[Z06] Video LS7 Wear Exhaust Valves
Thread Starter
Drifting
Joined: May 2011
Posts: 1,337
Likes: 0
Video LS7 Wear Exhaust Valves
I did this video today. It shows different valves and how they wear. These are SS Valves and what they look like when they have miles on them.
These are all the other videos I have posted over the past year or so. Please take no offense if I sound mad in some of these videos. At the time I was.
Look at these videos and make up you mind. I take this very seriously.
These are all the other videos I have posted over the past year or so. Please take no offense if I sound mad in some of these videos. At the time I was.
Look at these videos and make up you mind. I take this very seriously.
Last edited by z0sicktanner; Mar 28, 2013 at 01:08 AM.
Safety Car
Joined: Dec 2004
Posts: 3,526
Likes: 18
From: Santa Fe TX
I would like to see a picture comparison of an ls7 stainless one pc valve out of bronze guide with 10k street miles vs the stock ls7 valve at 10k
But I think the comparison in the video to the mustang valve yields the same result.
People around here say the valve stems do t wear, but mine were. Half the clearance was guide wear, the other half was stem wear.
But I think the comparison in the video to the mustang valve yields the same result.
People around here say the valve stems do t wear, but mine were. Half the clearance was guide wear, the other half was stem wear.
Thread Starter
Drifting
Joined: May 2011
Posts: 1,337
Likes: 0
I would like to see a picture comparison of an ls7 stainless one pc valve out of bronze guide with 10k street miles vs the stock ls7 valve at 10k
But I think the comparison in the video to the mustang valve yields the same result.
People around here say the valve stems do t wear, but mine were. Half the clearance was guide wear, the other half was stem wear.
But I think the comparison in the video to the mustang valve yields the same result.
People around here say the valve stems do t wear, but mine were. Half the clearance was guide wear, the other half was stem wear.
Burning Brakes
Joined: May 2006
Posts: 947
Likes: 5
From: Wiesbaden, Germany
I love watching these videos, they really help with putting it all together.
Do you ever get LS6 heads in? One of the more common arguments is that since LS6s had sodium-filled exhaust valves that worked then that means the LS7 sodium-filled exhaust valves must work too.
Do you ever get LS6 heads in? One of the more common arguments is that since LS6s had sodium-filled exhaust valves that worked then that means the LS7 sodium-filled exhaust valves must work too.
Melting Slicks
Joined: Mar 2005
Posts: 2,202
Likes: 15
From: Keswick Ontario
Trouble is they are not matched,just mixed up in a box. 16 guides and 8 valves.
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Thread Starter
Drifting
Joined: May 2011
Posts: 1,337
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Thank you Sir It is clear what is causing this Heat and valves that can't be quality controled. this is why some guides wear more than others this is also why some cars make it 170k. please guys listen to me gm is covering their *** on this issue. yes I do ls6 243 casting heads alot I've done a few hundred sets. I have not seen burnt marks on the valves. the ls6 heads used diff valve angles 15'vs ls7 12' but a diff company made these valves and they got them right. this was the main reason why I thought it was guides at first. it's not. I've tested valves from the ls7 I'm 100% sure it's the valve. I've seen some valve with know sodium in the valves at all.
Last edited by z0sicktanner; Mar 28, 2013 at 06:01 PM.
Burning Brakes
Joined: Oct 2012
Posts: 943
Likes: 5
From: Columbia Maryland
Thank you Sir It is clear what is causing this Heat What is causing the heat?and valves that can't be quality controled. Why can't they be?this is why some guides wear more than others this is also why some cars make it 170k. please guys listen to me gm is covering their *** on this issue. yes I do ls6 243 casting heads alot I've done a few hundred sets. I have not seen burnt marks on the valves. the ls6 heads used diff valve angles 15'vs ls7 12' but a diff company made these valves and they got them right. this was the main reason why I thought it was guides at first. it's not. I've tested valves from the ls7 I'm 100% sure it's the valve. I've seen some valve with know sodium in the valves at all.
Trying to understand your points but I am having difficulty following..
Thread Starter
Drifting
Joined: May 2011
Posts: 1,337
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Yes I have seen one with No sodium in the valve none. once the valve head is welded on thats it..gm gets them and install in the head. sorry for the difficulty call richard at wcch if you can.
Last edited by z0sicktanner; Mar 29, 2013 at 04:37 AM.
Safety Car
Joined: Aug 2012
Posts: 4,706
Likes: 5
From: KY
Thread Starter
Drifting
Joined: May 2011
Posts: 1,337
Likes: 0
No the soduim is to reduce heat because the valve is hollow it would be like taking a torch to a hollow valve and a solid one and see which one melts first
Last edited by z0sicktanner; Mar 30, 2013 at 05:21 PM.
