[Z06] Please help! Blew my engine in my C6 Z06. :(
06-04-2015, 03:48 PM
#21
So you didn't hit the Rev limiter Op but slipped the clutch and failed too engage second gear? just trying to figure out how this happened..Operator or mechanical failure...Not blaming just want some facts...Thanks
06-04-2015, 03:50 PM
#22
Hey everyone,
I'm in a little desperate need of advice. Last week I was driving my mint Atomic Orange C6 Z06 Vette with only 11,000 miles on it. I redlined it in 1st gear on an open road, like I usually do, and when I shifted to 2nd my foot slipped off the clutch and I accelerated. The car lunged forward and I heard a pop and saw nothing but white smoke out the back. I was so sad, the Z06 is all stock. I was hoping that it was just a blown gasket, but when the mechanic looked at it, he said that the coolant and oil mixed and that it looked like there was something trying to make its way out of the block (they still need to take it apart of diagnose). On person on another corvette forum said a faulty valve is probably at play.
He's thinking its going to need a whole new block and other parts (like rolling gear assembly is what I believe he called it). Gave me an initial quote of $3600 for the rebuild, $2800 for a new block, and $2600 for the rolling gear assembly + whatever can't be salvaged. I'm hoping for good news on that end, but am not holding my breath. Didn't expect to have a $9K+ expense right now. I drove my previous black C6 Z06 80,000 miles hard, and never had an issue. Not sure how or why this all happened, BUT...does anyone have any advice on purchasing parts for the rebuild? Have any contacts for less expensive parts/suggestions/used LS7 engines for a good price? Or suggestions on mods for the most bang for your buck in doing the rebuild? Camshaft suggestions? I'm wanting to keep it naturally aspirated still, and if the engine is going to get torn a part I am entertaining the idea of mods for street performance, boosting HP another 40-80 HP and extra torque as well. Very curious, if you were having an engine rebuilt, what mods would you do it while keeping the price down as much as possible?
I'm pretty pissed at myself and bummed out in general, so any advice would be GREATLY appreciated...my baby is dead right now.
The engine will be disassembled this weekend 6/5/15 and I'll be looking to order parts once I know the diagnosis. Thanks in advance! - Francisco
I'm in a little desperate need of advice. Last week I was driving my mint Atomic Orange C6 Z06 Vette with only 11,000 miles on it. I redlined it in 1st gear on an open road, like I usually do, and when I shifted to 2nd my foot slipped off the clutch and I accelerated. The car lunged forward and I heard a pop and saw nothing but white smoke out the back. I was so sad, the Z06 is all stock. I was hoping that it was just a blown gasket, but when the mechanic looked at it, he said that the coolant and oil mixed and that it looked like there was something trying to make its way out of the block (they still need to take it apart of diagnose). On person on another corvette forum said a faulty valve is probably at play.
He's thinking its going to need a whole new block and other parts (like rolling gear assembly is what I believe he called it). Gave me an initial quote of $3600 for the rebuild, $2800 for a new block, and $2600 for the rolling gear assembly + whatever can't be salvaged. I'm hoping for good news on that end, but am not holding my breath. Didn't expect to have a $9K+ expense right now. I drove my previous black C6 Z06 80,000 miles hard, and never had an issue. Not sure how or why this all happened, BUT...does anyone have any advice on purchasing parts for the rebuild? Have any contacts for less expensive parts/suggestions/used LS7 engines for a good price? Or suggestions on mods for the most bang for your buck in doing the rebuild? Camshaft suggestions? I'm wanting to keep it naturally aspirated still, and if the engine is going to get torn a part I am entertaining the idea of mods for street performance, boosting HP another 40-80 HP and extra torque as well. Very curious, if you were having an engine rebuilt, what mods would you do it while keeping the price down as much as possible?
I'm pretty pissed at myself and bummed out in general, so any advice would be GREATLY appreciated...my baby is dead right now.
