why would this leak?

[Flint]

[After taking this head off i found number 1 head to cylinder was leaking and wondering what would cause it?[image][image]

[Amskeptic]

The most usual cause of leaking between head and cylinder barrel is the typical result of thousands of heating and cooling expansions/contractions. Etremely diligent engine assembly can reduce this. Cleanliness, beautifully cleaned stud threads and cylinder head nut threads correctly torqued and checked after an overnight "settling", and careful break-in during the intense heat generated by parts breaking in to each other, all will help. Any subsequent engine overheat event will relax the clamping forces and require a cylinder head re-torque. I would recommend a prophylactic retorque regardless after about 50,000 miles if you are doing much interstate driving.

[JLT]

The most usual cause of leaking between head and cylinder barrel is the typical result of thousands of heating and cooling expansions/contractions. Etremely diligent engine assembly can reduce this. Cleanliness, beautifully cleaned stud threads and cylinder head nut threads correctly torqued and checked after an overnight "settling", and careful break-in during the intense heat generated by parts breaking in to each other, all will help. Any subsequent engine overheat event will relax the clamping forces and require a cylinder head re-torque. I would recommend a prophylactic retorque regardless after about 50,000 miles if you are doing much interstate driving.

When I'm doing such a head re-torquing, I am working on only the four nuts that are exposed when you're taking the valve covers and valve rockers off, not the other four that are shrouded in the sheet metal. Should I be taking the engine out and removing the sheet metal to get at those upper four? Or would the lower four be enough?

[Amskeptic]

The most usual cause of leaking between head and cylinder barrel is the typical result of thousands of heating and cooling expansions/contractions. Etremely diligent engine assembly can reduce this. Cleanliness, beautifully cleaned stud threads and cylinder head nut threads correctly torqued and checked after an overnight "settling", and careful break-in during the intense heat generated by parts breaking in to each other, all will help. Any subsequent engine overheat event will relax the clamping forces and require a cylinder head re-torque. I would recommend a prophylactic retorque regardless after about 50,000 miles if you are doing much interstate driving.

When I'm doing such a head re-torquing, I am working on only the four nuts that are exposed when you're taking the valve covers and valve rockers off, not the other four that are shrouded in the sheet metal. Should I be taking the engine out and removing the sheet metal to get at those upper four? Or would the lower four be enough?

Take the engine out, retorque the heads, replace the oil cooler seals, check end play.
Colin

[JLT]

It sounds like a spring/summer project for me, but I guess you're right. While I'm there, I should also replace the muffler gaskets.