Leave it stock Gm talked about how even a cold air intake and exhaust will mess the engine up It's a engine that's very special and shouldn't be touched like the ls3
I did the same as Derek. Brodix BR7s. I went with the Archangel from AHP. Stage 2 cam. Tony Mamo MSD AirForce Intake. Replacing the heads was the only way I could get peace of mind. It is THE source of the problem. Pony up the cash & fully enjoy the benefits of a 7 liter LS. 604 RWHP 552 lbs tq And this is a streetable car. A pleasure to drive. I left 40 HP on the table for better street manners. The heads breathe so good I can. They are worth the insane price.
i bought a car with these heads on it already. What plugs do you run with them? Brodix reccomends a step colder plug. as far as i know the car is stock minus heads, has stock tune on it.
I own a 08 C6 Z06 with 11k miles I had American heritage performance take care of the heads and yes at 11k the valves had play. GM won't admit that they made a big mistake with out of spec valves and or guides.
I used oil testing to detect titanium in the oil, before any damage. Pulled the heads at my cost, removed the springs and showed the GM warranty inspector the intake valves just fell out of the heads. He authorized need heads and valves under warranty. This was a GM extended warranty j had purchased. I used Blackstone Laboratories fir testing they pointed out the titanium ppm was there but low. On the next oil change 22,000 it was up a lot. I called several dealers Corvette specialist they agreed stop driving it and pull the heads. Testing the oil saved my Ron Fellows 427. Dennis
I've never seen any hard data for this issue- only anecdotes on the internet. Zero issues with my '08 in seven years of ownership, but I have no interest in racing or modding it. There were over 28,000 of these made. How many of that number have dropped a valve? How many are tracked regularly? How many had a cam that wasn't stock? How many were over-revved? What is the breakdown by model year? You could read thousands of posts across the internet saying "this happened to me", or "I know a guy it happened to", but all of these posts could be referencing the same 200 cars for all we know. I'd love to see answers to those questions.
Statistically it effects at least 10% of them and most shops with experience working on them say that it effects all of them. It’s not a matter of if, it’s a matter of when.
@STEVEdh8xy the story is Chevy outsourced a batch of heads in 2006 I think it was 1600 and speed shops are profiting off of that to this day. It's always the same story person buys a used c6z takes it to a shop the shop says the same thing you barely made it in time LOL (on a 15 year old car). That said, is this an aluminum 500 horsepower small block which gigantic pistons and valves that you can blow up? Yes it is obviously. My oil gets changed every 3,000 mi at least, it's always brought up to temperature before I get on it and has never done donuts in a parking lot...I work hard for my money
@@clutchcarabelli8054 Thanks for the reply. I had met a another guy with an '08 that has over 120K on the odometer that looked at me like I was a whacko for even thinking about swapping the heads preemptively. You sound a bit like me..I can't even get on it to work and back, because the oil doesn't get up to temperature in time. Thought about just ditching the oil cooler.
way back when I first got my car I used to study it on forums incessantly. My favorite was a guy who had an 06 who tracked it at its limits constantly knowing the supposed problem like damn the torpedoes a few years later he finally popped it at 86,000 hard tracked miles. Another favorite was recently an older guy on a forum hearing about it for the first time saying well I guess I better get mine checked because I have 149,000 mi.. I hope he didn't because you know the shop would have said you just made it on time 😅 then took his money and by the way the supposed head fix does not fix the supposed issue the shops rework those over and over to @STEVEdh8xy
Mine had several out of spec guides at 30,000 miles. The cam was also showing accelerated wear. Upgraded both with AHP parts and loved that engine for years.
Great content, good luck with the new purchase! Over the past 10 years I’ve had two C6 ZO6s. The first one I had ECS replace the stock LS7 heads with fixed LME LS7 heads. Drove that car with stock cam for 12,000 hard miles not one issue. Sold it a few years back. The new owner recently told me it runs flawlessly. Recently purchased a bone stock 2008 C6Z and after reading on the forums and talking to multiple engine builders, decided to completely abandon the LS7 heads and go with AHP’s Arch Angel heads. In my opinion there are just too many variables with the factory LS7 platform heads to keep them and considering you can no longer purchase a new LS7 from GM, buying aftermarket heads is the next best thing. Going to keep stock cam for reliability but install ported Mamo MSD and ARH 1 7/8 headers plus a tune along with American Heritage Performance Arch Angel heads. I ordered parts from Mamo, ARH & AHP and it’d been months of waiting. The hardest part is not driving the car while waiting for parts. I won’t drive the car with stock LS7 heads.
Mine sat in my shop for years, trying to find a reputable shop to conduct task in Canada. I heard of Davenport Motorsports in Calgary last winter, and now have OEM Lingenfelter upgraded heads, and enjoy driving once again. Risk vs Reward. Risk mitigated :-) cheers
@@robyna8995 My Nephew has had work there also on his C7 Z, and enjoyed the process. I also had new tires and an in-depth four wheel alignment. My Z runs so true, It's a dream to drive. Happy driving in 2024 robyna :-)
@@marinellzs4335 If you're talking to me, I just asked Namela a rep at Davenport Motorsports many questions. He answered all with detailed info, and confidence that my engine would be reliable and strong, like the dozens they had done already. Calling is easy, and information was free. Cheers.
