Livefast1098

Hi!
I have just purchased my very first Vette (nice stock '11 Z w/Z07 and CFZ) and haven't even taken delivery yet.

Last night I was browsing the threads and ended up on several "LS7 failure" posts and am now freaking out a little.

I purchased this car as a summer DD and track car (10-12 HPDE events a year). Reading those threads I'm sort of discouraged to read stuff like: "as long as you keep it at/or under 5500rpm you should have no issues with this engine" ... WTH? ... Isn't this Chevys answer to the 911 GT3? A car even Porsche dealers incourage you to track (I know I owned a 2014 until this spring). To me the Z06 was always presented as a car to let loose on the track, pushing your own and the cars' limits.

I can't back out of the deal cause have a bunch of parts ordered for it (Daytona seats being the major one) so I'm asking the "track guys" (road course) out there if I really need to drive it like a grandma around the track? Am I stuck with a garage queen?
Thanks!

redbird555

In short no the ls7 is a hell of an engine and will take the 7000 rpm abuse. The ls7 failures are due to a head guide issue on the exhaust valves. The guides wear very quickly ( some in as little as 5k miles) and the excessive play in the guide causes the valve to wobble and eventually break and drop into the motor. People tell you to leave the engine at 5500 with stock valves but honestly thats not going to help anything.

The solution to all of this is to pull the heads and have them "fixed" the fix involves replacing all 16 guides and checking tolerances and then installing new exhaust valves. Some go back with new oem valve others play it safe and use aftermarket valves. Personally I think the problem isnt as widespread as some believe, I know 3 other people besides myself who own z's all of varying years and with miles ranging from 8k-56k and none are garage queens and all runs fine. However I just did my heads 1500 now is cheaper than possibly 10k later, the fix depending on what you want can be anywhere from 1200-3k depending on how much work you do and what head options you look at. Personally I didnt reuse the stock valves. No one seems to have a solid answer what really causes the issue so I played it safe and went with hollow aftermarket valves.

With that said if you choose to get the heads fixed go with some PM or moldstar guides as bronze will wear faster and thats not good f youre beating on it out on the track. Also since you will see 7k often the lightest valvetrain would be the best option so either ti exhaust valves, new oem, or hollow ferrea stainless would be good. Those options can even use stock valve springs but a psi 1511 setup would shed even more weight

Livefast1098

Anyone? Aside from purchasing an extended warranty (which I will) and shortening my service intervals is there anything else I can do to drive with peace of mind?

Edit: sorry to redbird who probably posted while I was making my bump.

psp6158

do not regret buying the car!!!!!

redbird555

Fixing the heads is a lot cheaper than a warranty if you have some tools and can DIY when I did mine it took me a full day start to finish, had all the parts pulled the old heads cleaned the block and put on the new reworked ones

kenw

Get the heads checked and if need be fixed. These cars stand up to incredible abuse without many failures. You made the right choice.

Lawdogg

Have the heads done and flog the car at will.

Quicker10u

I just sold my 911 and bought a Z06 for the same reasons. I too am going to get the Valve guides replaced, however, I am going to buy an aftermarket set of heads and simply swap them out. The job is not too hard supposedly and there are several DIY's out there for the procedure. I also am going to say something that some people on here might disagree with, I think a number of failures of the LS7 come from driver error. I have witnessed 2 Z06's lose engines in braking zones while downshifting. The 427 has some tremendous piston speed near red line, so it is sensitive to mechanical over-rev. I typically shift at 6500-6700 on track. Either way, fixing the heads makes them pretty stout. You have a later model Z06 so you have a better dry sump tank and oiling system than the earlier C6 Z's (like mine).

With my 911, everyone told me it was a ticking time bomb with the IMS Bearing. Every car has it's Achilles heel.

Is it as nice a car as the 911, no....Is it as fast and capable, yes...more so...it's scary what this car can do...

Racingswh

My Wife's car is going into its 7th HPDE and Track season. It has won a Regional Time Trials Championship and 1 time a runner up. It was all stock until last season. It has never had a major mechanical failure.

In my experience they are fabulous.

Brian71

I had a 911 as well and sold it and bought an 07 Z06. I've tracked mine twice at Mosport. I wasn't aware of the valve guide issue. I'm having it checked and will get the repair done. The engine is good but I'd rather pay for a head exchange than a new engine.
It's still cheaper to repair than a 911.

Quicker10u

What he said.

Ken

Livefast1098

Thanks a lot for the reply guys. Feel a bit better though wasn't planning on spending anymore money but s**t happens I guess! I'll call the Chevy dealer who'll perform the inspection for the GM warranty and ask him to do the "wiggle test" and go from there.

If the heads clear that test does that mean I'm set or do I need to perform this test regularly? Since I'll have a 2 year warranty on the car is there a GM fix that's worth it or it's only in aftermarket (which I would have to wait to get done only once the waranty expires)?

My GT3 was a real oil pig, especially at the track! How's the LS7 in that respect and can I rely on the gauges to let me know it's getting low (like on the 911 which had NO dipstick)? Sorry if this last question sounds stupid but not a mecanic and this will be my first experience with GM's dry sump.

shane p

I would just do the heads and be done with it, if not it is something you will need to do on a regular basis and tracking the car I would assume you will need to do it more often than normal and that could start to get costly, for 1500 or so you can have the heads redone and there are a couple vendors here that can sell you heads and once you change them out you send them your old ones back so there is no down time.

lamboworld

Spend 3k and get the heads done and you won't every have to worry about this issue. I just bought a 2011 Z06 with less than 4k miles and decided to go ahead and have the heads done so I wouldn't have to worry about them. I also went FBO, but fixing the heads seems like a no brainer to me if you plan to keep the car for a while.

redbird555

I seriously want to know where everyone is spending 3k for a basic head fix unless you paying the shop for labor. AH head package is 1300 plus shipping or another 500 for porting and includes new hollow exhaust valves and pm guides. It's about as good as you get for a stockish car and it's no where near 3k

lamboworld

$1,800 is about what I paid for the heads including 280cc porting, CHE Guides, new Ferrea exhaust valves etc... but I am doing a lot more to my car, so I am not really sure of the labor cost to just switch out the heads. Probably 1k but could be a few hundred more or less.

redbird555

I understand that 1800 is far away from 3k though and what you got is far from a basic fix like I posted. I see the 3k figure thrown around here all the time and it's grossly inaccurate unless you do some crazy stuff to the heads and pay someone to swap them for you. But again that's far from just a "basic" fix

LFZ

You could just leave it alone and drive it.......

starchedup

Leave it alone =

I would say the 3K figure includes labor for someone to remove the heads. Darin Morgan just ported and "fixed" my heads and he always uses the nickel/ bronze valve guides for ALL his motors (they do NHRA big motor builds). Anyway, Head porting and replacing exhaust guides and for me bent exhaust valves (totally different story as to why- long story) is about $1500. Thus, I would say no porting and just fix is probably around 1k or less. Depending on who does your "fix" and if you remove the heads yourself.

These are pics of my heads BEFORE any porting. Just replacing the guides in these pics




Nickle/ bronze valve guides






Suggeted only replacing the exhaust valves guides. Darin says they don't see issues with the intake valve guides



Long and short of it is... BUY THE CAR!

shane p

3k isn't grossly inaccurate, it depends on what you have done, you do the head swap and pay for heads to get new stainless exhaust valves, new guides, polish intake valves new springs, and a port and polish job, average I would say is 1500 bucks if you start upgrading then it goes up from there you could use all new valves and have over 3000 bucks in just the valves.