piston slap
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piston slap
I know much has been written about piston slap and I was thinking it was only Ford's problem. I talked to a fellow the other day while I was out of town and he has a Chevy pickup with a large decal in back that says GM owners beware. Then the web link...WWW.Pistonslap.com.
Don't know if this URL has been posted here before, but it's worth a look. In a weird kind of way it makes me feel better that we're not aone!!
Mike
Don't know if this URL has been posted here before, but it's worth a look. In a weird kind of way it makes me feel better that we're not aone!!
Mike
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From: Massachusetts
GM engine have battled piston slap for 20 or 30 years. Thier newest V8, the 6.0L is disgusting how it sounds at start up. It does not go away as quick as the V10 does. It is scary how loud and harsh it sounds. Trust me...I know I traded in a 2001 2500HD about a year ago because of it. Not to mention it kept throwing belts.....dropped a voltage regulator.....tail shaft of tranny leaked....just a big piece of crap. I drove Chevy/GMC's for 20 years.......had enough of them....so here I am a proud Ford Super Duty owner...and that first cold morning....slap slap slap oh no.....piston slap....fustrating that todays engineers cannot design a engine with the proper size piston and cylinders. But I have got good news...Amsoil 5W-20 fully synthetic has helped greatly with piston slap.....It is virtually gone....once in a great while on the coldest New England morning I might get a peep out of it.
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From: Long Island USA
There has been a big discussion about OHC vs pushrods in another forum here, and someone posted this:
http://support.adams.com/kb/faq.asp?ID=kb9359.dasp
It seems Ford has known about for a long time, and some ingenious engineers figured out how to computer-model the problem and somewhat accurately predict what the sound level would be. At the end of the above presentation, they still had not gone back and pulled apart the motors to measure everything and come up with a solution.
Key part, cold soaking the motor at 32 degrees F.
It's a complicated thing, and even in the last few years, few computer models exist of the entire range of motion of a piston related to bore clearance, temp, speed, etc. What makes it worse is the blocks are getting thinner, and sound is more easily transmitted to the outside.
http://support.adams.com/kb/faq.asp?ID=kb9359.dasp
It seems Ford has known about for a long time, and some ingenious engineers figured out how to computer-model the problem and somewhat accurately predict what the sound level would be. At the end of the above presentation, they still had not gone back and pulled apart the motors to measure everything and come up with a solution.
Key part, cold soaking the motor at 32 degrees F.
It's a complicated thing, and even in the last few years, few computer models exist of the entire range of motion of a piston related to bore clearance, temp, speed, etc. What makes it worse is the blocks are getting thinner, and sound is more easily transmitted to the outside.
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Does the v-10 have a mylar coating on the pistons? I was told this would reduce the noise. My T/A 2002 LS1 sounds like a diesel and uses about 1 quart every 1700 mi. My 03 F250 6.8 runs and sounds great. I dont know.. It just dosent seem right to be consuming oil too much. I think its just poor quality in the tolerances. They both run great and dont blow any smoke but who knows how they will be after 100k or so. 
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Originally posted by mooseknuckle
Does the v-10 have a mylar coating on the pistons? I was told this would reduce the noise. My T/A 2002 LS1 sounds like a diesel and uses about 1 quart every 1700 mi. My 03 F250 6.8 runs and sounds great. I dont know.. It just dosent seem right to be consuming oil too much. I think its just poor quality in the tolerances. They both run great and dont blow any smoke but who knows how they will be after 100k or so.
Does the v-10 have a mylar coating on the pistons? I was told this would reduce the noise. My T/A 2002 LS1 sounds like a diesel and uses about 1 quart every 1700 mi. My 03 F250 6.8 runs and sounds great. I dont know.. It just dosent seem right to be consuming oil too much. I think its just poor quality in the tolerances. They both run great and dont blow any smoke but who knows how they will be after 100k or so.
I think the piston slap is not there in certain motors because they are at the low-end of the piston-to-bore clearance. You may be one of the lucky ones to have a block that was done with a worn cutter and is in the low end of the piston clearance. Like me, I have no piston-slap, even though I have heard of it in 4.6L's and up.
Usually high piston-to-bore clearances are for high-revving high-perf motors. My machinist for my FE 390 said that high-clearance motors would certainly show a lot of piston-slap until they are fully warm. The Chevy 6000, I can understand, it's a "perf" motor - Ford truck motors, well, I can't see them screwing it up that much, unless they over-estimated the clearance needed at cold starts.
Three modulars, bought new, two 96/97 4.6L's and now a '01 V10, no piston slap, although it sounded a little loud on a 2 degree F cold-start.
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Thats what I understood also, they are put togather a little loose to get the hp rating out. i will try to find some pics of the mylar coating iam referring to. They look like two pieces of black tape on each side of the piston. My v-10 sounds tight but we dont get the low temps here in tampa like elsewhere. I can see how the spec's could change in cold weather. and slap until she's warmed up.
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