Ls1 piston slap noise
Ls1 piston slap noise 
12-04-2016, 09:54 AM
#5
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Engine treatment ,I believe, have to check when I return to Garage. Will let you know if I told you wrong information. Turns out tick,tap,rap,slap is still there but on cold start only , doesn't return after up to full temperature like it did before
12-04-2016, 10:55 AM
#7
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You probably had a sticky lifter, the engine cleaner cleaned it out and now it works properly. The noise at cold startup could be piston slap (which is normal) or could be the lifters before they fill with oil, because they bleed out quickly (which is normal).
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12-04-2016, 04:16 PM
#8
No actually what he was hearing is carbon build up on the tops of the pistons. When the engine is cold it shrinks enough for the built up carbon on the piston tops to make contact with the heads. Once the engine gets hot it expands enough and the noise is gone.
The cleaner removed the carbon and the noise stops.........for now.
The cleaner removed the carbon and the noise stops.........for now.
12-05-2016, 05:51 AM
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Still there on cold start, doesn't increase in intensity with increased in RPM, actually goes away with increased RPM. Still hard start on cold start. Going to replace fuel filter, if doesn't cure guess I will have to cut access in floor board to get to fuel pump n
12-07-2016, 11:29 AM
#10
It's my understanding that the long time accepted reason for cold start piston slap in LS engines is the piston rocks in the bore at BDC when the rod swings from one side of the crank throw to the other.
As the piston warms up to operating temperature, it expands enough to reduce the rocking eliminating the sound.
I doubt any oil or oil additive can cure it. Coated piston skirts help.
As the piston warms up to operating temperature, it expands enough to reduce the rocking eliminating the sound.
I doubt any oil or oil additive can cure it. Coated piston skirts help.
