[Z06] Ferrea Competition Hollow Stem Valves. Thoughts?
11-19-2013, 08:10 AM
#1
Safety Car
Thread Starter
Ferrea Competition Hollow Stem Valves. Thoughts?
Looking to change out the sodium valves in the Z06 to the new Ferrea hollow stem valves. They only weigh 85g. I know Katech doesnt recommend the Rev or the Ferrea SS valves due to bounce, however these only weigh roughly 10-12g more than the sodium valves... Compared to the 98-100+g SS valves. Would bounce still be an issue with these valves and would this "save" the motor if it were to fail like a SS is though to do under similar circumstances?
11-19-2013, 09:15 AM
#3
Le Mans Master
I actually asked Jason directly, and naturally no one can determine anything unless they are tested on the Spintron with everything else (cam lift will change variables as will choice of springs and lifters). But he did say it was "moving in the right direction".
Thus, your question cannot be directly answered because no one knows.
Thus, your question cannot be directly answered because no one knows.
11-19-2013, 10:14 AM
#4
Safety Car
A little bit of prudence can go a long way. A question back at you. Do you insist on keeping a 7000-7100 rpm redline? If so any additional weight is something GM engineers didn't like.
If you are adding a bit of weight and are willing to tune to a 6600-6800 rpm redline that starts to be a better combination to my thinking.
I built a forged max effort LS2 402 and while everyone said it would run to 7000 I ran it with a 6600 rpm redline in the computer. My dyno runs showed that the car was not laying over at 6600 but also wasn't continuing to make more power there so I felt I was giving up little and gaining a lot of piece of mind around valve train issues.
Now that motor had oiling issues and was rebuilt a couple of times due to the stress of running a wet sump LSx in a road racing environment. Never had valve train issues at considerably more rwhp than a LS7 has stock.
If you are adding a bit of weight and are willing to tune to a 6600-6800 rpm redline that starts to be a better combination to my thinking.
I built a forged max effort LS2 402 and while everyone said it would run to 7000 I ran it with a 6600 rpm redline in the computer. My dyno runs showed that the car was not laying over at 6600 but also wasn't continuing to make more power there so I felt I was giving up little and gaining a lot of piece of mind around valve train issues.
Now that motor had oiling issues and was rebuilt a couple of times due to the stress of running a wet sump LSx in a road racing environment. Never had valve train issues at considerably more rwhp than a LS7 has stock.
11-19-2013, 10:29 AM
#5
Team Owner
Sounds like a good setup. As for bounce, Katech tested a few combos. It is hard to say what any other combo will do. A little more spring and even the "heavy" valves may not have had issues. A little less aggressive cam, different lobes, etc.
11-19-2013, 11:24 AM
#6
Le Mans Master
I spoke with Ferrea about these at Sema. They told me they are strong because they are not cast as hollow valves, but drilled from solid. They also are not hollow all the way through the stem. The bottom inch or so near the head is solid.
From what I was explained, they seem like a good option, but they weight savings are not really an issue unless you are having valve float issues.
I use Ferrea Super alloys, and have no valve float issues to 6900, which is the max I want to run my motor, so they advised me there is no point to using the hollow stems for me.
From what I was explained, they seem like a good option, but they weight savings are not really an issue unless you are having valve float issues.
I use Ferrea Super alloys, and have no valve float issues to 6900, which is the max I want to run my motor, so they advised me there is no point to using the hollow stems for me.
11-19-2013, 11:27 AM
#7
Le Mans Master
I spoke with Ferrea about these at Sema. They told me they are strong because they are not cast as hollow valves, but drilled from solid. They also are not hollow all the way through the stem. The bottom inch or so near the head is solid.
From what I was explained, they seem like a good option, but they weight savings are not really an issue unless you are having valve float issues.
I use Ferrea Super alloys, and have no valve float issues to 6900, which is the max I want to run my motor, so they advised me there is no point to using the hollow stems for me.
