Cracked block or scratch?

[FarmallAddict]

Head gasket leaked so took the head off to clean and try again. Saw this mark on the block while cleaning. I can't afford a new block. Is this cub engine toast? Is it even a crack or just a Mark? Can I patch it?

I can feel it slightly with my fingernail. No crack in the cylinder wall that I can see it feel with my fingernail. It doesn't appear to come out anywhere on the outside.

[Eugene]

Lightly hone the cylinder and take a hand wire brush to the "crack". Check for a crack. Also check the outside of the block, same general area.

Earlier you mentioned a coolant seep from the head/gasket. Where did the seep occur? Same area as the "crack"?

[FarmallAddict]

To be clear, the head gasket was not leaking at the spot of the crack. No crack I can feel in the cylinder wall. It was leaking in front of two of the head bolts.

[FarmallAddict]

Lightly hone the cylinder and take a hand wire brush to the "crack". Check for a crack. Also check the outside of the block, same general area.

Earlier you mentioned a coolant seep from the head/gasket. Where did the seep occur? Same area as the "crack"?

Still no crack I can see or feel in the cylinder. Nothing at all on the outside of the block. It almost seems like an imperfection in the casting.

[tst]

I would put a new head gasket on it, seal the bolts and head gasket, even if it gives you problems it is only the price of a head gasket to find out

[FarmallAddict]

Should I try to fill the imperfection? I plan to use permatex copper spray on the gasket along with a small amount of nonhardening sealant in the headbolt threads. I have some JB Weld but I think that might be asking for trouble if I use that on the block. I can see that going very wrong, especially on the machined surface.

[tst]

I would just do 3-4 coats of the copper spay, I like putting the gasket on when its still tacky

[FarmallAddict]

I would just do 3-4 coats of the copper spay, I like putting the gasket on when its still tacky

I'll give it a shot. Thanks for the assistance.

[ricky racer]

If you can take the block or the tractor, to a machine shop and ask them to use a Spotcheck dye penetrant test. It only takes a few minutes and they may do a small job for you for little to no money. That way you'll know if it's a crack or a scratch for sure. Most any machine shop or engine shop can do the check for you.

https://www.youtube.com/watch?v=UtJTkrgvt2c

[BigBill]

I’d pull the engine and get the block decked first at least .010” to see if the crack or scratch disappears.

[Jim Becker]

It is hard for anyone to say with certainty, particularly if you only see a picture. My call is that it is nothing. Even though this isn't the reason, your head gasket leaked for SOME reason. I would check the head with a straight edge and have it corrected if there is a problem. Otherwise, I would reinstall the head using whatever your favorite gasket sealer is. Install the head bolts using your preferred sealer/lube on ALL head bolts. Be sure to torque the bolts in steps and in sequence. Be very fussy when torqueing the bolts down.

[Jim Reid]

Could you not put a small amount of permatex at each end of the crack then put water in the crack or imperfection and see if the water dissappears.

[SONNY]

Just looks like a minor scratch in the pic.. I have just put sealer on head gaskets over some nasty scratches and they never leaked.
As long as it is not leaking water into the oil you will be fine.

[FarmallAddict]

Just an update. After looking very closely at the defect I think it is just a scratch so I decided to put a new gasket on and see what happens. When I first saw the mark it scared the heck out me. The head and gasket went on yesterday with a good coating of copper spray and we are waiting at least 24 hours for the sealant to dry before adding coolant and trying to start it. When we took the old head bolts out we found there was no sealant used when it was reassembled the first time. This time we used light amounts of a non hardening thread sealant on each new bolt. We chased all the threads as well and the new bolts went in very smoothly. I'm praying this works.

[tst]

You want to retorque the head bolts after it warms up