[Z06] Post your LS7 Guide wear here - Master list
09-06-2012, 10:03 PM
#21
Team Owner
09-06-2012, 10:07 PM
#22
Well, I want to be clear, in that these are not the heads on my car.
This is my spare set of heads.
The heads on my car are coming off next week and will be delivered to the buyer, and these, now that they have been reworked, will be going onto my car.
But this is what happened in 31K miles in an unmodded car.
My car has 20k miles on it, and whatever my guide wear currently is, I could have expected it to look like this in another 11K miles.
So yes, I am glad that I made the move. That #1 exhaust guide on this spare set of heads, was way out of spec.
This is my spare set of heads.
The heads on my car are coming off next week and will be delivered to the buyer, and these, now that they have been reworked, will be going onto my car.
But this is what happened in 31K miles in an unmodded car.
My car has 20k miles on it, and whatever my guide wear currently is, I could have expected it to look like this in another 11K miles.
So yes, I am glad that I made the move. That #1 exhaust guide on this spare set of heads, was way out of spec.
09-06-2012, 10:09 PM
#23
Team Owner
Well, I want to be clear, in that these are not the heads on my car.
This is my spare set of heads.
The heads on my car are coming off next week and will be delivered to the buyer, and these, now that they have been reworked, will be going onto my car.
But this is what happened in 31K miles in an unmodded car.
My car has 20k miles on it, and whatever my guide wear currently is, I could have expected it to look like this in another 11K miles.
So yes, I am glad that I made the move. That #1 exhaust guide on this spare set of heads, was way out of spec.
This is my spare set of heads.
The heads on my car are coming off next week and will be delivered to the buyer, and these, now that they have been reworked, will be going onto my car.
But this is what happened in 31K miles in an unmodded car.
My car has 20k miles on it, and whatever my guide wear currently is, I could have expected it to look like this in another 11K miles.
So yes, I am glad that I made the move. That #1 exhaust guide on this spare set of heads, was way out of spec.
DH
09-06-2012, 10:18 PM
#25
the question I have always wondered....what would a test of a brand new GM head look like? does WCCH give you a chart of the head after its finished? what is the spec of a brand new guide? @.002?
10-11-2012, 11:19 PM
#27
Team Owner
Max allowable clearance is 0.0037 for both intake and exhaust
Replace the steel guides with bronze guides, replace the exhaust valves with OEM, and replace the intake valves with Katech's moly coated. They are giving me a 1 year 12,000 mile warranty so they are confident in this route. If you want my honest opinion, I wish I would have gone with an aftermarket set of heads like Mast or PRC to rule out the head all together as being the problem. With that said though, my observations about the driver side having more wear could be related to oil. The car was not tracked either so that's something that makes me wonder.
Also Cylinder #7 is usually the one that has the valve drop on these because of fueling/tuning right....well my #5 exhaust guide was worn out the worst. So to me I don't think it's a fueling issue when it comes to the wear, sure that can cause failure but I don't think it's related to the wear of the guides.
Last thing, I would really appreciate if people post their stats like I have above and we can make a long list!
Very last thing, I'm not a professional engine builder but I'm not a dumb either but just take everything I say with a grain of salt. It's just my opinion but the numbers I have posted are all accurate.
Replace the steel guides with bronze guides, replace the exhaust valves with OEM, and replace the intake valves with Katech's moly coated. They are giving me a 1 year 12,000 mile warranty so they are confident in this route. If you want my honest opinion, I wish I would have gone with an aftermarket set of heads like Mast or PRC to rule out the head all together as being the problem. With that said though, my observations about the driver side having more wear could be related to oil. The car was not tracked either so that's something that makes me wonder.
Also Cylinder #7 is usually the one that has the valve drop on these because of fueling/tuning right....well my #5 exhaust guide was worn out the worst. So to me I don't think it's a fueling issue when it comes to the wear, sure that can cause failure but I don't think it's related to the wear of the guides.
Last thing, I would really appreciate if people post their stats like I have above and we can make a long list!
Very last thing, I'm not a professional engine builder but I'm not a dumb either but just take everything I say with a grain of salt. It's just my opinion but the numbers I have posted are all accurate.
10-12-2012, 07:29 PM
#31
Burning Brakes
2007 Z06 with 65k miles.
Mods:
Tuned by RPM Motors in Santa Clarita, CA
K & N intake
B & B Bullets...not the Fusion
Not tracked, Hit the rev limiter in 1st, 2nd and 3rd a few times.
Mobil 1 5W-30
Mods:
Tuned by RPM Motors in Santa Clarita, CA
K & N intake
B & B Bullets...not the Fusion
Not tracked, Hit the rev limiter in 1st, 2nd and 3rd a few times.
Mobil 1 5W-30
[/IMG]
01-12-2013, 09:03 PM
#34
Instructor
I had a tech bring up the specs for measuring valve guides and it has a picture of a gauge clamped to a rocker post, measuring from the top. Long story short, you can get the spec measurements with the heads on. I took a picture of it too because no one around here believes anything anyone says.... specs are <= .0037"
Thanks
01-12-2013, 10:49 PM
#35
Racer
Member Since: Aug 2012
Location: On a back road Bavaria
Posts: 263
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Didn't get the actual numbers, but had a set of 06 heads with 25,000 miles built for my 09. Purchased here on the forum.
Had them built at RPM over the holidays, Charlie's words were "as usual, exhaust guides were shot" as he showed me the build process. The heads look AMAZING now, can't wait to put them on!
Had them built at RPM over the holidays, Charlie's words were "as usual, exhaust guides were shot" as he showed me the build process. The heads look AMAZING now, can't wait to put them on!
01-13-2013, 09:41 AM
#36
Melting Slicks
If I could figure out how to post attachments, I would post it.
However, it really doesn't say much other than
"Measure the valve stem-to-guide clearance using a dial indicator. Position the tip of the dial indicator at the top of the valve guide.
Valve stem-to-guide clearance may also be obtained by using a micrometer to measure the valve stem diameter and a ball type measuring gage to measure the guide bore."
And shows the picture above. The rest of the documents goes into valve inspection, which would require removal of the head.
However, it really doesn't say much other than
"Measure the valve stem-to-guide clearance using a dial indicator. Position the tip of the dial indicator at the top of the valve guide.
Valve stem-to-guide clearance may also be obtained by using a micrometer to measure the valve stem diameter and a ball type measuring gage to measure the guide bore."
And shows the picture above. The rest of the documents goes into valve inspection, which would require removal of the head.
01-13-2013, 11:34 AM
#39
Melting Slicks
I uploaded it to these sites.
http://www.fileswap.com/dl/iIs4fU0jxP/
http://www.freefilehosting.net/docsy...55745pubcellsy
http://www.fileswap.com/dl/iIs4fU0jxP/
http://www.freefilehosting.net/docsy...55745pubcellsy
