What do you make of this odd rust?

[Una]

I popped the head off my '83 SC today, and found this oddity. It's a ring of rust, below where the rings should be running, it's only in one cylinder, and it was in an engine that had been run a minimum of 20 miles a day for over a year, about 20k miles since it was last parked for any period of time, and I had the head off that time that it was last parked, this rust wasn't there then. So how can this rust even be there? The engine was last driven yesterday, and started up and drove into the garage about 2 hours before I took this picture..

[turbovanman]

I am a little confused by your story but if I read it right, you had the had off for a while, then put it back on and drove it a few miles. If this is true, then what I assume happened is the bore rusted and the few miles you have driven it wasn't enough to scrape away the rust yet!

[russ jerome]

If you pull that slug you will probably find some rings that wont
go "pop" after leaving bores, just kinda lay in grooves of piston.

The piston is forced to one side or other (front/rear) as it travels
thru bore, we are looking at backside I am guessing right?

[macncheese]

ummmmm intake valve open with gas washing the oil off the cylinder wall and either water from the intake (how?) or a really humid day started some flash rusting. that's my guess, sherlock. of course, watson usually did miss something....
tony

[turbovanman]

Quote:

Originally Posted by russ jerome The piston is forced to one side or other (front/rear) as it travels thru bore, we are looking at backside I am guessing right?

Thats the side of the bore, hence why the rust is still there, needs a good beating to wear that rust off.

[Una]

Quote:

Originally Posted by turbovanman I am a little confused by your story but if I read it right, you had the had off for a while, then put it back on and drove it a few miles. If this is true, then what I assume happened is the bore rusted and the few miles you have driven it wasn't enough to scrape away the rust yet!

No. Completely wrong. I had the head off over a year and 20k miles ago. 2 hours after the engine ran last I was looking at this rust in the cylinder.
I'm goin with stuck rings, this engine had blowby like mad.

[Turbodave]

Maybe it's just my monitor, but that "rust" looks pretty day-glo orange to me, not like normal rust, plus it also looks like it wiped right off in a few spots. Is it possible that's not rust but some kind of other residue?

Out of curiousity, what kind of antifreeze are you using (dex-cool?), any octane booster or other fuel additives? Engine oil?

[Una]

There is a smudge in the middle of it where I rubbed it with my finger. It feels like rust, looks like rust. Was using normal old green anti-freeze, oil was pretty black from the blowby and not caring much about it for the past 4k miles or so since the engine was dieing. Oh, and just normal gas..
It's not a life or death question, just was surprised to see it in there. I wasn't planning on reusing the engine or anything, so it's not a big deal to me.

[mock_glh]

Quote:

Originally Posted by Una It's not a life or death question, just was surprised to see it in there. I wasn't planning on reusing the engine or anything, so it's not a big deal to me.

Then why are you wasting our time

[Una]

Intellectual advancement.

[PentastarTurbo]

That was one of those rare hybrid fuel setups When gas is too expensive, it runs on "Tang"

Ive seen that before.. possible flaw in the bore where its a slightly larger bore in that one section? Ive seen a few 350's like that..

[Una]

Fair guess, I'd buy that answer. That and the stuck rings sound plausible.

[turbovanman]

Quote:

Originally Posted by Una No. Completely wrong. I had the head off over a year and 20k miles ago. 2 hours after the engine ran last I was looking at this rust in the cylinder. I'm goin with stuck rings, this engine had blowby like mad.

Well then, write english, sheesh,

[Una]

I'm a mechanic, not a college professor.

[Ondonti]

Made sense to me.