[Z06] my LS7 saga with wiggle test video
03-17-2013, 07:16 PM
#1
Racer
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my LS7 saga w/ wiggle test and NEW video, shocking.
Hey All,
I posted last week about getting a puff of blue smoke on start up. It's an 09Z with 28,500 miles and a build date of 08/08. I returned from my vacation, and proceeded to do the "wiggle" test, which is really crude..it will just tell you if your guides are beyond worn, not if they are just outside tolerance.
I pulled the plugs, they all looked great. Pulled the valve covers and removed all 8 exhaust rockers, and wiggled. My worst fears were confirmed, I found two wigglers. I am in the process of tearing the rest of it apart, as I have all the replacement parts on hand. Here's a bad video of the wiggle test, as you can see at the end #6 exhaust is all over the place. Might be a little hard to see just how much, but I would guesstimate 1/16-3/32 play at the valve tip.
UPDATE: new video with valve out of head. #6 as shown in the previous video
Here is a pic of the plugs:
Here is how the car sits now:
And the freshened RPM heads with ferrea super alloy valves, CHE guides and dual springs:
So here is pics of the oily #6 exhaust port. The next pic is the clean #8, followed by the combustion chambers. Don't mind the mild spotting, that's coolant. These pics were taken right as the heads came off.
Forward progress! One head on and torqued.. I'm done for tonight...been wrenching 15 hours today.
I posted last week about getting a puff of blue smoke on start up. It's an 09Z with 28,500 miles and a build date of 08/08. I returned from my vacation, and proceeded to do the "wiggle" test, which is really crude..it will just tell you if your guides are beyond worn, not if they are just outside tolerance.
I pulled the plugs, they all looked great. Pulled the valve covers and removed all 8 exhaust rockers, and wiggled. My worst fears were confirmed, I found two wigglers. I am in the process of tearing the rest of it apart, as I have all the replacement parts on hand. Here's a bad video of the wiggle test, as you can see at the end #6 exhaust is all over the place. Might be a little hard to see just how much, but I would guesstimate 1/16-3/32 play at the valve tip.
UPDATE: new video with valve out of head. #6 as shown in the previous video
Here is a pic of the plugs:
Here is how the car sits now:
And the freshened RPM heads with ferrea super alloy valves, CHE guides and dual springs:
So here is pics of the oily #6 exhaust port. The next pic is the clean #8, followed by the combustion chambers. Don't mind the mild spotting, that's coolant. These pics were taken right as the heads came off.
Forward progress! One head on and torqued.. I'm done for tonight...been wrenching 15 hours today.
Last edited by 1981turbota; 03-18-2013 at 07:13 PM.
03-17-2013, 07:26 PM
#3
Hey All,
I posted last week about getting a puff of blue smoke on start up. It's an 09Z with 28,500 miles and a build date of 08/08. I returned from my vacation, and proceeded to do the "wiggle" test, which is really crude..it will just tell you if your guides are beyond worn, not if they are just outside tolerance.
I pulled the plugs, they all looked great. Pulled the valve covers and removed all 8 exhaust rockers, and wiggled. My worst fears were confirmed, I found two wigglers. I am in the process of tearing the rest of it apart, as I have all the replacement parts on hand. Here's a bad video of the wiggle test, as you can see at the end #6 exhaust is all over the place. Might be a little hard to see just how much, but I would guesstimate 1/16-3/32 play at the valve tip.
Ls7 exhaust valve wiggle test - YouTube
Here is a pic of the plugs:
Here is how the car sits now:
And the freshened RPM heads with ferrea super alloy valves, CHE guides and dual springs:
I'll keep you all posted with future progress
I posted last week about getting a puff of blue smoke on start up. It's an 09Z with 28,500 miles and a build date of 08/08. I returned from my vacation, and proceeded to do the "wiggle" test, which is really crude..it will just tell you if your guides are beyond worn, not if they are just outside tolerance.
I pulled the plugs, they all looked great. Pulled the valve covers and removed all 8 exhaust rockers, and wiggled. My worst fears were confirmed, I found two wigglers. I am in the process of tearing the rest of it apart, as I have all the replacement parts on hand. Here's a bad video of the wiggle test, as you can see at the end #6 exhaust is all over the place. Might be a little hard to see just how much, but I would guesstimate 1/16-3/32 play at the valve tip.
Ls7 exhaust valve wiggle test - YouTube
Here is a pic of the plugs:
Here is how the car sits now:
And the freshened RPM heads with ferrea super alloy valves, CHE guides and dual springs:
I'll keep you all posted with future progress
Well, at least you're getting it fixed.
2009 with just 28,500 miles on it. That kind of movement under spring pressure is remarkable.
Who knows how much longer it had, but good thing you didn't continue to wait and find out.
03-17-2013, 07:45 PM
#4
Drifting
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because thats with a 100lbs on the seat.
03-17-2013, 07:50 PM
#5
Racer
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My thoughts exactly. I didn't bother pulling the springs since the heads are coming off anyways. I'm sure they are all worn, but decided to whip out the camera when I found the wigglers.
Quick, it might have lasted a long time or popped the next drive. I don't want to even think about it!
Quick, it might have lasted a long time or popped the next drive. I don't want to even think about it!
03-18-2013, 01:37 PM
#7
Race Director
Wow, that 2nd vid is 
. Amazing, and a damned good thing you got into it to check it when you did. I'll be getting mine checked this Thurs. and will post results. Good luck with the new heads.
. Amazing, and a damned good thing you got into it to check it when you did. I'll be getting mine checked this Thurs. and will post results. Good luck with the new heads.
03-18-2013, 04:24 PM
#8
Le Mans Master
So based on your plugs, does this mean that non-oiled plugs does NOT necessarily mean the guides are not worn? Are those plugs even oiled? I can't tell from the picture. They seem pretty clean compared to other pictures of oiled plugs I've seen in past threads.
Ron
Ron
03-18-2013, 05:11 PM
#10
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The plugs were perfect. Oil didnt seem to make it into the combustion chamber, it was just burned in the exhaust port. The one visual giveaway was the #6 exhaust port. It was shiny with coked oil, while the other 7 were nice matte carbon. I have pictures which I will post when I get access to my computer.
wow
03-18-2013, 07:28 PM
#14
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The plugs were perfect. Oil didnt seem to make it into the combustion chamber, it was just burned in the exhaust port. The one visual giveaway was the #6 exhaust port. It was shiny with coked oil, while the other 7 were nice matte carbon. I have pictures which I will post when I get access to my computer.
03-18-2013, 08:09 PM
#15
Shouldn't this be under engine warranty? I am having my heads replaced for this same problem by GM at 0 cost. I know they are still GM heads, but 0 is good. But I will be checking for "wiggle" well before 24000 miles next time around.
03-18-2013, 08:15 PM
#16
So, oily plug threads are, at this point, inconclusive. Need to check intake/exhaust ports to help determine origin.
03-18-2013, 09:03 PM
#18
OTOH, these plugs below are oily and his guides weren't too bad.
http://forums.corvetteforum.com/c6-z...rn-guides.html
03-18-2013, 09:58 PM
#20
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Would have second guess my purchase if I had known this was such an epidemic. Just bought my 08' a couple of weeks ago, 22,000 miles.
Really sad GM isnt standing behind what seems to be a "known" issue.
Really sad GM isnt standing behind what seems to be a "known" issue.