[Z06] The "In Spec" guide wear registry
05-21-2014, 02:31 PM
#141
Melting Slicks
Thread Starter
Agree, We'll just have to see how the bronze guides last, with all choices of valves.
Solid might only give you a couple thousand more miles than stock before they fail, or 10's of thousand. But if those extra miles are enough for you to catch it, then it's worth it. Depends on how worn guides are, who knows, all will eventually fail with out of spec guides. Fatigue is not their friend, lol.
My first couple of checks will be way sooner than 10k miles, until I get some confidence in the guides.
Solid might only give you a couple thousand more miles than stock before they fail, or 10's of thousand. But if those extra miles are enough for you to catch it, then it's worth it. Depends on how worn guides are, who knows, all will eventually fail with out of spec guides. Fatigue is not their friend, lol.
My first couple of checks will be way sooner than 10k miles, until I get some confidence in the guides.
I've always had a bad feeling about bronze guides... which goes against what I believe every vendor on here except AH. The 1.8 rockers have a lot of side load and the bronze is a softer metal. This of course will cause guide wear. Many vendors who push this setup run roller tipped rockers in their personal cars. When I hear this it makes me go hmmmm.... This is another reason I wait for more cars with inspection before I say this or that is good or bad.
If the guides are in spec you will most likely never have to catch anything regardless if you run SS or OEM. The question then becomes what are the long term adverse effects of the heavier valve without setting the redline to 6600. Another example only time will prove.
05-21-2014, 02:33 PM
#142
Agree, We'll just have to see how the bronze guides last, with all choices of valves.
Solid might only give you a couple thousand more miles than stock before they fail, or 10's of thousand. But if those extra miles are enough for you to catch it, then it's worth it. Depends on how worn guides are, who knows, all will eventually fail with out of spec guides. Fatigue is not their friend, lol.
My first couple of checks will be way sooner than 10k miles, until I get some confidence in the guides.
Solid might only give you a couple thousand more miles than stock before they fail, or 10's of thousand. But if those extra miles are enough for you to catch it, then it's worth it. Depends on how worn guides are, who knows, all will eventually fail with out of spec guides. Fatigue is not their friend, lol.
My first couple of checks will be way sooner than 10k miles, until I get some confidence in the guides.
I admit, it sure would be nice to eventually know WCCH bronze guide job typically stays in spec until xx-xx mileage, RPM xx-xx mileage, AH xx-xx mileage. With the oem guides being out of spec as early as 2000 miles in some cases, some like myself were willing to accept the tradeoff of a bronze guide not lasting 100,000 miles, but with more predictable wear that won't be way out of spec at 2000 miles like some we have seen.
I have received some great information on this from a very reputable vendor that has been run off of this topic by e-thugs, and its too bad. There is a lot of information that just isn't being shared because folks aren't mature enough to have a discussion or accept data that doesn't support their theories.
05-21-2014, 02:53 PM
#143
I've always had a bad feeling about bronze guides... which goes against what I believe every vendor on here except AH. The 1.8 rockers have a lot of side load and the bronze is a softer metal. This of course will cause guide wear. Many vendors who push this setup run roller tipped rockers in their personal cars. When I hear this it makes me go hmmmm.... This is another reason I wait for more cars with inspection before I say this or that is good or bad.
If the guides are in spec you will most likely never have to catch anything regardless if you run SS or OEM. The question then becomes what are the long term adverse effects of the heavier valve without setting the redline to 6600. Another example only time will prove.
If the guides are in spec you will most likely never have to catch anything regardless if you run SS or OEM. The question then becomes what are the long term adverse effects of the heavier valve without setting the redline to 6600. Another example only time will prove.
Dang Invo's.
I don't remember where that thread about the spintron testing is at. It's kind of debatable how bad .015" of bounce is vs. .014" with all the other variables added in.
