61x cylinder cracks

[mybad]

Found 2 small hairline cracks in top of cylinder surface as seen below. Thought I had a head gasket leak. Now I think Im completely licoriceed. Im assuming under pressure and heat these will become major issues. Right now they are just showing at top surface of cylinder. But I am thinking it is all the way down. Any input?

 

[Blue]

Are u sure there cracks? Are you getting water in cyl? I can see them in the picture but cant tell if there cracks or machining marks from truing the top of the cylinder.

 

[Blue]

I see the lines on both cylinders which looks more like a machining mark.

 

[OCD Solutions]

I'm with Blue, the one groove follows through the sleeve and into the cylinder which a crack would not do. Looks like a tooling mark to me.

 

[Blue]

Plus i dont see the aluminum cracking outside the sleeve. Im curious if it was running bad as its burning really good.

 

[mybad]

Its a Group K hammer package. Porting, 195 psi, ignition, carb boring. Hauls ass. Yes, It ran awesome until last weekend when top end started going. I thought it was leaking at the head gasket and getting water into cylinders. Water was in front cylinder. When I took apart I a$umed the marks were cracks. But like I said they only show on top surface. I hope your right....it makes sense now. Hopefully from machine work. Ill just install new gasket and let it rip. Thanks for helping.

 

[OCD Solutions]

I'd try and fill those cracks with something a little more solid than gasket sealer just to rule them out as the starting point for future gasket erosion.

 

[mybad]

Thanks

 

[mybad]

Update. Rode it all day. Back to full power. Guess the head was leaking. Torqued the head to 20 ftlbs. After the ride I retorqued the head. Amazjng how much the OEM gasket will crush after a couple heat cycles. Group K mentioned to me this step is critical. They are right on. Another interesting find was that the blow head gasket was allowing me 195 psi compression.

 

[CRJ]

With cast sleeves, cracks almost always run down the length of the sleeve, no matter how small. At least its not that case here!

 

[Blue]

Glad to hear it was nothing serious.