redzone

I cannot believe they want to put a used engine in your car. Well,actually I can,they're weasels trying to get out as cheaply as possible.

But,since they going used,I'd assume they're going to find the cheapest one possible. Which most likely will have more miles than the one its replacing.

And God only knows how it was treated...was it stock? tuned?..who knows.

jschindler

As I read through this thread I had a lot of comments. But now that I've read the entire thread I'm not sure I would really be adding anything that has not been said more than once already.

I see you are new here - nothing you are reporting has not come up on the forum before. You are not the first to report a "blown" engine just cruising down the road in a Z. But for what it's worth, I personally know quite a few owners of Z's, several of who have owned their cars for a long time. I do not personally know a single person who has had any problems at all with a Z. I know it happens, but as Richie said - its actually not very many. But I do understand that even if it's only one in a million, if you are that one it is very painful.

Any of us in your shoes would be just as upset or more than you are, regardless of all the point/counterpoints. Best of luck getting it fixed and thanks for keeping us all posted.

C5 Frank

This is what backs up the fact that it was and is a real issue!!! I know of 5 LS7s personally, not from this forum mind you, in person that have broken a valvespring and dropped a valve.... It happened to me as well (broken valvespring) and I was lucky enough to shut the motor down before catastrophic failure. In my research 3 years ago when it happened to me, I found that there were several cases at three different local Chevy dealers of LS7 failures. I also had someone inside Chevy admit off the record that there was a "Bad batch" of valvesprings that GM was aware of! So yes... this is a real issue. It effected late '06 and early '07 LS7s..... Most failed withing the 1st 15k miles... so by now most have already shown up. But if a car has very low miles, or was babied.... it might show up later. Like in this case of the OP.

JWell

I noticed this as well from reading different posts. I almost think its better to buy an '06 or '07 with 30,000 miles because if a valvetrain issue was going to surface it would have done so by that point.

BSSN

This is a bad batch of parts. It could happen to anyone. It happened to Ferrari, it happened to GM, no big. What I am concerned with is...is there a design flaw?

While you corroborated that yes, there were part issues, you lead me to think there was not a design flaw.

jschindler

Frank, I respect what you are saying, but can't help point out that "real" is a relative term. If one in a million parts fail, it's a real failure. but that does not mean its a real problem. As Richie said earlier, anything mechanical will have a failure rate. And that failure rate is exaggerated on a vehicle that is bought by people who bought it because they like speed. It's also exaggerated on internet forums. This thread is a perfect example.

As best as I can tell, the OP became a member of this forum when something bad happened. A large percentage of people who have a failure report it on the forum. But hardly anyone who has not had a problem starts a thread to say they have not had a problem.

I'm not trying to imply that there was not an issue of some sort with bad springs, but I'm trying to keep it in perspective. You know five guys who have had problems - and it's likely that because you are an avid drag racer that your five guys drag race their car. I'd have to count the number of people I personally know with Zs - but I'm guessing about ten. Not a single one has had a problem - and a couple of them are 06-07's. But then again, none of them has drag raced their car either.

Landru

Shouldn't matter.
You paid good money for a good car, didn't "beat" it and claim it was not modified in any way, including tune.

Bought their extended warranty, huh?
That is a BIG plus in your favor, my friend.
Valve spring(s) on some Z06s do break...not a pleasant thing acknowledge happening but it does happen, nonetheless.

As well you SHOULD; however, let's hope & pray it doesn't come to that.

IIRC the LS-7 cannot be repaired after one of these catasrtophic valve failures. You're entitled to & in-need of a brand new LS-7. Period.

As another poster already mentioned the 5/100 didn't begin 'til '07 so your purchasing an extended warranty is all that stands between you & total disaster. We're pullin' for you, let everyone know what Carmax & their warranty company does or doesn't do.

RichieRichZ06

There is a thread in the Auto-X/Road race section right now about the large number of LS3's that have popped on track. There are more of them on the road so the rate may be higher, but there are a decent number of them that've blown. Like I said, we've done 3 times as many LS3's then LS7's and they've been out 2 less years.


FWIW, the warranty should not have covered the tranny failure. It failed because the dealer that replaced the engine and forgot to top off the trans fluid that leaked out of the cooler and lines when they had everything disconnected, leaving the trans a quart low on fluid. It's great it was covered, but the dealer should've ate that repair.


If you have any warranty other then a GMPP, it's likely your policy states they can use whatever part they want. They look at it like your car had 20k miles on it so an engine/trans with the same mileage is OK. It is very common on trucks, Tahoe's etc to have a used part sent out by the warranty company when a failure happens. We get stuck installing them all the time for aftermarket warranty companies if we can't get them to budge on purchasing a new motor.


Well stated. The forum is a great example of the "Snowball Effect". One person reads a story of an LS7 blowing and tells 50 of his friends, they tell another 50 and the cycle repeats. Pretty soon everyones best friends uncles cousin blew up an LS7 and the sky is falling.

