I just pulled my heads and notice this. The motor runs good.

 

Looks pretty normal to me except for that on #4 cyl wall. What is it?

 

Dam your fast. Yeah I dont know what that is.

 

does it whipe off? Kinda looks like a oil and wate mixture.

 

No it doesn't. I tried to wipe it off, no luck. Its bumpy. It looks like a rust mark. How did that happen? Like if water sat there and it started to rust. I dont know, but that is what it looks and feels like.

 

I tried to see if the piston rings was sealing and they were. I put water in the cylinder and tried to see if the level went down with in 5 minutes and it held fine. Not the best way to test it but, it was the best way I could think of.

 

That engine obviously got some rain water in it at one time. You bought it used didn't you? You obviously weren't burning much oil from the looks of the chambers. I wouldn't worry about it. Run it!

 

Yeah! I think I will. Thanks again for chiming in.

 

Had something similar happen to a "C" model Cummins diesel. I made the mistake of storing it dry (no coolant) in a non climate controlled barn. Apparently, the cylinder walls will sweat due to humidity and temperature changes. The engine was locked up tight after about a two year sit. Pulled the injectors and sprayed a bunch of penetrating oil in each cylinder and eventually it broke loose. I ran it for about another 5000 hrs before excessive oil consumption necessitated a rebuild. When I pulled the pistons and liners, you could still see where each set of rings had rusted to the liners. Marks real similar to yours.

Your engine looks like it had a cylinder head gasket leak that let a little coolant into that one cylinder and it sat for a while. Not sure that I would put that engine back together as is. You might try pulling that piston and honing the cylinder wall. I don't know what your budget will stand. If your time is cheap, you can put a band aid on it and put it back together knowing that you'll be back in it before too long. If you want to button it up and not have to worry about it, you need to unearth some money from the back yard and fix it right.

 

I think the same thing happed to this motor. It was sitting for about two years, my buddy at work had it. I remember now, that it had this rust spot before. I dont remember it being this bad. It looks like its getting worst. I think I will just put it back together and push it harder untill it blows or starts sucking oil. Lets see If I can hit the 700hp 800tq mark. Maybe low 11's high 10's with some NOS, and then BOOM! I think I will just let her go in the battle feild. I just picked up some rod bolts, Patriot heads, shaft mount roller rockers , 60lbs injectors and cts-v roller lifters. I think I will throw these on and see what she will do get the tuning done and put another 5.3 in. These motors are strong. I am also going th400 or 4l80e. I can't figure out whitch one.