From what I was explained, they seem like a good option, but they weight savings are not really an issue unless you are having valve float issues.
I use Ferrea Super alloys, and have no valve float issues to 6900, which is the max I want to run my motor, so they advised me there is no point to using the hollow stems for me.
11-19-2013, 11:37 AM
#9
Le Mans Master
11-19-2013, 12:08 PM
#10
Le Mans Master
I just assume my valvetrain works well as I have no signs otherwise. Runs great to redline, no power loss or breaking up of any kind. Since I don't race professionally, that's good enough for me.
I have an aversion to hollow stem valves, maybe totally unfounded. I have bent a valve on my old setup, (due to mechanically caused over reving) and always wondered.. .. if it was a hollow stem, would it have broken and cost me a motor. I really don't know, and hope to never find out.
11-19-2013, 12:12 PM
#11
Team Owner
You can go to any other forum and not be bugged about bounce. People have been swapping cams/springs for the past 50 years and only here is it an issue. Funny stuff.
11-19-2013, 12:18 PM
#12
Le Mans Master
Ok, you win. Not getting into this. I was just offering up what I was told by Ferrea...
I just assume my valvetrain works well as I have no signs otherwise. Runs great to redline, no power loss or breaking up of any kind. Since I don't race professionally, that's good enough for me.
I have an aversion to hollow stem valves, maybe totally unfounded. I have bent a valve on my old setup, (due to mechanically caused over reving) and always wondered.. .. if it was a hollow stem, would it have broken and cost me a motor. I really don't know, and hope to never find out.
I just assume my valvetrain works well as I have no signs otherwise. Runs great to redline, no power loss or breaking up of any kind. Since I don't race professionally, that's good enough for me.
I have an aversion to hollow stem valves, maybe totally unfounded. I have bent a valve on my old setup, (due to mechanically caused over reving) and always wondered.. .. if it was a hollow stem, would it have broken and cost me a motor. I really don't know, and hope to never find out.
I'm using the hollow stems after a long conversation with Ferrea. None of the hollow part of the valve extends below the guide, so it would bend no differently (in theory). It's not a two piece design like the OEM valves. But a mechanical over rev with the valves bending/breaking is the least of your worries. You're lucky you didn't spin a bearing or punch a hole in the piston(s). No company can guarantee you won't have major problems when you drastically exceed the design parameters. And that goes for any mechanical device.
Anyway, happy motoring.
11-19-2013, 12:23 PM
#13
Le Mans Master
I wasn't trying to win. I was just trying to gather data. I am an engineer by trade, so my mind typically doesn't accept things without empirical data. Please don't take it personally.
I'm using the hollow stems after a long conversation with Ferrea. None of the hollow part of the valve extends below the guide, so it would bend no differently (in theory). It's not a two piece design like the OEM valves. But a mechanical over rev with the valves bending/breaking is the least of your worries. You're lucky you didn't spin a bearing or punch a hole in the piston(s). No company can guarantee you won't have major problems when you drastically exceed the design parameters. And that goes for any mechanical device.
Anyway, happy motoring.
I'm using the hollow stems after a long conversation with Ferrea. None of the hollow part of the valve extends below the guide, so it would bend no differently (in theory). It's not a two piece design like the OEM valves. But a mechanical over rev with the valves bending/breaking is the least of your worries. You're lucky you didn't spin a bearing or punch a hole in the piston(s). No company can guarantee you won't have major problems when you drastically exceed the design parameters. And that goes for any mechanical device.
Anyway, happy motoring.
Good luck with the data gathering. Always good to see real data.
11-19-2013, 09:09 PM
#14
Safety Car
Thread Starter
I wasn't trying to win. I was just trying to gather data. I am an engineer by trade, so my mind typically doesn't accept things without empirical data. Please don't take it personally.