For example a stock valve bouncing .014" would have more stress on the valve, than .015" bounce on the solid. But all instances would get much worse as guide wear opens up. And what effect does more bounce have on guides and wear?
But all info is good info. Just need a lot more.
And this forum + vendors / shops is about all we're gonna get. GM isn't gonna do anything.
Last edited by adamgl; 05-21-2014 at 03:18 PM.
05-21-2014, 03:53 PM
#144
Melting Slicks
On the street, I can't get over around 4000 - 4500 rpm without spinning the tires in first 4 gears anyway, lol.
Dang Invo's.
I don't remember where that thread about the spintron testing is at. It's kind of debatable how bad .015" of bounce is vs. .014" with all the other variables added in.
For example a stock valve bouncing .014" would have more stress on the valve, than .015" bounce on the solid. But all instances would get much worse as guide wear opens up. And what effect does more bounce have on guides and wear?
But all info is good info. Just need a lot more.
And this forum + vendors / shops is about all we're gonna get. GM isn't gonna do anything.
Dang Invo's.
I don't remember where that thread about the spintron testing is at. It's kind of debatable how bad .015" of bounce is vs. .014" with all the other variables added in.
For example a stock valve bouncing .014" would have more stress on the valve, than .015" bounce on the solid. But all instances would get much worse as guide wear opens up. And what effect does more bounce have on guides and wear?
But all info is good info. Just need a lot more.
And this forum + vendors / shops is about all we're gonna get. GM isn't gonna do anything.
.http://forums.corvetteforum.com/c6-z...tte-forum.html
Last edited by Minkster; 05-21-2014 at 03:59 PM.
05-21-2014, 04:00 PM
#145
Melting Slicks
Thread Starter
On the street, I can't get over around 4000 - 4500 rpm without spinning the tires in first 4 gears anyway, lol.
Dang Invo's.
I don't remember where that thread about the spintron testing is at. It's kind of debatable how bad .015" of bounce is vs. .014" with all the other variables added in.
For example a stock valve bouncing .014" would have more stress on the valve, than .015" bounce on the solid. But all instances would get much worse as guide wear opens up. And what effect does more bounce have on guides and wear?
But all info is good info. Just need a lot more.
And this forum + vendors / shops is about all we're gonna get. GM isn't gonna do anything.
Dang Invo's.
I don't remember where that thread about the spintron testing is at. It's kind of debatable how bad .015" of bounce is vs. .014" with all the other variables added in.
For example a stock valve bouncing .014" would have more stress on the valve, than .015" bounce on the solid. But all instances would get much worse as guide wear opens up. And what effect does more bounce have on guides and wear?
But all info is good info. Just need a lot more.
And this forum + vendors / shops is about all we're gonna get. GM isn't gonna do anything.
Thats for sure...
Here is the link:
http://forums.corvetteforum.com/c6-z...tte-forum.html
Good points on .015 verse .014 and how much worse. The answer is both are at the limit.
As well is a valve bouncing at .015 which is solid verse a valve bouncing at .014 which is hollow and which is under more stress.
A thorough inspection would need to be completed to get those answers. Inspecting the keeper grooves, checking to ensure the seat pressure hasn't changed, check the valve faces and the seat faces for runout, inspection of the springs checking to see if they are shiny from taking a beating, also inspection of the coils for any sign of coil bind, the keeper face... ect....
In the end it is a delicate balance in the most complex part of your engine which can easily lead to a broken valve or spring over time if unstable.
Check out this article. Its a really good read and very informative.
http://www.vetteweb.com/tech/1406_ho...xhaust_valves/
Last edited by propain; 05-21-2014 at 04:06 PM.
05-21-2014, 04:33 PM
#146
Team Owner
My thoughts are a lot of people don't have confidence in the guides, even after getting new bronze ones and a valve job. I know I don't. I'll be checking mine every year.
And a solid stainless valve will be more durable than stock if you do get outside the tolerance before you can catch it. As would the beefier and better made ferrea hollow stem.
