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? 🤣
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.
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!
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.
I'm currently planning on buying my first Corvette. Your videos have been so helpful with learning about these cars, especially the C5 z06 which I've got my eye on. Thanks for sharing the knowledge!
get a c6 from 2008 to 2013 with the Ls3 is just is powerful is the Z06 , or if u really want a Zo6 get a c7 Zo6 if u really want some power,,, I have my 2008 with Ls3 537HP and I don't have to worry about a dam head, or valve ,, I even install a Zr1 widebody fenders and bumper too, it looks a lot better than a Zo6 C6 ,,,
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!
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?
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.
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.
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.
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
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?
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.
Great information, but..... I had a completely stock, 2008 Z06 that I purchased with 1,400 miles. At 19,xxx miles it dropped an intake valve and cratered the engine. It had not been tuned. It had not been to the track for a single mile. It was absolutely bone stock. So, while this is great information and likely applies to most people, just be aware that it does not apply to all. The likelihood that you will have a catastrophic engine failure may be small, but it is no small deal if you happen to be the one it happens to. Especially if you are out of warranty age-wise at the time the failure happens.
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.
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.
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.....
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.
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.
I have a 2013 427 and no issues with 30k miles. Didn’t have any issues with my previous Z06 either with 44K miles. In 2011 GM improved the valves and created more allowable tolerances for improved reliability. They learned that from the C6R race-car in 2010. Good luck.
I've had three C6 Zo6s 07,08,09 about 50,000 mi driven combined and never dropped a valve, I was very aware of the valve drop issue, it never happened to me. I still have the 09 and am thinking about heads and cam. Best of luck to every other LS7 owner out there.
I just bought my first 06 z06, 75k miles. After buying it I read that they spontaneously combust every 5-10k miles so I’m debating on whether to check my guides or just just bury my head in the sand and have a backup plan if the ls7 does decide to shit the bed.
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 .
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.
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.
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.
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’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.
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.
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 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 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
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.
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.
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
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.
You know it’s the weirdest thing, just as one of my pistons melted and the engine sucked two valves, my rear tires had gone completely bald down to the steel. I tell ya they were smoking somethin fierce.
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
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.
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
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
my 2007 c6 zo6 had catastrophic valve failure on three valves, at 42k. completely stock. Fortunately the extended warranty paid for two brand new sets of heads however at 84k, (42k on the new heads)...guess what the valve train is ready for replacement. So out with the factory heads in with a custom set... ls7 uses a 1.8 rocker arm ratio that puts a lot of side load on the guides themselves, if you get new guides, get bronze but also research longer guides to assist with the additional side load stress
Meh. I have an LS7 making 650hp. Heads/cam, FBO, SBE LS7. Been on the same motor. No issues. I learned the hard way, hot rodding ain’t cheap. I was once young and broke and couldn’t afford to do things right. Went through motors. Now, much older, different position in life I’ve learned. Quality parts, and it’s all in the TUNE. Car is on nitrous as well. I remember going to TX2K and running my car damn near all night, still was able to drive home after 8-10 spray passes. Hot rodding can be reliable, from my experience but there’s a triangle. Cheap, reliable, fast. You can only choose two. If you are not going to spend the money on the right, parts, tuning, safety measures, etc. Keep it stock.
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
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?
I trust his words. This is very useful info and normally I wouldn't care about info like this but since I own a 2007 c6 it was helpful watching. On a side note, this guy is legit, if anyone happens to read this comment or watch this video and has been thinking about buying stuff from their shop I would 100% recommend it. I've bought a harmonic balancer from them and it was shipped in less than three days, these guys work fast😂. Great video!
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.
I have a bone stock 2007 Z06 corvette I purchased new and the engine dropped the valves in one cylinder at 44,000 miles. The failure caused the rod to punch a hole in the block which totally ruined the engine. I purchased a new complete engine from a local chevy dealer for $10,900. dollars and another $4,500.00 to install the new engine. The corvette presently sits in my heated garage with only 500 miles on the new LS-7 engine. I am now concerned about the quality of the engine which was purchased about 2021 and therefore do not drive it. It sits along side of my new 2023 corvette stingray collecting dust. It will serve as a collector vehicle. I got no help from chevy at all.
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.
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.