I called AHP and spoke to Kohle. Told him what I wanted to do with my car and these heads. Kohle then advised on what spring, valve, etc setup for the heads. You can also email them and Kohle usually replies within 48-hours.
From what I’ve read it can happen at 10K miles and it can happen at 80K and anything in between. It’s best to get it fixed and possibly do a cam upgrade. It depends on the valves and the heat treatment they received. It can definitely be fixed.
I bought 08 Z with 13k miles. I tested valves and some exhaust valves had tons of play. replaced exhaust valves and guides and installed btr-2 cam n kit. running great
I bought a ‘09 Z06 with 17k km and I took it in to have it inspected and the mechanic was surprised I even made it to his shop. Said he never seen anything like that before. Anyways, had the issue addressed plus some extras and this thing is a beast.
Good info. , Ive researched this issue also and im currently looking for a C6 Z , I think the only way is to change out the stock heads to be 100% confident in not having any failures
Aside from the heads, witch also need the upgraded rocker bearing, some LS7s have a tendency to break a piston land. When the motor gets hot, which they do in the vette because it does not evacuate heat out of the engine bay, the rings will expand and push up breaking the piston land. You'll also get micro cracks in the stock sleeves. If this happens to you (like it did to me and another guy in my town) don't let the shop ditch you LS7 block, crank and rods. There are a few places that are proficient at LS7 re-sleeve and thats the route you should go. My shop talked me into a Texas speed 427 block (board out 5.3L) and forged rods/pistons. Although it can hold more power now (1200 crank), for a naturally aspirated setup, the car revs significantly slower. I should have never sold my LS7 block and rods...
That's good info for others. The LS7 has titanium rods which might explain a little lower REV. On the other hand the LS1 in the '04 C5 I drive around in revs a little faster and higher now with a BTR stage 1 cam, dual valve springs, titanium retainers, Johnson lifters, etc. from Michigan Motorsports. I picked up a couple hundred RPM at red line. As long as your cam is the same, heads are the same, and valve train is the same it should rev the same. Ignition timing is computer controlled on the Vette since the C5 (not like an old distributor on the C3 and C4 where the timing can be physically changed by rotating the distributor Retarded/Advanced). Something has to be different in the new valve train; crank shaft stroke, compression ratio, cam duration/lift is different somewhere.
Huh I went with tsp ls3 resleeved, and mine is a beast. I wonder if your windage tray is there or if oil is lingering in your sump and creating an oil mist ?
Great vid, thanks for the reference to my channel near the end. It seems that there the best answer is that there is no right answer...and it depends on more than one factor. So on my channel, I made another video and gave my opinion on what to do...just to be safe.
"The LS7 engine is known to be quite reliable, even after owners push it to its limits. However, there has been one major problem that it suffered, and it has to do with its valves. General Motors released a statement that said the problem was traced back to the supplier of its cylinder heads. They managed to figure this out by studying the heads returned under warranty. The problem occurred simply because some heads weren’t machined correctly. As a result, the valve guides and valve seats weren’t concentric, and that caused major damage to the valve guides. The LS7 engine valve issue isn’t as major as the news articles online would lead you to believe. General Motors believes that only 10 percent of the Corvette Z06s are affected - that’s a total of 1300 units." So just get high quality heads with good valves and guides and you're fine.
The "issue" is the improper valve guide machining process, not the guide material or the valves or the oiling system. The C6 ZR1 is a 6.2 liter engine, so you are comparing apples to oranges here
I almost always find that the C6 Z06 owners that’s say they dont have a valve problem also don’t track the car or drive it how it was built to be driven. That’s a big variable. A local SCCA member bought a 2009, with the upgraded oil system. He thought the issue was exaggerated and it finally blew up requiring a new engine.
I agree, my bone stock 2011 z06 has 60k miles I purchased it with 20k miles. Rarely sees past 5500 rpm since it’s more than enough to overtake 99% of ppl on any highway. Occasionally sees 7k rpm on a Sunday morning
Got my heads done in 2023. OEM Lingenfelter upgraded with inconel exhaust valves. Shop has done many, and most failures ( mainly stock) were just noted as " just rolling into throttle lightly at lo RPM". Broken exhaust valve! Can't get crate engines anymore, so not worth the risk for me.
I had a 2008 c6 z and I had the heads done at 24k miles. Put 25k on it with no problems besides blowing up my bell housing with the 545 rwtq. But I was freeway racing my buddies stock 2008 c6z with my c6z with the heads fixed. He dropped a valve and blew his engine. I currently have a 2023 zl1
I figured it was valve guides installed off center and therefore leading to uneven guide wear and when it develops enough play valve will not seat properly and force to break.
Josh has begun the process of getting the engine back in the Z06. If you follow the channel, you probably have seen. Can't wait for him to get it back on the road.
To answer the title question in a word.....yep. If you think rebuilding or replacing the heads alone will fix the issue.......nope. Yes, worn heads will need to be fixed or replaced for starters but what is overlooked most is rocker arm geometry. Quality roller rocker arms or a roller rocker shaft setup (and setup properly) is needed to minimize valve and guid wear.