I'm using the hollow stems after a long conversation with Ferrea. None of the hollow part of the valve extends below the guide, so it would bend no differently (in theory). It's not a two piece design like the OEM valves. But a mechanical over rev with the valves bending/breaking is the least of your worries. You're lucky you didn't spin a bearing or punch a hole in the piston(s). No company can guarantee you won't have major problems when you drastically exceed the design parameters. And that goes for any mechanical device.
Anyway, happy motoring.
I'm using the hollow stems after a long conversation with Ferrea. None of the hollow part of the valve extends below the guide, so it would bend no differently (in theory). It's not a two piece design like the OEM valves. But a mechanical over rev with the valves bending/breaking is the least of your worries. You're lucky you didn't spin a bearing or punch a hole in the piston(s). No company can guarantee you won't have major problems when you drastically exceed the design parameters. And that goes for any mechanical device.
Anyway, happy motoring.
11-19-2013, 11:04 PM
#15
Le Mans Master
There are no guarantees in life except death and taxes.
11-20-2013, 09:22 AM
#16
That depends on the failure. Worn guides? Mechanical over rev? Detonation? There are still plenty of situations that will grenade your engine. My contention is that these are better than the stock valves without the excessive weight of the solid stems. And for my application, they're better suited. It's a reasonable compromise. For a forced induction, 1000HP dragster on methanol fuel? Not likely.
There are no guarantees in life except death and taxes.
There are no guarantees in life except death and taxes.
http://forums.corvetteforum.com/c6-z...d-special.html
These being 11 grams lighter than the solid stems, offer that as an advantage.
The continued reported failures of the stock exhaust valves, are likely to result in similar offerings from other valve manufacturers.
While the solid stems thus far have apparently been a very effective, if one can do the same thing with a lighter valve, well then so much the better.
Real Canuck mentions above:
What I see in all of this is that if one is concerned about the QC, wall thickness, and integrity of the stock exhaust valves, and there are reasons to be based upon what has been observed, and the opinions of others...
...
Hollow stem exhaust valves
I do believe the hollow stem exhaust valves are an issue due to two reasons.
#1 I don’t think .030” wall is sufficient to open against the cylinder pressure that an exhaust valve has to open against. There’s a LOT of pressure still in the cylinder when the exhaust valve attempts to open. The piston is only half to two/thirds of the way down the bore on the power stroke when the exhaust valve tries to open. On a top fuel car they can’t open the exhaust valve when they would like to in order to make more power. This is due to the fact that they don’t have good enough components to open the exhaust valves against that much pressure. They replace the Inconel exhaust valves every pass because the squash the stem above the valve head, every pass… They used to break lifters, then bend and break pushrods, and then break lifters. Now that all of those components are pretty much bullet proof, they squash the stems on solid stem Inconel valves. Bear in mind that most aftermarket LS7 cams open the exhaust valves way earlier in the power cycle than the stock cam does. Opening the exhaust valves sooner increases the stress on them. Increased stress on those .030” thick walls can’t be good. Also bear in mind a .080” wall pushrod of the same approximate diameter have a hard time opening against that pressure also.
#2 I also think the hollow stem valves don’t carry away heat like they should and might possibly cause coking of the oil on the stem and guide.
I haven’t seen any issues with hollow stem intake valves, however they will not tolerate float as well as solid stem valves will....
Hollow stem exhaust valves
I do believe the hollow stem exhaust valves are an issue due to two reasons.
