[Z06] Wiggle test video... opinions welcome
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Wiggle test video... opinions welcome
First, sorry for the pretty awful video quality... my smartphone makes a good phone but a not-so-great video camera. If it goes full size (720p) the dial indicator face is a little easier to read.
This is a quick check of the #1 exhaust valve. It's a little tough to see in the video but the indicator positioned in-line with the rocker movement so I would think that should show the most wear. With the valve lowered off the seat ~.25", I get 0.004-0.005" movement.
Couple of questions...
1. Am I doing this right? Will this method give me numbers I can use to gauge the wear?
2. How's the 0.004-0.005" movement?
If it looks like I'm doing this right, I'll go though and check the others (even though this is a PITA). FYI, this is a 2006 Z06 with 35k miles and no engine mods or aftermarket tune that I am aware of although, I have only had the car the last 20k miles of its life.
Thanks!
Burning Brakes
Joined: Aug 2008
Posts: 857
Likes: 39
From: Honolulu, Hawaii
I do not have an opinion, but appreciate your post. 
Like you, I am not too clear on how to properly measure the guides, but am still trying to learn and holding out hope for a precise DIY. 
Your test looks pretty good to me and I am subscribed.
Like you, I am not too clear on how to properly measure the guides, but am still trying to learn and holding out hope for a precise DIY. Your test looks pretty good to me and I am subscribed.
Safety Car
Joined: Aug 2012
Posts: 4,706
Likes: 5
From: KY
1. It looks like you are doing it right.
2. The numbers look good. Check the intake valve as well, that will confirm everything. My bet is that you will get the same, or only very slightly less, numbers on the intake. Write down all the numbers and respective valves so you can keep track and make sense of it later. Sometimes one head is better than the other.
Unfortunately yes, you need to do them all. If only you'd got .025 on this first one, then you could have stopped
2. The numbers look good. Check the intake valve as well, that will confirm everything. My bet is that you will get the same, or only very slightly less, numbers on the intake. Write down all the numbers and respective valves so you can keep track and make sense of it later. Sometimes one head is better than the other.
Unfortunately yes, you need to do them all. If only you'd got .025 on this first one, then you could have stopped
Melting Slicks
Joined: Nov 2009
Posts: 3,296
Likes: 1,149
From: Klein TX
2023 C6 of the Year Finalist - Unmodified
2022 C6 of the Year Finalist - Unmodified
1. Yep, that's how you do it, and a properly done test will give you a very close, although not exact indication of your valve-to-guide clearance.
2. Wiggle test numbers are usually about 2x actual clearance when measured with a micrometer and bore gauge. So your .004 to .005 would correspond to .002 to .0025. The shop manual shows .0037 as the maximum for valves in service. Therefore based on this one test yours would not be out of spec. But you might want to check some more valves and get some more data.
Nice post, thanks for sharing. Hopefully some more guys with hands on experience will comment.
Btw, how did you mount your dial indicator? Use the gooseneck on a vice grip thingy?
2. Wiggle test numbers are usually about 2x actual clearance when measured with a micrometer and bore gauge. So your .004 to .005 would correspond to .002 to .0025. The shop manual shows .0037 as the maximum for valves in service. Therefore based on this one test yours would not be out of spec. But you might want to check some more valves and get some more data.
Nice post, thanks for sharing. Hopefully some more guys with hands on experience will comment.
Btw, how did you mount your dial indicator? Use the gooseneck on a vice grip thingy?
Last edited by wjnjr; Apr 27, 2013 at 07:31 PM.
Melting Slicks
Joined: Jun 2004
Posts: 2,503
Likes: 70
your this far, i would check em all. if the rest of them are like that one, i would say you have more time left. recheck in a few thousand miles again. this is the first one ive seen in spec. nice to see that. how many miles? ect.?
Melting Slicks
Joined: Aug 2006
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From: KY/TN
St. Jude Donor '13-'14-'15-'16
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Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Thanks for the info, everyone!! I'm glad I'm on the right track with this procedure.
I've only been able to check the valves on 1, 8 and 7, so far. The intakes have all measured .003-.004" and the exhausts have all been .004-.005". I wish I could get a better measure but without pulling the heads I think this is as good as I'm going to get.
I'll keep checking the others and report back. These next cylinders should go faster as there is less other stuff in the way. This is making me miss the clam shell hood on my C4 - leaning over the fender is killing my back.
Thanks!
I've only been able to check the valves on 1, 8 and 7, so far. The intakes have all measured .003-.004" and the exhausts have all been .004-.005". I wish I could get a better measure but without pulling the heads I think this is as good as I'm going to get.
I'll keep checking the others and report back. These next cylinders should go faster as there is less other stuff in the way. This is making me miss the clam shell hood on my C4 - leaning over the fender is killing my back.
Thanks!
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Mfg Date: 4/2006
35,000 total miles
0-15k: Unknown history
15k-present: mainly a DD, spirited driving, a little autocross. No engine, exhaust or tuning mods (yet).
I was thinking if everything checks out on the remaining 5 cyls, I'd recheck again next winter since the car will be hibernating, anyway. At least this will be a good baseline.
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Safety Car
Joined: Aug 2012
Posts: 4,706
Likes: 5
From: KY
Thanks for the info, everyone!! I'm glad I'm on the right track with this procedure.
I've only been able to check the valves on 1, 8 and 7, so far. The intakes have all measured .003-.004" and the exhausts have all been .004-.005". I wish I could get a better measure but without pulling the heads I think this is as good as I'm going to get. [...]
I've only been able to check the valves on 1, 8 and 7, so far. The intakes have all measured .003-.004" and the exhausts have all been .004-.005". I wish I could get a better measure but without pulling the heads I think this is as good as I'm going to get. [...]
So, you're doing good
Yeah, those locks get kinda stuck.
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Well, to update, I finished checking the rest of the valves and the rest were almost all like the first batch - intakes .003 -.004 and exhausts .004-.005. I did find two intakes that were at .005-.006 so I'll have to keep an eye on those since they are close to or at the service limit.
I'll probably repeat this exercise again this winter and see where I'm at. I'll probably start setting some mod money aside for head work, just in case.
Thanks!
I'll probably repeat this exercise again this winter and see where I'm at. I'll probably start setting some mod money aside for head work, just in case.
Thanks!
Thread Starter
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
The lash caps on the intakes weren't particularly shiny but I didn't see anything that jumped out at me. The tips of the intakes also weren't very shiny but they were clean and smooth.
Sorry I don't have a pic but I already put the car back together.