Can someone tell what this is. "Pics inside"

[Steve885]

When I was cleaning the block I noticed these lines in the cylinder walls when u rub you finger over them there is no difference in smoothness( strange

 

[fuel]

doesn't look good! that is a portion of the bore/crosshatch honing marks which have been worn away due to a few possibilities like overheated pistons, cracked ring-lands and/or cracked rings, debris/carbon stuck between piston skirt/crown and cylinder walls.

Either way I would be checking the bore dimensions to check if the bore is still round and within spec otherwise you'll need to bore it one size over and fit oversized pistons/rings.

 

[Fiascoxl]

If those walls look like that then the skirts on the pistons are also gonna be worn down pretty badly. That engine needs to be pulled and checked, my guess is it is gonna need a bore not just a hone.

 

[MellowVR4]

This is exactly the way one of my cylinder walls where on my GGSX when I removed my head, but compression is still at 150+ on that cylinder, plus the engine has 148k /ubbthreads/images/graemlins/dunno.gif im sure in the future ill do a rebuild because i know it might need it. But for now, its good

 

[Wizardawd]

Usually I have seen those marks from overheating. But if everything checks out in spec, it'll still run fine.

Wiz

 

[MellowVR4]

I just asked a tech here at work, and he said those scratches are usually caused from piston slap /ubbthreads/images/graemlins/dunno.gif

 

[Wizardawd]

Not sure how a slap would drag up and down the cylinder. Not to mention, it's all the way to the top which is beyond the piston's contact area. Again, more than likely just over time the different expansion rates of the metals causes some out of roundness. This is accelerated greatly during overheating.

Wiz

 

[MellowVR4]

You may be right

 

[GSX_TC]

The Wiz has spoken.

 

[FlyingEagle]

Is it just me. The pistons rock front to back, back to front of the block, not side to side inline with the wrist pins. Slap at the skirts should be one the back and front walls. /ubbthreads/images/graemlins/dunno.gif
I could see pistons getting hot causing unusual contact, as the top of the piston head is the only thing travelling up that far.

 

[Steve885]

U know Thinking back when I first took off the tranny all the flywheel bolt were loose and I could move the flywheel around with my hand I wonder if it was slightly moving the crank side to side when engaging the clutch..

 

[EHmotorsports]

Excessive thrust clearance has caused issues like that before.

 

[prove_it]

Beat me too it. If your getting wear like this on the sides of the cylinder then you have excessive thrust bearing wear. Think crankwalk. If the lines were on the load sides of the cylinders its a bit more normal if your running bigger power. The sides though, bad bearings. Better check the rods and see if they have excessive side wear and also on the crank.

Pending on the condition of the cylinder, ie taper, out of round and surface quality sometimes a good hone can clean it out. If you can't catch it with a nail you MIGHT be ok. If your making stock power, you don't have to have a perfect engine to be ok. It could get by. Otherwise any mods and you'll want it done right.

 

[misterfixit]

The shininess is the piston rubbing in that area for any of the reasons stated above. Shiny bit is usually ally being deposited or filling the hone surface ( think sandpaper loading up.)

i'd open her up just to see what the pistons. look like. As has been mentioned, you may be able to dress it all out and be in spec, but best tear into it to be sure.

Rich

 

[mitsuturbo]

I'd have to say that may be attributed to crankwalk or excessive crankshaft endplay. That is most certainly NOT possible due to "piston slap", as the skirt of the piston is unable to contact that part of the cylinder wall.