Owned a 2011 Z06, second owner, purchased at 14K miles, never modified from stock. Wiggle tested at 30K miles, exhaust guides out of spec, heads replaced under GM warranty with GM LS7 heads (due to factory warranty). Had those heads checked gain at 38.8K miles just prior to GM powertrain warranty expiring at 5 years, intake guides were out of spec. A second set of GM warranty GM heads were installed. However, both sets of replacement heads were of the same lot (2013), so expected intakes to prematurely wear. As predicted, had heads checked at 48XXX miles, intakes worn, replaced with aftermarket heads on GMPP warranty. Replaced that Z06 with 2011 Carbon Edition Z06 in Oct 2021, 6.6K miles, all original and stock. Had OEM heads replaced with aftermarket heads to be proactive. Checked guides on OEM heads and intakes were out of spec at only 6.6K miles.
Well dang it that is very concerning all round! What the hell?? What are we to believe then?? I’m concerned my 2014 Z28 will spit valves any day. Constant concern.
This video was mostly BUNK! I've seen hundreds of out of spec LS7 valves/valve guides, they range from every model year GM made the LS7 (including in the Z/28)... ALL THE YEARS POTENTIALLY HAVE THIS ISSUE!!! It's more rare to not see a stock LS7 without at least one valve close to being, or being completely out of spec. Mileage isn't a huge flag either, I've seen them loose with under 10k miles. This doesn't mean they will grenade at any moment (it's a fairly low percentage that totally nuke), but the point is every LS7 is suspect and an eye needs to be kept on them to make sure they don't get to the point of excessive wear. Please do not listen to the BS GM is spewing that it was only a few cars and only 2006!
What about LS3? I have one in my Holden Commodore SS paired to a T56... is there anything to worry about? (Mime still has the machined roller rockers not the cast ones btw)
@@GregoryShtevensh the ls3 is the most bulletproof out of the entire LS series. The only thing on them are the stock rocker arm needle bearings (all ls engines) if installing a high lift aftermarket cam.
Very strong opinion. I have found that folks with a strong opinion are often not 100% accurate. Get the heads replaced by a reputable company, AHP comes to mind. Get a mild cam and you are set. I did that and dyno numbers were 550.18 HP and 503 lbft torque.
Completely stock 06 Z06 with 30k miles dropped a valve without warning cruising on the freeway. Cost me the motor and oil system. 20k mistake thanks GM. This issue is very real. I high recommend anyone with an ls7 get there heads done.
If you are going to modify your LS7, I highly recommend Katech Performance in Detroit. They've been working with these engines from the beginning. Worked with GM to develop it, and built all of them for Corvette Racing ( Pratt and Miller). They know and address all the pitfalls of this engine.
@@toddhartmayer8327 which is pretty sad. And I don’t understand what this guy (original commenter) is saying either. Why would I go to a place that HELPED ruin the engine, to help fix it? 🤣
@@toddhartmayer8327 which is pretty sad. And I don’t understand what this guy (original commenter) is saying either. Why would I go to a place that HELPED ruin the engine, to help fix it? 🤣
Hey Lyle! It was great meeting you at Carlisle before you left. Just got my C4 safely back to Arizona now. Thanks for your advice, and glad you enjoyed the show!
Nice vid, however you forgot to mention!The LS7'S use relatively high lift camshafts. Premature valve train failures can be caused by high lift cams that cause long rocker arm travel. Long rocker travel causes lateral force on the valve stem when the valve is open. This lateral force wears out valve guides. Which causes valve and guide tolerance to go out of spec. GM even had a service bulletin with a valve stem "wiggle test". GM also acknowledged that several batches of valve stems were installed incorrectly at the wrong "angle". Valve issues are widely documented. Race Proven Motorsports to this day continues to find bad valve guides in LS7 Camaro's.
Ya he missed a lot of stuff, like how high rpms are needed when holding a gear thru corners, going thru traps on a drag strip, etc... You know the kinda things you buy a Z06 for. My guess is he is either really stupid, or trying to cover GM's ass over a well known well documented problem GM doesn't want to admit to. I laughed when he said you don't need high rpm's and not to over rev your engine. You CAN'T over rev a engine with stock tuning, the ECU will not allow it....
@Milo Jones I'm a fan of roller rockers. Also, just wanted to ask, are those duration numbers @.050 or advertised duration? Cuz if that's .050, good God that's gotta be a rowdy camshaft, especially at 111 lsa 😂. Unless the LS7 manages high duration well and those numbers are kind of normal for it. I know it is set up for high lift, so the 684/683 doesn't shock me.
@Milo Jones That's badass, man. And I agree on the rollers. I kinda think GM should have just used rollers to begin with. The thing has just about .6" of lift from the factory, and it's a nice, expensive engine. Just use rollers GM! Of course, GM has been pretty famous about cheaping out on rocker arms. Needle bearings with open trunions that scatter the needles everywhere comes to mind. But that is really, really good info about the swipe pattern with the rollers. I'm an Fbody guy, but of course one day would like to buy an ls7 car, probably a c6 Z06.
Lyle, Sorry I missed you at Carlisle, love your videos and this one in particular. I have a 2013 427 convertible with a little over 30,000 miles. I have read all of the dread on the forums, so I have changed the oil and filter every 5,000 miles or year whichever comes first. I also send the oil off to be analyzed and the reports have come back clean each time. I plan on keeping this car and enjoying the drive. Keep up the good work. Wish your shop was close to me, need a good shop in Eastern Va.
Now here is a smart owner. Don't believe all the BS GM is spewing. You don't hear of ANY of these problems with the LS1, LS2, LS3, LS4, LS6, LSA, or LS9. There was, is, and are reasons for cause and effect.....
Is 5 000 miles not standard oil change interval? If, with Covid, one could put that many on in a year. I went to once a spring change the last couple of years. I would think spring is better than fall to get out any winter moisture in oil? Yes/No?
Wish I had, ha. I enjoyed my 2002 electron blue Z06 straight away 177 per hour tunnel vision for $55,000.00. Had 5 other vets various degrees lol. 3 C7s not impressed with Bowling Green. C6 felt kind of slippery. I probably will go back C5 when the dollar adjusts my way lol.
This video is another example of why I love this channel. Lyle lays it out with words everyone can understand and gives us the knowledge we need when making that huge decision to buy a Corvette. And this is coming from a former Corvette owner, five different ones over a 12 year history. Love the channel, Lyle.
Wow, this information is so helpful. Its getting more and more difficult to find a Corvette that is bone stock . The head issues explained is very helpful as well. Thank you so much for sharing.
This is BS. The issue was NOT fixed after 2006.The official GM bulletin specifically states the 08-11 cars which is also incorrect. Of course the GM engineer is going to say there was no issues but the truth is, its very much a real problem that still exists today. Please do your research before buying one of these cars even if its STOCK.
Totally agree from experience too!! Dropped a valve on a 2007 1st gear pull w a customer while tuning him, (stock limiter). Needless to say, destroyed the engine. I typically love your content, but this was complete bs on the airflow and tuning aspect affecting guide wear. The whole stock engine lives is bs, related to the valve guide wear issue. I’m a GM tuner and Mechanical Engineer from the automotive industry, I can back up my info too. I do generally agree w everything else that was said.
completely agree 💯. The only leg they have to stand on is that there are little to no issues with stock LS7 engines. Nobody leaves an LS7 completely stock! This is the most common form of manipulative statistics! Find a C6 Z06 without an intake or headers, and I'll show you a garage queen. Even when completely stock, and just well driven as designed, you'll have the same valve issues as they ALWAYS have eventually. Still a great platform if you're willing to spend the time and money necessary to make it perform and be reliable.
I owned my 2007 Z06 for 10 years and no engine problems (thankfully). However, I was well aware of the potential for a catastrophic engine failure. But I did have the clutch replaced under warranty due to something the dealer tech called an overcenter condition. In real world terms what this meant was the clutch pedal stuck to the floor and wouldn’t release until I backed off the accelerator. Even though a gm engineer told me the single disc clutch could handle the LS7 torque, I never believed it. It should have been built with the dual disc clutch like in the ZR1.
117,000 miles on mine so far. Bone stock engine. Even the air filter is the stock AC Delco Donaldson Power Core. Was very diligent during break in period, swapped the oil/filter at 1100 miles. LS7 continues to be a gem of an engine for me. A very interesting article in Corvette Action Center by Hib Hiberson "The Ruthless Pursuit of Power' states (if I'm remembering correctly) Feb 2011, GM asked or required Linimar Manufacturing (they machined the heads) to do a 100% inspection on them instead of spot inspections. And the valve guide issue was largely 2008-2010. My engine was built in 2012 for the 2013 model year.
Great stuff, recently purchased a 07 . No more mid life crisis. Awesome beast, I am an ex state trooper, could never catch a Vette lol. Subbed and shared .Kudos..
