GM INSIDER TELLS ALL -- LS7 PART DEUX
Welcome back, everybody, to C&S Corvettes in Sarasota, Florida. I'm your Corvette buddy Lyle, here to talk to you about more interesting and exciting Corvette stuff. Today's episode is particularly exciting because I know many of you have been waiting for it. This is my follow-up video to the original one I did a few months ago about the LS7 in the C6 Z06.
Last time, I interviewed Paul Kerner at Carlisle, who is GM's lead tech, and he shared some information about the engine. However, many of you had opposing viewpoints and experiences, which you left in the comments. So, I promised to get an opposing or at least a different point of view on the LS7. Thankfully, one of the viewers on this channel is someone who used to be very high up in GM. For privacy reasons, we'll refer to him as "Code Name X." I recently spent about two hours on the phone with him, discussing the LS7 and his insights into the engine, especially the early versions.
But before we dive into that, I want to remind you that we cover all kinds of special Corvette topics on this channel. If you find it useful and have specific videos you'd like to see, please leave a like, subscribe, and comment below. Your engagement helps me create content that serves you better. Thank you very much.
(Music)
Now, let's talk about the LS7. Code Name X began by discussing several aspects of the LS7 that nobody at GM really wants to talk about because the engine was such a great performer. However, some of the early versions had a serious Achilles' heel. According to Code Name X, the 2006 to 2008 dry sump oiling system, which differed from the one used in 2009 and onwards, was designed to work properly up to and including one lateral G. This means that when the car is in a tight corner at speed, experiencing one full G, the system should still effectively oil the engine.
However, the Z06 was so competent that when you put sticky tires on it and drove it at a track like Sebring, pushing the car to its limits, you would be generating well over 1G in cornering. This put a strain on the LS7 engine, which wasn't initially designed to handle those conditions. GM realized this during testing but had already refined the design by then. They made the decision that it was good enough for what most people would use the car for. Unfortunately, they still released the 2006, 2007, and 2008 models, knowing that if you used those cars as marketed, there was a high chance of damaging the engine. At this point, there's nothing that can be done about it, and GM isn't willing to address it.
Fast forward to 2008, when they were developing the LS3 engine, they opted for a wet sump system instead. They found that the LS3 performed well above 1G with race tires on it at the track, without any issues. Seeing this, they made a significant change in 2009. They modified the dry sump tank and added what they called the "goiter," a small auxiliary tank that provided an additional two and a half quarts of oil capacity. This modification allowed the dry sump system to function well above 1G, even in demanding track conditions.
Code Name X recommends that if you are buying one of the earlier LS7 cars and plan on driving it at any kind of performance level, at a minimum, upgrade to the 2009 and later dry sump tank. You can still find these tanks available, either from GM or salvage places like ours. This upgrade will help address some of the oiling issues.
Furthermore, Code Name X strongly advises against turbocharging, supercharging, or adding nitrous to the LS7. The hyper-eutectic pistons used in the LS7, which were infused with silicone for hardness during manufacturing, do not respond well to these performance add-ons. The engine had a piston slap problem, and adding those modifications would only exacerbate the issue and potentially damage the engine. If you want to add power to the LS7, Code Name X recommends switching to the special forged pistons made by K-Tech. These pistons were specifically developed to handle the increased demands and won't encounter the problems associated with hyper-eutectic pistons under extreme performance conditions.
Code Name X also provided a couple of tips for C6 Z06 owners. Firstly, upgrade to the 2009 and later dry sump tank, regardless of the LS7 car you have. Secondly, it is crucial to check for valve wobble by pulling the valve covers and removing the rocker arms. Valve wobble can be an issue, and if present, immediate action is necessary, such as replacing the guides. While replacing the guides works and lasts for a long time, Code Name X suggests that if it were his car, he would consider getting the K-Tech heads, which come with all the necessary modifications already done. Although more expensive upfront, it eliminates the need to worry about the valve guides in the long run.
I found the conversation with Code Name X very insightful. However, there are other things he shared that I can't go into detail about due to confidentiality reasons. But I want to stress that he is providing this information to make you a more informed buyer and owner. He is helping you by putting this knowledge out there to help you avoid some of the pitfalls associated with the LS7, especially its early design.
