Best way to reduce piston slap?
02-01-2008, 11:08 PM
#23
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A year ago, when I tore down my 6.0 after blowing the head gaskets, the oil pump pick-up screen was covered with white lint material. I know that much lint didn't come from rags upon assembly. 100% of the screen was covered with a solid, dense layer. The only thing I could figure was it came from the delco filter i used when breaking in. I cut open the filter and the material looked loose and fuzzy compared to other filters i've opened up before. The engine had 2000 miles on it. I try to always use Wix, and yes the Napa and Carquest filters are Wix.
02-02-2008, 04:56 AM
#24
Isn't the piston slap just caused from the use of Hypereutectic pistons? I have those in my blazer and it does the same thing.
my understanding of them has always been that they swell up when they get hot. so if you fit the piston just right for the cylinder it will end up being too tight once it gets warm. So you have to fit it a little small so that it ends up the right size at operating temperatures, which in turns causes slap at cooler temps.
If my knowledge of this is accurate then the only sure fire way to eliminate it is to go Forged.
it's not so much a gm problem as it is a physics problem. I'd imagine it's hard to calculate how much the pistons are going to expand considering the engines are going to be exposed to all types of weather conditions around the country. majority of the piston is aluminum. aluminum just expands more than steel at the ideal temperatures to operate an engine.
my understanding of them has always been that they swell up when they get hot. so if you fit the piston just right for the cylinder it will end up being too tight once it gets warm. So you have to fit it a little small so that it ends up the right size at operating temperatures, which in turns causes slap at cooler temps.
If my knowledge of this is accurate then the only sure fire way to eliminate it is to go Forged.
it's not so much a gm problem as it is a physics problem. I'd imagine it's hard to calculate how much the pistons are going to expand considering the engines are going to be exposed to all types of weather conditions around the country. majority of the piston is aluminum. aluminum just expands more than steel at the ideal temperatures to operate an engine.
Last edited by viciousknid; 02-02-2008 at 05:03 AM.
02-02-2008, 09:35 AM
#25
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Isn't the piston slap just caused from the use of Hypereutectic pistons? I have those in my blazer and it does the same thing.
my understanding of them has always been that they swell up when they get hot. so if you fit the piston just right for the cylinder it will end up being too tight once it gets warm. So you have to fit it a little small so that it ends up the right size at operating temperatures, which in turns causes slap at cooler temps.
If my knowledge of this is accurate then the only sure fire way to eliminate it is to go Forged.
it's not so much a gm problem as it is a physics problem. I'd imagine it's hard to calculate how much the pistons are going to expand considering the engines are going to be exposed to all types of weather conditions around the country. majority of the piston is aluminum. aluminum just expands more than steel at the ideal temperatures to operate an engine.
my understanding of them has always been that they swell up when they get hot. so if you fit the piston just right for the cylinder it will end up being too tight once it gets warm. So you have to fit it a little small so that it ends up the right size at operating temperatures, which in turns causes slap at cooler temps.
If my knowledge of this is accurate then the only sure fire way to eliminate it is to go Forged.
it's not so much a gm problem as it is a physics problem. I'd imagine it's hard to calculate how much the pistons are going to expand considering the engines are going to be exposed to all types of weather conditions around the country. majority of the piston is aluminum. aluminum just expands more than steel at the ideal temperatures to operate an engine.
02-02-2008, 10:21 AM
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No, Forget pistins will only be louder. It all has to do with heat and expansion. The high silicon content of the 4032 forget pistons allows for a tighter piston to bore clearance, but they will still be noisier than the factor mahle pistons. If you want a good turbo piston, the 2618 material would be your choice, but it has a much lower silicon content, which equalls a stronger piston that expands more, so they will be the loudest.
02-02-2008, 10:35 AM
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No, Forget pistins will only be louder. It all has to do with heat and expansion. The high silicon content of the 4032 forget pistons allows for a tighter piston to bore clearance, but they will still be noisier than the factor mahle pistons. If you want a good turbo piston, the 2618 material would be your choice, but it has a much lower silicon content, which equalls a stronger piston that expands more, so they will be the loudest.
02-02-2008, 04:57 PM
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Ya, I failed to mention the shorter skit issue as well. But bottom line, after market forged pistons, weather it be the 4032 metal or the 2618, will be louder.