Awesome video! Good to have this info direct from the source. Early this year I was looking into buying a C6 Z06 early this year, but the main factor that triggered my doubt was these engine stories I found doing as much research as I could. It was a big part of what 'scared' me into buying a 2005 Viper instead.
so instead of getting a 1/15,000 chance of somthing goign wrong with your engine ( wich EVERY product on this planet has ) you chose a dodge that depreciated in value faster than any other brand. one that is not nearly so comphy to drive/ ride in, has more stuff going on engine and chassis wise that costs more to maintain and harder to find parts for, and once its at 100k miles noone wants them. Also jjust cant get past the fact that they sound like a grand am
Blown 2 engines. One at 34.000 km what was a warranty although the Importer did everything to blame me because i did trackday's with the car. The second blew ar 84.000 and was completely destroyed and was no warranty. Then i bought Katech "street attack" engine. That one is still running great.
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.
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.
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.
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
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?
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.
Malarky. A buddy and I both bought new 2006 Corvette Z06s. My Z06, I fully race modded the LS7 engine the first year with Kooks headers, cam and porting , roller rockers, heads milled .010" to up compression from 11:5 to 11.7:1, cold airbox induction. It dyno really rich with the stock maping at 12.5:1 fuel/air so we remapped it to a much leaner ideal 14:1 throughout the RPM range. The engine puts out 645hp @6,300rpm and 475ft lbs of torque at 5,000rpm. I run Mobile 1 20-50wt with ProLong Engine additive, and change it every 3,000 mile sor after a hard track day. I've bounced it off the rev limiter at 7,000 a number of times at the track, the engine runs perfect and currently has 20,000 mi. after 15 years. My buddy's Z06, he kept it box stock but ran track days with it at Willow Springs, CA, about 1-2 times month. In the first year he blew 2 engines and Corvette covered both of the engines under warranty. But by then he was fustrated with the blown engines and sold the car and got a Dodge Viper to track instead. My conclusion? Maybe if you run a 2006 year Z06 stock LS7 easy you'll never have problems. But put a good billet aluminum racing rocker arm assembly in the LS7 engine and you can then do other power mods as well. And run a good oil like Mobile 1 20-50wt with ProLong Engine Additive and change it regularly and after hard running, you should be fine.
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 😗
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
Another thing the Tech Nerd from Corvette Magazine has said is that if the engine is going to fail it will do so early in its life. I cannot recall the mileage but want to say 10k miles.
The LS7 was the perfect storm for valve wear, the 1:8-1 rocker ratio, 7000 rpm redline, offset rockers and sodium filled valve stems that added heat to the valve guide cooking the oil to a grainy slurry, plus the decision to not use the titanium valve mfgs. proprietary coating which caused the rough titanium surface to erode guides. I had a 09 with 34,000 miles stock and the valves had 13,000th slop..Yeah nothing to see here.......
How hard would it be to go with a set of LS3/L92 heads and a mild cam where you still have correct valve to piston clearance? Ls3 heads are as bullet proof as any other truck/car LS head IMO. I have heard of repaired and "fixed" gm ls7 heads still heaving issues. If you can take that away and put a still relatively good head on and decent cam I don't see power loss but gain reliability in the engine. Then sling it to 7K again or more. Idk, just throwing it out there. You can get the heads relatively cheap now over ls7 heads. The money you could save you could us in porting and better springs.
Even stock the LS7 needs vavletrain upgraded. Failure rates are way too common. As mentioned KSTech or RPM in Delaware (uses KS Tech parts) to have the valvetrain done. Throw a cam in it for more power while in there because the cam is cheap. It's the labor that's astronomical. Many with LS7s and knowledge of these motors knows the common failure component and it's well established as failing on stock motors with as low as 10k miles. Doesn't matter if stock or modded. It's a design flaw. You can't even buy the motor from GM Direct parts anymore.
Getting a C6 Z06 down the line and the first thing I'm doing is ordering a set of heads from Frankenstein Performance. Just to be sure I get good heads on a killer engine. I've seen too many videos on YT where the heads fail, drop a valve, and the owner is left picking up the pieces on a 20k motor assembly. Better to spend the 5k in heads and just get it over with. Then you'll have a happy LS7 for the rest of your ownership and may actually increase the price of the vehicle since you went out of your way to fix a reliability flaw that GM refuses to correct.
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.
