[Z06] Checking the Heads
10-23-2016, 08:15 PM
#2
Safety Car
Wiggle test
10-23-2016, 08:36 PM
#4
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Bronze guides, aftermarket springs or contacting the previous owner would probably be the easiest way. Other than finding which shop did the work, that still won't be an indication of the quality of work though.
10-23-2016, 08:42 PM
#5
Yeah, just didn't want to spend money twice for the same job. I don't have any valve train noise, so figured it might've been fixed. Car is a 2013 Z bone stock with 61k miles
10-23-2016, 08:47 PM
#6
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If you can't verify, have them checked!
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Landru (10-24-2016)
10-23-2016, 10:13 PM
#7
Race Director
WCCH and some other vendors mark their heads when they do work on them. That would not definitively indicate the valves/guides were done, but likely.
10-23-2016, 10:21 PM
#8
Safety Car
Sure it would.
If their tight, it probably has been addressed. And if so nothing needs to be done at this time.
If they are loose, you send them in to get them done. AHP does a great job and they use harder guide material that also looks close to stock.
10-23-2016, 10:26 PM
#9
Safety Car
You could start by pulling off the valve covers and see if there are aftermarket springs and retainers on there. The odds of having those and not other head work would be rare. You can also look on the front of the drivers side head to see if the stickers are still on there. You could also look at the head bolts. Most guys install the ARP one's after having the heads done instead of using new stock ones. Or spend a few hundred bucks and take it in to your local Corvette shop and have them do the dreaded wiggle test.
Good luck with your heads and I'm thinking after 60K they are either done or you're just lucky. I had mine none around 3500 miles.
Good luck with your heads and I'm thinking after 60K they are either done or you're just lucky. I had mine none around 3500 miles.
10-23-2016, 10:48 PM
#10
Truth is, you don't. Either removing the heads or a trusted source (paperwork, vouch, etc) is required.
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Landru (10-24-2016)
10-23-2016, 10:59 PM
#11
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I just had mine checked this weekend by a reputable shop here in Houston, I have 27k miles with no noise either. The shop tech said I had no signs of wear but I just liked to have piece of mind, I hated the whole "playing with fire" feeling I had when starting the car. I'm still gonna have the heads ported and polished regardless and when I do that the valve issue will be addressed also. The way I see it is if you can afford a "Z" you can afford the issues it comes with. Also from what I have heard and seen from the valve issue is that cylinder 8 is the one that shows the most wear for some reason, I could be wrong but it doesn't hurt to check all of them. Good luck with your diagnosis/repair.
10-23-2016, 11:02 PM
#12
Team Owner
Won't help you identify corrected GM heads but, like in my case, I have aftermarket PRC265 heads which can easily be identified by their six bolt hold downs, that can be seen without removing anything on the car.
10-24-2016, 04:34 AM
#13
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Just do a wiggle test. Its the quickest and easiest way to find out where your heads are at.
We have reworked some of our our competitors reworked heads, so just because they have been done does not mean they are good to go. Like note, easiest and cheapest just to do wiggle test.
If your hand with some tools you can do it yourself. We have a write up here on the forum:
https://www.corvetteforum.com/forums...-test-diy.html
http://www.americanheritageperformance.com/
We have reworked some of our our competitors reworked heads, so just because they have been done does not mean they are good to go. Like note, easiest and cheapest just to do wiggle test.
If your hand with some tools you can do it yourself. We have a write up here on the forum:
https://www.corvetteforum.com/forums...-test-diy.html
http://www.americanheritageperformance.com/
Last edited by American Heritage; 10-24-2016 at 04:35 AM.
10-24-2016, 11:01 AM
#15
Burning Brakes
Worn Valve Guides
The first time I had mine checked by Mac Haik Chevrolet, they pronounced them as fine, all within spec as well. Problem was, I had done the wiggle test before taking it to them. I had to stay on them and explain the correct way to do the test, and they were a little embarrassed to admit that I was right.
Make sure that the reputable shop removed valve spring retainers and springs and that the valve head is off the seat (partially depressed), and check the wiggle with a dial indicator. My valve guides were out of tolerance at 13k miles. Mac Haik installed new heads, all valves under the factory warranty.
I am approaching 10k miles on the new heads and I will have another wiggle test to ensure that GM got it right this time.
Make sure that the reputable shop removed valve spring retainers and springs and that the valve head is off the seat (partially depressed), and check the wiggle with a dial indicator. My valve guides were out of tolerance at 13k miles. Mac Haik installed new heads, all valves under the factory warranty.
I am approaching 10k miles on the new heads and I will have another wiggle test to ensure that GM got it right this time.
I just had mine checked this weekend by a reputable shop here in Houston, I have 27k miles with no noise either. The shop tech said I had no signs of wear but I just liked to have piece of mind, I hated the whole "playing with fire" feeling I had when starting the car. I'm still gonna have the heads ported and polished regardless and when I do that the valve issue will be addressed also. The way I see it is if you can afford a "Z" you can afford the issues it comes with. Also from what I have heard and seen from the valve issue is that cylinder 8 is the one that shows the most wear for some reason, I could be wrong but it doesn't hurt to check all of them. Good luck with your diagnosis/repair.
10-24-2016, 11:14 AM
#16
Safety Car
10-24-2016, 11:58 AM
#17
Team Owner
10-24-2016, 05:44 PM
#18
Race Director
10-26-2016, 01:21 PM
#19
Max G’s
My Z had heads done with new springs, guides and valves. 15,000 miles later and guess what; we need heads. Which I have new Mamofied heads ready to install. Anyone buying a Z should just plan to install new heads unless they plan to just do street driving and keep rpms below 5K.
10-26-2016, 01:37 PM
#20
Safety Car