Making way way more out of it than is necessary. I’m on my third C6 Z06 and I have owned a 2019 ZR1. The problem with the valve train does exist but you are overdoing the description. Simply put, get your valve guides miqued, better yet, get your heads redone. End of story and go on enjoying your LS motor.
One variable I'm interested in is which model years drop the valves. I understand GM began putting in thicker exhausted valves in the LS7s during the 2008 production. Also, I don't know what year Corvette increased the capacity of the dry sump. I wonder how many blown engines were modified? To get a clear picture of the issue, we need to look at all the variables.
18 years with my C6Z stock heads untouched $0.00 spent at shops or any repairs beyond maintenance, went rippin in it last night 😎👍 and will continue to.. but you do you 😂
I've spent nearly $20K on a HCI build... Only because I was scared about the valve drop issue. Just been unlucky so far with rocker bolt breaking, needing to replace new parts in barely 1~2k miles.. Going through it again where it sounds like I may need to replace my lifters and/or rockers again. Stressful! Car is great when it runs, but sucks when it keeps breaking.
LOTS OF KNOWLEDGE AND REALWORLD EXPERIENCE ON THESE COMMENTS. I STILL DONT UNDERSTAND WITH ALL THE ENGINE ISSUES HOW THESE HAVE INCREASED SO MUCH IN VALUE. I HAD A 08 WITH 12K I SOLD 4 YEARS AGO. NOW ITS WORTH 25K MORE LOL. I CHOCK IT UP TO PEOPLE HAVE JUST LOST THIER MINDS WITH USED CAR PRICING AND WHAT THEY ARE WILLING TO PAY.
I'm not trying to be a Richard, but the valve issue is more on exhaust valves which are not titanium. Only the intake valves are titanium and I don't think those drop but the guides and stems do wear prematurely. An oil starvation issue will destroy bearings long before it will damage valve guides. The lt4s do not share the same valvetrain as an ls7. Lt4s have completely different cylinder heads and utilize direct fuel injection, cylinder deactivation, have a different spec cam, and a lower redline.
I think it’s the improper valve rocker angle that sideloads the guide and hour glasses it. I went with trickflows and roller rockers, right move? Who knows. It makes power though.
I came to the same conclusion, but I think it's the higher rocker ratio and the 7,000rpms that create the side loading. Like you, I went with rollers. I went TSP with upgraded trunions. I have a big cam and the valve train sounds beautiful. My third oil change since rebuild coming up and going to send in for analysis. Wanted to pull heads at 10,000 to check everything, but if this analysis is clean, I don't see why. How long have you had your rollers?
@@esad-ij5ienot long, maybe 3-4k miles. The car has been down for the winter to do a clutch job, gears, e85, ironmask msd and so on and so on. You know how it goes.
For starters, without a doubt there is a problem even with fixed heads and Its mostly dependent on lift/cam choice. Fixed OEM heads with a stock or small cam will likely just run forever with no issues. High lift cams substantially stress and wear the valvetrain more and In my opinion would need aftermarket heads like brodix or CIDs. Even with aftermarket or fixed heads, it is recommended to get your valves tolerances checked every few years depending on what you do with the car. The small tank on the earlier models is only an issue on track with R comps not that big of a deal with you dont track it. Side note, the c6zr1 is an LS motor and the camaro zl1 is a LT motor they are actually very different and dont share the same issues with the oil pumps.
Im going back and forth between a C6 manual GS or buying a C6 Z06 , I know if I buy the C6Z the heads absolutely have to be addressed right away for piece of mind.
I have had two of these cars. Currently have one now. Both were all stock when i got them. The first one had guides that were egg shaped. It would blow smoke at start up. Took it in and had the heads done and never had another issue with it even after adding a cam. The second one was not as bad but the guides were out of spec when the heads were pulled. Car was bone stock and everything else was very good except the heads. This is a well documented issue. Some cars don't have an issue many do. I am two for two on cars with guide wear. The first was really bad.
GM should have had a recall on some of these 427 LS motors they would sling a valve off into the block and destroy the engine but they never took accountability for bad heads on some of these cars.
love the c6 zo6 but ill stick with my ls3 c6 , this is a bigger problem than gm admits to. to replace that motor is a complete deal breaker, especially since 90 percent of the people who own them will never drive them to their full potential.
If you're going to spend 35k on a car and the engine is 20k of that price, spend the 3k to get the heads fixed. Yes they are bad from the factory, yes it is worth fixing. Yes, this is the most amazing engine in the world.
I have a 07 c6 z06 blew the original motor at 28k miles but that's because I was spraying nitrous at the time. it was 09 and I still had warranty so had it covered. got a early 09 service engine still brand new 0 miles and 72k miles later car is still running strong! as a matter of fact I just had a oil change and no metal shavings came off the plugs from the oil.
@@failingup4907 I took off the kit a month before it happened. plus it happened when I was driving normally and they determined it was the valve that dropped.
It continues to amaze me all the GM and vette fan boys that are in denial about there actually being an issue! If you are like most and only drive your Z to cars&coffees at 35mph, maybe you will be fine. But to say not to track the car, not to Rev to redline, which BTW is computer Rev limited is ridiculous! GM should admit fault, but they are not going to do that and why would they??? Instead admit to partial fault with a very limited selection of engines that have to be beaten and abused to fail.... And the fan boys happily swallow and spread the story... it's genius damage control marketing!
