Block repair

[joe_padavano]

Well, it comes as no surprise that the alleged "leaking freeze plug" on my 215 Olds is really a crack in the water jacket.  The crack (actually, about a 3/8" dia hole) was behind the starter.  Since I plan to build a 4.6 eventually, I don't want to spend a lot of time or money replacing this block.  The engine does run.  The crack appears to be in a non-structural part of the water jacket.  I'd also like to avoid pulling the motor at this time, as the MIGHTASWELLS have a way of turning a weekend project into a multi-year project.  With the starter out, there appears to be good access from the bottom.  I'm considering using one of those aluminum repair rods that are frequently advertised at swap meets.  I considered JB Weld first, but I'm concerned about both my ability to get the surface clean enough for it to stick and also the effects of thermal expansion of the aluminum.  TIG welding was another option, but I'd probably need to pull the motor to do that right.  I also considered drilling and tapping the hole for a pipe plug, but I don't think the metal is thick enough and there might be small radial cracks in any case.  

Does anyone have any thoughts or experience in this area?  Thanks.

[WedgeWorks1]

I had a 1969 Rover 3500S block that cracked between two freeze plugs on the left side of the engine. Someone had gone in there and used Marine-tex (JB Weld) to repair it and to my surprose it worked fro the previous owner for 5 years till the brakes let go. I pulled the engine for a MGB-GT V8 project and had the crack reapired by a machine shop with TIG. It turned out great and I would have done it this way again!

[pcmenten]

One of the advantages of aluminum is the ability to easily weld it to repair it. Might as well tear it apart, get it welded, and throw on some new rings.

[roverman]

Joe, FWIW. There "used" to be a weld shop in LA,CA., that would, tig. weld-up coolant leaks on Rover blocks, in the vehicle, for local dealers. If you can tig., alum, I think you can do this. Maybe even drill the hole/wire brush ,till it's perfect clean. Good ground, ample amps,helium-dc. neg, even better. If you go the "JB" route, push in excess, to possibly, mushroom on the inside? Good Luck, roverman.