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5.7 hemi question for chrysler/ dodge techs

Posted By: PDFrogman

5.7 hemi question for chrysler/ dodge techs - 01/17/11 08:36 PM

my 04 Durango with a 5.7 hemi broke the 7 rod
the car sat for almost 6 weeks from sept to nov when I started the truck, the rod broke
I'm pretty sure it was a hydraulic lock my question is
would a bad injector leak down enough to cause it?
the cyl in question had a pretty dirty looking injector
(see pics) and the next cylinder was clean, looks brand new
motor ran great was well maintained and had 198K
cylinder walls still had a crosshatch pattern and there was no ridge
there was no evidence of a bad head gasket
had to replace motor had a crack where the rod broke want to avoid this in future
more pics
http://i375.photobucket.com/albums/oo200/pdfrogman/dirtyinjector.jpg
http://i375.photobucket.com/albums/oo200/pdfrogman/cleaninjector.jpg
http://i375.photobucket.com/albums/oo200/pdfrogman/2011-01-15_11-24-05_699.jpg

Attached picture 6423311-brokenpiston.jpg
Posted By: feets

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 08:45 PM

You've got what looks like water bubbles in the oil. Look at the near side bolt boss and the far side bearing surface.
Did that water come from teardown or the block cracking?
Posted By: PDFrogman

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 08:47 PM

Quote:

You've got what looks like water bubbles in the oil. Look at the near side bolt boss and the far side bearing surface.
Did that water come from teardown or the block cracking?



most likely from tear down
the oil was clean no evidence of water in the oil either. the truck sat another 6 weks after the motor broke we took the motor out over the weekend
Posted By: ZIPPY

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 08:51 PM

Quote:

would a bad injector leak down enough to cause it?





Yes
Posted By: PDFrogman

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 08:53 PM

Quote:

Quote:

would a bad injector leak down enough to cause it?





Yes



injector appears to be clogged I cant blow compressed air into it
the intake also had the crud around it.
could it just have been a build up of bad gas at the end of the rail and it just sat there?
Posted By: ZIPPY

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 09:53 PM

No airflow through it, with it removed from the engine means it isn't stuck wide open at the moment.

Normal fuel pressure is about 58psi, and if there is even the slightest injector leak at any time, pretty much all the fuel is going to come out into that cylinder.

The mechanism in the injector only needs to hang up or stick for a second, to destroy a motor.

Just a possibility....
Posted By: PDFrogman

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 10:17 PM

Quote:

No airflow through it, with it removed from the engine means it isn't stuck wide open at the moment.

Normal fuel pressure is about 58psi, and if there is even the slightest injector leak at any time, pretty much all the fuel is going to come out into that cylinder.

The mechanism in the injector only needs to hang up or stick for a second, to destroy a motor.

Just a possibility....




my question why is only that injector caked with crud?
Posted By: feets

Re: 5.7 hemi question for chrysler/ dodge techs - 01/17/11 11:27 PM

That injector probably had a bit of nastiness in it. That can change the spray pattern to more of a dribble. When that happens the fuel doesn't burn efficiently. Deposits build up and the situation gets worse.
It might have hung open long enough to flood the cylinder and closed afterwards.
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