Melting Slicks
Joined: Nov 2009
Posts: 3,425
Likes: 14
The point of the sodium was to take heat away from the seat of the valve, distribute it throughout the stem, and then out through the guides and whatever else.
Without the sodium, you have less effective heat transfer out of the valve resulting in a hotter valve and probably the lower parts of the stem. Possibly too hot causing the galling and burnt marks we've seen. All that heat and energy is now in less mass and has less distribution than there would be if there was sodium. The end result is a valve that is hotter and has less effective ways of getting rid of that heat, a self inflicted wounding cycle.
This is like suggesting an engine without that pesky hot coolant will run cooler. Sure, at some point a specific component may be cooler but the rest of the system isn't going to be happy.
Last edited by Jawnathin; Mar 28, 2013 at 07:53 PM.
Thread Starter
Drifting
Joined: May 2011
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My guess is that it would result in an overall hotter valve and possibly parts of the stem.
The point of the sodium was to take heat away from the seat of the valve, distribute it throughout the stem, and then out through the guides and whatever else.
Without the sodium, you have less effective heat transfer out of the valve resulting in a hotter valve and probably the lower parts of the stem. Possibly too hot causing the galling and burnt marks we've seen. All that heat and energy is now in less mass and has less distribution than there would be if there was sodium. The end result is a valve that is hotter and has less effective ways of getting rid of that heat, a self inflicted wounding cycle.
This is like suggesting an engine without that pesky hot coolant will run cooler. Sure, at some point a specific component may be cooler but the rest of the system isn't going to be happy.
The point of the sodium was to take heat away from the seat of the valve, distribute it throughout the stem, and then out through the guides and whatever else.
Without the sodium, you have less effective heat transfer out of the valve resulting in a hotter valve and probably the lower parts of the stem. Possibly too hot causing the galling and burnt marks we've seen. All that heat and energy is now in less mass and has less distribution than there would be if there was sodium. The end result is a valve that is hotter and has less effective ways of getting rid of that heat, a self inflicted wounding cycle.
This is like suggesting an engine without that pesky hot coolant will run cooler. Sure, at some point a specific component may be cooler but the rest of the system isn't going to be happy.
well said
Safety Car
Joined: Aug 2012
Posts: 4,706
Likes: 5
From: KY
The sodium acts as a coolant, transferring heat from the head of the valve to the stem (and thence to the guide, assuming the guide clearance is within spec).
Without the coolant (sodium), the head is hot, the stem is cool (respectively). With it, those extremes in temperature are balanced somewhat.
The NexTek valve uses XH-428 stainless steel and a completely new manufacturing technique to create a valve with a hollow stem and head. The hollow sections of the valve are filled with sodium. The sodium provides an internal cooling mechanism for the valve, drawing heat away from the valve head.
The NexTek valve runs cooler than a titanium exhaust valve at the critical valve head area [...]
Read more: http://www.circletrack.com/enginetec...#ixzz2OskSXHN9
The NexTek valve runs cooler than a titanium exhaust valve at the critical valve head area [...]
Read more: http://www.circletrack.com/enginetec...#ixzz2OskSXHN9
.
Last edited by Mark2009; Mar 28, 2013 at 08:04 PM.
Melting Slicks
Joined: Nov 2009
Posts: 3,425
Likes: 14
Good analogy which proves the earlier part of your post incorrect.
The sodium acts as a coolant, transferring heat from the head of the valve to the stem (and thence to the guide, assuming the guide clearance is within spec).
Without the coolant (sodium), the head is hot, the stem is cool (respectively). With it, those extremes in temperature are balanced somewhat.
The sodium acts as a coolant, transferring heat from the head of the valve to the stem (and thence to the guide, assuming the guide clearance is within spec).
Without the coolant (sodium), the head is hot, the stem is cool (respectively). With it, those extremes in temperature are balanced somewhat.
I think we agree the sodium acts as a coolant, but why do you think the rest of the valve stem will remain cool without the sodium? Even without the sodium the heat transfer will continue, just in a different format.
I suggested that parts of the stem may be too cool (top) and other parts may be too hot (lower) without the sodium. The sodium would have normally helped distribute it across the whole step so it is even, but without it, there would be a large variance across the length of the stem.
It isn't all or nothing like you seem to have suggested.
Additionally with less mass to contain the heat and a less effective way of distributing it, the stem would be hotter overall.
Here is an example, and without a measurement, I just made these numbers up, but something along these lines.
With Sodium
Valve Head - 2300F
Lower 1/3rd of the stem = 1700F
Middle 1/3rd of stem = 1500F
Upper 1/3rd of stem = 1300F
Without Sodium
Valve Head - 2500F
Lower 1/3rd of the stem = 2300F
Middle 1/3rd of stem = 1900F
Upper 1/3rd of stem = 900F