Cylinder wall scuffing, how deep is too deep that a 3.905 resize cant cure?
11-21-2010, 02:49 AM
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Cylinder wall scuffing, how deep is too deep that a 3.905 resize cant cure? I have a Ls1 block i want to get bore/honed for the 3.905 size in hopes to remove some cylinder wall scuffing from the pistons. You can feel them when you run your finger nail across them, but it wont snag your nail. They are fairly light, i can try to get some pics. The cylinder wall area above the rings (combustion side) on all 8 are fine, the cross hatching is still showing. Its when you look at the bottom of the cylinder walls through the bottom of the engine. Its only a few of them too, maybe 3 of 8. As if the piston's skirts were slapping them causing the scuffing. kinda wierd. Just trying to figure out if this block is junk or not basically. Thanks!
11-21-2010, 07:20 AM
#2
.005" inch piston to wall clearance is the upper limit for most pistons. In fact if you have hypereutectic pistons or higher silicon content pistons the piston wall clearance can be lowered down to .003" or even a bit less. If you get up over .008" piston to cylinder wall clearance, you can substantially rock the pistons in the hole, just hit it with the bottom of your fist on each side and it will rock. This doesn't mean you can't run it, it just won't be quiet.
Also why are the skirts scratching the cylinder walls, I would look into that further.
Also why are the skirts scratching the cylinder walls, I would look into that further.
11-21-2010, 09:51 AM
#3
I have a Ls1 block i want to get bore/honed for the 3.905 size in hopes to remove some cylinder wall scuffing from the pistons. You can feel them when you run your finger nail across them, but it wont snag your nail. They are fairly light, i can try to get some pics. The cylinder wall area above the rings (combustion side) on all 8 are fine, the cross hatching is still showing. Its when you look at the bottom of the cylinder walls through the bottom of the engine. Its only a few of them too, maybe 3 of 8. As if the piston's skirts were slapping them causing the scuffing. kinda wierd. Just trying to figure out if this block is junk or not basically. Thanks!
To answer the 3.905" question; yes, it can be honed & then the pistons replaced w/ 3.905" pistons.
Now, if it were mine, I'd take some 1200-1500 grit paper & lightly rub the scratches just to smooth the edges (lube the paper w/WD-40). Next, I'd gently clean up the skirts on the pistons w/ some 800 grit paper; again, basically to knock down the edges of the scratches. Add some new rings & bearings & then run it for another 200K miles.
11-21-2010, 01:10 PM
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.005" inch piston to wall clearance is the upper limit for most pistons. In fact if you have hypereutectic pistons or higher silicon content pistons the piston wall clearance can be lowered down to .003" or even a bit less. If you get up over .008" piston to cylinder wall clearance, you can substantially rock the pistons in the hole, just hit it with the bottom of your fist on each side and it will rock. This doesn't mean you can't run it, it just won't be quiet.
Also why are the skirts scratching the cylinder walls, I would look into that further.
Also why are the skirts scratching the cylinder walls, I would look into that further.
To answer the 3.905" question; yes, it can be honed & then the pistons replaced w/ 3.905" pistons.
Now, if it were mine, I'd take some 1200-1500 grit paper & lightly rub the scratches just to smooth the edges (lube the paper w/WD-40). Next, I'd gently clean up the skirts on the pistons w/ some 800 grit paper; again, basically to knock down the edges of the scratches. Add some new rings & bearings & then run it for another 200K miles.
Now, if it were mine, I'd take some 1200-1500 grit paper & lightly rub the scratches just to smooth the edges (lube the paper w/WD-40). Next, I'd gently clean up the skirts on the pistons w/ some 800 grit paper; again, basically to knock down the edges of the scratches. Add some new rings & bearings & then run it for another 200K miles.
11-21-2010, 04:21 PM
#5
Originally Posted by Hi Volume
;heh this has crossed my mind as well. Maybe il do that today.
11-21-2010, 05:28 PM
#6
To answer the 3.905" question; yes, it can be honed & then the pistons replaced w/ 3.905" pistons.
Now, if it were mine, I'd take some 1200-1500 grit paper & lightly rub the scratches just to smooth the edges (lube the paper w/WD-40). Next, I'd gently clean up the skirts on the pistons w/ some 800 grit paper; again, basically to knock down the edges of the scratches. Add some new rings & bearings & then run it for another 200K miles.
Now, if it were mine, I'd take some 1200-1500 grit paper & lightly rub the scratches just to smooth the edges (lube the paper w/WD-40). Next, I'd gently clean up the skirts on the pistons w/ some 800 grit paper; again, basically to knock down the edges of the scratches. Add some new rings & bearings & then run it for another 200K miles.
BEE sure to check ALL the piston sizes against the bore sizes to see where you are, especially the scuffed ones. You maybe able to move some around to get a better fit overall.
11-21-2010, 07:17 PM
#7
Yer a fart smeller! Excellent advice but don't forget to tell um to reuse the factory head bolts too!
BEE sure to check ALL the piston sizes against the bore sizes to see where you are, especially the scuffed ones. You maybe able to move some around to get a better fit overall.
BEE sure to check ALL the piston sizes against the bore sizes to see where you are, especially the scuffed ones. You maybe able to move some around to get a better fit overall.
How 'bout posting what you have to offer in the thread without the mouth... Now, where did I put the lighter used to light those farts. I do hate to waste the good ones.
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11-21-2010, 09:49 PM
#9
11-22-2010, 03:42 PM
#11
That was a compliment? Wow, my bad. I completely miss-interpreted it because of the "re-use factory bolt" comment, because that's a no no. Anyway, guess, I'm the one who needs things explained s-l-o-w-l-y to
. Please accept my apology. 
12-05-2018, 10:24 PM
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I’ve been looking everywhere and can’t locate the stock ls2 spec for piston to cylinder wall clearance I would assume it’s something close to your posted numbers?
.005" inch piston to wall clearance is the upper limit for most pistons. In fact if you have hypereutectic pistons or higher silicon content pistons the piston wall clearance can be lowered down to .003" or even a bit less. If you get up over .008" piston to cylinder wall clearance, you can substantially rock the pistons in the hole, just hit it with the bottom of your fist on each side and it will rock. This doesn't mean you can't run it, it just won't be quiet.
Also why are the skirts scratching the cylinder walls, I would look into that further.
Also why are the skirts scratching the cylinder walls, I would look into that further.
12-05-2018, 10:59 PM
#16
TECH Senior Member
heykw- Call WS6store and they would tell you what you want to know. No sense posting in about 6 OLD threads for the same answer.
