Can you tell anything from this piston

mbalbritton

mbalbritton

#@$%!
Joined
Mar 22, 2005
Location
Lakeland, FL
Not sure if it’s a tell tail sign of what the issue is, but I pulled the #5 piston on my 258 and noticed that the carbon build up was not even around the piston. 1/4-1/3 of it was clear of carbon build up and looked like it was rubbed.

The cylinder looks fine, but I’m wondering if this is a sign of piston slap? And yes, I pulled the rings off before the picture.
IMG_0481.jpeg
IMG_0482.jpeg
 
Yes does look like piston slap. Could have been caused by wrist pins, worn rod, thrust washer, oval cylinder, could also be bad head gasket that washing that side of the piston, but it does look like it was rubbing that side.
 
upnover said:
Yes does look like piston slap. Could have been caused by wrist pins, worn rod, thrust washer, oval cylinder, could also be bad head gasket that washing that side of the piston, but it does look like it was rubbing that side.
Click to expand...
Head gasket… interesting.

Why do I say interesting, you ask. In doing my best impression of a palm reading gypsy looking at the head gasket, I noticed back around 4,5&6 the area between cylinders was darker and when I pulled the head bolt next to 5, it had a lot of oil in it the hole.
If that tells anything.

There wasn’t a lot of carbon build up on any of the pistons or combustion chambers. I thought it all looked pretty good.
 
I'd also, before attempting to put the head back on, have it magnafluxed, not just the cylinder side, but pull the valve assembly, and have the top tested too. I'm not sure if there are any blind head bold holes, but that oil could be from the head being cracked around that bolt hole, leaking oil from the top of the head into that part of the head. A magnaflux test will show this up. Also (not sure how much of the engines history you know of) check the head for flatness, in case it had been run hot. Any idea of how many miles on the engine?, Reman? any heating issues, or other noises? Piston slap usually shows it face in a cold engine, that is until the piston skirt cracks and spreads, then it's sounds a lot like a rod knock.
 
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