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I bought a fully disassembled l31 vortec motor and I'm in the process of building it. None of the pistons/rods were marked. I cleaned and honed the block. It is all standard spec. The first piston I installed (#2 cylinder) has the rod chamfer on the big end facing the radiused crank side and the notch on the piston top is facing the front of the block. Upon spinning the crank, I heard a squeaking sound in the bore and I see that there are some vertical striations forming. You can't feel them with your fingernail, but you wouldn't want to run it that way. Does it matter that the pistons aren't going in the original bores (with all new bearings and rings)? Could the skirts be making contact? I'm at a loss. All the disassembled parts looked perfect. The striations are at the top of the cylinder/block.
Looks like it was just ball honed maybe? Actually looks more like a 3 stone hone.
My guess is those marks were there before the honing and you're just seeing them since the rings are contacting the "high" spots. If you can't feel them...I wouldn't worry. If it's just a quicky rebuild I wouldn't worry much even if you could feel them.
If nothing is marked, you don't have any choice but to do what you're doing. Just keep paying attention to which way rod and pistons face.
JIM
Last edited by 427Hotrod; Aug 21, 2016 at 01:17 AM.
It was a 3 stone hone. The marks were definitely not there in the honing process, but if they were, how can the metal on metal squeaking be explained when the piston passes that section of the cylinder? This is definitely a quickie rebuild, however, I have rebuilt many engines and I have never heard this squeak and seen these marks in a rebuild, especially after turning it over by hand a couple of times.
Did you check ring end gaps? I have seen that with a tight ring and once where the oil ring dislodged when it went though the ring compressor and caught the deck.
I would suggest that even tho This is a quickie, since there is no clue as to what goes where, you are going to have to do some basic measuring. Ring end gaps in 3 places, piston to cylinder wall clearance, ring to piston clearance, after you clean the grooves. It's hard enough to get things right sometimes if they go back where they came from, and no telling if for some reason one or two holes was .001 or .002 off from the others.
The honing marks look perpendicular to the stroke. Like the hone wasn't moved in and out very fast or not at all? That could cause the rings to chatter as they go down the bore. Was the bore taper measured?
Trying to avoid about engine building disaster