#1 I don’t think .030” wall is sufficient to open against the cylinder pressure that an exhaust valve has to open against. There’s a LOT of pressure still in the cylinder when the exhaust valve attempts to open. The piston is only half to two/thirds of the way down the bore on the power stroke when the exhaust valve tries to open. On a top fuel car they can’t open the exhaust valve when they would like to in order to make more power. This is due to the fact that they don’t have good enough components to open the exhaust valves against that much pressure. They replace the Inconel exhaust valves every pass because the squash the stem above the valve head, every pass… They used to break lifters, then bend and break pushrods, and then break lifters. Now that all of those components are pretty much bullet proof, they squash the stems on solid stem Inconel valves. Bear in mind that most aftermarket LS7 cams open the exhaust valves way earlier in the power cycle than the stock cam does. Opening the exhaust valves sooner increases the stress on them. Increased stress on those .030” thick walls can’t be good. Also bear in mind a .080” wall pushrod of the same approximate diameter have a hard time opening against that pressure also.
#2 I also think the hollow stem valves don’t carry away heat like they should and might possibly cause coking of the oil on the stem and guide.
I haven’t seen any issues with hollow stem intake valves, however they will not tolerate float as well as solid stem valves will....
As far as their wall thickness, another forum member posted up this information. Take it for what it is worth to you.
http://forums.corvetteforum.com/c6-z...post1581421445
According to Ferrea the standard thickness is supposed to be .039" 240's pictures however bring that into dispute.
Ferrea is supposed to release their off the shelf hollow stem (non sodium filled) late this summer. Wall thickness is quoted at .080", twice as thick as stock. Weight is estimated to be around 85 grams and should hold steady without any floating on a mild cam into the mid 7k rpm range.
Ferrea is supposed to release their off the shelf hollow stem (non sodium filled) late this summer. Wall thickness is quoted at .080", twice as thick as stock. Weight is estimated to be around 85 grams and should hold steady without any floating on a mild cam into the mid 7k rpm range.
Last edited by '06 Quicksilver Z06; 11-21-2013 at 09:36 PM.
11-20-2013, 09:30 AM
#17
Looking to change out the sodium valves in the Z06 to the new Ferrea hollow stem valves. They only weigh 85g. I know Katech doesnt recommend the Rev or the Ferrea SS valves due to bounce, however these only weigh roughly 10-12g more than the sodium valves... Compared to the 98-100+g SS valves. Would bounce still be an issue with these valves and would this "save" the motor if it were to fail like a SS is though to do under similar circumstances?
11-20-2013, 10:39 AM
#18
Le Mans Master
Going too far into this. A valve train is a system just like any other. Components work hand in hand to achieve operation. 1 component fails, the system fails. Where am I going with this? You can run ANY valve you want as long as the system is matched with it. For some reason the LS7 crowd seems to have it in their minds that 7K rpm is a high rpm. 7K rpm engine rpm is 3500 valve train rpm. NASCAR guys use sodium exhaust valves and rev to 9K+ rpm for hours on end. How? Through proper selection of valve train components. They use springs/locks/retainers/springs/valves that are all paired to operate with each other. How can this transfer to the end user? Talk to the valve manufacturer, tell them your setup and the valves you want to run. They will recommend a system of parts that will work for you. Keep in mind that Ferrea, Manley, Isky, Comp, etc. have all done the spintrons and excessive dynamics testing for you. No reason to take all this testing burden on your own shoulders. It's too expensive. So, OP pick whatever valve you want and then ask them to help select a spring for you. Purchase, install, and enjoy. That simple.
11-20-2013, 10:46 AM
#19
Le Mans Master
If it were that simple, stock engines wouldn't be coming apart as a result of valvetrain failure. There is concrete evidence that the heavy SS valves are unstable at higher RPMs. People can ignore the data if they want, but the data won't change because of it.
11-20-2013, 11:10 AM
#20
At least many of us do.
The testing which is sometimes pointed to in support of your comments above was not independent.
Even if the results are accepted, then few if any real world examples of penalty in the form of engine failure, have been described in here and over a period of years, in spite of those results.
Any prediction of fire and brimstone, no matter who makes it, had better bring exactly that.
Otherwise, people are going to continue doing that which they've always done.
Especially if it has worked and is working.
Last edited by '06 Quicksilver Z06; 11-20-2013 at 11:46 AM.