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cold start engine knock??

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Old Apr 12, 2013 | 05:45 PM
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Default cold start engine knock??

i have a 2000 camaro ss with 70k original miles. when i start it in the mornings it has a god awful engine tap. after it warms up its not there any more. how do i get rid of this noise??
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Old Apr 12, 2013 | 05:48 PM
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How is the oil pressure when you start? The noise you are hearing is probably piston noise but without a video its hard to say. Unfortunately Its common in the ls1 engines.
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Old Apr 12, 2013 | 06:01 PM
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Possible bent pushrod or failing lifter...
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Old Apr 12, 2013 | 06:07 PM
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Mine sounds terrible till its warmed up but I have other symptoms. Oil pressure gauge hangs for a second then rises and if I shut the engine off I see small bubbles on the dip stick. I'm sure my oil pickup tube oring is leaking air into the oil. Once mine is warmed up its quiet and no air bubbles.
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Old Apr 12, 2013 | 09:24 PM
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Upton, welcome to LS1tech! SEARCH will be your best friend around here.

This is the "normal" LS1 piston slap. What weight oil are you using? What oil filter?
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Old Apr 12, 2013 | 10:03 PM
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My oil pump oring caused all kinda of hell. Never showed any sign of a oil pressure problem on the dash guage either. Unfortunately it was the last thing I changed before I was gonna pull the engine. I changed everything chasing this problem. The oring fixed it.
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Old Apr 15, 2013 | 10:04 PM
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oil pressure is normally around 40 cold and around 45-50 hot. i use mobile 1 5w30 full syn and AC delco oil filter!
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Old Apr 15, 2013 | 10:22 PM
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Looks like you use decent oil & filter so no prob there.

If it goes away after warm-up, I wouldn't worry too much about it.

Your noise is called "piston slap". The cold pistons are moving slightly when they're at the bottom of the stroke. As the engine heats up, the piston skirts expand just enough to stop slapping.

This is perfectly normal for original LS1 engines.
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Old Apr 16, 2013 | 07:13 AM
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Possible bent pushrod or failing lifter...
Those usually do not go away after warming up, a bent pushrod or failed lifter is going to make a sound continually.

Given that it goes away with engine warming up it's most likely piston slap that goes away as the piston itself expands with heat.
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