 spring capability and what single spring replacement they would recommend for a little more stability and perhaps a mild cam, etc. Also, aftermarket base circle differences and geometry changes, pushrod length adjustment, etc. Where can I find these discussions on the LS7 instead of sale threads and these type of arguments? I want the technical question answered of WHY GM would spend the extra R&D, MONEY, etc on exotic valves if they could have simply used SS valve and it still all work the same without issue. Engineers have to FIGHT REALLY hard to a more expensive exotic part pass the bean counter test if it isn't NEEDED. Point me to the tech please.
So, all this brings back memories to good ole LS1 days. The LS1 pistons didn't have valve reliefs and guys were smacking them left and right and bending push rods. They would swap them out with aftermarket hardened push rods because the 'stock' push rods were weak and caused failures. Oh so much fun reading... haha later so many photos of 'notched' pistons, bent valves, busted motors from failed valves, etc. Different time, different forum, gotta love history.
While I will eventually have my LS7 heads modified, it won't be by ADDING valvetrain weight. (At least I am not convinced by these non technical buyerner threads at this time.) ESPECIALLY on an awesome motor like the LS7 with a factory 7200rpm rev range. In every LS engine I've had, I've done what I could to REDUCE weight in the valvetrain, etc.
I'm more interested in what the vendors have to say about piston to valve clearances, the stock LS7 spring capability and what single spring replacement they would recommend for a little more stability and perhaps a mild cam, etc. Also, aftermarket base circle differences and geometry changes, pushrod length adjustment, etc. Where can I find these discussions on the LS7 instead of sale threads and these type of arguments? I want the technical question answered of WHY GM would spend the extra R&D, MONEY, etc on exotic valves if they could have simply used SS valve and it still all work the same without issue. Engineers have to FIGHT REALLY hard to a more expensive exotic part pass the bean counter test if it isn't NEEDED. Point me to the tech please.
For me, a dropped valve would not be an easy pill to swallow knowing that all I had to do was have the heads reworked.
Last edited by Turbosixx; 06-27-2012 at 12:44 PM.
06-16-2012, 09:31 AM
#62
Intermediate
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Well maybe the issue is the clearance. We are going so large on the lifts not leavin much room for error? Then the valve hits the piston and kaboom just thinking out loud on the forum.
06-16-2012, 09:41 AM
#63
Safety Car
The Ti are the intake only, no issues with them.
06-16-2012, 10:27 AM
#65
Hey Michael,
This is all very true but you are leaving out the most important part...
I had a chance to talk with the gentleman at Del West that you spoke about and I also spoke with Ferrea. They both agreed that race teams were using the sodium filled valves because they are a cheap alternative to Ti. BUT they then scrap the valves after X amount of events. The valves were never made to last because they get weak and eventually break, they both confirmed this to me.
This is all very true but you are leaving out the most important part...
I had a chance to talk with the gentleman at Del West that you spoke about and I also spoke with Ferrea. They both agreed that race teams were using the sodium filled valves because they are a cheap alternative to Ti. BUT they then scrap the valves after X amount of events. The valves were never made to last because they get weak and eventually break, they both confirmed this to me.
One of the engineers at Ferrea said that the stock LS7 stem was about .038 thick (very thin) as it heats up the sodium will liquify and does a great job at disapating the heat, but over time with the extreme temp changes it will weakin and eventually break. Richard at WCCH has confirmed many of the guides and valves that he sees have a BBQed look to them.
One thing that I don't think many take into account when it come to the exhaust valve weight is it's relation to the weight and pure size of the intake valve. The 2.20 intake weighs 7 more grams than the sodium filled exhaust. On a spintron you are going to loose control of the intake sooner than the exhaust valve. Jason said on their spintron testing with the torquer cam maintained valve stability up to 7800, but he never confirmed with me if it was the intake or the exhaust valve that bounced first. My feeling is that the intake would bounce first even with less duration and lift because of it's size.
06-16-2012, 10:32 AM
#66
The exhaust is the one to worry about. It is always closer due to the valve events in relation to where the piston is in the bore. When I measured mine, I had over .250" on the intake, and roughly .185" on the exhaust. (I say roughly, because I used modeling clay) Lift is 646/670 and lsa is 113 with 18 deg overlap.
06-16-2012, 12:17 PM
#68
Team Owner
Too lean of a tune cause's extra heat in the combustion chamber and that is factor. Start a search
you will see where it's been mentioned as a factor. The theory is the factory
rich tune is for that reason. So my smart tuner has it set pretty rich
but it works well.
you will see where it's been mentioned as a factor. The theory is the factory
rich tune is for that reason. So my smart tuner has it set pretty rich
but it works well.