ANDY, ON THE SERMON AMOUNT CHRIST SAID "DO UNTO OTHERS AS YOU YOU WANT DONE UNTO YOURSELF". OBVIOUSLY YOU'RE DOING THE SAME THING WITH YOUR CAR THAT ALL THE OTHER PEOPLE DID. THAT YOU GAVE TICKETS TO. AM I CORRECT ABOUT THIS?
For ultimate performance, saying "shift 1000 rpm below redline" really doesn't work. You ARE losing performance. OTOH, for a street car which is not in serious competition, it makes perfect sense most of the time. Few if any street drivers need ultimate performance. If you drive any hi-po engine right up to its limits, it will need more maintenance, repair and will probably succumb earlier. That's the nature of the beasts.
Thank you for the great video. I've owned three corvettes and have been thinking of getting an LS-7 Corvette . I have done some research on them but didn't find the information that you provided. Thank you .
Great video Lyle thanks I learned a lot I still have my C5 and love it but I always enjoy your videos thank you for posting great presentation of valuable information
Never had a problem with my ls_7 it was a 2008 zo6. Autocrosses it for 3 Years bought it 27k sold it with 56k. Between 2 drivers it won 14 of 16 races. I also personally ran about 100 to 125 quarter miles runs in the 4 years I owed it. I ran cold air intake and hypertech programer. At different times. I also very early on I reduced the rev limiter. 6500. Ran like a rolex watch. Never missed a beat. Miss everything but the arrest me red color. Just 2 cents.
I also have a 2008 Z06. Ran the thing hard on the streets all the time. Bought it at 36K miles. Never had it tested for the heads. Just enjoyed it. Like you should. Tuned it and added aftermarket parts. At 52K miles finally upgraded the heads and cam and went right back to beating on it and enjoying it. Mines also red
@@joem1382 mine is a 07 but with a 09 service engine since I blew the original spraying a big shot lol. The 09 engine has now 70k miles and running strong.
Asking a GM representative about failures is about like asking a kid if he stole a piece of candy. You might get the truth. How many times have I called the manufacture of a part and heard, "We've never seen that problem before". Sure..often I knew of others with the same problem that had called the same manufacturer. It's a CYA. While I don't know how legitimate the LS7 issue is, they don't seem to be as reliable as say a LS6.
@@P71ScrewHead there are debates as to what the LS7 block can handle stock versus sleeved. Titanium rods have been used in forced induction applications before, notably the LS9 with their rods sourced from Austria.
@@jamesw.6931 Unfortunately, the LS7 rods do have issues even at stock power levels. They changed from Mahle to Pankl due to some of these issues. Titanium is super cool, but the cost of a single titanium rod covers an entire set of powdered metal rods in the LT4
One note: The C5-R and C6-R both used a 7.0L not a 5.5L. That was background on how the LS7 came to be. The 5.5L in the race car didn’t come along until 2010 when the team moved from GT1 to the GT2 class. The class restrictions limited displacement to 5.5L.
I have a confirmed valve drop 26k miles and absolutely no aftermarket parts. Stock exhaust, air intake ect. I’d like to know why mine dropped then and if 7000 rpm is to much maybe redline should have been lower from factory
Yep, should have just said "ls7's have weak valve springs stock. Dont buy a car that isn't bone stock, unless it has aftermarket head work or heads in general." instead we get this scotty kilmer spiel about how the engineers know better than you and it's just a bunch of mansplaining. Dislike from me. Gl with your vettes, wouldnt bring em here.
@@fry.master the issue with LS7 valve drops are not with the valve springs. It was related to the valve guides. The broken valve spring issue dropping valves is with the LS6.
Thanks for the video. But you were given wrong information. I own a C6 Z06 with an LS7, so I have researched it extensively. The titanium intake valves are chromium nitride coated from Del West (OEM valve) for guide compatibility. This is a good thing, but you got it wrong. The hollow stem sodium filled exhaust valves were supplied by the lowest bidder and the wall thickness is not consistent. Some will be as thin as .011". ALL the LS7 heads (not just 2006) had issues with the guides not being concentric with the seats. This was poor quality machine work done at a GM supplier facility in Canada. Combine these factors and the engine experiences excessive valve guide wear. When the wear gets to a point the thin wall exhaust valve stem breaks dropping the stainless-steel head into the chamber. The hypereutectic alum piston then hits the valve head and the result is catastrophic. Please add an addendum to this video to correct the information.
I have also seen cutaways of the GM exhaust valve. The stem material is NOT made with a consitent wall thickness, one side could be .030" then 180* its like .010" thick That valve is a POS!
Thanks Lyle for the info great video I talk to someone at your shop today about the new sun visor. I will order them tonight I have the C5/99 and I love it. It sure if I will move up to C6 later maybe if I fine a 03 that might just do it. Mine only has 72K and it’s stock the way I like it.
Lyle, I have a 1996 C4 although I have heard a lot of stories about the C6 LS 7. Basically if their motor was modified and beat up this is the concern. Thank you for the great content and dispelling certain rumors !!
Frank sorry but your misinformed. I have a 2011 C6 Z/ Z07 and have had the heads replaced with New GM heads. ( My engine was stock). The new heads were out of spec when my engine builder received them. He fixed them and made sure the valve guide bores were concentric with the valve seat. There have been a lot of Z owners that baby their cars and some even garage queens that have dropped valves pulling out of the driveway. Modified engines with high lift cams can be a problem, but if the heads are machined correctly, the engine should not be a problem. The biggest item to check are the valve springs at about 10K miles.
Thank you for for the information. This gives me some peace of mind with my bone stock 2011 Z06 with 6k miles on it. The chances of a valve drop appear to be very low due to the low mileage, being bone stock, and being a later year C6.
The head problems persist in every year Z06. This is not even debatable at this point. I know 3 individuals personally that have had dropped values. Failure on stock engines due to the valves is well well documented. Sorry...
Yea... This guy post me when he said just don't hit redline. Like are you for real right now? If your engine can't handle 7k rpm maybe don't put the redone there... The truth is LS motors can rev higher then 7k just not with stock components.
I’ve had two ls7s both of them failed both of them completely 100% stock. Absolutely no modifications, not even a custom tune. First one failed due to exhaust valve failure, second one spun a crank bearing. I really think it is a problematic engine. I didn’t have any problems like this with my previous ls2 and ls3.
What I've learned from getting involved with tuning the 96 C-4 with Jets DST is GM bogs these cars down with extreme knock tables and timing retard along with torque management in the ECM. Reducing some of these extreme measures they use for EPA, driveability and protection will greatly enhance performance as long as you know what you're doing. Tuning the stock 96 C-4 coupe with one of the tuner programs for the LT-1, I used JET, completely changed and enhanced performance. Slightly more horsepower but allot more torque over stock. I can only imagine what you can do to a C-5, C-6 and C-7 just by tuning them without bolt ons.
If you want to really have fun with a C4, replace the GM Injection with a Holley Sniper or anything else, even a Holley 750 double pumper carburetor. Put in a roller cam at 1970 LT1 specifications for street driveablilty. I also put in an MSD Distributor. My son has never lost street racing my old C-4 auto cross car when I put in my 1970 LT1 with the Doug Nash 4+3. scary fun
Head’s, Cam’s E85 an a tune is good for 640 reliable WHP. Mind you the transmission! If you behave and play like a nice boy all you theoretically need is a solid clutch combination and you should be good. Now! If you’re going to be banging that stick late at night with criminal intent! I would politely suggest you throw some axels in there for good measure. And again! We still playing nice here. Now if you really want to be naughty, and play with some oxygen supplementation… consider some good gears. A stock bottom end can live its entire existence @750hp, of course this is entirely dependent you your lvl of maturity.
After scrolling thru these comments, I STRONGLY URGE any of you who own an LS7 to join LS1 Tech, and/or the Corvette Forum. There are Engineers on BOTH forums who are just as smart, or smarter than Koerner, who do not have to answer to anyone higher up at GM, who will give you the flat out truth about what Koerner tried to bury. Coincidentally, the LS7 has been discontinued. Most people who have, or do own an LS7 (that hasn't blown!) absolutely love them. Now, if a product is extremely popular, and is profitable, why would a manufacturer discontinue it? GM still sells the original small block Chevy V8. They haven't ever stopped making it, since the Fall of 1954-68 consecutive years!!!
@@jamesw.6931 Exactly my point! They are popular, and they're profitable. The LS7 is also popular, so we're left with the "profitable" portion. There's only one reason they aren't profitable, and I think it's due to warranty claims.....
My 2007 z06 with 25k miles, cream puff miles box stock. Had valves checked when I bought it and and over half the valves were out of spec. You have to rev engine to 7k or shifting from 4 to 5 or 5 th is a pig. I did valves lifters and spring with cam. Use moldstar90 valve guides
Thanks for the video. I am looking at a 2006 Z06 Corvette that is fully stock with only 7500 miles on it and full maintenance records. It looks great. Is there any checks I could have a chev dealer do to check if the engine could have the valve issue you mention? Thx.