Talk to Dan at Katech he will fill you in on the heads my Corvette z06 2008 JSB I also had a Dewitt’s rad installed AT I Harmonic Blancer installed this spring Taking to Linefelter up grade to 11 qt oil up grade good Luck my vett has 20.000 miles
I have some Bridox B7 heads ported , Polished and milled with upgraded hardware by IronMask airflow being done now. I was going to go with fixed heads but I have see so many people have there heads fixed and still drop a valve are check them and they are still out of spec. I think there are a few variables that can cause this and one is the metal it’s self of the heads , How are they put to the right specs and still developing the same problem , I think the metal the heads was made of are trash, Not all but a lot of them , so I went with the B7’s they brand new fresh cut castings
Bought an 08' Z and got the heads addressed. BUT... while your in there change the cam. Change the radiator. Change the shocks. Change the clutch. Change the shifter. Change the stock manifolds to headers. Change the exhaust. Give it an HP tune. So when all is said and done it's some big $$$ to make the Z really perform. But why only do the heads? Make it great!
I was attending a seminar hosted by Paul Koerner at Corvettes at Carlisle last year and he stated that the best way to keep your LS7 from blowing up is to keep the engine completely bone stock. No cold air intake, cam or headers.
And yet I know 3 people with bone stock LS7’s that blew up. The video even shows Josh Van Velds channel, and his was bone stock. Now Josh is waiting for his new engine because it grenaded.
It’s got nothing to do with the mods it’s got to do with the hollow valves that will fail and drop into your engine. Very little research will show you this all over the net, just install new heads save yourself $20k for $4k
What I have heard is. One vendor was given the job to press in valve guides for these heads, another vendor assembled them. The quality control of press vendor was insufficient. Giving varying degrees of "true" seating of valve guide. Off by an inch or off by a mile? And how many? One, three or seven guides? We know it only takes one! Thus why some engines will live 5 thousand miles and others 100,000. But again, why risk it when I don't hear of many failures of engines with upgraded heads? Or am I wrong? Hope not, just did mine last year.
GM: Builds a Corvette with boasting promises of high revving.... Also GM: Don't rev it! You will brake poorly manufactured heads! Just buy some aftermarket heads and Cam -- not only will you be happy, you will he in it for the long haul!
The information that I got was that in the manufacture process, !/2 of the parts in question were made in Mexico..and 1/2 in the U.S. The ones from Mexico were done incorrectly and there was NOTHING (marking etc) that would tell Chevrolet which were from what factory. so you have a 50/50 chance of your LS7 going to shit. They didn't find and fix shit!!
Mr Gato, let me ask you this.. If I gave you a bowl of skittles and said eat them, but then told you there were 3 Skittles in there that might make you really sick, are you going to risk it? Don't risk it with the Z06 either. Just because some guys get lucky doesn't mean you will. Get the damn heads done and sleep well at night!
ruclips.net/video/ALuudpd6gRE/видео.html Another LS7 bites the dust due to valve drop! Keep rolling the dice? Please remember, "pride goes before destruction" and your C6 Z06 is just as likely to drop a valve as any other LS7 powered Z06. Pay a little more now or pay ALOT more later. A new engine is upwards of $20k or more though I've seen around $14k. Fixing the issue with the cylinder heads would be less than $14k for a new engine. Am I wrong in saying around $5k to fix the heads including labor?
theres no way to know when or if these motors will blow with this known defect. just get it addressed and enjoy it. id get a monster H/C setup and kick some ass.
Nope,not them all. 09Z06 100k,no problems at all. But did have the heads rebuilt,last month.GM claims they can't narrow the years with issue problem problem problem
Same design different manufacturing process.So they are not the same.Go ask many engine shops they will tell you the LS7 is a very problematic engine.There is no permanent fix for the problem.
First thing I did to my 2009 c6 Z06 was getting the heads addressed. It’s about $3k to do it and it’s a total investment / peace of mind.
They still fail after getting heads redone. Sorry
@@JackJones-fg1jx It really depends on the shop in all honesty.
Leave it stock
Gm talked about how even a cold air intake and exhaust will mess the engine up
It's a engine that's very special and shouldn't be touched like the ls3
I did the same as Derek. Brodix BR7s. I went with the Archangel from AHP. Stage 2 cam. Tony Mamo MSD AirForce Intake.
Replacing the heads was the only way I could get peace of mind. It is THE source of the problem. Pony up the cash & fully enjoy the benefits of a 7 liter LS.
604 RWHP 552 lbs tq
And this is a streetable car. A pleasure to drive. I left 40 HP on the table for better street manners. The heads breathe so good I can.
They are worth the insane price.
Im looking at the arcangels did you keep the same rockers for that head or upgrade those as well
For my AHP Arch Angel set-up Kohle recommended comp cams LS7 Shaft Rockers.
i bought a car with these heads on it already. What plugs do you run with them? Brodix reccomends a step colder plug. as far as i know the car is stock minus heads, has stock tune on it.
