What's is this?

[MalMac 1,332]

Had to tear down a motor that I just had honed and put in a new piston and rings in. The motor had only 20min run time. Found this, looks like almost a blow by. Hoping it is because the rings have not seated yet. Had to tear it back down because of virbration (subject of another post made earlier). Was getting ready to put a different rod in, don't want to button it back up if somethings not right. First time I have had this happen.

[Shynon 7,482]

What did the bore measure? was it within specs? proper piston clearance? ring gap? rings staggered? could be assembly oil depending on how much you used.

[MalMac 1,332]

Everything was in spec. I was thinking it might be assembly oil because I am very liberal with it. I will probably button it back up and hope for the best. can't think of what else it could be. I am going to go over the rings again make sure one is not broke. I have rebuilt a few Kohlers and have never had this problem, but then again I have never had to tear one down right after putting it back together.

[oldredrider 2,553]

With only 20 minutes of run time, it's very likely it is just assembly oil. As it appears only above the ring line, that's my conclusion and wouldn't worry about it.

[boomers_influence 106]

malmac
in the pic. i do not see a crosshatch pattern.
thank you. boomer

[MalMac 1,332]

When I picked it up from the machine shop the pattern I thought was ever so slight. I think it could have been a better job.

[Fordiesel69 271]

Crosshatch looks fine.  That carbon is very normal.  These are super dirty engines.  Wait until 25 hrs and you will be mad.  They look old and worn!!!!!!

[WH nut 553]

Looks normal to me
With 20 minutes running the rings aren't seated and the area you are looking at is burnt oil because of the heat near the exhaust port due  to the rings not traveling in that area.

[rmaynard 16,343]

malmac
in the pic. i do not see a crosshatch pattern.
thank you. boomer

I agree. The "crosshatch" looks much too straight. A good crosshatch should have about a 45 degree angle and look like this. 


While you have it apart, I would at least ball-hone it to get a better pattern. Make sure that when you test fit the rings that you have the proper gaps. If they are chrome moly rings, it will take many hours for them to seat properly. Non-chrome rings are my choice because they seat much quicker. I even had a K-241 that I had bored to ,020 over. I had a lot of blow-by after several hours of running, so I replaced the rings with .030 over and cut the gaps wider so they would fit. The tractor with that engine was sold in 2011, and the owner reports no oil burning 4 years later.

[rick 257]

The machinist I use puts a shallower crosshatch angle at the top of the cylinder. I am not sure why, but he builds big block Pontiac engines for European customers, maybe he knows something we don't. My engines don't use oil after break in.

[pacer 3,177]

Since its a sharp dividing line at the top of the ring and thats a good indication - and, 20min isnt much to get a good impression - I'd go back together and put some more time on it.

[Horse46 519]

My deglaze hone call it what you will was like yours too, It seems everyone has a right way to do things.