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Broken piston skirts??? HELP!!

3K views 8 replies 7 participants last post by  wjbertrand 
#1 ·
So I recently "blew my engine up". Lost compression in pistons #2 and #3 but it would still run and drive. I didnt so this long by the way. Just to get back home from work and to the dealer...I finally took engine apart after no luck with dealership. Come to find out #2 and #3 piston skirts are broken. #3 is so bad the pil ring and part of expander ring came out and is in the bottom of oil pan. What would cause the skirts to break?

I also added 2 images of the brace from skirt to the wrist pin area. I noticed one side is thicker than the other...the pistons that broke which are on the passenger side have the thinner side on intake. The driver side pistons all have the thicker side on intake. Could they be installed wrong??
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#3 ·
Typically load force.... the shorter the piston height the more prone the piston is to rocking which increases stress on the skirts. A crankshaft that is "moving" excessively due to bearing issues, etc. can induce this as well. Of course it can also be a defect in the pistons as well but that would be my last swag.
 
#4 ·
Well I'm not a professional of course BUT I don't think its anything to do with the crank moving or bearings issue due to engine only has 8900 miles on it...not saying that the bearings cant go bad that early, but I'm leaning more towards the piston broke on the weaker skirt(the side with thinner skirt brace from the pin area to the skirt.) so I was thinking it might have had to do with the orientation of the pistons, getting too much side load force as it stroke up, making the intake side receiving more force at higher RPMS than the exhaust side of the piston. with it being only 8900 miles I'm thinking its more assembly issue or faulty pistons or something wrong with the actual pistons. but just wanting everyone's opinions or if anyone knows the exact issue that breaks the skirt off.
 
#5 ·
You have a two year old car with 8900 miles and a bad engine? You should have a warranty, unless the dealer can prove that you were abusing it (drag racing, taking it to the track etc.) "I" would not have taken that engine apart & then posted pictures about it online. That may wreak havoc on the warranty. Good luck. I know we all think these cars are "performance" cars, but somewhere in the manual of mostly all cars it will state your warranty is void if you use the car for performance/race/exhibition of speed etc.
 
#6 ·
All these parts are made en mass. With that said it seems you got a couple of bad pistons. It’s more then likely a supplier issue and you got the raw end of couple of pistons of a bad batch. I would have a machine shop go over your engine and have them put it together. Some shops will give you either a 1/12K or a 2/24K on a “stock rebuild.” If you don’t care and can do it on your own then send it.
 
#7 ·
It’s been exactly 2 months since the original post. I sure would like to read an update on this, but the OP hasn’t logged-in since that post.
 
#9 ·
I also added 2 images of the brace from skirt to the wrist pin area. I noticed one side is thicker than the other...the pistons that broke which are on the passenger side have the thinner side on intake. The driver side pistons all have the thicker side on intake. Could they be installed wrong??
Not sure what caused the failure but I think the orientation of the thick vs thin sides has to do with engine rotation direction and is not relevant to the intake or exhaust side.
The pistons are all pushing the crank in the same direction so stresses would be the same regardless of which bank they’re in.


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