Block Fissure/hairline fracture

[Spacecrab]

So my recently rebuilt engine with replacement block seems to have a problem

Some tiny water droplets appear on the block wall between the distro and the head, too small to really show in photos but consistent enough to know there must be a fracture or pinhole

Has anyone else had this problem: if so what did you do?

We were thinking to test weld the old block to make sure a good weld is possible, then work some of the metal away and weld seal it shut

Any thoughts?

[Andrew]

I had similar problem, except the fissure was below the distributor mount. Ground a small V along the fissure, and tried to silver solder the V notch. Unfortunately the  fissure just extended longer. Eventually gave up, and used JB Weld over the entire repair. Have not run motor yet, but obviously hoping for success.

[Spacecrab]

Hadn't thought of that, when do you think you'll get to test it?

Let us know what results you get Andrew

Thanks,

[Rus Curtis]

Lots posted on cracks/welding etc.  I've not had any experience with welding but believe that with expanding/contracting from heat and pressure from the water jacket, it would be tough to get anything stuck on the outer surface to stay put. 

When you state replacement block, was it a donor or one of those new blocks being made now?  I've read that magnaflux is the way to identify cracks too small for the eye to see.

I'm sure the lurking welder's will add to this discussion soon.

[oldtime]

If you try to weld it make sure its 3/32" nickel rod and AC current.
Set your AC machine from 75 to 90 amps max.