It could give you more time to catch the loose guide b4 grenading the engine.
And a solid stainless valve will be more durable than stock if you do get outside the tolerance before you can catch it. As would the beefier and better made ferrea hollow stem.
It could give you more time to catch the loose guide b4 grenading the engine.
DH
05-21-2014, 04:47 PM
#147
Team Owner
I agree with your logic. Unfortunately there is little data available on how the bronze guides are wearing. I have about 10,000 hard miles on mine, but who knows what condition they are in. I think there are some others with more miles, and I think Dirty Howie just replaced his, not sure if he measured the old ones - haven't kept up on all this lately. Maybe some of these other folks can chime in.
I admit, it sure would be nice to eventually know WCCH bronze guide job typically stays in spec until xx-xx mileage, RPM xx-xx mileage, AH xx-xx mileage. With the oem guides being out of spec as early as 2000 miles in some cases, some like myself were willing to accept the tradeoff of a bronze guide not lasting 100,000 miles, but with more predictable wear that won't be way out of spec at 2000 miles like some we have seen.
I have received some great information on this from a very reputable vendor that has been run off of this topic by e-thugs, and its too bad. There is a lot of information that just isn't being shared because folks aren't mature enough to have a discussion or accept data that doesn't support their theories.
I admit, it sure would be nice to eventually know WCCH bronze guide job typically stays in spec until xx-xx mileage, RPM xx-xx mileage, AH xx-xx mileage. With the oem guides being out of spec as early as 2000 miles in some cases, some like myself were willing to accept the tradeoff of a bronze guide not lasting 100,000 miles, but with more predictable wear that won't be way out of spec at 2000 miles like some we have seen.
I have received some great information on this from a very reputable vendor that has been run off of this topic by e-thugs, and its too bad. There is a lot of information that just isn't being shared because folks aren't mature enough to have a discussion or accept data that doesn't support their theories.
DH
05-21-2014, 05:08 PM
#148
Since we keep seeing threads pop up now with more and more people inspecting their guides I think it would be a good idea to get a grasp of how many are coming back with in spec guides and from which years.
If you have inspected your guides and they have come back in spec please reply with the year of your Z06 and the miles at inspection. You can also attach a spec sheet of the measurements if you have one and cite who did the inspection. Hopefully we can use this data to get a better idea of the percentage of problems out there.
This is not a thread to debate the valve drop issues, or how to fix it. This is not a thread for cars who have found guide wear. This is not a thread for drama. Please try to keep it as clean as possible and on topic. [...]
If you have inspected your guides and they have come back in spec please reply with the year of your Z06 and the miles at inspection. You can also attach a spec sheet of the measurements if you have one and cite who did the inspection. Hopefully we can use this data to get a better idea of the percentage of problems out there.
This is not a thread to debate the valve drop issues, or how to fix it. This is not a thread for cars who have found guide wear. This is not a thread for drama. Please try to keep it as clean as possible and on topic.
[...]Last edited by Mark2009; 05-21-2014 at 05:11 PM.
05-21-2014, 06:32 PM
#149
Team Owner
Mark
This is not news. I posted it months ago. Go back and check it out. If you have any legit questions I will be happy to address them.
One guy had WCCH stage 2 done with SS valves. One guy had local shop do heads and used the hollow Ferera. The other guy decided to squeak in one more track day and his stock LS7 motor with hollow OEM valves grenaded !!!!!!!!!!
DH
This is not news. I posted it months ago. Go back and check it out. If you have any legit questions I will be happy to address them.
One guy had WCCH stage 2 done with SS valves. One guy had local shop do heads and used the hollow Ferera. The other guy decided to squeak in one more track day and his stock LS7 motor with hollow OEM valves grenaded !!!!!!!!!!
DH
Last edited by Dirty Howie; 05-21-2014 at 06:36 PM.