Super great advice. I used to tune my own chips on an older vette and I've seen this many times with owners. Motorcycle owners as well. Mostly people ignorant of the dynamics of the lamda leanout when making modifications which is exactly what this video targets. Fuel trims on most engines are so lean that it's a wonder that they even run in the first place. So a huge problem I think across the board. I've seen lots of WOT dyno run tunes which ignores possible problems at other throttle positions. People want to get that peak number for the track and more often bragging rights and then are burning up the engines on the way to to the country club where 99% of the street driving is done because no one bothered to check what was happening at regular throttle positions. Properly calibrated wideband O2 sensors are your friend, lol.
I'm pretty sure that there was a valve issue that was traced to a problem with the rocker arm needle bearings that affected the VERY late build 2006's (June/06, July/06 builds) as well as 07's built between August and November of '06 (I once owned an '06). Edited to include this - and then there was the valve spring issue affecting '02 Z06's as well as a few of the early-build '03's (I once owned an '03 and had the springs replaced as a precaution measure). Seems it's always something.
I enjoyed my 2002 electron blue Z06 straight away 177 per hour tunnel vision for $55,000.00. Had 5 other vets various degrees lol. 3 C7s not impressed with Bowling Green. C6 felt kind of slippery. I probably will go back C5 when the dollar adjusts my way lol.
The needle bearing issue was not related to the valve drop issue with the LS7. It was a separate issue in 2006 and was corrected for the 2007 model year. The LS7 heads had machining issues and the valve guide bores were not concentric with the valve seat which caused wear on the valve guides. The exhaust valve was a hollow stem and was the weak point when the tolerance moved out side GM spec. Once out side the spec you we’re on borrowed time.
I'm sorry,but if putting a cold air package,or a set of headers on an engine,can bring about an engine failure,I would have to say there is a problem with that engine,and your GM friend is just covering his ass!If it can't handle those minor additions,I wouldn't trust it to last very long even i stock condition.
Brass valve guides?! I think you meant to say bronze. I repair cylinder heads professionally. The guide problems affect all LS7 engines. There may have been some machining problems at one point, but the bigger issue is the nitride coating on the titanium intake valve eating up the powdered metal oem guide. There are various fixes, including a heat treated powdered metal guide, and manganese bronze guides. I have redone several sets of LS7 heads for local Chevrolet dealers that were trying to service customers, and didn't want to wait to get parts from GM. I used manganese guides in those, with very good results. No further problems, some in service 9 years now. It would have been better to use a valve seat compatible with a titanium valve, and forego the coated valves, but I guess GM found that cost prohibitive.
Well your’s is the most interesting reply here, thank you and yes he did say brass. I’m impressed you’ve had such success with your fix techniques. How do we got hold of you??
@@540chevhell9 To be clear, I am not here to solicit business. If anyone has questions you can message me, I am happy to try to help or point you in the right direction.
I have a question on the electrical system on the C6. As it would apply to my C6 Z06, I find it off how and when the start button is lit up. Sometimes when the key fob is in the house and I open the driver doors, all the gauges and the green ring around the start button will light. Sometimes, when I have a fob in my pocket and open the driver door, the gauges are lit but the green ring around the start button is not lit. Do you think that's odd because I do.
Lyle thanks for the information you only back up what was told to me by a mechanic at zip products people got to understand and realize when you add aftermarket components to an engine such as this problems will occur but I hear you what you said and basically you're backed up what was already told to me thank you great contact and I have a 2011 ZO6 and it has 38,000 miles on it I was thinking about putting headers on it I did put a halltec cold air intake on it and now I'm just rethinking that 😗
I have a 09 C6Z and have tracked it since I got it. A track friend had one too and while running at Sebring with NCM he dropped a valve on the back straight. His was stock. Luckily, there were GM Engineers there and jumped on the car and had new heads delivered to the local Chevy dealer the next day and all was good. My engine, after my 2nd trip to Daytona, a distinct “ticking” was heard. It was under an extended warranty so my local dealer swapped heads for me.
Great video Lyle ! Other then the higher price, more expensive tires, better looks compared to a base C6 and of course 505 hp!, if im not tracking it, why go Z06 ? My current plan is to buy a Base C6 manual, one owner (or 2), no mods and as bone stock as possible next September. Saving up about $5k for a deposit. If the prices drop back to pre-Covid days (not too likely) by then a Z06 maybe an option. As with most things it comes down to $ and what fits a budget. Like i said, i wont be tracking it, this will be my 2nd car, more of a cruiser with some spirited driving. I joined the Corvette Forum last week and will keep my eyes open on there and CarGurus etc. As of today im still thinking base coupe but if the right C6 Z06 (07 or newer) comes along i may take that leap
My neighbor was one of those 2006 owners who likely had the heads that were machined wrong based on research of likely builds. GM knew exactly which ones had it they just weren’t admitting it. He’s not an “Internet car guy” and just drives it around occasionally so he wasn’t aware of this issue until a couple years ago. When he reached out to GM they refused to do anything about it so he was SOL. Poor guy really had no choice to sell or live with the likely event, take it to an aftermarket shop (which he didn’t want to do). Old guy with a very low mile Vette too. I feel bad for him. This is a real concern for those folks who aren’t car guys, and specifically buy these cars to keep them stock.
Thanks for the LS7 information my question is l know the LS3 is a slightly different design than a LS7 the LS3 has a smaller bore 3.62 crankshaft and different heads and slightly less compression I've seen these engines run reliability and dependable for a fairly long time that rev to 7200rpm with a BTR EPS camshaft with 228 intake duration and 240 exhaust duration with good maintenance and surpass the LS7 505 horsepower rating by 55-65 horsepower with no ill effects while being streetable with a broad powerband from 2000-7200rpm just wondering why these engines modified seem to be perfectly fine while the LS7 is so much more finicky l could be wrong but l prefer the LS3 shorter stroke crankshaft of 3.62 over the 4.00 stroker crankshaft of the LS7 have a 2011 Camaro SS with a new GM performance LS3 495 horsepower that runs on E85 with many upgrades since December 2021 and so far I'm very happy with the performance and reliability of this engine
Gloria, I totally agree that the LS3 is an excellent platform for tuning and adding power. From what Paul told me, the LS7 isn't a good platform for those same things due to its design and the materials used. Lyle
Hi your videos are extremely important and very much qualified. I bought a 2006 Z06 a month ago, with 40k miles on it. Car is totally stock. I do not want to do anything to the car, a friend of mine very experienced tuner and track racer and owned a Z06 would like to tune the car, only tune. Do you think it can be worthy ( he is a professional) . Thanks. Where can I find a list of things to do for maintenance( change oil a part)? Say monthly
Lyle, I appreciate your U tube videos & respect your knowledge but the LS7 had (has) valve guide issues through the 2013 model year...even the Z28 LS7 Camaros had ( have) this issue. Corvette Forum has many posts about the later model year LS7 cars suffering catastrophic engine issues. I own an LS7 Corvette & love the power the car has but this issue is always in the back of my head. This issue is real & it follows all model years
It's a $2-$3k job. Peace of mind goes a long way. When I bought my '08 Z06, I had it in the budget right away. It is BS that this affects only modded cars.
@@jrobles1019 And you just chose to believe the propoganda Lyle chose to believe FROM Chevrolet ?? Also...the new painting process the used in the late 80's had zero issues, the owners neglected to properly maintain the finish !
Great content Lyle. I always appreciate you being straight forward, to the point, matter of fact. Cut through all the Bull and hype. Please keep up the great work!!!
I used oil analysis to detect titanium in the oil, before damage. GM warranted the repair and I saved the LS7 in my Ron Fellows Z06. I used Blackstone Laboratories. Ask them about it. Dennis
I have a 2006 Z06 with 101,000 miles on it. I shift at 5800-6000. The engine has so much torque that there is no reason to rev past that. (only has had oil changes--still has the factor spark plugs-new clutch at 98,000)
We have a fairly large LS scene here, all the go to guys say the valves have issues no matter what. That's all I really need to know. Additionally, a lot of us want to mod the car. Especially an LS7 given the appeal of making over 600 wheel, NA. Shouldn't have to worry about mods wiping a motor, when done correctly and with a tune. Just my opinion.
Right? To me it almost sounds like this motor wants to be modified to rectify the issue with the heads. Like getting good heads and a good tune would actually be better for it than leaving it stock. Like those guys with the early 6th gen Camaros that got sick of the torque converter problems and just went and got a stall put in. No more torque converter issues lol
Thanks for the info , it gives a potential buyer something to think about.. negative comments usually come from hot Rod enthusiasts..anytime you street race or just hot Rod an engine there’s a possibility of doing some kind of damage that can rear its ugly head later on.. I have a 2006 C6 LS2 coupe ,in the garage , I bought new. 34,000 original miles, have not abused this car.. I plan on taking it to Lyle one day for work ( balancer) that’s been needed so I can get it back on the road.. even though it’s a stock 400hp engine there’s plenty of power to enjoy.. thx Lyle
I recently got myself a z06 with 30k miles bone stock. I almost have enough for a Texas speed fix/ porting. My valvetrain is a but noisy as well. Should I commit to the head fix or is there nothing to worry about?
