Author Topic: light vertical scoring after rebuild? (Read 6021 times)

dillenger1 · « **on:** January 20, 2009, 07:33:35 pm »

I blew my HG so I pulled my head only to find some light vertical scratches in the walls in all 4 cylinders.Its uniform in all cylinders.This block was bored and worked by a shop.Its only got like 120 miles on it.theyre so light they dont catch a nail.What causes this?

Dakotakid · « **Reply #1 on:** January 20, 2009, 08:33:30 pm »

There is currently a discussion 3 blogs down from this one in this same category re: dry vs. lubed ring/cylinder installation. Is there a chance this is helpful here??
The banter ranges from oil to dry to adequate block laundering.

dillenger1 · « **Reply #2 on:** January 20, 2009, 08:59:36 pm »

nevermind,thats not what im talking.I did have a low oil episode for a short time,when i took it down the street (oil cooler line blew off)Its never been overheated.

boosted_diesel_84 · « **Reply #3 on:** January 20, 2009, 09:22:17 pm »

everytime ive seen scoring, its always been because of high temps, everything expands and has no where to go, so maybe if it was not properly bored and honed to the correct final size? possible it expanded and tore up the cylinder wall.

Rabbit TD · « **Reply #4 on:** January 20, 2009, 10:48:38 pm »

Quote from: "dillenger1"

I blew my HG so I pulled my head only to find some light vertical scratches in the walls in all 4 cylinders.Its uniform in all cylinders.This block was bored and worked by a shop.Its only got like 120 miles on it.theyre so light they dont catch a nail.What causes this?

I know that is irritating when you see those little lines but I think everybody has them to some extent and it could be just from the new rings moving in the piston grooves taking a flake off here and there till they find a good home. If you can't feel them at all I wouln't worry too much about it, usualy there is matching mark on the skirt of the piston too but if you can't feel them with your nail I don't think its a big deal. Obviously something gets between the skirt and the cyl as the mark is almost always on both at the same place. Hopefully you don't have any cracked rings though, but if it' in all four I think it's just microscopic break in particles. But it does piss you off when you see them and know you did everything right doesn't it?. Kind of like the first scratch on a new paint job, it's going to get one but nobody notices it but you. But how long did it run whn the oil line blew?

jtanguay · « **Reply #5 on:** January 20, 2009, 11:09:11 pm »

my 1Z TDI motor had them.. couldn't feel them with my finger though. they looked more like staining than anything...

dillenger1 · « **Reply #6 on:** January 21, 2009, 06:05:41 am »

it was ran for maybe a 1/4 mile with low oil(normal driving)It was just touching the bottom of the stick.I have a relocation kit and i was hoping there was still enough in the system to be ok.

arb · « **Reply #7 on:** January 21, 2009, 09:44:47 am »

Can you post a photo ? How far up the bore are they (if high, rings, if low, skirt / FOD)

When you installed the pistons, could you move them from side to side a slight amount or were they snug in the bore ?

Rabbit TD · « **Reply #8 on:** January 22, 2009, 02:33:39 am »

Quote from: "dillenger1"

it was ran for maybe a 1/4 mile with low oil(normal driving)It was just touching the bottom of the stick.I have a relocation kit and i was hoping there was still enough in the system to be ok.

Oh yeah, you would be okay oil wise if you only went that far and still showed some on the stick, the pump was still pumping oil

Smokey Eddy · « **Reply #9 on:** January 22, 2009, 03:28:06 am »

This is my only damaged cylinder.

that what you mean?
This was caused from driving with a ring that was broken for who knows how long. This scoring is barely noticeable with a finger nail. I would say it's not unless you were being extremely precise and careful with feeling it.

clbanman · « **Reply #10 on:** January 22, 2009, 06:22:29 am »

I always use a small stone to remove any burrs, sharp edges from the outer corners on the piston ring end gaps to prevent this. Also, fingernails are not always ideal, I find it easier to use the edge of a nickel.

dillenger1 · « **Reply #11 on:** January 22, 2009, 08:09:13 am »

thats what it looks like on all four maybe alittle less.The block was machined to bentely tolerences and i used kolbenschmidt pistons.Eddy you say the ring was broken?where?

arb · « **Reply #12 on:** January 22, 2009, 11:04:26 am »

Most of your scratches are from the top ring - notice where they stop. At least one of them looks like it was from installation. I would pull the piston if you have not already and inspect the rings. I would hone the bore and measure it to verify it is within specs.

Or, you could just run the engine until it doesn't start well or the oil consumption gets too high.

zukgod1 · « **Reply #13 on:** January 22, 2009, 11:36:44 am »

That pic is Ed's engine not dillenger1.

I wouldn't worry about it at all man, I bet if you pulled the head again )hope you don't need to) after say 8k you wont be able see them.

Reassemble and run it.

dillenger1 · « **Reply #14 on:** January 22, 2009, 03:37:21 pm »

Thanks dan!i needed that reassurance.Its just frustrating paying 350 dollars for machine work and seeing this.i even had the bores individualy punched for each piston,call me crazy

Weird it never overheated,the head is flat and true.It was burning the coolant though.Maybe it did get a little hot.maybe there was no coolant in the upper rad. hose (where my sender is) giving me a normal temp.

Author Topic: light vertical scoring after rebuild? (Read 6021 times)

arb

arb