Help! Valve guide wear on ZO6 427 engine

[L over D]

errata.......

toms 007 said..........

L, I see this is your firs
t post, so "Welcome" to CAC. From the sound of your post, you have some knowledge in the area of engine build/function. We can always use such knowledge here. Don't be shy about posting and enjoy CAC.

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well thanks for the kudos.........reason I came to CAC is it is a cut above. After seeing/reading all of Hib's writings I thought right. I have had a few Corvettes in the last century. Now I have been lurking and looking to buy another in near months....C6 or C7.

Now that I did some digging, and found that the LS7 cylinder head design and longevity was subject to my scrutiny (IMO), I should be prepared to pull things apart at some time after I buy. I found here and elsewhere a trove of information....and discarded the MIS-information. What I believe after two weeks of reading and looking on the designing of the LS cylinder heads with the LS7 package to deliver OVER 500 hp was a mighty goal 13 years ago. Very possibly the GM politicians pressured the 500 + and more possibly Ti valves, lash caps and more exotica. And numbers and goodies sells cars. I might think that using Stellite or even stainless valves would mean using higher valve spring numbers. back then in the dark ages Ti was magic ! So backing down the packaging would only deliver...400....450 ?? but with better longevity. But maybe I'm wrong. More displacement? Maybe. You cant have guns and butter. When you move into high gear production , as was West and the outsourced 5 axis machine company, it must be to tenths not inches when you are putting out a 500 hp street car. I still will be buying a Corvette.

 

[Tuna]

LS7 Work - maybe, maybe not
Depends on the engine, the year, miles and whether the heads have already been worked on.
It seems that by 2013, the LS7 heads were no longer an issue. I have 48,000 miles on my LS7 and it hasn't missed a beat or rattled or done anything else but scream to redline and ask for more.

 

[Iroc2Vette]

I'm heading toward 60K, rapidly. And mine is also a 2013. And, both oil test samples had zero wearable metals in the oil, even after 8Kmi oil changes. In fact, Blackstone said I can easily go over 10K.

But, my car may've been made early enough in 2012 where I might've gotten a set of older heads in inventory. Since the inspection process isn't retroactive, it's a bit like having a sword dangling above my head. My PT warranty goes bye-bye Oct. 4rth, 2017. That's 2 days from now.

I'm assuming, or speculating the new heads will cost about $2-3K. Maybe a bit more. But, compared to a $21K+ new engine, it's looking more like good preventative maintenance. The owner of the shop said it might be more cost efficient to just buy a set of HP heads (Trick Flow, Brodix, RHS, Texas Machine, Dart, etc.) than to have them shipped out and back and the machining, disassembly/reassembly...But, he's got to look more into it.

If it's workable, it might be possible to install heads which might give even better performance (25-40 more bhp), as long, and ONLY as long as the OE intake manifold and headers bolt up and work properly. And no engine check light DTCs. Any change in drivability the way I have now will be unacceptable. Especially getting stuck in traffic. I need lots of idle range torque for clutching.

What I'm also thinking of as long as the top of the engine is being broken into (yech!!!), I might as well also get top notch lifters, rods, rockers and springs. The parts cost little and as long as the heads are off, so will the labor.

Geezzz! I was SO hoping NOT to have to do this...