Yes the heads are a major issue, this guy is wrong about this issue. Sounds like hes shilling for chevy, maybe the guy told him all that bullsht and he believed it, but the guy works for chevy and was covering for them . The ls7 head issue is why the grandsport and z06 are selling used for the same price and why I have a grandsport and not a z06, same looks no ls7 issues
The valvetrain noise is the first clue the guides are bad. The problem will get progressively worse. Notice any oil consumption, or smoke on an upshift?
Had a 7.0 bone stock 2009 from brand new, and it eat a value, oil change ,rocker adjustment, and it was a lash check ,even the coolant, all under 30000, and boom exhaust valve gone. Had a machine shope build one , and man it still runs today ,got power to five grand, big cam opened up the heads. Gmail made them last past the warranty and after that blow on the dice and hope for seven or eleven.
american heritage and katech did a lot of work on these heads over 10 years ago. while it's more likely they fail under mods or repeated hard use some have failed bone stock. that coating GM used on the ti valves was sometimes not done as well as it could have been, this coupled with out of spec guides or uncoated valves wearing on loose guides and then grenading themselves is mostly what's behind this urban legend. for $3500 ahp will completely rebuild the heads with new PM guides, new much better ti / moly intake valves and hollow ss or new stock exhaust valves. for $600 more you can even run F1 guides. the cost of the ls7 is so high to replace i could not imagine having a c6z without factoring in $3500 for the cylinder heads the day i took ownership. it's like the stock valve springs on the c5z, moderate deal on the 01, major problem on 02-03 and less of an issue on 04 but worth changing if you go racing even on the 04. if a valve does go through the piston on the ls7 there's at least a 50/50 chance it also takes out the block and that means. realistically you're spending 10-15k for a used motor or 20k+ for a new / built
happy to see someone recognize how tightly engineered modern engine design is, even down to the temperatures for optimum combustion events. As a C5 owner, because of the age of the car, there are a tremendous amount of " modifications you must do", "Five essential mods" ,"ten essential must do changes " out there with very few considerations as to the actual end result and ownership goals for the car. One should remember these cars are very carefully designed for efficiency . You move one system outside of the original design specifications , and you will probably effect that systems efficiency , and efficiency is optimum speed and power. You might even, as mentioned in the presentation, start breaking things.
I've owned a C5 for 15 years and have done no mods to it. Just regular maintenance. What am I missing out on? Just curious. Btw, put about 90,000 on the car and still love her. She routinely gets 33mpg around town. Yes, it's a 6 speed and I do a lot of coasting, up and down hills. LOL! I call it "Energy Management 101". 😆
Some call it “efficiency” others like myself refer to it as budget parts from the cheapest contract bid. I’ve owned 3 C5’s and still own my highly modified 640whp/568wtq C5 since new in 1999. Build them right, take care of them and they will last. 140k+ miles and counting.
Interesting to read all the negative comments. I bought a new ‘07 ZO6, and had all the forum negatives all around me. To save myself the possible $20K to $25K expense of a destroyed engine, I went to a local Chevrolet dealer and said I wanted the heads replaced. The work was done under warranty, new heads, but the old valves, springs, etc. The engine never gave me a bit of trouble, it was not modded, and maintenance was done by the book. Unfortunately, I had to sell the car due to physical impairments.
I’ve noticed a ticking sound in the valve train of my 73,000 mile C5 Z06. Is that normal or is there some wear in the guides or something that needs to be fixed before it fails?
One thing to consider is, with those tight tolerances, you should be very careful about high revs when the engine is cold. I always drove my 2008 Z06 very carefully so as to not rev above about 2500 until the oil was at temp. I owned that car from new until I got my 2019 Z06 and never had any issues.(48k miles) My 2019 changes the red line on the tachometer until it has reached a safe temp. Remember that all metals grow with heat and the engines are designed to be have correct clearances once at operating temp. They are out of tolerance when cold, so high revs will cause way more wear.
Excellent overview Kyle, I purchased a Z06 c6 a few years ago, after the purchase I started reading all of these horror stories about the valves and heads. All around lots of talk no answers. I even got a hold of Will Cooksey He said he really had not about the head issue. Shortly after that I sold the car, Your conversation would have been very help back. Thanks for turning the light on. Regards Ralph
Such bad information. It is a known fact that ALL YEARS OF LS7 have valve guide issues, even on bone stock, lower mileage cars. Too many forum members have dropped valves. There isn't an issue with '06 heads and that wasn't even the year GM claimed was bad. And he didn't even mention things like: - Rocker issues on the '07 - Rod bearing issues on the '12-13 when GM changed materials (though most of those have been corrected unless you found an ultra low mileage example) - Coating on the connecting rods wearing away. Intake valves aren't the only source of titantium in your oil analysis As a former LS7 owner, I left for a reason. I (fortunately) came out unscathed and profited a bit on the car, but many others aren't as lucky as I was.
the story line here from GM just doesn't jive. Its the same one we've ALL heard before. Just look at all the comments here and around the Corvette forums of 100% bone STOCK cars dropping valves. These are limited production motors, not like there is 100K of them out there on the streets. Guys that have modded and upgraded their heads are probably at LESS risk, not MORE.
Lyle, you've helped me tremendously concerning this issue. Now I can continue in my search for one of these with more confidence and knowledge. You're the man!!
Hello Lyle! Thanks for this video. I have a bone stock 2007 Z06 and was thinking about having a Borla CAT back exhaust system added. Are you recommending that I don't do this? Thanks!
I installed a cold air high performance air filter that really made my C6 faster. Now that I've heard your advice, that filter will be replaced soon with an OEM filter, and in the mean time, I'll drive very moderately. Thanks for the expert advice.
I'm going to purchase a C5 Z06 that has aftermarket headers. My question is will the aftermarket headers damage the engine because they aren't original equipment?
yes, we all know the STOCK motor is unlikely to have a valve drop. the problem is NONE of us leave the LS7 stock! we're all gonna do MINIMUM intake, headers, tune. Most of us do a cam as well. So we all replace the heads so that we don't grenade the motor
I got a c6 z already canned and ported heads to avoid any issues not to mention it can beat or at least run next to a c7 z. 566 to the wheels which is what c7 put out And the answer is a c6 z is rolling the dice with out new heads.
Not to sure if this is true , I’ve hade a few machinist tell me that gm had the LS7 heads machined by a second party and they made the valve guids to lose , witch made the valve go side to side when the valve closed eventually beating the valves to death and eventually braking the head off the valve.
Owned a 2011 Z06, second owner, purchased at 14K miles, never modified from stock. Wiggle tested at 30K miles, exhaust guides out of spec, heads replaced under GM warranty with GM LS7 heads (due to factory warranty). Had those heads checked gain at 38.8K miles just prior to GM powertrain warranty expiring at 5 years, intake guides were out of spec. A second set of GM warranty GM heads were installed. However, both sets of replacement heads were of the same lot (2013), so expected intakes to prematurely wear. As predicted, had heads checked at 48XXX miles, intakes worn, replaced with aftermarket heads on GMPP warranty. Replaced that Z06 with 2011 Carbon Edition Z06 in Oct 2021, 6.6K miles, all original and stock. Had OEM heads replaced with aftermarket heads to be proactive. Checked guides on OEM heads and intakes were out of spec at only 6.6K miles.
My gosh. You just took me right out of that market.
Wow. That is really good info. Thank you for responding! Lyle
Well dang it that is very concerning all round! What the hell?? What are we to believe then?? I’m concerned my 2014 Z28 will spit valves any day. Constant concern.
@@540chevhell9 Buy aftermarket heads ! Additional power, eliminate worries 😁
Go buy a lingenfelter eliminator motor....amazing
This video was mostly BUNK! I've seen hundreds of out of spec LS7 valves/valve guides, they range from every model year GM made the LS7 (including in the Z/28)... ALL THE YEARS POTENTIALLY HAVE THIS ISSUE!!! It's more rare to not see a stock LS7 without at least one valve close to being, or being completely out of spec. Mileage isn't a huge flag either, I've seen them loose with under 10k miles. This doesn't mean they will grenade at any moment (it's a fairly low percentage that totally nuke), but the point is every LS7 is suspect and an eye needs to be kept on them to make sure they don't get to the point of excessive wear. Please do not listen to the BS GM is spewing that it was only a few cars and only 2006!
as a former ls7 owner I agree. They also love to have rod bearing failures.
What about LS3? I have one in my Holden Commodore SS paired to a T56... is there anything to worry about? (Mime still has the machined roller rockers not the cast ones btw)
@@GregoryShtevensh the ls3 is the most bulletproof out of the entire LS series. The only thing on them are the stock rocker arm needle bearings (all ls engines) if installing a high lift aftermarket cam.
