Piston Carnage Pic...
Thread Starter
Melting Slicks
Joined: Aug 2002
Posts: 2,737
Likes: 2
From: California USA
Piston Carnage Pic...
Stock LS6 shortblock, 02 Z06, 62k miles:
Recently replaced the 62k shortblock because of a "power loss". I am posting this for informational purposes for those diagnosing their engine. This damage resulted from a lean engine. Cylinder pressure was 60psi accompanied with a quick leak down. There was no visual clue the engine was damaged until I removed the piston. The rings, bearings, and cylinder wall looked unremarkable.
Recently replaced the 62k shortblock because of a "power loss". I am posting this for informational purposes for those diagnosing their engine. This damage resulted from a lean engine. Cylinder pressure was 60psi accompanied with a quick leak down. There was no visual clue the engine was damaged until I removed the piston. The rings, bearings, and cylinder wall looked unremarkable.
Pro
Joined: Dec 2003
Posts: 651
Likes: 1
From: Z16 #1990 Ridgecrest CA
Ouch.....what cylinder did that come out of? #7 
I have made a special tune to account for very dry conditions here in the desert (< 10% humidity). With my wideband installed I noticed that under very dry conditions my WOT AFR would lean out to 13.4 at 4K RPM up
Sorry to see the damage, time to make it an even better motor
I have made a special tune to account for very dry conditions here in the desert (< 10% humidity). With my wideband installed I noticed that under very dry conditions my WOT AFR would lean out to 13.4 at 4K RPM up
Sorry to see the damage, time to make it an even better motor
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
You mean it richened up to 13.4. It was at ~14.7 when you floored it.
Thread Starter
Melting Slicks
Joined: Aug 2002
Posts: 2,737
Likes: 2
From: California USA
I put a new Innovate LC1 Wideband in because I was getting ready for a race. I apparently did not do a proper free air calibration on the sensor as the A/F was way off. Combine this with the RoadRunner, live tuning. Note, the RoadRunner (can and was) setup to react to the wideband and lean the mixture automatically/real time. Made a few hard accelerations wearing et st radials (high load on engine), heard the "infamous" rattling in the can noise, then lost a lot of power. I knew something was wrong, but did not know what until the next day.
After free air calibrating the wideband the next day I found it was about 2.4 A/F off. That means, I was aiming for 12.7 and probably got 15.2 or more A/F, WOT, w/et sts, hooked and engine loaded.
.
I do however categorically deny all the nitrous runs a few years ago.
Yes, was #7. See this post for the resulting replacement. LOL I am still using the same wideband, only its calibrated now.
http://forums.corvetteforum.com/show....php?t=2081506
After free air calibrating the wideband the next day I found it was about 2.4 A/F off. That means, I was aiming for 12.7 and probably got 15.2 or more A/F, WOT, w/et sts, hooked and engine loaded.
.I do however categorically deny all the nitrous runs a few years ago.
http://forums.corvetteforum.com/show....php?t=2081506
Race Director
Joined: Dec 2000
Posts: 19,304
Likes: 85
From: San Diego CA
Well, to make you feel better, here's a piston and what's left of the valve from my 68's 327 block. A spring broke and dropped the valve while I was doing 80 MPH. Needless to say, the cylinder and head were destroyed as well.
Le Mans Master
Joined: Feb 2006
Posts: 5,488
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From: USA
