AreOhBeeC6Z

I am the latest victim of the dreaded LS7 exhaust valve drop My car is a 2006, has 29k miles and Intake/Headers/Ported TB/Manifold/Tuned by CMS. The valves were not upgraded at the time, was something I was looking to do down the road when I upgrade the cam but now it looks like I am going to need a new motor. At the time of the incident, I was making a left hand turn onto a busy street, going about 40mph, 2nd gear coasting along and all of a sudden the car got louder, my initial reaction was something with the exhaust came loose, but before I made it to the side of the road, I heard lot's of noise coming from the motor and seconds later a big puff of white smoke.

This is not a thread however to bash the LS7 or GM, but simply a thread to get some ideas from others that have been through this headache situation and what they did to get their car back on the road stronger than ever. My car spent most of it's life in the garage during the week, occasional redline pulls to 7k/spirited driving and participated in two side by side events put together by the guys at Shift-S3ctor.

Any issues with dropping motors even after upgrading the valves? My current plan would be to go with another LS7 with the upgraded heads with a upgraded streetable cam, not sure if I want to port the heads while I'm at it or not? Would I also need a clutch? Any ideas would greatly be appreciated.

'06 Quicksilver Z06

So it had the stock exhaust valves in it?

We were just talking about this yesterday.

Good luck with the rebuild.

gatti-man

Please all of you modded guys get your heads upgraded! Good luck in your new build OP. make it amazing.

LS9Drew

I'm sure that car will be a beast after CMS mods it again for u

briancb1

Dang sorry to hear this. My 06 had 37K on stock guides but had upgraded solid exh valves. The guides were extremely worn.

Plan on going with a stock short block?

FrankTank

and maybe pointless at this point but OP should have the guides measured in his heads , I'd be curious to see measurements


OP sorry about your car this blows good luck with the rebuild

GMuffley

Turbooo2u

It seems like this scenario is just a matter of time for all Z owners??

Jawnathin

Bummer to hear, this strikes close to home as I've got an 06 with almost 22k miles and soon will get similar mods & tune. I guess I'll invest in a set of heads sooner than I thought.

How many miles on the setup?

1981turbota

Sorry to hear about the damage, good luck with the rebuild!

zoomz

Im doing my 06 now , a new block , Calies stroked 440 crank , Manley rods , clevite bearings , Wisco pistons , reworked stock heads with new valve guilds , dual springs , stock titanium intake and inconel exhaust valves

Or you can buy a short block from Katec nicely prepped for around $7-7500 and a set of heads for around $3500 , which is a good deal if you have to buy a block and want to stay with stock displacement .

zoomz

Dont guess , stop driving the car and have new valve guids put in the heads NOW .

Taking the heads off and replacing the valve guilds is stupid cheap compared to buying a new motor .

You dont need new heads or valves tho , just new guides installed that fit the valves better

Mine popped sitting at a traffic light

chadyellowz06

Sorry to hear op........but remember the shop that starts with a K has never seen this.it's the pistons.lol...I got to ask why in the hell would anyone buy from someone that says the valves are not a problem?or that there even is a problem, they've never seen it?...the wrighting has been on the wall for years...it's happing to all ranges of miles stock to modded it doesn't matter..most of the time the car shows know warrning sighs,and will have all of it's power till it blows...untill ppl stand up in numbers this will keep happing, and GM don't give a f*** about you or your car. it's the last gm car I will ever buy.

chadyellowz06

I would be replacing the part that keeps breaking weather it caused the problem or not

AreOhBeeC6Z

Thanks for the kind words fellas. Would a stock short block be sufficient enough for a street car? I am trying to save as much as I can and at the same time without going half ***. I'd like to go with my old modifications with upgraded exhaust valves and a street cam.

Yes, stock exhaust valves thanks man!

Most likely scenario would be a stock short block, buy the parts on my own and have CMS put it all together for me.

Thanks man! I'll get all that once I start the process

I had about 8k miles on the setup. I'd do this as soon as you can, considering what I just went through.

FrankTank

I think what you mentioned above is fine for the street. The Guides/valves seem to be the main issue, rest of the motor is fine. I would go with stock block, street cam, upgraded heads good tune and you should be good to go

When I mentioned having the guides measured, I was talking about the guides from the heads on the motor that blew, just to see what they looked like, I should have been more specific.

Iceman427

No, all ~28k Z's will not have this happen. Go crawl back in your anti Z06 hole.

LS9Drew

Stock Short Block would be fine, or get Forged Pistons then leave the rest stock those are the only "weak" part of the stock bottom end which is already good for 650+whp

MTIRC6Z

Well maybe it might happen to all of them if we wait long enough and nothing else blows up while we're waiting...like Jimman who has 160,000 miles on his, it could just be a matter of time before he too drops a valve

Cheers, Paul.

ralphsmithiii

Did you have stock, factory installed GM guides when it popped? If so, did you replace them with another set of GM guides or with a bronze alternative?