06-16-2012, 01:25 PM
#69
Safety Car
Too lean of a tune cause's extra heat in the combustion chamber and that is factor. Start a search
you will see where it's been mentioned as a factor. The theory is the factory
rich tune is for that reason. So my smart tuner has it set pretty rich
but it works well.
you will see where it's been mentioned as a factor. The theory is the factory
rich tune is for that reason. So my smart tuner has it set pretty rich
but it works well.
06-16-2012, 02:09 PM
#70
Safety Car
They are rich on every stock LSx car though, I highly doubt its LS7 specific.
Not sure what AFR they should run when modded but mines between 12.2-4 area can't remember which, because my tuner said they like to be ran a little on the rich side. Normal spot from my understanding for NA cars is 12.5-12.8 although I have heard people running even leaner than that
Not sure what AFR they should run when modded but mines between 12.2-4 area can't remember which, because my tuner said they like to be ran a little on the rich side. Normal spot from my understanding for NA cars is 12.5-12.8 although I have heard people running even leaner than that
Last edited by LS9Drew; 06-16-2012 at 02:12 PM.
06-26-2012, 12:27 AM
#71
Cruising
Member Since: May 2009
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Hey Micheal,
This is all very true but you are leaving out the most important part...
I had a chance to talk with the gentleman at Del West that you spoke about and I also spoke with Ferrea. They both agreed that race teams were using the sodium filled valves because they are a cheap alternative to Ti. BUT they then scrap the valves after X amount of events. The valves were never made to last because they get weak and eventually break, they both confirmed this to me.
One of the engineers at Ferrea said that the stock LS7 stem was about .038 thick (very thin) as it heats up the sodium will liquify and does a great job at disapating the heat, but over time with the extreme temp changes it will weakin and eventually break. Richard at WCCH has confirmed many of the guides and valves that he sees have a BBQed look to them.
If you read the Ferrari forums you will see the same thing with the old 308's, they sound just like we do on this forum about the sodium filled. It has become clear to me that this is not a new problem but one that has been going on for a while now.
Ferrea is coming out with a "non sodium filled" hollow stem SS valve that the stems will be around .080 thick and will weigh in around 85 grams (only 7 more that the Ti intake).
One thing that I don't think many take into account when it come to the exhaust valve weight is it's relation to the weight and pure size of the intake valve. The 2.20 intake weighs 7 more grams than the sodium filled exhaust. On a spintron you are going to loose control of the intake sooner than the exhaust valve. Jason said on their spintron testing with the torquer cam maintained valve stability up to 7800, but he never confirmed with me if it was the intake or the exhaust valve that bounced first. My feeling is that the intake would bounce first even with less duration and lift because of it's size.
I say all that to say if you add 15 grams to the much smaller exhaust valve I don't feel that reving into the lower 7000s would be any problem at all, and I will sleep much better at night knowing the Ferrea hollow stems are in my heads.
This is all very true but you are leaving out the most important part...
I had a chance to talk with the gentleman at Del West that you spoke about and I also spoke with Ferrea. They both agreed that race teams were using the sodium filled valves because they are a cheap alternative to Ti. BUT they then scrap the valves after X amount of events. The valves were never made to last because they get weak and eventually break, they both confirmed this to me.
One of the engineers at Ferrea said that the stock LS7 stem was about .038 thick (very thin) as it heats up the sodium will liquify and does a great job at disapating the heat, but over time with the extreme temp changes it will weakin and eventually break. Richard at WCCH has confirmed many of the guides and valves that he sees have a BBQed look to them.
If you read the Ferrari forums you will see the same thing with the old 308's, they sound just like we do on this forum about the sodium filled. It has become clear to me that this is not a new problem but one that has been going on for a while now.
Ferrea is coming out with a "non sodium filled" hollow stem SS valve that the stems will be around .080 thick and will weigh in around 85 grams (only 7 more that the Ti intake).
One thing that I don't think many take into account when it come to the exhaust valve weight is it's relation to the weight and pure size of the intake valve. The 2.20 intake weighs 7 more grams than the sodium filled exhaust. On a spintron you are going to loose control of the intake sooner than the exhaust valve. Jason said on their spintron testing with the torquer cam maintained valve stability up to 7800, but he never confirmed with me if it was the intake or the exhaust valve that bounced first. My feeling is that the intake would bounce first even with less duration and lift because of it's size.
I say all that to say if you add 15 grams to the much smaller exhaust valve I don't feel that reving into the lower 7000s would be any problem at all, and I will sleep much better at night knowing the Ferrea hollow stems are in my heads.
Richard does no work with GM racing unless things have changed in the last day.
the Ferrea valve you speak of has been around for some time... the blank is a short order item. We also use the Sinus and xts valve from time to time as it is availible. IMO... the Detroit valve is the best.
Katech will most likely confirm this
GM racing will do the same
as will Ferrea and DW.... If you talk to someone other then the receptionist.
06-27-2012, 12:32 AM
#72
Melting Slicks
Like Michael_d says (paraphrasing) - anecdotal evidence is essentially worthless.