05-21-2014, 08:34 PM
#150
Mark
This is not news. I posted it months ago. Go back and check it out. If you have any legit questions I will be happy to address them.
One guy had WCCH stage 2 done with SS valves. One guy had local shop do heads and used the hollow Ferera. The other guy decided to squeak in one more track day and his stock LS7 motor with hollow OEM valves grenaded !!!!!!!!!!
This is not news. I posted it months ago. Go back and check it out. If you have any legit questions I will be happy to address them.
One guy had WCCH stage 2 done with SS valves. One guy had local shop do heads and used the hollow Ferera. The other guy decided to squeak in one more track day and his stock LS7 motor with hollow OEM valves grenaded !!!!!!!!!!
06-18-2014, 01:42 PM
#151
Pro
'07 w/ 62k miles
Total Performance just checked the valve-to-guide clearances on the 100% stock 2007 Z06 I bought a few weeks ago with just under 62k miles. Results: ".0031 MAX FOUND VALVE TO GUIDE CLEARANCE - IT IS WITHIN FACTORY SPECS." The tech wasn't there when I picked it up, so I requested that each individual measurement be forwarded to me later as a baseline for next time (maybe at 100k miles?). Meanwhile, I am so relieved! 
Thanks to everyone who patiently answered my many questions as I tried to get my head around the problem and explore options for mitigation in preparation for the worst (I was leaning toward American Heritage package #4 but with OEM valves and springs).
Thanks to everyone who patiently answered my many questions as I tried to get my head around the problem and explore options for mitigation in preparation for the worst (I was leaning toward American Heritage package #4 but with OEM valves and springs).
06-18-2014, 09:10 PM
#153
Pro
That's for sure! Here are the individual measurements:
Code:
CYL INT EXH #1 .0028 .0030 #3 .0030 .0026 #5 .0027 .0031 #7 .0030 .0030 #2 .0025 .0028 #4 .0030 .0028 #6 .0027 .0030 #8 .0030 .0029
06-19-2014, 09:01 AM
#155
Pro
The wiggle test raw measurements were multiplied by .62 to arrive at the numbers I posted above.
I should also mention that there is a fair amount of valve train clatter. I can hear ticking while driving past guardrails with the windows down, but it's not nearly as loud as the infamous lash adjuster ("lifter") tick my '94 Stealth Twin-Turbo would occasionally make.
Code:
raw raw*.62 raw/2-.0005 CYL INT EXH INT EXH INT EXH #1 .0045 .0048 .0028 .0030 .0018 .0019 #3 .0048 .0042 .0030 .0026 .0019 .0016 #5 .0044 .0050 .0027 .0031 .0017 .0020 #7 .0048 .0048 .0030 .0030 .0019 .0019 #2 .0040 .0045 .0025 .0028 .0015 .0018 #4 .0048 .0045 .0030 .0028 .0019 .0018 #6 .0044 .0048 .0027 .0030 .0017 .0019 #8 .0048 .0047 .0030 .0029 .0019 .0018
Last edited by bjmsam; 01-17-2015 at 11:06 AM. Reason: fixed table
06-19-2014, 07:10 PM
#156
Melting Slicks
Thread Starter
Congrats. I will update the list.
62K miles and still in spec. Impressive. Cars like yours confirm how this issue, while abundantly found in the LS7, is indeed an issue out of the factory. There are simply too many high mileage cars with no issues out there to deny this.
I would inspect again in 10 to 15K though just to be sure you stay in spec.
62K miles and still in spec. Impressive. Cars like yours confirm how this issue, while abundantly found in the LS7, is indeed an issue out of the factory. There are simply too many high mileage cars with no issues out there to deny this.
I would inspect again in 10 to 15K though just to be sure you stay in spec.
Last edited by propain; 06-19-2014 at 07:21 PM.
06-21-2014, 04:21 PM
#160
Melting Slicks
Thread Starter