User Omega

[QUOTE=rockinSeat;1596467052]
He speaks of the heads that were out of spec off of the shelf/off the lot. There were some heads this way but I do not know the timeline. It has absolutely nothing to do with the fact that guidewear in the LS7 is at pandemic levels.

FYI... Just because you, your uncle Randy, and some guys you saw on this forum beat on their cars ever day and it didn't blow up does not mean that the valve guides were in spec. It is unreal to me that some of them get as sloppy as they do before found. The valve drop is hit or miss. The wear is not.

1972bluelt1

Did Linimar, Inc provide any other engine components for the LS7?

farmington

Don't know if this is what's happening with the LS7 guides, but we ran across a bunch of guides from a supplier that the inner diameter wasnt concentric with the outside diameter. It was off over .0015". This caused the drill and reamer to follow the offset hole causing an out of round condition.

NotreOkc

You are making me think on a Sunday! LOL
I bought it in 2011 I think and sold it in 2015.

NotreOkc

[QUOTE=tobaccokid;1596464383]So the majority of guys who have owned their Z06, never touched the engine, never had problems........we are all wrong? LOL, got it!!

reasonable suspicion

[QUOTE=NotreOkc;1596470388]
correct

1972bluelt1

AHP Raw Wiggle Test Report

Here is the results you were after. Measurements over .008" are considered to be out of spec.

Cyl 1
Int .006"
Exh .005"
Cyl 3
Int .006"
Exh .009"
Cyl 5
Int .005"
Exh .007"
Cyl 7
Int .006"
Exh .005"
Cyl 2
Int .009"
Exh .005"
Cyl 4
Int .009"
Exh .005"
Cyl 6
Int .006"
Exh .005"
Cyl 8
Int .010"
Exh .006"

This is off the car, heads received by AHP 1-26.
.010 x .62 = .0062, service limit is .0037. By that formula .006 is right at the SL.

This is from my 2007 Z06 w/10,350 miles. Bone stock waxer\cruiser.

Draw your own conclusions, don't shoot the messenger.

keeso6z

Not addressing the heads/valve issues at any mileage, but particularly with higher mileage, is a time bomb waiting to go off. I did mine at 2,300 miles, but when I did some other performance mods and had the heads ported and milled. Why take the chance of $15K+ in engine damage? It's preventive maintenance and a cost of ownership of a high performance Corvette. My performance shop warned me about it and said they saw dropped valves with cars that had low miles on them.

NotreOkc

A time bomb? Only on this forum you would think it is a time bomb. My Z had high mileage at 48K when I sold it and it had zero issues. As do the majority of stock LS7's - zero issues. Was I just very very very lucky?
Preventative maintenance? Oil changes and fluid changes are preventative. Addressing the heads is simply peace of mind. Not preventative. For those that deem it necessary, more power to them. But to call the LS7 a time bomb? That would imply that 100% of them will eventually explode. Would it not?

keeso6z

I'm just reporting what my performance shop is telling me and those guys really know Corvettes. I trust their judgment, they are honest and they don't try and sell you something just to make money. They want you to be happy with your car. If you want to take a chance on the stock valves/heads, go ahead. But for what the car cost and how much it is to fix it, it is not a huge pile of money. Plus you can actually improve the performance of the car at the same time. I meant of peace of mind and not preventive maintenance. GM won't take care of the faulty engineering so we are stuck with the cost of the fix. Small price to pay to own such an awesome car.

nexxone_05

Can anyone here recommend a good shop in Southern Cali to get it done.

Thanks!

Les

You're lucky that these guys are so close. For my money they are the best.
http://www.americanheritageperformance.com/home.html

Les

Just curious- what were the valve guide specs when you sold it?

grcor

I would recommend American Heritage Performance.
http://www.americanheritageperformance.com/

Unreal

For socal another great option, and one of the best shops in the country is CMS. Cunningham motorsports.

NotreOkc

Hi Les,
I never had them checked. I guess that is kind of my point and I am guessing it is yours as well. I had no need to get them checked, and I tracked the car hard (4-5 events a year). Could they have been out of spec? Possibly.
But the vast majority of owners never have them checked, never alter the engine and have zero issues.

nexxone_05

I actually emailed them too!

Les

Our perspectives and our points are actually different, but that's OK. I see the purpose of threads like this being to seek the truth, hopefully with respect when differences occur.

I've had my valve guides checked twice and the heads were replaced both times under extended warranty- they were badly out of spec both times. The second time I spent extra to have AHP install their Moldstar 90 guides. I have a number of Z06 buddies who have been through the same drill.

My point to you is that, since you never had the guides checked, you can accurately say only that your LS7 had zero known issues. For all you know, the guides could have been badly out of spec and a valve stem could have been cracked with the valve head ready to snap off. I'm not saying that was the case but you can't say it wasn't either.

Apocolipse

$2000 isnt enough for me to worry if my valves are in or out of spec. Plus, gives me the option to add a bit extra power with a proper valve job / deck the head for more compression.

For those that want to risk it - all the power to ya - I would just rather know for sure that mine is okay and that TO ME is worth the money.

Same can be said about guys running on old aged tires...

2fastz06

I've seen my own heads out of spec after rework..I've seen all pro heads prc wcch ect all out of spec.

Shame Chad isn't still on here, He told the truth about this issue!