@@KNS_Racing awesome haha
Very strong opinion. I have found that folks with a strong opinion are often not 100% accurate. Get the heads replaced by a reputable company, AHP comes to mind. Get a mild cam and you are set. I did that and dyno numbers were 550.18 HP and 503 lbft torque.
Hey Lyle welcome home .Glad to hear you had a great time when you were ..up the road . P.S. You make amazing great videos..Thanks 👍🚗
Completely stock 06 Z06 with 30k miles dropped a valve without warning cruising on the freeway. Cost me the motor and oil system. 20k mistake thanks GM. This issue is very real. I high recommend anyone with an ls7 get there heads done.
If you are going to modify your LS7, I highly recommend Katech Performance in Detroit. They've been working with these engines from the beginning. Worked with GM to develop it, and built all of them for Corvette Racing ( Pratt and Miller). They know and address all the pitfalls of this engine.
Very true
Good input and thank you.
I wonder who needs more than 500hp? 🤔
Lyle just said to find a bone stock LS7 and don’t screw with it. It’s the best it’s going to be.
@@toddhartmayer8327 which is pretty sad. And I don’t understand what this guy (original commenter) is saying either. Why would I go to a place that HELPED ruin the engine, to help fix it? 🤣
@@toddhartmayer8327 which is pretty sad. And I don’t understand what this guy (original commenter) is saying either. Why would I go to a place that HELPED ruin the engine, to help fix it? 🤣
Hey Lyle! It was great meeting you at Carlisle before you left. Just got my C4 safely back to Arizona now. Thanks for your advice, and glad you enjoyed the show!
Thank you for the great advice, great seeing you Friday at Carlisle.
Nice vid, however you forgot to mention!The LS7'S use relatively high lift camshafts.
Premature valve train failures can be caused by high lift cams that cause long rocker arm travel.
Long rocker travel causes lateral force on the valve stem when the valve is open.
This lateral force wears out valve guides.
Which causes valve and guide tolerance to go out of spec.
GM even had a service bulletin with a valve stem "wiggle test".
GM also acknowledged that several batches of valve stems were installed incorrectly at the wrong "angle".
Valve issues are widely documented.
Race Proven Motorsports to this day continues to find bad valve guides in LS7 Camaro's.
Excellent analysis 👍
Ya he missed a lot of stuff, like how high rpms are needed when holding a gear thru corners, going thru traps on a drag strip, etc... You know the kinda things you buy a Z06 for. My guess is he is either really stupid, or trying to cover GM's ass over a well known well documented problem GM doesn't want to admit to. I laughed when he said you don't need high rpm's and not to over rev your engine. You CAN'T over rev a engine with stock tuning, the ECU will not allow it....
@Milo Jones I'm a fan of roller rockers. Also, just wanted to ask, are those duration numbers @.050 or advertised duration? Cuz if that's .050, good God that's gotta be a rowdy camshaft, especially at 111 lsa 😂.
Unless the LS7 manages high duration well and those numbers are kind of normal for it. I know it is set up for high lift, so the 684/683 doesn't shock me.
@Milo Jones That's badass, man. And I agree on the rollers. I kinda think GM should have just used rollers to begin with. The thing has just about .6" of lift from the factory, and it's a nice, expensive engine. Just use rollers GM!
Of course, GM has been pretty famous about cheaping out on rocker arms. Needle bearings with open trunions that scatter the needles everywhere comes to mind.
But that is really, really good info about the swipe pattern with the rollers. I'm an Fbody guy, but of course one day would like to buy an ls7 car, probably a c6 Z06.
Lyle, Sorry I missed you at Carlisle, love your videos and this one in particular. I have a 2013 427 convertible with a little over 30,000 miles. I have read all of the dread on the forums, so I have changed the oil and filter every 5,000 miles or year whichever comes first. I also send the oil off to be analyzed and the reports have come back clean each time. I plan on keeping this car and enjoying the drive. Keep up the good work. Wish your shop was close to me, need a good shop in Eastern Va.
Now here is a smart owner. Don't believe all the BS GM is spewing. You don't hear of ANY of these problems with the LS1, LS2, LS3, LS4, LS6, LSA, or LS9. There was, is, and are reasons for cause and effect.....
Is 5 000 miles not standard oil change interval? If, with Covid, one could put that many on in a year. I went to once a spring change the last couple of years. I would think spring is better than fall to get out any winter moisture in oil? Yes/No?
@@codyhatch4607 I change the oil and filter on all of my cars at 5,000 miles or once a year whichever comes first.
@@milojanis4901 , Katech HAS found the same problem with the LS9.
Owned a 2009 ZO6. No mods. Ran flawless. Sold it with 73k miles. Bought a 2010 ZR1.
Wish I had, ha. I enjoyed my 2002 electron blue Z06 straight away 177 per hour tunnel vision for $55,000.00. Had 5 other vets various degrees lol. 3 C7s not impressed with Bowling Green. C6 felt kind of slippery. I probably will go back C5 when the dollar adjusts my way lol.
This video is another example of why I love this channel. Lyle lays it out with words everyone can understand and gives us the knowledge we need when making that huge decision to buy a Corvette. And this is coming from a former Corvette owner, five different ones over a 12 year history. Love the channel, Lyle.
Wow, this information is so helpful. Its getting more and more difficult to find a Corvette that is bone stock . The head issues explained is very helpful as well. Thank you so much for sharing.
Great info, as always!!! Thanks Lyle!!!
This is BS. The issue was NOT fixed after 2006.The official GM bulletin specifically states the 08-11 cars which is also incorrect. Of course the GM engineer is going to say there was no issues but the truth is, its very much a real problem that still exists today. Please do your research before buying one of these cars even if its STOCK.
Totally agree, and can speak from experience...
Totally agree from experience too!! Dropped a valve on a 2007 1st gear pull w a customer while tuning him, (stock limiter). Needless to say, destroyed the engine. I typically love your content, but this was complete bs on the airflow and tuning aspect affecting guide wear. The whole stock engine lives is bs, related to the valve guide wear issue. I’m a GM tuner and Mechanical Engineer from the automotive industry, I can back up my info too.
I do generally agree w everything else that was said.
completely agree 💯. The only leg they have to stand on is that there are little to no issues with stock LS7 engines. Nobody leaves an LS7 completely stock! This is the most common form of manipulative statistics! Find a C6 Z06 without an intake or headers, and I'll show you a garage queen. Even when completely stock, and just well driven as designed, you'll have the same valve issues as they ALWAYS have eventually. Still a great platform if you're willing to spend the time and money necessary to make it perform and be reliable.
I owned my 2007 Z06 for 10 years and no engine problems (thankfully). However, I was well aware of the potential for a catastrophic engine failure. But I did have the clutch replaced under warranty due to something the dealer tech called an overcenter condition. In real world terms what this meant was the clutch pedal stuck to the floor and wouldn’t release until I backed off the accelerator. Even though a gm engineer told me the single disc clutch could handle the LS7 torque, I never believed it. It should have been built with the dual disc clutch like in the ZR1.
@@jamesw.6931why are you yelling?
117,000 miles on mine so far. Bone stock engine. Even the air filter is the stock AC Delco Donaldson Power Core. Was very diligent during break in period, swapped the oil/filter at 1100 miles. LS7 continues to be a gem of an engine for me. A very interesting article in Corvette Action Center by Hib Hiberson "The Ruthless Pursuit of Power' states (if I'm remembering correctly) Feb 2011, GM asked or required Linimar Manufacturing (they machined the heads) to do a 100% inspection on them instead of spot inspections. And the valve guide issue was largely 2008-2010. My engine was built in 2012 for the 2013 model year.
Comes with a redline of 7k from the factory.. gm engineers “geez guys don’t rev it to redline”
Great video, the Z06 platform is one of the best street and track corvettes that chevy has ever made.
This is like asking the wolf if there are any problems with the Hen house.
Great stuff, recently purchased a 07 . No more mid life crisis. Awesome beast, I am an ex state trooper, could never catch a Vette lol. Subbed and shared .Kudos..
ANDY, ON THE SERMON AMOUNT CHRIST SAID "DO UNTO OTHERS AS YOU YOU WANT DONE UNTO YOURSELF". OBVIOUSLY YOU'RE DOING THE SAME THING WITH YOUR CAR THAT ALL THE OTHER PEOPLE DID. THAT YOU GAVE TICKETS TO. AM I CORRECT ABOUT THIS?
@@Frank289100most definitely 😂
For ultimate performance, saying "shift 1000 rpm below redline" really doesn't work. You ARE losing performance. OTOH, for a street car which is not in serious competition, it makes perfect sense most of the time. Few if any street drivers need ultimate performance. If you drive any hi-po engine right up to its limits, it will need more maintenance, repair and will probably succumb earlier. That's the nature of the beasts.
No point in reving to redline as power is dropping off a lot.
Thank you for the great video.
I've owned three corvettes and have been thinking of getting an LS-7 Corvette . I have done some research on them but didn't find the information that you provided. Thank you .