The only real data available is from Katech and they have stated, very clearly, the reasons for not going with a heavier valve. Their reasons appear to be rooted in physics, not profit... Nice to see from a company IMO. Lots of tuners, and lots who will do a good job, but only a few that have the CV to build the motors for GM's race cars... In my book, pretty hard to argue with a group with that level of experience.
I'm guessing some MechE on this site could probably come up with an equation that compared the risk at any given RPM of a broken stock valve due to the apparent "thinness" of the sidewall to the risk of a broken SS valve due to valve train instability due to higher mass? Instead of opinions and the ensuing pi$$ing match, why not come up with something a bit more concrete for discussion?
The only real data available is from Katech and they have stated, very clearly, the reasons for not going with a heavier valve. Their reasons appear to be rooted in physics, not profit... Nice to see from a company IMO. Lots of tuners, and lots who will do a good job, but only a few that have the CV to build the motors for GM's race cars... In my book, pretty hard to argue with a group with that level of experience.
I'm guessing some MechE on this site could probably come up with an equation that compared the risk at any given RPM of a broken stock valve due to the apparent "thinness" of the sidewall to the risk of a broken SS valve due to valve train instability due to higher mass? Instead of opinions and the ensuing pi$$ing match, why not come up with something a bit more concrete for discussion?
06-27-2012, 02:40 AM
#73
Team Owner
06-27-2012, 09:18 AM
#74
Safety Car
whom did you talk to at Ferrea and Del West?
Richard does no work with GM racing unless things have changed in the last day.
the Ferrea valve you speak of has been around for some time... the blank is a short order item. We also use the Sinus and xts valve from time to time as it is availible. IMO... the Detroit valve is the best.
Katech will most likely confirm this
GM racing will do the same
as will Ferrea and DW.... If you talk to someone other then the receptionist.
Richard does no work with GM racing unless things have changed in the last day.
the Ferrea valve you speak of has been around for some time... the blank is a short order item. We also use the Sinus and xts valve from time to time as it is availible. IMO... the Detroit valve is the best.
Katech will most likely confirm this
GM racing will do the same
as will Ferrea and DW.... If you talk to someone other then the receptionist.
I spoke with Phil Martin at DW (great guy to talk to) and John Verburg at Ferrea. From what John told me you could get the exhaust valve made from a blank but in Aug-Sept. they would have a permenant off the shelf valve ready to go. He thought it would be around 85-87 grams with a stem thickness of .080.
Can you tell me about the Detroit valve? this is the first I have heard of it. Is it a hollow stem and do you know the weight? Thanks for the input!
06-27-2012, 11:19 AM
#76
whom did you talk to at Ferrea and Del West?
Richard does no work with GM racing unless things have changed in the last day.
the Ferrea valve you speak of has been around for some time... the blank is a short order item. We also use the Sinus and xts valve from time to time as it is availible. IMO... the Detroit valve is the best.
Katech will most likely confirm this
GM racing will do the same
as will Ferrea and DW.... If you talk to someone other then the receptionist.
Richard does no work with GM racing unless things have changed in the last day.
the Ferrea valve you speak of has been around for some time... the blank is a short order item. We also use the Sinus and xts valve from time to time as it is availible. IMO... the Detroit valve is the best.
Katech will most likely confirm this
GM racing will do the same
as will Ferrea and DW.... If you talk to someone other then the receptionist.
Glad to see you post though. This forum could stand an infusion of input from legitimate professionals.
06-27-2012, 11:37 AM
#77
Le Mans Master
Careful Dennis, you'll be labeled a heretic and burnt at the stake if you bring common sense, IC theory or physics into any discussion related to this topic on this forum. Katech has already put it in writing that there is nothing wrong with the exhaust valve, to only be ridiculed by the keyboard mechanics who know more about engines than Katech and GM Racing.
Glad to see you post though. This forum could stand an infusion of input from legitimate professionals.
Glad to see you post though. This forum could stand an infusion of input from legitimate professionals.
06-27-2012, 11:57 AM
#78
Racer
Member Since: Feb 2011
Location: San Diego / Murrieta CA
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Careful Dennis, you'll be labeled a heretic and burnt at the stake if you bring common sense, IC theory or physics into any discussion related to this topic on this forum. Katech has already put it in writing that there is nothing wrong with the exhaust valve, to only be ridiculed by the keyboard mechanics who know more about engines than Katech and GM Racing.
Glad to see you post though. This forum could stand an infusion of input from legitimate professionals.
Glad to see you post though. This forum could stand an infusion of input from legitimate professionals.
06-28-2012, 08:55 AM
#80
Safety Car
OP, if you actually get any DATA on stainless valves and wear (meaning, whether or not they are truly more durable or not than the OEM valves) - please update the original post.
That way we can avoid having to scavange the entire thread for details.
That way we can avoid having to scavange the entire thread for details.