The engine will be disassembled this weekend 6/5/15 and I'll be looking to order parts once I know the diagnosis. Thanks in advance! - Francisco
06-04-2015, 04:13 PM
#23
Advanced
06-04-2015, 11:55 PM
#25
Race Director
^ maybe, but if so then GM should have set the "redline" at a lower threshold...
if the oil is hot this is what the engine is designed to withstand, is it not ? (putting aside for the moment the known valve-train issues)
when I run the Texas Mile, I push the properly warmed-up engine to redline through the first four gears every time...
OP, sorry to hear of your misfortune...G-L with a replacement engine.
if the oil is hot this is what the engine is designed to withstand, is it not ? (putting aside for the moment the known valve-train issues)
when I run the Texas Mile, I push the properly warmed-up engine to redline through the first four gears every time...
OP, sorry to hear of your misfortune...G-L with a replacement engine.
Last edited by Gary '09 C6; 06-04-2015 at 11:58 PM. Reason: sp
06-05-2015, 12:03 AM
#26
Drifting
LS7
06-05-2015, 12:53 AM
#27
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Bill
06-05-2015, 01:33 AM
#29
Racer
But, Tadge had never heard of this.
06-05-2015, 02:50 AM
#30
06-05-2015, 10:46 AM
#33
Heel & Toe
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Some info about the Valve dropping...West Coast Corvettes told me that this happens due to faulty rocker arms in '06-'07 Z06's. They have never seen this issue in '08 and above (I'm pretty sure they said '08). Had I known this, I probably wouldn't have bought a 2007 or I would have replaced the rocker arms and had heads done. I bought this in Phillie last year with only 5,000 miles on it, its the LT3 (or whatever package includes the DVD/Nav). Bummer. Yup, I'd get those suckers replaced ASAP before driving it too hard...the rebuild will cost nearly as much as a new engine.
06-05-2015, 11:00 AM
#35
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Ok, new news on the damage report and some info about the LS7 from '06-'07. WCC in Anaheim informed me that faulty rocker arms are the culprit of valves dropping in these years (said it doesn't happen in '08 and above). Happens on very RARE occasions and is just a faulty of the LS7's these years. Causes Catastrophic failure.
I have hit the rev limiter on a few occassions...rev limiter works just fine. I didn't miss a shift, I shifted to 2nd when my foot slipped off the clutch and I accelerated. Shifting into a higher gear, my REV's should be less, so it is not an issue about over revving or anything like that. I've owned 2 Z06's for about 7 years now and I do drive them hard on occasion...engines are meant to be driven hard. This unfortunately was just crap luck and there was nothing I could have done (except drive it like a caddy or modified factory headers). I had no idea '06-'07 had this issue or I wouldn't have bought the vehicle. I bought it a year ago from a collector in Philidelphia who only had 5,000 miles on it and it was (and still is) in show room condition.
The mechanic opened up the heads and Cylinder 6 failed. The head here is obliterated, and the small valve shot down, causing the piston to shrapnel and dropping this debris to the bottom of the engine where the crankshaft slammed it into the block. The block is cracked at the cylinder of cylinder 6.
The assessment is still the same with regards to buying a new block $2800, New Rotating assembly $1900, but now new rockers, a new rod, and some other miscellaneous parts. The rebuild will include modified stock injectors, a performance camshaft, custom tune, maybe a headers/exhaust package and that's about it.
Regarding the heads...I have 1 good one now. $1300 GM Factory for a bare head. I'd need to get this new one and existing one CNC'ed also. Not sure on the price for all this, but does anyone have suggestions on buying Completed CNC'ed heads that are not the most expensive out there? Or suggestions on the heads? Estimating about over $10K now. oye! But should come out with over 600 HP. I'll try to include some pics...bummer, but hopefully this will help the next person (or prevent another victim).