Thanks, as always, great info! 👍🏻
Great video Lyle thanks I learned a lot I still have my C5 and love it but I always enjoy your videos thank you for posting great presentation of valuable information
Great info as usual! Explained very well!
Never had a problem with my ls_7 it was a 2008 zo6. Autocrosses it for 3 Years bought it 27k sold it with 56k. Between 2 drivers it won 14 of 16 races. I also personally ran about 100 to 125 quarter miles runs in the 4 years I owed it. I ran cold air intake and hypertech programer. At different times. I also very early on I reduced the rev limiter. 6500. Ran like a rolex watch. Never missed a beat. Miss everything but the arrest me red color. Just 2 cents.
When was your build date?
I also have a 2008 Z06. Ran the thing hard on the streets all the time. Bought it at 36K miles. Never had it tested for the heads. Just enjoyed it. Like you should. Tuned it and added aftermarket parts. At 52K miles finally upgraded the heads and cam and went right back to beating on it and enjoying it. Mines also red
@@joem1382 mine is a 07 but with a 09 service engine since I blew the original spraying a big shot lol. The 09 engine has now 70k miles and running strong.
You never daily drove it only quarter mile passes and autocross sounds like to me that's why you had no issues
How often have done your oil changes and what kind of oil did you use?
I just picked up a 15 z28 with 5k kms on it
Asking a GM representative about failures is about like asking a kid if he stole a piece of candy. You might get the truth. How many times have I called the manufacture of a part and heard, "We've never seen that problem before". Sure..often I knew of others with the same problem that had called the same manufacturer. It's a CYA. While I don't know how legitimate the LS7 issue is, they don't seem to be as reliable as say a LS6.
@@jamesw.6931 Change the Ti rods, too.....
@@jamesw.6931 I believe that he meant the titanium rods in the LS7
@@BiscuitMcgriddleson yes bcuz they're meant to stay n/a, how much power can the ls7 block handle??
@@P71ScrewHead there are debates as to what the LS7 block can handle stock versus sleeved. Titanium rods have been used in forced induction applications before, notably the LS9 with their rods sourced from Austria.
@@jamesw.6931 Unfortunately, the LS7 rods do have issues even at stock power levels. They changed from Mahle to Pankl due to some of these issues.
Titanium is super cool, but the cost of a single titanium rod covers an entire set of powdered metal rods in the LT4
Thankyou for your hard work
One note: The C5-R and C6-R both used a 7.0L not a 5.5L. That was background on how the LS7 came to be. The 5.5L in the race car didn’t come along until 2010 when the team moved from GT1 to the GT2 class. The class restrictions limited displacement to 5.5L.
C5-R originally used a 6.0L LS1.R
I have a confirmed valve drop 26k miles and absolutely no aftermarket parts. Stock exhaust, air intake ect. I’d like to know why mine dropped then and if 7000 rpm is to much maybe redline should have been lower from factory
Yep, should have just said "ls7's have weak valve springs stock. Dont buy a car that isn't bone stock, unless it has aftermarket head work or heads in general."
instead we get this scotty kilmer spiel about how the engineers know better than you and it's just a bunch of mansplaining. Dislike from me. Gl with your vettes, wouldnt bring em here.
@@fry.master the issue with LS7 valve drops are not with the valve springs. It was related to the valve guides.
The broken valve spring issue dropping valves is with the LS6.
Thank You for this teachings
Thanks for the video. But you were given wrong information. I own a C6 Z06 with an LS7, so I have researched it extensively. The titanium intake valves are chromium nitride coated from Del West (OEM valve) for guide compatibility. This is a good thing, but you got it wrong. The hollow stem sodium filled exhaust valves were supplied by the lowest bidder and the wall thickness is not consistent. Some will be as thin as .011". ALL the LS7 heads (not just 2006) had issues with the guides not being concentric with the seats. This was poor quality machine work done at a GM supplier facility in Canada. Combine these factors and the engine experiences excessive valve guide wear. When the wear gets to a point the thin wall exhaust valve stem breaks dropping the stainless-steel head into the chamber. The hypereutectic alum piston then hits the valve head and the result is catastrophic. Please add an addendum to this video to correct the information.
I have also seen cutaways of the GM exhaust valve. The stem material is NOT made with a consitent wall thickness, one side could be .030" then 180* its like .010" thick That valve is a POS!
Thanks Lyle for the info great video I talk to someone at your shop today about the new sun visor. I will order them tonight I have the C5/99 and I love it. It sure if I will move up to C6 later maybe if I fine a 03 that might just do it. Mine only has 72K and it’s stock the way I like it.
Dam missed you at Carlisle, would have love to meet you....good video 📹
Lyle, I have a 1996 C4 although I have heard a lot of stories about the C6 LS 7.
Basically if their motor was modified and beat up this is the concern.
Thank you for the great content and dispelling certain rumors !!
Frank sorry but your misinformed. I have a 2011 C6 Z/ Z07 and have had the heads replaced with New GM heads. ( My engine was stock). The new heads were out of spec when my engine builder received them. He fixed them and made sure the valve guide bores were concentric with the valve seat. There have been a lot of Z owners that baby their cars and some even garage queens that have dropped valves pulling out of the driveway. Modified engines with high lift cams can be a problem, but if the heads are machined correctly, the engine should not be a problem. The biggest item to check are the valve springs at about 10K miles.
Thank you for for the information. This gives me some peace of mind with my bone stock 2011 Z06 with 6k miles on it. The chances of a valve drop appear to be very low due to the low mileage, being bone stock, and being a later year C6.
Thank you so much.
This is awesome to here. Thanks for laying this evil tail to bed. Ive always wanted one.
Best corvette information center 👍👍 respects
The head problems persist in every year Z06. This is not even debatable at this point. I know 3 individuals personally that have had dropped values. Failure on stock engines due to the valves is well well documented. Sorry...
Yea... This guy post me when he said just don't hit redline. Like are you for real right now? If your engine can't handle 7k rpm maybe don't put the redone there... The truth is LS motors can rev higher then 7k just not with stock components.
Really?? I have had 4 Z06s and never had any head problems.
@@vincentbucci671 that is sweet. Yoy are one of the good ones!
@@vincentbucci671 how long did you have them...unfixed z06 are ticking time bombs. It's a matter of time before they let go.
@@defaultuser48 idk...I've seen a few for sale with over 200k on them.
As a long term c6 z06 owner this was valuable information, thankyou
I’ve had two ls7s both of them failed both of them completely 100% stock. Absolutely no modifications, not even a custom tune. First one failed due to exhaust valve failure, second one spun a crank bearing. I really think it is a problematic engine. I didn’t have any problems like this with my previous ls2 and ls3.
Very informative,Don't have a LS7,LM7 here,But knowledge is King,Thank You.
What I've learned from getting involved with tuning the 96 C-4 with Jets DST is GM bogs these cars down with extreme knock tables and timing retard along with torque management in the ECM. Reducing some of these extreme measures they use for EPA, driveability and protection will greatly enhance performance as long as you know what you're doing. Tuning the stock 96 C-4 coupe with one of the tuner programs for the LT-1, I used JET, completely changed and enhanced performance. Slightly more horsepower but allot more torque over stock. I can only imagine what you can do to a C-5, C-6 and C-7 just by tuning them without bolt ons.
If you want to really have fun with a C4, replace the GM Injection with a Holley Sniper or anything else, even a Holley 750 double pumper carburetor. Put in a roller cam at 1970 LT1 specifications for street driveablilty. I also put in an MSD Distributor. My son has never lost street racing my old C-4 auto cross car when I put in my 1970 LT1 with the Doug Nash 4+3. scary fun
Head’s, Cam’s E85 an a tune is good for 640 reliable WHP. Mind you the transmission! If you behave and play like a nice boy all you theoretically need is a solid clutch combination and you should be good. Now! If you’re going to be banging that stick late at night with criminal intent! I would politely suggest you throw some axels in there for good measure. And again! We still playing nice here. Now if you really want to be naughty, and play with some oxygen supplementation… consider some good gears. A stock bottom end can live its entire existence @750hp, of course this is entirely dependent you your lvl of maturity.
@@carazo321 you must be talking about a C5 or newer, because that ain’t happening with an LT1 in a C4
After scrolling thru these comments, I STRONGLY URGE any of you who own an LS7 to join LS1 Tech, and/or the Corvette Forum. There are Engineers on BOTH forums who are just as smart, or smarter than Koerner, who do not have to answer to anyone higher up at GM, who will give you the flat out truth about what Koerner tried to bury. Coincidentally, the LS7 has been discontinued. Most people who have, or do own an LS7 (that hasn't blown!) absolutely love them. Now, if a product is extremely popular, and is profitable, why would a manufacturer discontinue it? GM still sells the original small block Chevy V8. They haven't ever stopped making it, since the Fall of 1954-68 consecutive years!!!
@@jamesw.6931 Exactly my point! They are popular, and they're profitable. The LS7 is also popular, so we're left with the "profitable" portion. There's only one reason they aren't profitable, and I think it's due to warranty claims.....
