One bad valve spring = new engine
Thread Starter
Navigator
Joined: Jun 2007
Posts: 9
Likes: 0
From: Columbus Ohio
One bad valve spring = new engine
Last Thursday as I was driving on a local interstate during rush hour at about 60 MPH, my 2008 C6 lost power. I depressed the clutch,selected neutral, and coasted to the side of the road. Monday, 11/1/10, I learned that a valve spring had broken and the valve had entered the cylinder and caused major damage. GM was prompt in authorizing a new engine under warranty. It will be shipped from Michigan (Wixom?) and should arrive Tuesday 11/9/10.
Does anyone have any advice? One thing I wonder about is whether the new engine will require special break-in procedures. Also, does anyone know whether LS3’s that are destined for manual transmission cars go through an extra balancing and tuning step prior to installation?
TIA
Does anyone have any advice? One thing I wonder about is whether the new engine will require special break-in procedures. Also, does anyone know whether LS3’s that are destined for manual transmission cars go through an extra balancing and tuning step prior to installation?
TIA
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I don't know about extra balancing, but the damper is balanced to match the crank.
Coming from the Wixom plant, it may well be a 2011 block with the stronger webs and internal windows to improve crankcase air flow.
I can only assume you had a stock engine tune.
Coming from the Wixom plant, it may well be a 2011 block with the stronger webs and internal windows to improve crankcase air flow.
I can only assume you had a stock engine tune.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I just picked up my 2011 from BG and the limits were engine RPM less than 4000 rpm and less than 135 MPH for 500 miles for the drive train. We did that and gave it a good run at 600 miles (after it quit raining).
BC
BC
Team Owner
Joined: Sep 2000
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
Although many folks say the official break-in procedure is more for the transmission and differential than for the engine, I'd still follow the procedure as if it were a new car.
If you dealer does the job right, you could be getting a real deal here. How many miles on the original engine?
If you dealer does the job right, you could be getting a real deal here. How many miles on the original engine?
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Team Owner
Joined: Sep 2000
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
Tech Contributor
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
The clutches are also not balanced. The pressure plates can be oriented in 6 positions and they arent marked as to how they go on the flywheel. My LS7 was so far off when I ordered it that the machine shop said it was the worst clutch they had seen for balance in 30years. It required over a dozen holes to be drilled.
GM cant balance for sheet.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
I had the same thing happen to me with a brand new 73 Z28. Coming back from vacation I heard a ticking and kept driving. Dropped a valve with about 60 miles left in the trip. Towed it to the dealer and got a new long block on warranty. A friend of mine with a 73 Z28 also dropped a valve at about the same time (less than 12,000 miles). About a year later I heard the ticking again, stopped immediately and towed it back to my house. Pulled the valve covers and another broken valve spring. Replaced all the springs again with stock GM springs. You got it, a year later ticking again. This time I pulled the heads and took them to Mondello's in California and got some better Manley valve springs and did a valve job. Never had another problem with that car.
Did you notice a loud ticking in your engine prior to the failure? I'd like to know because there could be a bad batch of springs out there.
Thanks,
Glenn
Did you notice a loud ticking in your engine prior to the failure? I'd like to know because there could be a bad batch of springs out there.
Thanks,
Glenn
Race Director
Joined: Sep 2007
Posts: 16,557
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From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Hey Spin. So as not to hijack this thread, I'm starting one in Tech called "M6 crank balancer replacement and underdrive pulley". Come on over.
Burning Brakes
Joined: May 2006
Posts: 786
Likes: 58
From: New Paltz NY
I also had a broken valve spring and bent push rod - while travelling away from home....22,000 miles - so under warranty.
Apparently, no major damage other than the stupid dealer tech didn’t replace the pushrod seal. Immediately after the repair I complained about excessive exhaust smells...like burning oil. I finally figured out that the seal wasn’t replaced and after a year of haggling with my local dealer to replace the seal...despite his assurance that it probably won’t matter....he finally replaced it.
Now it's much improved...though the smell appears during heavy acceleration. I think the converter and exhaust may be fouled by the oil leaking through the damaged seals...or contaminateed with oil, or the cylinders may be scratched.
PLEASE, does ANYONE have any ideas what may be happening with the smell?
Apparently, no major damage other than the stupid dealer tech didn’t replace the pushrod seal. Immediately after the repair I complained about excessive exhaust smells...like burning oil. I finally figured out that the seal wasn’t replaced and after a year of haggling with my local dealer to replace the seal...despite his assurance that it probably won’t matter....he finally replaced it.
Now it's much improved...though the smell appears during heavy acceleration. I think the converter and exhaust may be fouled by the oil leaking through the damaged seals...or contaminateed with oil, or the cylinders may be scratched.
PLEASE, does ANYONE have any ideas what may be happening with the smell?
Thread Starter
Navigator
Joined: Jun 2007
Posts: 9
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From: Columbus Ohio
In my case the engine failure was obvious. The engine stopped running and when I engaged the starter it would not start and sounded like a box of rocks was being churned. At the shop they removed the valve cover and the spring was in two pieces.The cylinder affected was front-right but I don’t remember the number. They used a camera device to examine the interior of the cylinder. The valve had come loose, fallen into the cylinder, and wedged against the side.
