[Z06] Who's running Ferrea hollow stemmed exhaust valves? F2042P
#201
Le Mans Master
Not referring to guide material. The issue is "heat transfer to the guides increasing guide wear". Article on Sodium-Filled valves suggests that the heat transfer of sodium may be contributing to guide wear. We see lot's of evidence of intake guides showing wear and high temp's are absent. All of which suggests that temp may not be a first order failure culprit in guide wear!
http://forums.corvetteforum.com/1578667842-post31.html
But, of course, you weren't around in 2011 when we were discussing this.
"The root cause of the guide wear is engine oil coking due to severe temperature. To fix the problem at the fundamental level, GM needs to go with smaller multi exhaust valves instead of one large one. Horsepower is heat, and there is too much horsepower flowing thru one exhaust valve. That's why GM, as well as Katech, runs pig rich mixture in an attempt to cool the combustion temp."
Last edited by VetteVinnie; 07-10-2014 at 03:19 PM.
#202
Burning Brakes
That's not from the article. That's from Katech's empirical data. There have also been several discussions about the oil getting coked to the stems.
http://forums.corvetteforum.com/1578667842-post31.html
But, of course, you weren't around in 2011 when we were discussing this.
"The root cause of the guide wear is engine oil coking due to severe temperature. To fix the problem at the fundamental level, GM needs to go with smaller multi exhaust valves instead of one large one. Horsepower is heat, and there is too much horsepower flowing thru one exhaust valve. That's why GM, as well as Katech, runs pig rich mixture in an attempt to cool the combustion temp."
http://forums.corvetteforum.com/1578667842-post31.html
But, of course, you weren't around in 2011 when we were discussing this.
"The root cause of the guide wear is engine oil coking due to severe temperature. To fix the problem at the fundamental level, GM needs to go with smaller multi exhaust valves instead of one large one. Horsepower is heat, and there is too much horsepower flowing thru one exhaust valve. That's why GM, as well as Katech, runs pig rich mixture in an attempt to cool the combustion temp."
Whence guide wear starts, oil will start to coke on the valves and accelerate guide wear, but not the principle instigator..
#203
Melting Slicks
That's not from the article. That's from Katech's empirical data. There have also been several discussions about the oil getting coked to the stems.
http://forums.corvetteforum.com/1578667842-post31.html
But, of course, you weren't around in 2011 when we were discussing this.
"The root cause of the guide wear is engine oil coking due to severe temperature. To fix the problem at the fundamental level, GM needs to go with smaller multi exhaust valves instead of one large one. Horsepower is heat, and there is too much horsepower flowing thru one exhaust valve. That's why GM, as well as Katech, runs pig rich mixture in an attempt to cool the combustion temp."
http://forums.corvetteforum.com/1578667842-post31.html
But, of course, you weren't around in 2011 when we were discussing this.
"The root cause of the guide wear is engine oil coking due to severe temperature. To fix the problem at the fundamental level, GM needs to go with smaller multi exhaust valves instead of one large one. Horsepower is heat, and there is too much horsepower flowing thru one exhaust valve. That's why GM, as well as Katech, runs pig rich mixture in an attempt to cool the combustion temp."
However it has since been proven by the inspection of heads and having the intake side being out of spec and the exhaust side being in spec that this theory is wrong. We have also seen LS7 heads with zero miles straight out of the supplier with machining issues that would have lead to premature guide wear.
As well as who knows how many 1000's of Z06's out there with ZERO issues and no guide wear what-so-ever. If this was a heat issue 100% of the Z06's would have measured guide wear. They do not.
#204
Team Owner
I clearly stated why I feel heat is not appearing to be an issue in these failures according to the data we see in my post above. So, per the data we have (nothing points to an issue with heat), I see no reason to think these air filled valves would behave any differently than the OEMs or SS - besides the weight factor. I understand the science behind the sodium filled valve, but I'm not convinced we are seeing a difference in LS7s running either type.
I agree, I'm just not seeing any issues caused by heat with any type of valve. Howie - when you checked your guides after thousands of miles of use with track days, they weren't cooked. This was all with an SS valve which supposedly has terrible heat transfer characteristics, but who cares if it has no known side effects? The guide didn't cook, and that's the key point here.
While I chose OEM valves with my rebuild of bronze guides, I didn't do it because of the heat transfer theories. I did it because I had more intake wear than exhaust wear (like ALL LS9s lately), so the OEM valve clearly wasn't the culprit and was well suited for my use. I stuck with the OEM valve because of the weight and to keep my valvetrain balanced as I live at 7200 rpm. Years later while enduring hard use (on original 2006 lifters and rockers with 26,000 cammed hard miles), all is perfect.
So I'm just saying, we have no supporting evidence that heat, heat transfer and the sodium valve has ANYTHING to do with the issue of out of spec guides. So these ferrea valves should be a happy medium to those unsure of which route to take. Its not always left or right, sometimes its the middle!