I own a 08 C6 Z06 with 11k miles I had American heritage performance take care of the heads and yes at 11k the valves had play. GM won't admit that they made a big mistake with out of spec valves and or guides.
was this measurement with the wiggle test?
I used oil testing to detect titanium in the oil, before any damage. Pulled the heads at my cost, removed the springs and showed the GM warranty inspector the intake valves just fell out of the heads. He authorized need heads and valves under warranty. This was a GM extended warranty j had purchased. I used Blackstone Laboratories fir testing they pointed out the titanium ppm was there but low. On the next oil change 22,000 it was up a lot. I called several dealers Corvette specialist they agreed stop driving it and pull the heads. Testing the oil saved my Ron Fellows 427. Dennis
I've never seen any hard data for this issue- only anecdotes on the internet. Zero issues with my '08 in seven years of ownership, but I have no interest in racing or modding it. There were over 28,000 of these made. How many of that number have dropped a valve? How many are tracked regularly? How many had a cam that wasn't stock? How many were over-revved? What is the breakdown by model year? You could read thousands of posts across the internet saying "this happened to me", or "I know a guy it happened to", but all of these posts could be referencing the same 200 cars for all we know. I'd love to see answers to those questions.
Statistically it effects at least 10% of them and most shops with experience working on them say that it effects all of them. It’s not a matter of if, it’s a matter of when.
Mine's going on 18 years with stock heads
@STEVEdh8xy the story is Chevy outsourced a batch of heads in 2006 I think it was 1600 and speed shops are profiting off of that to this day. It's always the same story person buys a used c6z takes it to a shop the shop says the same thing you barely made it in time LOL (on a 15 year old car).
That said, is this an aluminum 500 horsepower small block which gigantic pistons and valves that you can blow up? Yes it is obviously.
My oil gets changed every 3,000 mi at least, it's always brought up to temperature before I get on it and has never done donuts in a parking lot...I work hard for my money
@@clutchcarabelli8054 Thanks for the reply. I had met a another guy with an '08 that has over 120K on the odometer that looked at me like I was a whacko for even thinking about swapping the heads preemptively. You sound a bit like me..I can't even get on it to work and back, because the oil doesn't get up to temperature in time. Thought about just ditching the oil cooler.
way back when I first got my car I used to study it on forums incessantly. My favorite was a guy who had an 06 who tracked it at its limits constantly knowing the supposed problem like damn the torpedoes a few years later he finally popped it at 86,000 hard tracked miles. Another favorite was recently an older guy on a forum hearing about it for the first time saying well I guess I better get mine checked because I have 149,000 mi.. I hope he didn't because you know the shop would have said you just made it on time 😅 then took his money and by the way the supposed head fix does not fix the supposed issue the shops rework those over and over to @STEVEdh8xy
Mine had several out of spec guides at 30,000 miles. The cam was also showing accelerated wear. Upgraded both with AHP parts and loved that engine for years.
Great content, good luck with the new purchase! Over the past 10 years I’ve had two C6 ZO6s. The first one I had ECS replace the stock LS7 heads with fixed LME LS7 heads. Drove that car with stock cam for 12,000 hard miles not one issue. Sold it a few years back. The new owner recently told me it runs flawlessly. Recently purchased a bone stock 2008 C6Z and after reading on the forums and talking to multiple engine builders, decided to completely abandon the LS7 heads and go with AHP’s Arch Angel heads. In my opinion there are just too many variables with the factory LS7 platform heads to keep them and considering you can no longer purchase a new LS7 from GM, buying aftermarket heads is the next best thing. Going to keep stock cam for reliability but install ported Mamo MSD and ARH 1 7/8 headers plus a tune along with American Heritage Performance Arch Angel heads. I ordered parts from Mamo, ARH & AHP and it’d been months of waiting. The hardest part is not driving the car while waiting for parts. I won’t drive the car with stock LS7 heads.
Mine sat in my shop for years, trying to find a reputable shop to conduct task in Canada. I heard of Davenport Motorsports in Calgary last winter, and now have OEM Lingenfelter upgraded heads, and enjoy driving once again. Risk vs Reward. Risk mitigated :-) cheers
@@robyna8995 My Nephew has had work there also on his C7 Z, and enjoyed the process. I also had new tires and an in-depth four wheel alignment. My Z runs so true, It's a dream to drive. Happy driving in 2024 robyna :-)
How long did it take for them to respond to you.. theres so manu options for the arcangel heads. How did you figure out what you wanted..
@@marinellzs4335 If you're talking to me, I just asked Namela a rep at Davenport Motorsports many questions. He answered all with detailed info, and confidence that my engine would be reliable and strong, like the dozens they had done already. Calling is easy, and information was free. Cheers.
I called AHP and spoke to Kohle. Told him what I wanted to do with my car and these heads. Kohle then advised on what spring, valve, etc setup for the heads. You can also email them and Kohle usually replies within 48-hours.
From what I’ve read it can happen at 10K miles and it can happen at 80K and anything in between. It’s best to get it fixed and possibly do a cam upgrade. It depends on the valves and the heat treatment they received. It can definitely be fixed.
