SR71!

Yes, but that means doing it yourself. While I'm an advocate of doing things for oneself, I know I would pay a professional who has done this many time before to do the work to my car...which in turn gets to the 4k mark.


I just doubt most people want to have a first time at removing and re-installing cylinder heads on their car that costs them 40k all in an effort to save 2k. It's like being penny conscious but dollar foolish when looking at the big picture in the cost of the car and success of the re-build of the top half of your engine.


It's what has me on the fence while looking at these cars.....sadly.

95rtturbo

You can get it done at a reputable shop for $2K including labor (potentially 2500).

SR71!

Then I can promise that I will shop around for a shop (reputable to the LS engines) when or if the time comes that I get me that LeMans Blue ZO6.

Aliquantus

Since the market is well aware of the issue and the resale value is down accordingly, seems like a great opportunity to get a lot of car and simply have the issue fixed with the money you saved, especially for those of us who are DIY'rs.

ssbowtie1

Buy the heads from AHP and have a reputable LS shop install them. Max out of pocket will be $2500.

USA1 427

Ditto.

Konadog06

It continues to be promoted that these cars are time bombs. An owner since '06 I had never heard of this problem till maybe 2015. A Chevy GM tech friend had never heard of this problem going back to '06.
So I researched the claims and complaints. I couldn't find 100 complaints at the time of the search let alone 300 which would be 1% of the LS7 population. 90% of the claims did not occur till 2015 or later. No history of the cars, just the fact that it had problems, now GM's fault. No doubt some cars may be out of spec, and that there are some legitimate claims. Have your car checked first if your concerned before you take a factory assembled car apart. The work you have done may not be better than what you started with.
There are good shops out there when work needs to be done and there are plenty that aren't good. You then have two variables, the machine work and the guy who's reassembling it. And this leaves you with maybe a warranty on the heads.
If you take apart most any mass produced car, you will be surprised how many things are out of spec. Manufactures have a grey area of tolerances.

Does anyone else do any research besides what's posted on this forum. I know there are post that a car blew on the track or a friend of a friend knew somebody. It just keeps going feeding on itself. The real percentages on a well maintained, well managed car are overwhelming in the favor of an owner. If you buy a high performance car of any type with an unknown history, you take chances. Just my 2 cents.
Bill
FL

pickleseimer

Finally, a voice of reason. All machines have some percentage of failures, you seldom hear from the majority of folks who own these cars and have no issues with them.

TorchRedFred

I also know someone who has a 06 Z since new. He's not a forum member and is older and not an internet guy. I asked him about the heads issue and he had no idea what I was talking about. The phrase "ignorance is bliss" comes to mind and he just goes out and enjoys his car. What the percentage of failures are I don't know, and is probably a very small number compared to overall number of LS7's out there. The problem is that when you do hear of failures, it is such a catastrophic and expensive failure that you can't help but worry about it. Getting the heads done properly, is like getting an insurance policy, you might not of ever needed to get them done but it gives you peace of mind. If you spend any time on the Z06 section of the forum, the issue does come up a lot and I will admit that this is one of the reasons I didn't look at the Z06 more seriously when I was shopping.

Z0SIS

Is this a serious question?

Unreal

Cost is no where near $4k. More like $800-1500 depending on if you do it yourself or pay a shop. $4k gets you ported, worked heads with a lot of upgrades, along with a cam/springs, etc. Most people go that route while in there, but if you just want to fix the heads it is less than a set of tires.

It is very very real. Keep the car under warranty, or spend the $800-1500 to fix it and move on.

I've seen it happen twice, in person, right in front of me. I've seen 30+ sets of heads measured, and all but one were out of spec. I've met at least 4 owners at various shows/etc that were on motor #2 or 3 because of it. I sold my stock block to a guy on motor 3, and when I had the ad up I was getting flooded by people looking for a ls7 because of this issue. Local shop gets about 1 z06 in a month with a grenaded motor. It is very very real.

CaPilotMark

Ok, so I'll call myself a noob, since it's been some time since I've been on the forum...

But, I thought all of the 427 head issues were resolved around '09-'10??? I just test drove a '13 GS M6 Vert with ~20k miles and it and it ran amazing! Sales guy even encouraged me to romp on it on a long uphill grade, I felt like I was flying. Got to the top of the hill and was doing just over 55 (cough 104 cough). It was, to say the least, very exhilarating!

If I go back & make an offer, do I need to ask to throw a "head rebuild" discount into the deal?

