DOn't weld the block -

It's cast iron and to weld in correctly without stressing the surrounding metal requires heating that area to about 600F.

I have succesfully repaired a frozen block crack by drilling a small 3/16" hole at either end of the crack - this stops migration of the crack due to thermal stresses. The grind the crack spotless and use Marine Tex epoxy.

I repaired a hole in an 7.5hp outboard engine cylinder wall that had occured when sailt water was allowed to sit in the engine for 2 years. I honed the wall - set the piston and fired the engine and ran it for 2 hours. Marine Tex is good stuff and I'm sure there are other super strong epoxies out there specifically developed for steel or cast iron.

 

Freeze plugs usually will not bottom out - I set them about 1/16" deep of the block - And a liberal coating of sealant.

 

That's a wierd one. Seems like it would be a casting problem not freeze problem. But I froze my 327 small block i my boat and all the freeze out plugs were tight. Maybe too tight?

 

I could stop drill one end, but the other end terminates under the freeze plug. How would I seal that end and still allow the plug to seal properly?

 

how many miles on your psd? can you take some pics for us please?

 

136,000. It's about 1/3 the size of the one jimkidd posted in OBS. Starts down in the freeze plug bore below the plug and runs back about 2" behind the plug in the side of the block.

 

Let me see if I have the crack direction correct.

The crack is from the front of the block through the freeze out plug hole and into the rear of the block. I.e. along the freeze out wall, and the entire thickness of the block?

To stop the migration any further away from the freeze out plug, I would drill the hole at the end of the crack. By increasing the surface area of the crack at the end of it there is less chance of stress developing further into the block.

I would would fill that hole with epoxy and either grind or file a V groove into the crack where the freeze out plug goes. Not very deep - maybe 1/32 or so, enough to increase surface area for the epoxy to grip. Then, while the epoxy is setting up I would take a brand new sacrificial freeze plug and press it in slightly deeper than a permanent freeze out plug will be presses. This way the freeze out plug acts like the hone would and not only exerts pressure on the epoxy, filling the V groove, but also make a nice smooth transition seal. When the plug is at the correct depth push it in at the repaired side (tap it with a punch and hammer), thus turning it sidewise in the bore and pull it out so it doesn't gouge the smoothed epoxy. Once the epoxy sets up a liberal amount of gasket sealant and press the new freeze plug.

It sound like a lot of work, but a fluid leak only leads to a siezed engine.

 

Ok....that sounds like a pretty good plan.

How big of a hole would I want to drill, and where would I find this marine grade epoxoy?

Also...does anybody know what size the freeze plugs are on the block sides? I know a 1 1/8" socket fits perfectly to drive them in, but I don't know the actual size of the plug.

 

http://www.marinetex.com/

And the stuff that I've used to repair a freeze crack on an old car many years ago.

http://www.marinetex.com/PRODUCT%20P...rod%20info.htm

 

I hope that works for you Scott. That's one nice truck you have.

 

Thanks Jim...nice of you to say. Yours is going to be a nice truck once we get it up and running.

I found a tube of JB weld stick putty on the back of my sealant shelf. I'm going to take one more crack (no pun intended) at sealing it with that to get me through the holidays....then after the first of the year when I'll have a full weekend I'll grind it back down and do it the right way.