I bought 08 Z with 13k miles. I tested valves and some exhaust valves had tons of play. replaced exhaust valves and guides and installed btr-2 cam n kit. running great
I bought a ‘09 Z06 with 17k km and I took it in to have it inspected and the mechanic was surprised I even made it to his shop. Said he never seen anything like that before. Anyways, had the issue addressed plus some extras and this thing is a beast.
Good info. , Ive researched this issue also and im currently looking for a C6 Z , I think the only way is to change out the stock heads to be 100% confident in not having any failures
Aside from the heads, witch also need the upgraded rocker bearing, some LS7s have a tendency to break a piston land. When the motor gets hot, which they do in the vette because it does not evacuate heat out of the engine bay, the rings will expand and push up breaking the piston land. You'll also get micro cracks in the stock sleeves. If this happens to you (like it did to me and another guy in my town) don't let the shop ditch you LS7 block, crank and rods. There are a few places that are proficient at LS7 re-sleeve and thats the route you should go. My shop talked me into a Texas speed 427 block (board out 5.3L) and forged rods/pistons. Although it can hold more power now (1200 crank), for a naturally aspirated setup, the car revs significantly slower. I should have never sold my LS7 block and rods...
That's good info for others. The LS7 has titanium rods which might explain a little lower REV. On the other hand the LS1 in the '04 C5 I drive around in revs a little faster and higher now with a BTR stage 1 cam, dual valve springs, titanium retainers, Johnson lifters, etc. from Michigan Motorsports. I picked up a couple hundred RPM at red line.
As long as your cam is the same, heads are the same, and valve train is the same it should rev the same.
Ignition timing is computer controlled on the Vette since the C5 (not like an old distributor on the C3 and C4 where the timing can be physically changed by rotating the distributor Retarded/Advanced). Something has to be different in the new valve train; crank shaft stroke, compression ratio, cam duration/lift is different somewhere.
Huh I went with tsp ls3 resleeved, and mine is a beast. I wonder if your windage tray is there or if oil is lingering in your sump and creating an oil mist ?
Great vid, thanks for the reference to my channel near the end. It seems that there the best answer is that there is no right answer...and it depends on more than one factor. So on my channel, I made another video and gave my opinion on what to do...just to be safe.
"The LS7 engine is known to be quite reliable, even after owners push it to its limits. However, there has been one major problem that it suffered, and it has to do with its valves. General Motors released a statement that said the problem was traced back to the supplier of its cylinder heads. They managed to figure this out by studying the heads returned under warranty.
The problem occurred simply because some heads weren’t machined correctly. As a result, the valve guides and valve seats weren’t concentric, and that caused major damage to the valve guides. The LS7 engine valve issue isn’t as major as the news articles online would lead you to believe. General Motors believes that only 10 percent of the Corvette Z06s are affected - that’s a total of 1300 units."
So just get high quality heads with good valves and guides and you're fine.
Just after spending 100k on car that should have this already I gotta spend another 7k in parts and 3k in labor hahaha not everyone is a mechanic
@@KeepSycklids c6z06 was never 100k, get your generations straight
The "issue" is the improper valve guide machining process, not the guide material or the valves or the oiling system. The C6 ZR1 is a 6.2 liter engine, so you are comparing apples to oranges here
I almost always find that the C6 Z06 owners that’s say they dont have a valve problem also don’t track the car or drive it how it was built to be driven. That’s a big variable. A local SCCA member bought a 2009, with the upgraded oil system. He thought the issue was exaggerated and it finally blew up requiring a new engine.
I agree, my bone stock 2011 z06 has 60k miles I purchased it with 20k miles. Rarely sees past 5500 rpm since it’s more than enough to overtake 99% of ppl on any highway. Occasionally sees 7k rpm on a Sunday morning
Got my heads done in 2023. OEM Lingenfelter upgraded with inconel exhaust valves. Shop has done many, and most failures ( mainly stock) were just noted as " just rolling into throttle lightly at lo RPM". Broken exhaust valve! Can't get crate engines anymore, so not worth the risk for me.
I had a 2008 c6 z and I had the heads done at 24k miles. Put 25k on it with no problems besides blowing up my bell housing with the 545 rwtq.
But I was freeway racing my buddies stock 2008 c6z with my c6z with the heads fixed. He dropped a valve and blew his engine.
I currently have a 2023 zl1
I figured it was valve guides installed off center and therefore leading to uneven guide wear and when it develops enough play valve will not seat properly and force to break.
Josh has begun the process of getting the engine back in the Z06. If you follow the channel, you probably have seen. Can't wait for him to get it back on the road.
I did watch his last update, it’s going to be a well sorted Z06
To answer the title question in a word.....yep.
If you think rebuilding or replacing the heads alone will fix the issue.......nope.
Yes, worn heads will need to be fixed or replaced for starters but what is overlooked most is rocker arm geometry. Quality roller rocker arms or a roller rocker shaft setup (and setup properly) is needed to minimize valve and guid wear.
Making way way more out of it than is necessary. I’m on my third C6 Z06 and I have owned a 2019 ZR1. The problem with the valve train does exist but you are overdoing the description. Simply put, get your valve guides miqued, better yet, get your heads redone. End of story and go on enjoying your LS motor.