Mordeth

Unfortunately, the issues with the LS7 were never resolved from the factory. Blame GM for letting Linamar screw us. They all run great, are exhilarating etc until the guides wear prematurely and a valve snaps and drops. The odds are in your favor that this doesn't happen though. So it is a crap shoot. Only you can decide if it is worth the risk, no matter how small. Like Unreal, I have also seen FIRST HAND the problem. I have measured valve-stem to guide clearance. I have literally seen an LS7 grenade from a dropped valve. At the track, almost every LS7 either has dropped a valve or fixed the problem. Very few guys are still safely running the original heads. Happens on the street, on the track, high mileage, low mileage etc.

I also know guys with 80k-100k miles on stock heads that are still running strong and laugh at us "FIX THE DAMN HEADS" guys. But then again I also saw some kids playing in traffic yesterday and they weren't killed. Doesn't mean I let my kids go play in traffic.

At a minimum perform a wiggle test. This procedure isn't 100% accurate but it will tell you if there is a problem. Or just spend $2500 and fix the potential problem. ($1500 from AHP for fixed heads + $1000 to install). Or save the $1k and install them yourself.

Unreal

Even the "$1500 ahp heads" are ported, and have a lot of extra work. Actual guides/valve work/etc is <$800. No reason to spend extra on port work if you aren't doing it for performance.

long_tall_texan

OK. Now that I have some actual first-hand data on the subject, I'll add my 2 cents. Time for me to beat the dead horse too...

I read and read and read about the potential problem with the LS7 heads. I've got an 07 Z06 with only 25k miles on it. I was not having any excessive valve train noise. But I'm a mechanical engineer, how loves to do my own work on my Vette. It actually relaxes me to come home and dig in under the hood for a couple hours after a day at work. So I decided to pull my heads myself and take them to a local head shop that I have used before and trust. I decided to have them replace all of the intake and exhaust guides with new bronze guides. I also went ahead and replaced all of the exhaust valves while they were at it, since there is a potential failure on the early LS7 exhaust valves too. They gave me all of the old valves and guides when I picked up the re-worked heads. So when I got home, I got out my micrometer and my small hole bore gauges and went to measuring. According to GM, anything over 0.0037" valve stem to guide diameter clearance is out of spec. Here's my numbers:

I only measured the old exhaust valves, since they put the intake valves back in the heads. But all of the valve stems measured between 0.3125" and 0.3135". That is pretty close to zero wear on the valve stems themselves.

Then I got into measuring the guides. I just measured the max diameter I could find in the bore of each guide. I'll go back and do a full analysis later with measurements at top, middle, and bottom of bore. Here's the data:
0.322
0.317
0.318
0.317
0.317
0.317
0.321
0.318
0.318
0.321
0.319
0.320
0.337
0.320
0.318
0.318

So just for simplified comparison, and since I did not know which valve came from which guide, lets assume the max valve stem is 0.3140" and GM spec is rounded up to 0.004". That would mean any guide equal to or larger than 0.318 would be out of spec. As you can see above, that means that only 4 out of my 16 guides were within GM spec. And those 4 are right on the edge, and might even be out of spec too, if they were mated with a valve stem that was 0.3125" (0.3125 + 0.0037 = 0.3162").

So there you have it. One more true data point that shows there was a problem in my particular set of LS7 heads. As a geeky, nerdy, engineer, I am driven by actual data, not just hear-say. And this data does not lie. That one valve guide with 0.025" of wear already could have been the cause of a dropped valve had I not taken care of it. Or it could have held together for 100k miles. I chose to not find out the hard way.

Stavesacre21

I really trusted my 427 LS7 enough to buy a 7-year GMEPP warranty.

Whether it be hoopla or not, I'm figuring the damage would happen during that timeframe IF it were going to.

P.S. - Does still sound like a sewing machine between 1200-2200 RPMs tho. I've been told this is normal

Stavesacre21

You have nothing to worry about...the valve issue only applies to LS7 engines, not the LS3 that would be in the Grand Sports. The LS2 and LS3 engines are practically bulletproof and extremely reliable.

The LS7 was only used in the 2006-2013 Z06 and the 2013 427 Convertible.

mfj427

sounds good to me! FOUR TWO SEVEN!

Gary '09 C6

f y i the LS7 was also used in certain recent Camaro models...2014+ Z28s.

philadd

Overreacting a bit, are we? You should probably take your own advice first.