bjmsam

Fair questions. Last year, I bought my 2007 Z06 to replace a 20 year old import with a 7200 RPM twin-turbocharged V6 that produced well over 400 horsepower for nearly 200k trouble-free miles including several HPDEs. Yes, for the LS7, I might allow my definition of "acceptable" to be half that many miles before needing to worry about internal wear. Having to check and possibly replace the valve guides every 15k - 30k following a GM or American Heritage "fix" might be acceptable to some, but not to me. If Tadge and/or Jordan indicate that my expectations are unreasonable, then I will regrettably sell the car. I hope they weigh in.

Unreal

Replacing guides/etc if you do it yourself is ~800-900s. Lots of cars have timing belt changes every 60k that cost at least that. Part of owning a high performance car is higher maintenance. Maybe GM built a car that the owners weren't ready for.

Only motors that have valve guides that don't need replaced are Teslas and rotarys. Every other motor will need them serviced at one point or another.

For me, if it is replace them every 30k, that is fine. That is 4-5 years of use, and a weekend and $1000 every 4-5 years it completely acceptable to me for a high performance car. Hell my motorcycle needs valves adjusted and major service every 15k that is about the same cost but it isn't strange and people don't complain to Ducati to fix the valve issue, that is just normal on motorcycles.

bjmsam

Such critical inspection / replacement intervals should be clearly stated in the maintenance schedule. Perhaps someone can post a link to the one for the C6Z and highlight the published interval for the valve guides. If it's 15k - 30k, then my bad for failing to consider this before purchasing the vehicle.

<<427_V8>>

Ha - are you trolling us, Unreal? This must be a joke... cause it sure sound ridiculous to think internal motor components need to be replaced like spark plugs and timing belts. Well, unless you think that's the best engineering that GM can offer these days. I'm pretty sure Tadge would expect no less than at least 125k-150k+ good miles out of these LS7's. Otherwise, I'd be quite embarrassed to be on that team that engineered this motor.

Maybe we should all just wait until Tadge or someone else from GM has additional input. Otherwise we're just rehashing all the same things that were stated in the other million threads...

SHM

IMO, I feel normal wear for a engine like the LS7 under street use, well maintained with no track use should be about 150Kmiles. It would be reasonable to me if the engine is raced a lot, service mileage would decrease accordingly. GM usually boggy'd their vehicles for 100K miles during the 1980s, I remember reading some time ago.

BearZ06

Some really nutty replys here, actually unbelievable. Replacing heads more often than spark plugs, yeah that's normal. Much easier to change the plugs with the heads off LOL.

MTPZ06

First of all, it would be wrong for them to make that anouncement retroactively now that the car is out of production. Had they made that statement in late 2005 upon the LS7's arrival, this would be a completely different conversation.

Secondly, if they are giving me a 5/100K powertrain warranty...then, yes; 100K is the absolute minimum I would accept before any valvetrain maintenace were needed.

Unreal

Agreed, just playing devils advocate. People say they want a fix, well what is a fix? If the fix is what I'm talking about (sadly 1/2 joking but that maybe as good as it ever gets) then are people just going to sell them and move on?

I think no internal motor work through warranty is what should be acceptable, so 100% agree on the 5 year 100k part.

Not trolling, just trying to have a decent conversation.

So what about track then? Would it be unreasonable to have to refresh a ls7 every 30-50k miles if it sees track 5-10 times a year?

Maybe in the future, if this is what is expected, GM makes it very clear in the manual, and sales what people are getting. If a z06 or "race ready" track day car is going to be sold, and can't go 100k+ without just your normal oil changes/etc, then it should be presented as such.

The Highlander

a couple of abused track LS6s lost valves... There was no widespread issue with the engine.. but it did happen... track duty is such a different thing than street duty.. track miles are 10x tougher than street miles if not more....

That being said... There is no design flaw. The LS7 is as good as it gets... and sadly after this debacle we will never have a similar engine from GM again... but had GM used the technology they are using now (robots and pictures) they would have gotten the issue before it got widespread.

AzDave47

GM is still using the same outside supplier (Linamar) that messed up the heads for the C6 Z06, and they managed to not do proper oil fill on the e-difs of several thousand new C7 Z06's, with resulting failures as the low fluid level was not discovered in many PDI's, including at the NCM. One CA buyer got to Texas before the e-dif ate itself.

