[Z06] Valve guide issue
12-13-2016, 06:01 PM
#62
Safety Car
Member Since: Dec 1999
Location: Virginia Beach, VA & Port Charlotte, FL (snowbird)
Posts: 4,407
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Well I live in Alaska. Does that count as "North"? And yes, when I pulled my heads off the first time, the guides were shot. I have also re-built two other LS7's "up here". Both engines came off air boats, and both sets of heads had significantly worn valve guides.
But, at this point in this threads life, I'm fairly certain the OP is either trolling for a reaction, just to have some sort of twisted fun, or is too daft to comprehend the technicalities centered around the question he asked. Can't believe I wasted five minutes of my life responding to this..
But, at this point in this threads life, I'm fairly certain the OP is either trolling for a reaction, just to have some sort of twisted fun, or is too daft to comprehend the technicalities centered around the question he asked. Can't believe I wasted five minutes of my life responding to this..
12-13-2016, 06:22 PM
#64
Team Owner
Its been one of the more entertaining threads as of late...
That it has!
12-13-2016, 06:34 PM
#66
12-13-2016, 11:46 PM
#67
Le Mans Master
It's probably bad form and might label me a bit, but I secretly hope these select few deny-ers, the ones that go out of their way to convince others of "Corvette Forum / Internet hype" conspiracy theories, I hope their **** blows up (in a safe, friendly, I-told-you-so kind of way of course).. Sorry.. 
Last edited by Dan_the_C5_Man; 12-14-2016 at 01:39 AM.
12-14-2016, 05:06 AM
#68
Melting Slicks
At the very moment ATC made this post, he proved his own point.
12-14-2016, 10:47 AM
#69
Le Mans Master
I have a 10 Z06 bought new with 4,000 miles on it today and believe that there is an issue with the valves/guides. I do much of my own car work as a hobby now for 35+ years and recently rebuilt/upgraded my 78 L-82 engine in my garage but did use a VERY respected High performance engine builder in my area for the reconditioning of the block, rods, crankshaft, new pistons/rings etc. I did everything else and other stuff as well.
I spoke to the builder who was a field tech for GM for 16 years before opening his shop in 2010 about the Z06 issue and he concurs the issue is the 2 piece exhaust valve and guide material. With that said, he also told me that he has never seen personally or heard of LS7 failures with the exception of those that drag race or road race their cars. Not saying that there are not other failures but the predominance are those LS7 engines that have been exposed to very high performance use.
With all that said, the builder will check my valves Spring 2017 for wear. Depending on that check, I am going with his solution of Manley exhaust valves with a DLC coating (diamond Like Coating), OEM titanium valves, CNC porting of the heads, bronze or MOLD 90 guides etc.
FWIW-I have used Mobil 1 0W-40 European Formula/Mobil 1 filter, pretty much from day 1 first oil change at 500 miles and always prime the engine without starting before the engine actually engages....eliminated all valve clatter on cold startup....
I spoke to the builder who was a field tech for GM for 16 years before opening his shop in 2010 about the Z06 issue and he concurs the issue is the 2 piece exhaust valve and guide material. With that said, he also told me that he has never seen personally or heard of LS7 failures with the exception of those that drag race or road race their cars. Not saying that there are not other failures but the predominance are those LS7 engines that have been exposed to very high performance use.
With all that said, the builder will check my valves Spring 2017 for wear. Depending on that check, I am going with his solution of Manley exhaust valves with a DLC coating (diamond Like Coating), OEM titanium valves, CNC porting of the heads, bronze or MOLD 90 guides etc.
FWIW-I have used Mobil 1 0W-40 European Formula/Mobil 1 filter, pretty much from day 1 first oil change at 500 miles and always prime the engine without starting before the engine actually engages....eliminated all valve clatter on cold startup....
Last edited by jb78L-82; 12-14-2016 at 10:49 AM.
Here we go! 
12-15-2016, 02:46 PM
#71
Drifting
I have a 10 Z06 bought new with 4,000 miles on it today and believe that there is an issue with the valves/guides. I do much of my own car work as a hobby now for 35+ years and recently rebuilt/upgraded my 78 L-82 engine in my garage but did use a VERY respected High performance engine builder in my area for the reconditioning of the block, rods, crankshaft, new pistons/rings etc. I did everything else and other stuff as well.
I spoke to the builder who was a field tech for GM for 16 years before opening his shop in 2010 about the Z06 issue and he concurs the issue is the 2 piece exhaust valve and guide material. With that said, he also told me that he has never seen personally or heard of LS7 failures with the exception of those that drag race or road race their cars. Not saying that there are not other failures but the predominance are those LS7 engines that have been exposed to very high performance use.
With all that said, the builder will check my valves Spring 2017 for wear. Depending on that check, I am going with his solution of Manley exhaust valves with a DLC coating (diamond Like Coating), OEM titanium valves, CNC porting of the heads, bronze or MOLD 90 guides etc.
FWIW-I have used Mobil 1 0W-40 European Formula/Mobil 1 filter, pretty much from day 1 first oil change at 500 miles and always prime the engine without starting before the engine actually engages....eliminated all valve clatter on cold startup....
I spoke to the builder who was a field tech for GM for 16 years before opening his shop in 2010 about the Z06 issue and he concurs the issue is the 2 piece exhaust valve and guide material. With that said, he also told me that he has never seen personally or heard of LS7 failures with the exception of those that drag race or road race their cars. Not saying that there are not other failures but the predominance are those LS7 engines that have been exposed to very high performance use.
With all that said, the builder will check my valves Spring 2017 for wear. Depending on that check, I am going with his solution of Manley exhaust valves with a DLC coating (diamond Like Coating), OEM titanium valves, CNC porting of the heads, bronze or MOLD 90 guides etc.
FWIW-I have used Mobil 1 0W-40 European Formula/Mobil 1 filter, pretty much from day 1 first oil change at 500 miles and always prime the engine without starting before the engine actually engages....eliminated all valve clatter on cold startup....
12-15-2016, 03:07 PM
#73
Team Owner
With all that said, the builder will check my valves Spring 2017 for wear. Depending on that check, I am going with his solution of Manley exhaust valves with a DLC coating (diamond Like Coating), OEM titanium valves, CNC porting of the heads, bronze or MOLD 90 guides etc.
I'm sure you've probably seen AHP's guide hardness test, but just in case here it is again...
You already know and understand what the underlying issues are...you're in the clear. 
12-15-2016, 04:39 PM
#74
Le Mans Master
Cool. How are you priming? I never had valve clatter on cold startups anyway but just curious. If there was clatter it would just be lifters that aren't pumped up which one would think, only happen after sitting a really really long time? If the lifter wasn't pumped up it will pump up very quickly. Maybe that roller slapping the cam would cause damage but at low rpm (600 rpm spinning off the starter?) and for less than a second I don't think it matters.
Last edited by jb78L-82; 12-15-2016 at 04:40 PM.
12-15-2016, 05:29 PM
#76
Team Owner
I dropped my car at AHP last year...I have the OE Ti intakes, Ferrea F2042p hollow stem (1-piece) exhaust, MS90 guides, PSI 1511 Beehives w/Ti retainers, and CHE rocker trunions.
12-15-2016, 05:55 PM
#77
Drifting
12-15-2016, 06:08 PM
#78
12-15-2016, 06:09 PM
#79