My 2007 z06 with 25k miles, cream puff miles box stock. Had valves checked when I bought it and and over half the valves were out of spec. You have to rev engine to 7k or shifting from 4 to 5 or 5 th is a pig. I did valves lifters and spring with cam. Use moldstar90 valve guides
Thanks for the video. I am looking at a 2006 Z06 Corvette that is fully stock with only 7500 miles on it and full maintenance records. It looks great. Is there any checks I could have a chev dealer do to check if the engine could have the valve issue you mention? Thx.
Hey, Lyle. Sorry I missed you at Carlisle. I looked all over the fairgrounds and went to your vendor spot, but I never saw you. Maybe next year.
Super great advice. I used to tune my own chips on an older vette and I've seen this many times with owners. Motorcycle owners as well. Mostly people ignorant of the dynamics of the lamda leanout when making modifications which is exactly what this video targets. Fuel trims on most engines are so lean that it's a wonder that they even run in the first place. So a huge problem I think across the board. I've seen lots of WOT dyno run tunes which ignores possible problems at other throttle positions. People want to get that peak number for the track and more often bragging rights and then are burning up the engines on the way to to the country club where 99% of the street driving is done because no one bothered to check what was happening at regular throttle positions. Properly calibrated wideband O2 sensors are your friend, lol.
Great info thank you!
Please talk more about the C5. Thanks!
I'm pretty sure that there was a valve issue that was traced to a problem with the rocker arm needle bearings that affected the VERY late build 2006's (June/06, July/06 builds) as well as 07's built between August and November of '06 (I once owned an '06). Edited to include this - and then there was the valve spring issue affecting '02 Z06's as well as a few of the early-build '03's (I once owned an '03 and had the springs replaced as a precaution measure). Seems it's always something.
I enjoyed my 2002 electron blue Z06 straight away 177 per hour tunnel vision for $55,000.00. Had 5 other vets various degrees lol. 3 C7s not impressed with Bowling Green. C6 felt kind of slippery. I probably will go back C5 when the dollar adjusts my way lol.
The needle bearing issue was not related to the valve drop issue with the LS7. It was a separate issue in 2006 and was corrected for the 2007 model year. The LS7 heads had machining issues and the valve guide bores were not concentric with the valve seat which caused wear on the valve guides. The exhaust valve was a hollow stem and was the weak point when the tolerance moved out side GM spec. Once out side the spec you we’re on borrowed time.
Good information. My 08’ Z06 is a blast.
I'm sorry,but if putting a cold air package,or a set of headers on an engine,can bring about an engine failure,I would have to say there is a problem with that engine,and your GM friend is just covering his ass!If it can't handle those minor additions,I wouldn't trust it to last very long even i stock condition.
Precisely
Brass valve guides?! I think you meant to say bronze. I repair cylinder heads professionally. The guide problems affect all LS7 engines. There may have been some machining problems at one point, but the bigger issue is the nitride coating on the titanium intake valve eating up the powdered metal oem guide. There are various fixes, including a heat treated powdered metal guide, and manganese bronze guides. I have redone several sets of LS7 heads for local Chevrolet dealers that were trying to service customers, and didn't want to wait to get parts from GM. I used manganese guides in those, with very good results. No further problems, some in service 9 years now. It would have been better to use a valve seat compatible with a titanium valve, and forego the coated valves, but I guess GM found that cost prohibitive.
Well your’s is the most interesting reply here, thank you and yes he did say brass. I’m impressed you’ve had such success with your fix techniques. How do we got hold of you??
@@540chevhell9 To be clear, I am not here to solicit business. If anyone has questions you can message me, I am happy to try to help or point you in the right direction.
You are absolutely correct--I meant bronze. Lyle
hi, I thought the silicone bronze was prefered for ti valves- that is what the NASCAR guys use- pro stock too.
The head problem is so real I wouldn't take a chance on not addressing it, and GM didn't recall it.
I have a question on the electrical system on the C6. As it would apply to my C6 Z06, I find it off how and when the start button is lit up. Sometimes when the key fob is in the house and I open the driver doors, all the gauges and the green ring around the start button will light. Sometimes, when I have a fob in my pocket and open the driver door, the gauges are lit but the green ring around the start button is not lit. Do you think that's odd because I do.
Lyle thanks for the information you only back up what was told to me by a mechanic at zip products people got to understand and realize when you add aftermarket components to an engine such as this problems will occur but I hear you what you said and basically you're backed up what was already told to me thank you great contact and I have a 2011 ZO6 and it has 38,000 miles on it I was thinking about putting headers on it I did put a halltec cold air intake on it and now I'm just rethinking that 😗
I have a 09 C6Z and have tracked it since I got it. A track friend had one too and while running at Sebring with NCM he dropped a valve on the back straight. His was stock. Luckily, there were GM Engineers there and jumped on the car and had new heads delivered to the local Chevy dealer the next day and all was good. My engine, after my 2nd trip to Daytona, a distinct “ticking” was heard. It was under an extended warranty so my local dealer swapped heads for me.
Great information!
Great video Lyle ! Other then the higher price, more expensive tires, better looks compared to a base C6 and of course 505 hp!, if im not tracking it, why go Z06 ? My current plan is to buy a Base C6 manual, one owner (or 2), no mods and as bone stock as possible next September. Saving up about $5k for a deposit. If the prices drop back to pre-Covid days (not too likely) by then a Z06 maybe an option. As with most things it comes down to $ and what fits a budget. Like i said, i wont be tracking it, this will be my 2nd car, more of a cruiser with some spirited driving. I joined the Corvette Forum last week and will keep my eyes open on there and CarGurus etc. As of today im still thinking base coupe but if the right C6 Z06 (07 or newer) comes along i may take that leap
Excellent video. Good information.
The Gulf gas pump reminds me of a Gulf station that was on Mexico Beach, Fl
My neighbor was one of those 2006 owners who likely had the heads that were machined wrong based on research of likely builds. GM knew exactly which ones had it they just weren’t admitting it. He’s not an “Internet car guy” and just drives it around occasionally so he wasn’t aware of this issue until a couple years ago. When he reached out to GM they refused to do anything about it so he was SOL. Poor guy really had no choice to sell or live with the likely event, take it to an aftermarket shop (which he didn’t want to do). Old guy with a very low mile Vette too. I feel bad for him. This is a real concern for those folks who aren’t car guys, and specifically buy these cars to keep them stock.
Thanks for the LS7 information my question is l know the LS3 is a slightly different design than a LS7 the LS3 has a smaller bore 3.62 crankshaft and different heads and slightly less compression I've seen these engines run reliability and dependable for a fairly long time that rev to 7200rpm with a BTR EPS camshaft with 228 intake duration and 240 exhaust duration with good maintenance and surpass the LS7 505 horsepower rating by 55-65 horsepower with no ill effects while being streetable with a broad powerband from 2000-7200rpm just wondering why these engines modified seem to be perfectly fine while the LS7 is so much more finicky l could be wrong but l prefer the LS3 shorter stroke crankshaft of 3.62 over the 4.00 stroker crankshaft of the LS7 have a 2011 Camaro SS with a new GM performance LS3 495 horsepower that runs on E85 with many upgrades since December 2021 and so far I'm very happy with the performance and reliability of this engine
Gloria, I totally agree that the LS3 is an excellent platform for tuning and adding power. From what Paul told me, the LS7 isn't a good platform for those same things due to its design and the materials used. Lyle
Hi your videos are extremely important and very much qualified. I bought a 2006 Z06 a month ago, with 40k miles on it. Car is totally stock. I do not want to do anything to the car, a friend of mine very experienced tuner and track racer and owned a Z06 would like to tune the car, only tune. Do you think it can be worthy ( he is a professional) . Thanks. Where can I find a list of things to do for maintenance( change oil a part)? Say monthly
Lyle, I appreciate your U tube videos & respect your knowledge but the LS7 had (has) valve guide issues through the 2013 model year...even the Z28 LS7 Camaros had ( have) this issue. Corvette Forum has many posts about the later model year LS7 cars suffering catastrophic engine issues. I own an LS7 Corvette & love the power the car has but this issue is always in the back of my head. This issue is real & it follows all model years
99 percent of people in forums are modifying/modified the car. Lyle literally said you start having issues when you modify
It's a $2-$3k job. Peace of mind goes a long way. When I bought my '08 Z06, I had it in the budget right away. It is BS that this affects only modded cars.
@@jrobles1019 And you just chose to believe the propoganda Lyle chose to believe FROM Chevrolet ??
Also...the new painting process the used in the late 80's had zero issues, the owners neglected to properly maintain the finish !
People modify with heads and cam and have zero issues. Find a shop that has done hundreds and you'll never have a problem.
Well, thank you!
Very well explained!
Just leave well enough alone ! it still kicks ass !
Great content Lyle. I always appreciate you being straight forward, to the point, matter of fact. Cut through all the Bull and hype. Please keep up the great work!!!