I agree, I'm just not seeing any issues caused by heat with any type of valve. Howie - when you checked your guides after thousands of miles of use with track days, they weren't cooked. This was all with an SS valve which supposedly has terrible heat transfer characteristics, but who cares if it has no known side effects? The guide didn't cook, and that's the key point here.
While I chose OEM valves with my rebuild of bronze guides, I didn't do it because of the heat transfer theories. I did it because I had more intake wear than exhaust wear (like ALL LS9s lately), so the OEM valve clearly wasn't the culprit and was well suited for my use. I stuck with the OEM valve because of the weight and to keep my valvetrain balanced as I live at 7200 rpm. Years later while enduring hard use (on original 2006 lifters and rockers with 26,000 cammed hard miles), all is perfect.
So I'm just saying, we have no supporting evidence that heat, heat transfer and the sodium valve has ANYTHING to do with the issue of out of spec guides. So these ferrea valves should be a happy medium to those unsure of which route to take. Its not always left or right, sometimes its the middle!
Hopefully we agree on this concept
DH
#205
Melting Slicks
I understand that there are two separate issues. All I am saying is that your same logic can be applied to the SS valves...........they don't exhibit any affects on the valve train although theoretically (via spintron) they should.
Hopefully we agree on this concept
DH
Hopefully we agree on this concept
DH
Not really enough time or a big enough sample to conclude the heavier valve has no long term effects on the valve train.
#206
Team Owner
We really don't know how large the sample size is, only how many CF members have employed this fix.
Certainly the sample size on the new hollow unfilled valve is very small at this point.
DH
#207
To set the record straight (as I often see the misleading claim above repeated), the Ferrea Competition Hollow Stem valve is not "new" -- it has been out for years, available for the Chevys, Chryslers, Fords, and Toyotas. From what I have read on more professional-oriented forums, they enjoy an excellent reputation amongst engine builders.
They are only "new" in the LS7 size. Therefore, like Michelin making a new sized tire for the new C7, I don't think there is anything to 'fear'... their reputation in similar applications precedes them.
They are only "new" in the LS7 size. Therefore, like Michelin making a new sized tire for the new C7, I don't think there is anything to 'fear'... their reputation in similar applications precedes them.
#209
I've sent you one interview candidate via PM.
.
Last edited by Mark2009; 07-10-2014 at 05:37 PM.
#210
Burning Brakes
No, I would go with the TI valve. Of course weight is a big issue in this setup but not near enough when we are talking about valves separating and destroying blocks. So when the SS valve has been used for how long by so many people and seems to work good why even take a chance with that cheap *** sodium filled garbage. Simple as that. I spray my motor so titanium was not an option but if it was that would have been the route I took
#211
Melting Slicks
As you can see from the replies above that beat me to the punch... these valves have been around for a very long time.
Last edited by propain; 07-10-2014 at 06:44 PM.
#212
Melting Slicks
No, I would go with the TI valve. Of course weight is a big issue in this setup but not near enough when we are talking about valves separating and destroying blocks. So when the SS valve has been used for how long by so many people and seems to work good why even take a chance with that cheap *** sodium filled garbage. Simple as that. I spray my motor so titanium was not an option but if it was that would have been the route I took
HAHAH... as if the SS valves are some type of expensive upgrade...
As well your build does not apply since its super secret and "proprietary".
#213
Pro Mechanic
Pro Mechanic
I did get the PM, "Mark2009". I have been doing what you suggest. Since 2001, a regular source, when I've done articles about Gen 3/4 V8s, has been Jim Hicks, the GMPT engineer who designed and developed the valves and the rest of the valvetrain in the LS1,2,3,6,7 and 9.
Last edited by Hib Halverson; 07-10-2014 at 06:54 PM. Reason: changed a word.
#214
Team Owner
To set the record straight (as I often see the misleading claim above repeated), the Ferrea Competition Hollow Stem valve is not "new" -- it has been out for years, available for the Chevys, Chryslers, Fords, and Toyotas. From what I have read on more professional-oriented forums, they enjoy an excellent reputation amongst engine builders.
They are only "new" in the LS7 size. Therefore, like Michelin making a new sized tire for the new C7, I don't think there is anything to 'fear'... their reputation in similar applications precedes them.
They are only "new" in the LS7 size. Therefore, like Michelin making a new sized tire for the new C7, I don't think there is anything to 'fear'... their reputation in similar applications precedes them.
Obviously, my reference to new, was as in new for the LS7
Do we want to start discussing how many makes of cars modded or otherwise have been using SS valves for decades.
So please ignore my posts as you have requested me to ignore yours
DH
#215
Team Owner
I could make the same argument for the SS valves. They have been around for a lot longer than Ferrea and used in many more applications.