One variable I'm interested in is which model years drop the valves. I understand GM began putting in thicker exhausted valves in the LS7s during the 2008 production. Also, I don't know what year Corvette increased the capacity of the dry sump. I wonder how many blown engines were modified? To get a clear picture of the issue, we need to look at all the variables.
2009 was the first year they increased sump capacity and made a few changes, ported over from the ZR1
18 years with my C6Z stock heads untouched $0.00 spent at shops or any repairs beyond maintenance, went rippin in it last night 😎👍 and will continue to.. but you do you 😂
I've spent nearly $20K on a HCI build... Only because I was scared about the valve drop issue. Just been unlucky so far with rocker bolt breaking, needing to replace new parts in barely 1~2k miles.. Going through it again where it sounds like I may need to replace my lifters and/or rockers again. Stressful! Car is great when it runs, but sucks when it keeps breaking.
LOTS OF KNOWLEDGE AND REALWORLD EXPERIENCE ON THESE COMMENTS. I STILL DONT UNDERSTAND WITH ALL THE ENGINE ISSUES HOW THESE HAVE INCREASED SO MUCH IN VALUE. I HAD A 08 WITH 12K I SOLD 4 YEARS AGO. NOW ITS WORTH 25K MORE LOL. I CHOCK IT UP TO PEOPLE HAVE JUST LOST THIER MINDS WITH USED CAR PRICING AND WHAT THEY ARE WILLING TO PAY.
I'm not trying to be a Richard, but the valve issue is more on exhaust valves which are not titanium. Only the intake valves are titanium and I don't think those drop but the guides and stems do wear prematurely. An oil starvation issue will destroy bearings long before it will damage valve guides. The lt4s do not share the same valvetrain as an ls7. Lt4s have completely different cylinder heads and utilize direct fuel injection, cylinder deactivation, have a different spec cam, and a lower redline.
I think it’s the improper valve rocker angle that sideloads the guide and hour glasses it. I went with trickflows and roller rockers, right move? Who knows. It makes power though.
I came to the same conclusion, but I think it's the higher rocker ratio and the 7,000rpms that create the side loading. Like you, I went with rollers. I went TSP with upgraded trunions. I have a big cam and the valve train sounds beautiful. My third oil change since rebuild coming up and going to send in for analysis. Wanted to pull heads at 10,000 to check everything, but if this analysis is clean, I don't see why. How long have you had your rollers?
@@esad-ij5ienot long, maybe 3-4k miles. The car has been down for the winter to do a clutch job, gears, e85, ironmask msd and so on and so on. You know how it goes.
For starters, without a doubt there is a problem even with fixed heads and Its mostly dependent on lift/cam choice. Fixed OEM heads with a stock or small cam will likely just run forever with no issues. High lift cams substantially stress and wear the valvetrain more and In my opinion would need aftermarket heads like brodix or CIDs. Even with aftermarket or fixed heads, it is recommended to get your valves tolerances checked every few years depending on what you do with the car. The small tank on the earlier models is only an issue on track with R comps not that big of a deal with you dont track it. Side note, the c6zr1 is an LS motor and the camaro zl1 is a LT motor they are actually very different and dont share the same issues with the oil pumps.
Haven't LS7's dropped valves in daily driving? How could this be a lubrication problem will driving to get groceries?
Im going back and forth between a C6 manual GS or buying a C6 Z06 , I know if I buy the C6Z the heads absolutely have to be addressed right away for piece of mind.
I have had two of these cars. Currently have one now. Both were all stock when i got them. The first one had guides that were egg shaped. It would blow smoke at start up. Took it in and had the heads done and never had another issue with it even after adding a cam. The second one was not as bad but the guides were out of spec when the heads were pulled. Car was bone stock and everything else was very good except the heads. This is a well documented issue. Some cars don't have an issue many do. I am two for two on cars with guide wear. The first was really bad.
Great video, sounds like you did a lot of legwork.
I always think of it this way: you can do 3-5k in preventative work, or you can spend 10-20k on an another engine.
you always drive on both sides of the road crossing the double yellow?
GM should have had a recall on some of these 427 LS motors they would sling a valve off into the block and destroy the engine but they never took accountability for bad heads on some of these cars.
love the c6 zo6 but ill stick with my ls3 c6 , this is a bigger problem than gm admits to. to replace that motor is a complete deal breaker, especially since 90 percent of the people who own them will never drive them to their full potential.
Get heads updated...cheap entry fee for one of the best engines ever made. Never look back...
If you're going to spend 35k on a car and the engine is 20k of that price, spend the 3k to get the heads fixed. Yes they are bad from the factory, yes it is worth fixing. Yes, this is the most amazing engine in the world.
I have a 07 c6 z06 blew the original motor at 28k miles but that's because I was spraying nitrous at the time. it was 09 and I still had warranty so had it covered. got a early 09 service engine still brand new 0 miles and 72k miles later car is still running strong! as a matter of fact I just had a oil change and no metal shavings came off the plugs from the oil.
How did the warranty cover it if you were using nitrous?
@@failingup4907 I took off the kit a month before it happened. plus it happened when I was driving normally and they determined it was the valve that dropped.