Thank You for Covering the LS7. Going to the GM source ‼️😁👍
I used oil analysis to detect titanium in the oil, before damage. GM warranted the repair and I saved the LS7 in my Ron Fellows Z06. I used Blackstone Laboratories. Ask them about it. Dennis
Thank you for the heads-up on Blackstone Labs, Dennis! Lyle :)
I have a 2006 Z06 with 101,000 miles on it. I shift at 5800-6000. The engine has so much torque that there is no reason to rev past that. (only has had oil changes--still has the factor spark plugs-new clutch at 98,000)
We have a fairly large LS scene here, all the go to guys say the valves have issues no matter what. That's all I really need to know. Additionally, a lot of us want to mod the car. Especially an LS7 given the appeal of making over 600 wheel, NA. Shouldn't have to worry about mods wiping a motor, when done correctly and with a tune. Just my opinion.
Right? To me it almost sounds like this motor wants to be modified to rectify the issue with the heads. Like getting good heads and a good tune would actually be better for it than leaving it stock. Like those guys with the early 6th gen Camaros that got sick of the torque converter problems and just went and got a stall put in. No more torque converter issues lol
What was the specific issue with the 06 zo6? Just purchased one with 24k miles and am nervous about the heads.
Thanks for the info , it gives a potential buyer something to think about.. negative comments usually come from hot Rod enthusiasts..anytime you street race or just hot Rod an engine there’s a possibility of doing some kind of damage that can rear its ugly head later on.. I have a 2006 C6 LS2 coupe ,in the garage , I bought new. 34,000 original miles, have not abused this car.. I plan on taking it to Lyle one day for work ( balancer) that’s been needed so I can get it back on the road.. even though it’s a stock 400hp engine there’s plenty of power to enjoy.. thx Lyle
What about valve guide concentricity? Is the GM tech unbiased?
I recently got myself a z06 with 30k miles bone stock. I almost have enough for a Texas speed fix/ porting. My valvetrain is a but noisy as well. Should I commit to the head fix or is there nothing to worry about?
Yes the heads are a major issue, this guy is wrong about this issue. Sounds like hes shilling for chevy, maybe the guy told him all that bullsht and he believed it, but the guy works for chevy and was covering for them . The ls7 head issue is why the grandsport and z06 are selling used for the same price and why I have a grandsport and not a z06, same looks no ls7 issues
The valvetrain noise is the first clue the guides are bad. The problem will get progressively worse. Notice any oil consumption, or smoke on an upshift?
Your the best....
Had a 7.0 bone stock 2009 from brand new, and it eat a value, oil change ,rocker adjustment, and it was a lash check ,even the coolant, all under 30000, and boom exhaust valve gone. Had a machine shope build one , and man it still runs today ,got power to five grand, big cam opened up the heads. Gmail made them last past the warranty and after that blow on the dice and hope for seven or eleven.
american heritage and katech did a lot of work on these heads over 10 years ago. while it's more likely they fail under mods or repeated hard use some have failed bone stock. that coating GM used on the ti valves was sometimes not done as well as it could have been, this coupled with out of spec guides or uncoated valves wearing on loose guides and then grenading themselves is mostly what's behind this urban legend. for $3500 ahp will completely rebuild the heads with new PM guides, new much better ti / moly intake valves and hollow ss or new stock exhaust valves. for $600 more you can even run F1 guides. the cost of the ls7 is so high to replace i could not imagine having a c6z without factoring in $3500 for the cylinder heads the day i took ownership. it's like the stock valve springs on the c5z, moderate deal on the 01, major problem on 02-03 and less of an issue on 04 but worth changing if you go racing even on the 04. if a valve does go through the piston on the ls7 there's at least a 50/50 chance it also takes out the block and that means. realistically you're spending 10-15k for a used motor or 20k+ for a new / built
Cool Allman brothers sounding theme music at the end.
happy to see someone recognize how tightly engineered modern engine design is, even down to the temperatures for optimum combustion events. As a C5 owner, because of the age of the car, there are a tremendous amount of " modifications you must do", "Five essential mods" ,"ten essential must do changes " out there with very few considerations as to the actual end result and ownership goals for the car.
One should remember these cars are very carefully designed for efficiency . You move one system outside of the original design specifications , and you will probably effect that systems efficiency , and efficiency is optimum speed and power. You might even, as mentioned in the presentation, start breaking things.
I've owned a C5 for 15 years and have done no mods to it. Just regular maintenance. What am I missing out on? Just curious. Btw, put about 90,000 on the car and still love her. She routinely gets 33mpg around town. Yes, it's a 6 speed and I do a lot of coasting, up and down hills. LOL! I call it "Energy Management 101". 😆
Ive modded my c5 a lot and have no issues with it.
Some call it “efficiency” others like myself refer to it as budget parts from the cheapest contract bid. I’ve owned 3 C5’s and still own my highly modified 640whp/568wtq C5 since new in 1999. Build them right, take care of them and they will last. 140k+ miles and counting.
Interesting to read all the negative comments. I bought a new ‘07 ZO6, and had all the forum negatives all around me. To save myself the possible $20K to $25K expense of a destroyed engine, I went to a local Chevrolet dealer and said I wanted the heads replaced. The work was done under warranty, new heads, but the old valves, springs, etc. The engine never gave me a bit of trouble, it was not modded, and maintenance was done by the book. Unfortunately, I had to sell the car due to physical impairments.
Yep! My thoughts exactly... Thanks for great video!
I’ve noticed a ticking sound in the valve train of my 73,000 mile C5 Z06. Is that normal or is there some wear in the guides or something that needs to be fixed before it fails?
Roller lifters go bad. Made in China.
@@generalsixty2133 thanks! I hope not!🙏
One thing to consider is, with those tight tolerances, you should be very careful about high revs when the engine is cold. I always drove my 2008 Z06 very carefully so as to not rev above about 2500 until the oil was at temp. I owned that car from new until I got my 2019 Z06 and never had any issues.(48k miles) My 2019 changes the red line on the tachometer until it has reached a safe temp. Remember that all metals grow with heat and the engines are designed to be have correct clearances once at operating temp. They are out of tolerance when cold, so high revs will cause way more wear.
Excellent point!!!
I have my 06 Z06 early run engine out on the stand How do I check to see if I have one of the bad ones and can it be fixed??
That is going to require someone more knowledgeable than I! Contact Race Proven Motorsports at 302-798-4000 to see what they have to say. Lyle
Excellent overview Kyle, I purchased a Z06 c6 a few years ago, after the purchase I started reading all of these horror stories about the valves and heads. All around lots of talk no answers. I even got a hold of Will Cooksey He said he really had not about the head issue. Shortly after that I sold the car, Your conversation would have been very help back. Thanks for turning the light on. Regards Ralph
Such bad information. It is a known fact that ALL YEARS OF LS7 have valve guide issues, even on bone stock, lower mileage cars. Too many forum members have dropped valves. There isn't an issue with '06 heads and that wasn't even the year GM claimed was bad.
And he didn't even mention things like:
- Rocker issues on the '07
- Rod bearing issues on the '12-13 when GM changed materials (though most of those have been corrected unless you found an ultra low mileage example)
- Coating on the connecting rods wearing away. Intake valves aren't the only source of titantium in your oil analysis
As a former LS7 owner, I left for a reason. I (fortunately) came out unscathed and profited a bit on the car, but many others aren't as lucky as I was.
the story line here from GM just doesn't jive. Its the same one we've ALL heard before. Just look at all the comments here and around the Corvette forums of 100% bone STOCK cars dropping valves. These are limited production motors, not like there is 100K of them out there on the streets. Guys that have modded and upgraded their heads are probably at LESS risk, not MORE.
Lyle, you've helped me tremendously concerning this issue. Now I can continue in my search for one of these with more confidence and knowledge. You're the man!!
Hello Lyle! Thanks for this video. I have a bone stock 2007 Z06 and was thinking about having a Borla CAT back exhaust system added. Are you recommending that I don't do this? Thanks!
I installed a cold air high performance air filter that really made my C6 faster. Now that I've heard your advice, that filter will be replaced soon with an OEM filter, and in the mean time, I'll drive very moderately. Thanks for the expert advice.
Thank you dad
I'm going to purchase a C5 Z06 that has aftermarket headers. My question is will the aftermarket headers damage the engine because they aren't original equipment?
yes, we all know the STOCK motor is unlikely to have a valve drop. the problem is NONE of us leave the LS7 stock! we're all gonna do MINIMUM intake, headers, tune. Most of us do a cam as well. So we all replace the heads so that we don't grenade the motor
I got a c6 z already canned and ported heads to avoid any issues not to mention it can beat or at least run next to a c7 z. 566 to the wheels which is what c7 put out
And the answer is a c6 z is rolling the dice with out new heads.
Not to sure if this is true , I’ve hade a few machinist tell me that gm had the LS7 heads machined by a second party and they made the valve guids to lose , witch made the valve go side to side when the valve closed eventually beating the valves to death and eventually braking the head off the valve.
2007 corvette 33,000 engine fail just driving back from home no mods no over revved