Another saying is "make someone happy and they will tell their neighbor, but **** them off and they will tell the world." Another perfect example of the forum. Not many people take the time to tell of their good experiences, but **** them off and they feel the need to tell the entire forum.

jimbob8915

I wonder what the price difference between a new crate motor an a used motor is? If for some reason you do find in the fine print of the warranty they can replace your motor with a used motor maybe you can make up the difference if all else fails.

Hercules Rockefeller

FWIW I'd like to add that my stock LS7 ('08) blew at just under 20k miles, so there's another data point for all you guys who want to believe this problem isn't as bad as it seems. And guess what caused my failure? Yep, a busted valve spring. You all can believe whatever you want to believe, but every time you start a car with a stock LS7 you are rolling the dice. Maybe you'll get lucky and never have this failure for 100+k miles, then again maybe you won't make it to the end of your next 100 mile trip. You can chalk it up to the forum effect, you can try to blame the majority of these failures on modded cars, or maybe you like to tell yourself that this problem only affects people who track and/or abuse their cars. But at the end of the day, if you don't think your LS7 (yes, yours too) is at risk you're just whistling past the graveyard. After seeing my motor go up in smoke, I decided to invest in a set of decent quality dual coil valve springs; whether or not you think that this is a worthwhile investment for your LS7, that's your call.

AirBusPilot

http://www.racingsprings.com/Multime...talog_2011.pdf

Page 14, PAC valve springs #1518.

High performance LS1 spring that features
additional nitriding processing for increased
durability for high lift applications up to 0.650 lift.
This spring remains a drop in replacement for
extremely high demanding applications.

I might consider upgrading to this spring w/titanium retainers. It's a drop in, single ovate bee hive that would outlast the engine by several times.

I'm thinking the stock LS7 spring is near it's limit with the stock camshaft. JMHO.

AirBusPilot

Based on the pic of your car in your profile, you are a serious track racer. The Z06 is not a dedicated race car, so if you have an engine failure, it shouldn't be too big a shock (and even dedicated race engines will fail in racing). See the post above for what you should have at a minimum.

BSSN

Any defect at all in a spring will lead to failure. It happens. It happens on Enzo's, it happens on Corvette's. It even happened on my friend's LS2 GTO with aftermarket springs that HPE put in when they did the cam. (after about 15-20K miles, cam was a touch under .600).

It's not a design problem, it's a spring quality issue, if it is an issue at all.

Hercules Rockefeller

I am now, but I wasn't back then. Since losing the engine and increasing the durability of the valve springs (like you suggest) I have begun to campaign it at the track... hard. And yet, with all the track miles I've put on this 2nd motor, no failures!

Dedicated race engines will fail, but considering what they go through (far less than anyone like me puts on their car) it's amazing how well they usually hold together. And spec race engines are almost bullet proof. Not many failures at the 24 hours of LeMans, especially in the lower classes, and they are driving 10/10ths for a full day non-stop!

RichieRichZ06

Just slapping a dual spring on the stock valves may not be a good idea either. Some research shows that a hight rate dual spring may increase the probability of the exh valve failing. Other research shows the guides clearances are all over the map and also contributes to failures. I would recommend a good single spring like the one Pilot recommended over a dual spring on a stock cam application.


I'm glad that you brought that up. Out of only a few hundred Enzo's built, I've heard of 4 engines failing at less less than 10k miles. That's a much higher failure rate and it's also on a million dollar car vs a $60k car. The other difference is a replacement Enzo engine is $150k

Hercules Rockefeller

Good point, which is why I replaced my exhaust valves with solid stem pieces when I threw in the set of dual coil springs. As far as the Enzo failures, well, all this shows is that high failure rates can affect cars of all different values, but especially the high end. Clearly price isn't an indicator of durability, as seen in both the C6 Z06, the Ferrari Enzo, and I'm sure many other cars. The lower the production volume of the car, the higher the chance that a defective and/or under-engineered part will make it's way into the OEM design. Just look at all the problems Ferrari has documented with the 360, and look at what's happening now with the spontaneously combusting 458's.

thesubfloor

I'd strongly recommend against a single spring because even if you don't race like I do, if one of them ever does let go you're screwed. I was having all kinds of trouble last year with my so-called "recommended springs" (by a vendor who will remain nameless) breaking every few weeks at the track and on one occasion I even found two broken ones at the same time.

In that instance the only thing that kept my engine from being another statistic was that they were dual springs.

RichieRichZ06

I'm surprised there's a spring out there to control that donkey d!ck cam that you have.

AirBusPilot

Those PAC springs have a pretty good rep and are used in Nascar. If you want a drop in spring with the stock cam, you won't see a failure. Dual springs, like Richie suggests, might have their own issues (the spring holds, but the pressure causes the valve to separate).

JMHO.

thesubfloor

Nice....