It continues to amaze me all the GM and vette fan boys that are in denial about there actually being an issue! If you are like most and only drive your Z to cars&coffees at 35mph, maybe you will be fine. But to say not to track the car, not to Rev to redline, which BTW is computer Rev limited is ridiculous! GM should admit fault, but they are not going to do that and why would they??? Instead admit to partial fault with a very limited selection of engines that have to be beaten and abused to fail.... And the fan boys happily swallow and spread the story... it's genius damage control marketing!
The fact that GM says there is no problem is meaningless to me. What do you think they're going to say?
GM says the same valves and guides on ls9,lt4 and no issues
Talk to Dan at Katech he will fill you in on the heads my Corvette z06 2008 JSB I also had a Dewitt’s rad installed AT I Harmonic Blancer installed this spring Taking to Linefelter up grade to 11 qt oil up grade good Luck my vett has 20.000 miles
I have some Bridox B7 heads ported , Polished and milled with upgraded hardware by IronMask airflow being done now. I was going to go with fixed heads but I have see so many people have there heads fixed and still drop a valve are check them and they are still out of spec. I think there are a few variables that can cause this and one is the metal it’s self of the heads , How are they put to the right specs and still developing the same problem , I think the metal the heads was made of are trash, Not all but a lot of them , so I went with the B7’s they brand new fresh cut castings
According to the engineers who developed the LS7 the most common reason for engine failure is engine modification by the owner.
Bought an 08' Z and got the heads addressed. BUT... while your in there change the cam. Change the radiator. Change the shocks. Change the clutch. Change the shifter. Change the stock manifolds to headers. Change the exhaust. Give it an HP tune. So when all is said and done it's some big $$$ to make the Z really perform. But why only do the heads? Make it great!
I was attending a seminar hosted by Paul Koerner at Corvettes at Carlisle last year and he stated that the best way to keep your LS7 from blowing up is to keep the engine completely bone stock. No cold air intake, cam or headers.
And yet I know 3 people with bone stock LS7’s that blew up. The video even shows Josh Van Velds channel, and his was bone stock. Now Josh is waiting for his new engine because it grenaded.
It’s got nothing to do with the mods it’s got to do with the hollow valves that will fail and drop into your engine. Very little research will show you this all over the net, just install new heads save yourself $20k for $4k
What I have heard is. One vendor was given the job to press in valve guides for these heads, another vendor assembled them. The quality control of press vendor was insufficient. Giving varying degrees of "true" seating of valve guide. Off by an inch or off by a mile? And how many? One, three or seven guides? We know it only takes one! Thus why some engines will live 5 thousand miles and others 100,000. But again, why risk it when I don't hear of many failures of engines with upgraded heads? Or am I wrong? Hope not, just did mine last year.
Is it engine issues that prevented you from staying on the right side of the double yellow?
own the car since the break in period, maintenance and using good gas, built motor
Yes, of course they may. Do a wiggle test to see how bad the guides are. It's a little complicated but worth it. Vids on YT.
Before the video even starts- you damn right it will lol
Rpm picks up great hp with new heads and a tune
GM: Builds a Corvette with boasting promises of high revving....
Also GM: Don't rev it! You will brake poorly manufactured heads!
Just buy some aftermarket heads and Cam -- not only will you be happy, you will he in it for the long haul!
Bring to Race Proven Motorsports in DE. Get a stage 4 Cam and you’ll be GTG
The information that I got was that in the manufacture process, !/2 of the parts in question were made in Mexico..and 1/2 in the U.S. The ones from Mexico were done incorrectly and there was NOTHING (marking etc) that would tell Chevrolet which were from what factory. so you have a 50/50 chance of your LS7 going to shit. They didn't find and fix shit!!
Katech make a belt tensioner for corvettes and gm engines
Mr Gato, let me ask you this..
If I gave you a bowl of skittles and said eat them, but then told you there were 3 Skittles in there that might make you really sick, are you going to risk it?
Don't risk it with the Z06 either. Just because some guys get lucky doesn't mean you will.
Get the damn heads done and sleep well at night!
ruclips.net/video/ALuudpd6gRE/видео.html Another LS7 bites the dust due to valve drop! Keep rolling the dice? Please remember, "pride goes before destruction" and your C6 Z06 is just as likely to drop a valve as any other LS7 powered Z06. Pay a little more now or pay ALOT more later. A new engine is upwards of $20k or more though I've seen around $14k. Fixing the issue with the cylinder heads would be less than $14k for a new engine. Am I wrong in saying around $5k to fix the heads including labor?
theres no way to know when or if these motors will blow with this known defect.
just get it addressed and enjoy it. id get a monster H/C setup and kick some ass.
Nope,not them all. 09Z06 100k,no problems at all. But did have the heads rebuilt,last month.GM claims they can't narrow the years with issue problem problem problem
Get the heads done by now??
Same design different manufacturing process.So they are not the same.Go ask many engine shops they will tell you the LS7 is a very problematic engine.There is no permanent fix for the problem.
Hey man, peace! 👍💪✌
Peace!
Hea leve it alone..
i have never heard of a cam breaking in my life.
I broke on in three pieces in a 69 Y block 400 pontiac.
Way to long of a video. Pls get to the point what’s the fix for these LS7’s
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