what happened to the LS1 I bought - #7 piston busted
#1
TECH Resident
Thread Starter
iTrader: (19)
Join Date: Jun 2005
Location: Los Angeles, CA (Burbank)
Posts: 755
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Hey guys, trying to figure out what happened to this engine; getting a little confused.
Bought an LS1 from a wrecked 2000 corvette with 40k miles, and I was told the engine was running just fine right before it was pulled.
Got it home, pulled the heads, and saw this:
![](https://sites.google.com/site/zigzautonotes/images/broken_piston1.jpg)
![](https://sites.google.com/site/zigzautonotes/images/broken_piston2.jpg)
Broken at the ring land, common on #7, etc (nitrous maybe???). Now all the other pistons are fine. What's confusing me though is...the cylinder wall looks fine, and the combustion chamber looks good, valves look good.
I mean with a broken piston like this, shouldn't there be some damage on the cylinder wall, or the combustion chamber/valves?? What could have happened?
Bought an LS1 from a wrecked 2000 corvette with 40k miles, and I was told the engine was running just fine right before it was pulled.
Got it home, pulled the heads, and saw this:
![](https://sites.google.com/site/zigzautonotes/images/broken_piston1.jpg)
![](https://sites.google.com/site/zigzautonotes/images/broken_piston2.jpg)
Broken at the ring land, common on #7, etc (nitrous maybe???). Now all the other pistons are fine. What's confusing me though is...the cylinder wall looks fine, and the combustion chamber looks good, valves look good.
I mean with a broken piston like this, shouldn't there be some damage on the cylinder wall, or the combustion chamber/valves?? What could have happened?
![Icon Confused](https://ls1tech.com/forums/images/smilies2/icon_confused.gif)
#3
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Mine did the exact same thing at 103,000ish miles, only on number 5. I also had a cracked block directly opposite the ring land failure (@5 o'clock position). I don't use nitrous either. Let me see if I can find the thread and pics.....
Here it is:
https://ls1tech.com/forums/generatio...-mile-ls1.html
Here it is:
https://ls1tech.com/forums/generatio...-mile-ls1.html
#4
TECH Resident
Thread Starter
iTrader: (19)
Join Date: Jun 2005
Location: Los Angeles, CA (Burbank)
Posts: 755
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Thanks guys. There were no shavings or broken chunks in the cylinder or anywhere. The connecting rod looked fine too. It's almost as if someone just installed a busted piston in a decent motor.
When I get a new piston/rod back from the engine shop, I'll put it in, do a compression check/leakdown test and see what the results are.
1CAM, read your thread, that sucks man, what motor did you end up going with? stroker?
When I get a new piston/rod back from the engine shop, I'll put it in, do a compression check/leakdown test and see what the results are.
1CAM, read your thread, that sucks man, what motor did you end up going with? stroker?
#5
Moderator
iTrader: (20)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Yeah, it's really weird (re: suspicious) that a huge chunk of aluminum piston like that evacuated the engine and didn't leave any damage behind. 9 times out of 10, a piece gets caught in the quench area between the head and piston, and sticks into either of the surfaces. You usually find chunks in the manifold as well.
See if you can find any signs that the engine might have been rebuilt. I think that might be the more likely explanation.
See if you can find any signs that the engine might have been rebuilt. I think that might be the more likely explanation.
#6
TECH Resident
Thread Starter
iTrader: (19)
Join Date: Jun 2005
Location: Los Angeles, CA (Burbank)
Posts: 755
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Thanks KCS...I might post a pic of the heads' combustion chamber when I get home. It looks fine to me but maybe I'm missing something.
The intake manifold was gone when the motor was pulled, btw...
The intake manifold was gone when the motor was pulled, btw...
Trending Topics
#12
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Very common, number 7 cylinder runs hot. Toss a tune in there with it and yer all set for a number 7 failure. GM stopped putting the rear water cross over on the later engines and this is the result.
#15
TECH Addict
iTrader: (1)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
The chances of a big chunk of metal finding its' way out of the cylinder through the exhaust valve without doing further damage along the way are VERY slim. Conversely, who would put a motor together with a piston that looks like that? Time to call Perry Mason on this one.
#18
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Mine made it out of the exhaust port. There were no pieces in the oil pan, and like stated in my thread, there was not any room around the ring for pieces to get by. It is very possible for a piece to shoot out of the exhaust valve.
I ended up with an iron 6.0L block bored to 4.07" with Wiseco pistons, Eagle rods, and a Compstar 4.100" crank
.
I ended up with an iron 6.0L block bored to 4.07" with Wiseco pistons, Eagle rods, and a Compstar 4.100" crank
![Devil](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_devil.gif)
#19
TECH Resident
Thread Starter
iTrader: (19)
Join Date: Jun 2005
Location: Los Angeles, CA (Burbank)
Posts: 755
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Thanks for the responses guys. That is crazy that the SAME SPOT is common on this piston when it breaks. lol
SS4, what was your solution, honestly? Did you get replace the pistons/rods on #5 and #7? Or did you pull the engine and take everything to a machine shop?
SS4, what was your solution, honestly? Did you get replace the pistons/rods on #5 and #7? Or did you pull the engine and take everything to a machine shop?