Unreal

No design flaw? So you have all the drawings? If so share them.

b4i4getit

Too bad nobody has an internal QC contact at Linamar. It would be interesting to see their take on the matter. I have often wondered if they were ordered by GM to fall on the sword over this head issue.

Rock36

I will echo what others have said. I expect a vehicle to typically last the length of a warranty in terms of mileage assuming standard responsible street use of the vehicle and 10K to 15K miles travelled per year. This would include a C6Z under those circumstances.

I understand track use is a major factor in wear; however, we know low mileage/mild use vehicles are wearing guides. That doesn't meet my personal expectations.

If guides need to be changed every 50K miles, then I expect to know up front about it so it can go into my decision making process prior to purchasing the vehicle.

As for a long term fix, the ability to identify/purchase/install a set of heads that will wear guides at a rate comparable to other GEN IV GM motors (LS2/LS3) under similar use is what I would consider a fix. I don't ever expect that to come from GM willingly, because it will increase their exposure to liability.

Mark2009

Based on the recommended service schedule in the owners manual, that is what GM is selling.

Based on the recommended service schedule in the owners manual, 100k with no head maintenance.

If the OEM tires wore out within 100 miles, would you consider that acceptable?

It's not what they sold.

Other mfrs produce high RPM 500hp push rod motors. Are they having this problem?

Maybe we as the consumers have too high of expectations for GM.

Unreal

I 100% agree.

Tires are a good point though. They put $2000 tires that wear out in 5-6k miles on the car, yet because people know that up front you don't see people bitching about it. Having $1000-2000 in head work more often than other cars sucks, but could be just part of owning one of these cars.

I completely agree, heads should last 100k miles no questions asked. Everything on the car besides the consumables (tires, brake pads, rotors, fluids) should last the warranty period.

The 06s did have a 3 year 36k mile warranty, so if they kept that would that change things? Maybe it was designed around that goal.

0RoadRunnerAutoTransport

I know that if I had a C6Z, I'd show this thread to my wife and use it as an excuse to get some nice ported heads

wcollette

I have a 2014 left over Blade Silver Corvette [had 5 other silver Corvettes] that I had to buy out of state, pretty common with Corvette owners. This is by far the worst paint job I ever had on any car. GM blows everyone off, Bowling Green admitted to paint issue among other things, changed their procedures?? so said... yet do absolutely nothing for the customers who have them? One is getting a little results from filing with the BBB and another has just filed [which I will do now to] and he is still waiting results.

In the past it was GoodYear tires vibrations, no tire life, 427 dropping valves, orange peel, mottling among other paint issues... mottling not actually admitted but I [an many others] have a car to prove it. Now ZO6 issues with Michelin tires cracking. One thing on top of others and nothing being done for the poor quality control paint jobs for one, that these owners purchased some sight unseen, [mine for a good reason, disabled veteran can not travel long distances] and GM saying it meets factory specs... scary... after using another car with the same issues to judge it buy?

I alone have talked two people out of buying Corvettes, and two people on trucks not to buy a GM product. You guys are writing your own epitaph.. Wake up GM and Bowling Green... spend the money on your customers instead of a big bash at the Corvette Museum in 2015 and get back to apple pie and Chevrolet Corvette... the American way..

Rock36

I've have similar feelings particularly on the HEMI engines especially the Apache 6.4L engine. The Apache does only have a 6400 rpm redline though; however, GMs own LS3 and LS9 have 6600 rpm redlines. I personally don't understand how another 400-600 rpm of rev range would cause guides to wear 3x as fast, if it were only the high performance nature of the LS7 causing the guide wear.

Rock36

But also with the tires, GM deliberately had GY develop the GEN 2 tire in order to maintain their buisness with corvette after a couple model years. Alternatively, Michellin offers tires like the PS2 that SS that both improve performance and wear better than the original GEN 1 GYs. So there are multiple options that are better all around that what GM originally provided.

Similarly, I know very little of the Brodix and/or MAST heads for the LS7, do those companies produce their own head castings? The Brodix website seems to indicate that they do.

If Linamar is indeed the culprit here, would it follow that going to a completely different head manufacturer potentially produce results we are looking for? I'm sure that question has been asked multiple times before.

Unreal

Yes, PRC, All Pro, Brodix, Mast, Trickflow, etc all cast their own heads.

LS9s have shown to have guide wear issues too.