Never seen this before?

[DieselSlug]

Long story short I had my '94 Lightning Roller Block bored 0.030 over and had flat tops installed about 1.5 years ago. Builder and I split ways on rough terms after several missed deadlines and blowing off meetings. Got the engine back supposedly finished, however valve train setup was horrid.

I hit a busy time in my life and the engine sat in my basement for this whole time. Tore the engine to the short block to inspect work and found a discoloration in one of the cylinders.

Has anyone ever seen this?? I want to know if this is ok to run? The wall feels smooth all the way down. This is the only cylinder with it.

This build cost me approximately $3,000...

I unfortunately cant say this was not here before the bore, but I don't remember it at all. I've had this engine apart 2-3x before this.

 

[schiker]

See if it will clean off. A little oil and scotch bright or other. Doesn't look like much to me more a stain.

 

[NVW]

x2

 

[DieselSlug]

I do have a piece at home, will gently try tonight.

 

[ak diesel driver]

looks like its been sitting

 

[DieselSlug]

Scrubbed an edge of it very lightly and some did come off. Looks like a stain of some type.

 

[schiker]

Good. I tore down an engine once and the backside of bearings had a weird dis coloring that worried me too. It looked like fretting but was a stain that polished off.

You can get anal about things but really lots of stuff can be rougher/uglier than you would imagine.

 

[JayTheCPA]

The stain's color kind of looks like you were 'moused'.

 

[Burning oil]

I'd be more worried about the groove by the piston. Whats that?

 

[DieselSlug]

I'd be more worried about the groove by the piston. Whats that?

Your talking about the area of dark gray color that looks like a "coin slot" right?

This is the area I am referring too. Its basically a discoloration, the slug wall is smooth all the way down. If you run your finger over this discoloration with your eyes closed you would never know it was there.

 

[Burning oil]

Yes. if thats not of concern then the rat piss stain is nothing.

 

[schiker]

I am guessing that was some magic marker he swiped the cylinders with to hone out and may have thought about doing another pass and didn't. Or might have marked cylinders somehow. Looks too good to be a machining mark.

I have seen grinders use markers a lot to color something and touch off by removing the ink.

 

[Will L.]

Umm, that is a sharpie mark. You do that BEFORE you use your hone for the 60 degree cross hatching that YOU DO NOT HAVE!

But you do it without the piston in place and never go more than it takes to fade the mark- not remove it. Then you clean the entire cylinder with acetone or something similar.

What do the other cylinders look like? Any cross hatch on those and he forgot to do this one?

The little bitty mark at the top idk never seen that before.

 

[DieselSlug]

Umm, that is a sharpie mark. You do that BEFORE you use your hone for the 60 degree cross hatching that YOU DO NOT HAVE!

But you do it without the piston in place and never go more than it takes to fade the mark- not remove it. Then you clean the entire cylinder with acetone or something similar.

What do the other cylinders look like? Any cross hatch on those and he forgot to do this one?

The little bitty mark at the top idk never seen that before.

Not sure on the hatching of the other cylinders, but this is the only one with the mark. The little mark up top is a little bit of standing oil.

 

[Will L.]

No like, seriously you should have 60 degree crosshatches in the cylinders to seat your rings when new and help stop blowby or cylinder leak down through the life of the engine.
Basic engine building 101.

The stains are nothing to worry about.

 

[schiker]

I agree. I see some honing marks but he might have wanted to go again but didn't or something.

Honing also takes out residual stresses of the bore machining depending on how they do it.

 

[Will L.]

This is what you're looking for.

 

[DieselSlug]

Hmm,

I didn't get a chance to look at all the others last night. I will tonight.