I have hit the rev limiter on a few occassions...rev limiter works just fine. I didn't miss a shift, I shifted to 2nd when my foot slipped off the clutch and I accelerated. Shifting into a higher gear, my REV's should be less, so it is not an issue about over revving or anything like that. I've owned 2 Z06's for about 7 years now and I do drive them hard on occasion...engines are meant to be driven hard. This unfortunately was just crap luck and there was nothing I could have done (except drive it like a caddy or modified factory headers). I had no idea '06-'07 had this issue or I wouldn't have bought the vehicle. I bought it a year ago from a collector in Philidelphia who only had 5,000 miles on it and it was (and still is) in show room condition.
The mechanic opened up the heads and Cylinder 6 failed. The head here is obliterated, and the small valve shot down, causing the piston to shrapnel and dropping this debris to the bottom of the engine where the crankshaft slammed it into the block. The block is cracked at the cylinder of cylinder 6.
The assessment is still the same with regards to buying a new block $2800, New Rotating assembly $1900, but now new rockers, a new rod, and some other miscellaneous parts. The rebuild will include modified stock injectors, a performance camshaft, custom tune, maybe a headers/exhaust package and that's about it.
Regarding the heads...I have 1 good one now. $1300 GM Factory for a bare head. I'd need to get this new one and existing one CNC'ed also. Not sure on the price for all this, but does anyone have suggestions on buying Completed CNC'ed heads that are not the most expensive out there? Or suggestions on the heads? Estimating about over $10K now. oye! But should come out with over 600 HP. I'll try to include some pics...bummer, but hopefully this will help the next person (or prevent another victim).
06-05-2015, 11:08 AM
#37
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My previous baby....I didn't mention this yet, but my '06 Z06 died shortly after a Dyno at West Coast Corvettes. Freak failure in a piston ring that caused all the oil to burn up during the Dyno and engine seized up. $14K rebuild pushing it to nearly 600 HP....so this is my 2ND rebuilt engine. 
I think i just threw up a little in my mouth. 
I think i just threw up a little in my mouth.
06-05-2015, 11:10 AM
#38
That failure is not due to faulty rocker arms. That is the all too common bad valve guides that fatigue the exhaust valve until it breaks and drops into the cylinder. Have your other 'good' head rebuilt, do not just bolt it back on the engine!
06-05-2015, 11:15 AM
#39
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Yes, will definitely do that. Thanks.
06-05-2015, 11:15 AM
#40
Melting Slicks
Some info about the Valve dropping...West Coast Corvettes told me that this happens due to faulty rocker arms in '06-'07 Z06's. They have never seen this issue in '08 and above (I'm pretty sure they said '08). Had I known this, I probably wouldn't have bought a 2007 or I would have replaced the rocker arms and had heads done. I bought this in Phillie last year with only 5,000 miles on it, its the LT3 (or whatever package includes the DVD/Nav). Bummer. Yup, I'd get those suckers replaced ASAP before driving it too hard...the rebuild will cost nearly as much as a new engine.
However, all year LS7's have an issue with excessive valve guide wear and a poorly manufactured sodium cooled exhaust valve. The exhaust valve has a hollow stem that is very thin in some areas. Many of us have the heads reworked with new valve guides and replace the OEM exhaust valves.
Another weak link in this engine is the hypereutectic (cast) aluminum piston. When a stainless steel valve comes in contact with a cast piston, the piston comes apart like a piece of glass. The piston actually acts as a guide for the connecting rod. When the piston comes apart, the connecting rod thrashes the engine block. With this combination, you have the recipe for a possible disaster.
You can purchase a used set of LS7 heads on this forum for around $1000. If you want to increase engine reliability, send the heads to either West Coast Cylinder Head or American Heritage. Both shops have a great reputation and extensive experience with LS7 heads. Additionally, I'd replace the cast pistons with quality forged pistons for extra reliability.
If you want to increase horsepower and torque, install a mild aftermarket camshaft and a set of quality headers (American Racing or Kooks).
Best of luck!
Last edited by Vito.A; 06-05-2015 at 11:21 AM.