DH
#216
Burning Brakes
Could care less on the price. $5---$5,000 it doesn't really matter if they bust in half and grenade the motor. I see your the type of guy that would rather pay more for a two-Piece valve and the name if ya know what I mean
#217
Team Owner
I did get the PM, "Mark2009". I have been doing what you suggest. Since 2001, a regular source, when I've done articles about Gen 3/4 V8s, has been Jim Hicks, the GMPT engineer who designed and developed the valves and the rest of the valvetrain in the LS1,2,3,6,7 and 9.
I'm not sure everyone knows how long you have been researching this issue. I know from our conversations that you are well connected and not shy about extracting information from your sources. Your mechanical abilities are also not widely known. Possibly stating your credentials might be helpful for some.
DH
#218
To set the record straight (as I often see the misleading claim above repeated), the Ferrea Competition Hollow Stem valve is not "new" -- it has been out for years, available for the Chevys, Chryslers, Fords, and Toyotas. From what I have read on more professional-oriented forums, they enjoy an excellent reputation amongst engine builders.
They are only "new" in the LS7 size. Therefore, like Michelin making a new sized tire for the new C7, I don't think there is anything to 'fear'... their reputation in similar applications precedes them.
They are only "new" in the LS7 size. Therefore, like Michelin making a new sized tire for the new C7, I don't think there is anything to 'fear'... their reputation in similar applications precedes them.
However we know where the discussion leads when we try and make that argument that they are OK for, and that they thus far are doing well in this LS7 engine.
The argument usually trends along the lines of "they might be OK for other engines, but not this one because the spintron says so", despite the fact that they are doing well in these cars.
It seems to me that if we are going to use that as a legitimate argument "against" the use of SS valves in the LS7, then I don't see how the same argument could not be made against the Ferrea hollow stems.
Ferrea hollow stems may well have been around, and used in other engines previously, but how about in the LS7?
And more importantly, as mentioned before, while the SS valve may not have shown stellar results on the spintron for these cars, that which might be the achilles heel for the Ferrea hollow stem valves in these cars, i.e. the question of adequate heat transfer from valve head to stem, cannot be tested or measured on the spintron.
While it may be Hib's opinion that the Ferrea hollow stem is the "worst" choice of the lot for these cars, he does make a good argument for that, and I am beginning to see his reasoning in making that assessment, we won't really know which of the two, SS valves, or the Ferrea hollow stems, actually end up being more "hazardous" to the LS7's health. But overheated exhaust valves, can and do lead to their failure.
At any rate, knowing what Hib pointed out, and the discussion thus far on it, well, whereas I once thought that changing over to the Ferrea Hollow stems could be done with virtually little to no consequences which would warrant concern, it appears that there are in fact some concerns to be taken into serious consideration, namely heat transfer, which might be just as significant as the weight concerns with the SS valves.
One aftermarket solution, the use of Ferrea hollow stem valves, might wind up being just as "risky", and potentially "deadly" as the other, the use of SS valves, but for different reasons.
It seems that "weight" has always been the concern. But there are other things which could end up being just as big of a concern.
There has to be a reason why GM used sodium in those valves instead of air.
If they were just looking to decrease "weight" in the stock valves, well then why fill them with sodium?????
We won't know though until the Ferrea Hollow stem has been in use in the LS7 for as long as the use of SS valves has been used thus far, and in a comparable number of C6 Z06s, before we can get any kind of assessment.
Last edited by '06 Quicksilver Z06; 07-10-2014 at 09:39 PM.
#219
I understand that point. But we are specifically talking about our LS7 which I think you will agree has its own set of peculiarities. I think we might also agree that not every valve is going to behave the same in different motors.
I could make the same argument for the SS valves. They have been around for a lot longer than Ferrea and used in many more applications.
DH
I could make the same argument for the SS valves. They have been around for a lot longer than Ferrea and used in many more applications.
DH
But when you do make that argument, what typically happens is a counter argument that while what you say is true, that does not apply to the LS7.
Hib
I'm not sure everyone knows how long you have been researching this issue. I know from our conversations that you are well connected and not shy about extracting information from your sources. Your mechanical abilities are also not widely known. Possibly stating your credentials might be helpful for some.
DH
I'm not sure everyone knows how long you have been researching this issue. I know from our conversations that you are well connected and not shy about extracting information from your sources. Your mechanical abilities are also not widely known. Possibly stating your credentials might be helpful for some.
DH
I have also had the pleasure of corresponding with Hib via email and PM on things ranging from the is issue all the way up to motor oil.
It would be good if he were to state his credentials.
Last edited by '06 Quicksilver Z06; 07-10-2014 at 07:45 PM.
#220
I clearly stated why I feel heat is not appearing to be an issue in these failures according to the data we see in my post above. So, per the data we have (nothing points to an issue with heat), I see no reason to think these air filled valves would behave any differently than the OEMs or SS - besides the weight factor. I understand the science behind the sodium filled valve, but I'm not convinced we are seeing a difference in LS7s running either type.