Please feel free to comment below, and I look forward to hearing your thoughts and additional questions. Thank you, and I'll speak to you soon.
Last time, I interviewed Paul Kerner at Carlisle, who is GM's lead tech, and he shared some information about the engine. However, many of you had opposing viewpoints and experiences, which you left in the comments. So, I promised to get an opposing or at least a different point of view on the LS7. Thankfully, one of the viewers on this channel is someone who used to be very high up in GM. For privacy reasons, we'll refer to him as "Code Name X." I recently spent about two hours on the phone with him, discussing the LS7 and his insights into the engine, especially the early versions.
But before we dive into that, I want to remind you that we cover all kinds of special Corvette topics on this channel. If you find it useful and have specific videos you'd like to see, please leave a like, subscribe, and comment below. Your engagement helps me create content that serves you better. Thank you very much.
(Music)
Now, let's talk about the LS7. Code Name X began by discussing several aspects of the LS7 that nobody at GM really wants to talk about because the engine was such a great performer. However, some of the early versions had a serious Achilles' heel. According to Code Name X, the 2006 to 2008 dry sump oiling system, which differed from the one used in 2009 and onwards, was designed to work properly up to and including one lateral G. This means that when the car is in a tight corner at speed, experiencing one full G, the system should still effectively oil the engine.
However, the Z06 was so competent that when you put sticky tires on it and drove it at a track like Sebring, pushing the car to its limits, you would be generating well over 1G in cornering. This put a strain on the LS7 engine, which wasn't initially designed to handle those conditions. GM realized this during testing but had already refined the design by then. They made the decision that it was good enough for what most people would use the car for. Unfortunately, they still released the 2006, 2007, and 2008 models, knowing that if you used those cars as marketed, there was a high chance of damaging the engine. At this point, there's nothing that can be done about it, and GM isn't willing to address it.
Fast forward to 2008, when they were developing the LS3 engine, they opted for a wet sump system instead. They found that the LS3 performed well above 1G with race tires on it at the track, without any issues. Seeing this, they made a significant change in 2009. They modified the dry sump tank and added what they called the "goiter," a small auxiliary tank that provided an additional two and a half quarts of oil capacity. This modification allowed the dry sump system to function well above 1G, even in demanding track conditions.
Code Name X recommends that if you are buying one of the earlier LS7 cars and plan on driving it at any kind of performance level, at a minimum, upgrade to the 2009 and later dry sump tank. You can still find these tanks available, either from GM or salvage places like ours. This upgrade will help address some of the oiling issues.
Furthermore, Code Name X strongly advises against turbocharging, supercharging, or adding nitrous to the LS7. The hyper-eutectic pistons used in the LS7, which were infused with silicone for hardness during manufacturing, do not respond well to these performance add-ons. The engine had a piston slap problem, and adding those modifications would only exacerbate the issue and potentially damage the engine. If you want to add power to the LS7, Code Name X recommends switching to the special forged pistons made by K-Tech. These pistons were specifically developed to handle the increased demands and won't encounter the problems associated with hyper-eutectic pistons under extreme performance conditions.
Code Name X also provided a couple of tips for C6 Z06 owners. Firstly, upgrade to the 2009 and later dry sump tank, regardless of the LS7 car you have. Secondly, it is crucial to check for valve wobble by pulling the valve covers and removing the rocker arms. Valve wobble can be an issue, and if present, immediate action is necessary, such as replacing the guides. While replacing the guides works and lasts for a long time, Code Name X suggests that if it were his car, he would consider getting the K-Tech heads, which come with all the necessary modifications already done. Although more expensive upfront, it eliminates the need to worry about the valve guides in the long run.
I found the conversation with Code Name X very insightful. However, there are other things he shared that I can't go into detail about due to confidentiality reasons. But I want to stress that he is providing this information to make you a more informed buyer and owner. He is helping you by putting this knowledge out there to help you avoid some of the pitfalls associated with the LS7, especially its early design.
Please feel free to comment below, and I look forward to hearing your thoughts and additional questions. Thank you, and I'll speak to you soon.