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new motor... already knocking, please help

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Old Aug 8, 2008 | 01:50 PM
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extremetoy's Avatar
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Default new motor... already knocking, please help

ive got an lq4 that i just went through, .010 over new bearings, pistons, etc.
just got it going and its got a tick thats definetly coming from the lower end.

could it have spun a bearing in under 100 miles? everything was torqued to spec ...
totally bummed, any ideas how this could have happened?

it will go away after its warm, it only lasts for a couple minutes
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Old Aug 8, 2008 | 02:15 PM
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Piston slap?

Usually a rod knock gets worse as it warms up....(at least in my experience with em)

You "could" try pulling off a plug wire off each cylinder while its running(and knocking) and see if the knock gets quiet when you pull off a particular wire, if it does, you know its either slap or a knock on that cylinder. Usually a slap sounds more like a lifter clatter then a rod knock though.

Either way you will be pulling it...
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Old Aug 8, 2008 | 02:22 PM
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i dont see how it could be piston slap when it had brand new pistons and the block was just machined. it literally has about 100 miles on it all.

ill get a video once the battery charges for the camera.

yea its got me confused since it goes away as well
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Old Aug 8, 2008 | 02:47 PM
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Forged pistons? If so they will make some noise until warmed up.
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Old Aug 8, 2008 | 02:48 PM
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yea, forged pistons... really hoping this is it but if i can figure out hoe to get a video up ill post it.
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Old Aug 11, 2008 | 04:11 PM
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When you measured clearances before assembly, what did you record for the following:

piston to cylinder:
main bearings:
rod bearings:
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