Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums - Camaro5.com - View Single Post - Super Chevy article says bronze valve guides can prevent LS7's from dropping valves

JeffInDFW · 02-20-2015, 03:44 AM

I've been part of the LS7 valve issue for 4-5 years now. I'm a Viper owner that is badly in love with the Z06 (and now Z/28), so I've followed this issue closely. There is a library of information available to you guys in the C6 Z06 section of the forum for Corvettes. You know, Forum for Corvettes. The latest info is, a few months ago a set of heads were purchased at the parts counter. Upon measurement, one head was perfect but the other one was wildly out of spec. This was at the end of 2014 on brand new never installed heads. Out of members who have had their heads inspected and reported back, over 200 of them, over 80% were out of spec.

They started a feature "Ask Tadge" where the Corvette chief engineer would answer one question a week. They asked him about all of this. He took double the length of time to answer, got some big wig from powertrain to chime in, and completely infuriated everyone. All they said was that the LS7 was a performance engine and the valvetrain made more noise than a normal car because it had big valves. They went on to say that a very small number of heads in 08 and 09 were machined wrong, and GM warrantied 33 engines. That was it. We had asked them to let us know what had gone wrong so we could know what to change. We needed specifics. We told them that brand new heads were out of spec, that we had a list a mile long of Z06 from 2006 to 2013 that had dropped a valve, we told them that over 80% of members cars checked were out of spec. Didn't matter. They just ignored the actual question and gave us a smoke screen.

Fortunately, the Z06 owners have already done an insane amount of leg work that you Z/28 guys can build on. For example, the Katech article you mention above, that spin tron testing where they tested the stainless steel valves and detected bounce, etc, that test was done because members of that forum asked Jason at Katech to do that testing. He said it was expensive to do. The members then donated the money to pay for it! All kinds of combinations have been tried, all kinds of motors have been destroyed. BUT, at least you guys will not be starting from scratch.

I just wanted to share that, I hope it helps get you guys kick started. Best of luck, and congrats on owning such a bad ass car.

02-20-2015, 03:44 AM	#14
JeffInDFW Camaro owner for 29 years Drives: 96 Viper GTS/09 Sky Redline/95 Z28 Join Date: Jul 2008 Location: Texas Posts: 115	I've been part of the LS7 valve issue for 4-5 years now. I'm a Viper owner that is badly in love with the Z06 (and now Z/28), so I've followed this issue closely. There is a library of information available to you guys in the C6 Z06 section of the forum for Corvettes. You know, Forum for Corvettes. The latest info is, a few months ago a set of heads were purchased at the parts counter. Upon measurement, one head was perfect but the other one was wildly out of spec. This was at the end of 2014 on brand new never installed heads. Out of members who have had their heads inspected and reported back, over 200 of them, over 80% were out of spec. They started a feature "Ask Tadge" where the Corvette chief engineer would answer one question a week. They asked him about all of this. He took double the length of time to answer, got some big wig from powertrain to chime in, and completely infuriated everyone. All they said was that the LS7 was a performance engine and the valvetrain made more noise than a normal car because it had big valves. They went on to say that a very small number of heads in 08 and 09 were machined wrong, and GM warrantied 33 engines. That was it. We had asked them to let us know what had gone wrong so we could know what to change. We needed specifics. We told them that brand new heads were out of spec, that we had a list a mile long of Z06 from 2006 to 2013 that had dropped a valve, we told them that over 80% of members cars checked were out of spec. Didn't matter. They just ignored the actual question and gave us a smoke screen. Fortunately, the Z06 owners have already done an insane amount of leg work that you Z/28 guys can build on. For example, the Katech article you mention above, that spin tron testing where they tested the stainless steel valves and detected bounce, etc, that test was done because members of that forum asked Jason at Katech to do that testing. He said it was expensive to do. The members then donated the money to pay for it! All kinds of combinations have been tried, all kinds of motors have been destroyed. BUT, at least you guys will not be starting from scratch. I just wanted to share that, I hope it helps get you guys kick started. Best of luck, and congrats on owning such a bad ass car.