Too-Fast

So this is a video of a "wiggle test" on my 2011 Z07 with 3100 miles I just did this afternoon. It is the passenger side bank and I did not remove the valve springs...I felt that if there is movement with the valve springs on, then there would be much more with them removed.

I was surprised to see the intake valves moving more then the exhaust I would appreciate it if those with experience in this area would chime in with your perspective. Should there be this much movement? Do I need to remove the springs or am I done with the movement demonstrated in the video? Thank for your feedback in advance. Oh, and the audio is a little low, sorry.

MTPZ06

Video doesn’t work for me

Too-Fast

Strange, I tested it in the test section and it works when I view it? Here is the YouTube link

BAAD LS2

Looks exactly like mine did on my ls9 heads on the intake valves. After I got them fixed with new guides there is zero movement with the springs on.

MTPZ06

I would definitely pull the springs on the ones you feel have the most movement and go from there, but it’s certainly discouraging to see some moving more than others.

Unreal

If they are moving that much on the seat, with springs, they are probably toast.

Too-Fast

Thanks for that feedback, I was surprised that they were moving.

Too-Fast

Thanks Unreal, that is what I am thinking also.

Dirty Howie

3,100 or 31,000 miles


DH

Minkster

My intakes were moving less than that, so I took it to Rich at Abel and they were .013"-.015". Got AHP heads with the following installed last week.







Now good to go. This is the third (and final) set of heads I've had Abel install, two under GM warranty (new GM heads), and lastly these AHP rebuilt heads under GMPP.

Too-Fast

3,100 Howie.

1972bluelt1

Wasn't sure my valves moved at all with the springs on. If they did it was very little. One exhaust and 4 intake guides were beyond the service limit.

meanjoe

Mine were also bad at less than 4K

Too-Fast

Yeah, I am going to put it back together today and order a redone set of heads from either AHP or AI and be done with it. Thanks for all of your feedback folks.

JerriVette

You pulled the heads? Or did you incorrectly test them on the car? My buddy is "the corvette mechanic" who does the Carlisle, bowling green , mid America, Bloomington gold service seminars and he is too tired to keep answering this question on line because people don't listen...

The wiggle test is not being done correctly and people are needlessly and incorrectly determining their car has a valve guide or valve angle problem...

He services my car and I bring this topic up from time to time and he just says how many times can you have this discussion on incorrect testing to incorrectly determine if your car needs new heads...

With 3100 miles your really just in the mood to do something with your z06 and if that's the case...have fun...

But from a reality standpoint...you really aren't doing the test correctly which cannot be done with the heads on the motor.

The incidence rate is less than 8 tenths of one percent.

I ve heard the heads can be done relatively inexpensively so if it makes you feel better do the heads but the issue has been overblown because of the Internet forums scaring would be buyers lowering residuals for literally an issue that has occurred less than 8 tenths of one percent ...

You d have a greater chance of a cam failure than a valve dropping failure but it doesn't matter those whose engines fail are automatically told by the "tuner" it was the valve issue...again just overblowing the fear in owners and would be owners to replace the heads.

I'm not going to argue with those who already changed their heads out of fear as they are venomous in their retorts and I am just suggesting with 3100 miles the chance of your valves being an issue are minuscule...literally less than 8 tenths of one percent of all ls7 s produced...

Anyway replacing the heads is relatively inexpensive so for those that feel better doing them. I'm sure the heads being replaced will enhance the resale value as the z06 residuals collapsed on this internet rumor being blown out of proportion. By paying "tuners" to replace the heads which is not expensive you are improving your residual values based off the fears that are created by these forum and tuners misdiagnosing any and all issues as valve issues...

Congratulations and no insult intended.

Just a perspective to consider since you asked the question..

We did over 200 episodes of the corvette mechanic podcast together.

hippy

So you're saying that there are roughly only 250 times these heads have failed? That number seems awfully low to get GM to respond to this non issue. Didn't they already admit to a manufacturing defect with the heads?

MTPZ06

Ah yes...if only us owners had listened to Jerri’s buddy the podcast mechanic

Then we’d all be in the clear. Yes, we should all listen to the two guys on a podcast that don’t own a C6Z and have probably never done an inspection on an LS7 cylinder head.

Too-Fast

I appreciate you’re perspective, thanks for your feedback.

My heads will be pulled and measured by a competent machine shop. However, it is pretty certain, that if they are moving like they are then they will be bad. I was very surprised to see that much movement, under full tension, especially the intakes. There is too much empirical evidence to ignore the issue and I don’t want to drop a valve at 170mph. I will not get into a protracted discussion with you, thanks for your comments.

Les

Yeah, good old Jerri is back to gift us with more of his "wisdom".

moose.b3

The incidence rate is less than 8 tenths of one percent.