I pulled a motor with my dad's help this past weekend. The intention is to tear it down, rebuild it, and yank the E36 M3ty, oil-drinking, head-gasket eating piece of garbage motor out of my sister's car (also a Saturn), swapping the good one in. I didn't really care what the condition of the engine we pulled was, unless there was a hole in the block, we're going to rebuild it anyhow. But that I wasn't expecting missing metal from a piston! I guess there was a good reason an otherwise solid-looking car was in the junkyard with only 116K miles on it.
I wish I had a picture. There is a chunk about two toothpick-widths wide and one deep from the top of the piston clear through to the first compression ring channel, and then the first ring land has an equivalent chunk missing. The top compression ring, which straddled this carnage, was somehow unharmed. The cylinder hone crosshatch also has a noticeable straight line in it, though it's not scored very deep as far as I can tell.
Ideas as to what caused this? Just curious 
If the hole/damage looks like a miature explosion, detonation is highly suspect. The explosion blasts off metal pretty much like dynamite would sitting on the piston.
If it's through to the crankcase, it will often look like a cutting torch did it, because that's what happened once the hole was created.
If it looks like a cold chisel mark or such, mechanical damage is the likely culprit. And a broken sparkplug would be my #1 suspect. But other things do get dropped down inside engines.
Not to threadjack but I gotsta post these:
These were from a customers Eagle Talon. He said I was trying to sell him unecessary repairs because "my timing belt is fine". A few weeks (maybe months) later he came in and this is what I found. Sweeeeeeet!!
In reply to DrBoost:
No, that is very obviously the work of Fuelmites. You can clearly see the little teeth marks.
Snrub
New Reader
7/2/10 9:22 a.m.
My god, those are insane pictures!
EDIT: Seems the pics aren't working. Click this link to see the carnage:
http://www.mx6.com/forums/1g-mx6-general/135475-new-car-15.html#post2308911
Heh... i can top that.
There USED to be a piston here:
Oh my. That's not gone well.
Poor little spark plug. You will be missed.
Is it bad when you pull your oil dipstick and it looks like this?
Marty! wrote:
In reply to 93celicaGT2:
It's scary how small the issue was that caused that.... Rebuilt head, ONE valve guide was slightly too tight.
Also scary: Losing a piston. LITERALLY.
And the fact that the rod managed to bust a hole in BOTH sides of the bore, in a cast iron block. DANG.
I'm keeping those pistons forever. I'll find a way to put them into a car-themed room one day.
I'm pointing at your problem:
This is BatVan's #3. Oy.
Sucked a valve that bounced around, peckered things up and cracked off a lot of everything above the top ring.
A picture would help reconstruct the incident and determine the initial failure.
Wow, much carnage. I wish I could find it on teh int3erw3b: I saw a picture of a spark plug with a nail jammed into it. The backstory was the owner had lost the air cleaner wing nut so he jammed a nail between the air cleaner lid hole and the stud, with predictable results. It seems the s-plug was removed, a new one installed, and our hero drove off into the sunset.
