Get a new block. It is next to impossible to weld cast iron properly. The application wuld actually deem welding as the only real way of fixing it. After talking at length with an old timer (that had been welding for over 3/4s of his life) about my cracked block he steered me in the direction of donating it to the scrap yard. He had fixed many a piece of cast iron (you need a way of heating the entire casting to even begin the welding process) but because of the nature of the application (hot block, cold block, harmonics of engine operation, etc.) the weld would more than likely not hold, if the process didn't weaken the block to the point of failure in the first place.

If it was an aluminum block you'd be fine (our FM dragster has been using the same busted-and-welded-back-together block for over five years... of course it has no cooling system).

You should be able to find a good 350 block just about anywhere. In fact, GM recommends that you leave the bores alone unless they are truly damaged. Have the block looked at, make sure that the mains are straight (they HARDLY ever need any work), and then have the block cleaned, and then lightly milled to true up the decks and you should be OK. Install new plugs and you're set.

Also... just for future reference. You might want to work on some of the grinding and such before you send the block off to the machine shop to be cleaned up. I prefer to work this way.

Sorry for your loss Traviss. Good luck!

that sucks!!!

get a new block. Why spend all yoru cash biulding your new engine only to grenade it the first month you run it. Spend some more money now to save a bunch more later....

i agree also that the best solution would be to start with a different block, but, if that is not an option due to $$, then you can weld it; i think for three reasons. your not welding in an extremely critical high pressure area like between the intake and exhaust valve and the place your talking about has a relatively constant temperature once the engine is warm. also, it's not an existing crack that can spider once heated.
cast iron is very hard to weld to begin with but if it is done RIGHT, than it can be strong and last a long time. preparation is the key. the block has to be VERY, VERY clean where you are welding because, dirt, oil, grease, dust, water, etc. will leave hydrogen in the weld which is the #1 reason for cold cracking. also, preheating is absolutely necessary and post heating or controlled cooling is also critical for it to work. the best way to heat the block would be in an old oven after it has been thorouly cleaned. preheat for cast iron is 200-300 degrees. temperature paint sticks are available at welding supply houses. nickel rods were the best thing to use up to a couple years ago but there is a new rod out now that is better. i can't remember the name right now though. might be called cast rod. anyway, the rods your welder uses should be new or kept in an over to keep moisture out. make the repairs as fast as possible and get it back in the oven for a slow cool down process and minimize the heat affected zone. sorry for writing a book. good luck,whatever your decision is. the worst part is i sold a 350 long block a few months ago for next to nothing just to get rid of it. i would have gladly donated it to a worthy cause like yours. Fran

Excaleagle42 is correct.
Depending on the size of the hole it could be welded up. But it has to be done correctly which means lots of labor time. How much are you willing to spend on labor before the price of another block looks good?

I have been a welder for over 8 years but have limited experience with cast iron. The times I have worked with it, I followed the same procedure. Preheat to 300 degrees, to prevent thermal shock, weld repair, reheat to normalize the weld and affected areas then a long slow cool down period.

Devcon is an excellent product. My Dad owned two machine shops for over 40 years and used tons of it since the early sixties to hold punches in forming dies. But I have no idea how it would hold up under the constant vibration of an engine.

well it seems the best thing to do is replace it. I do have another block in the barn, just needs to be machined. If the guys around here can't do anything to fix this block, we'll be using another block..





dammit :(

Thanks

Travis

Travis if you are going to use the other block do the grinding first then have all the machine work done. Then you will not be out that money for machining if you make a mistake.

Jon

anothe rthign to remember about a welded block. I have heard most machien shops won;t work on a welded block becasue the area that has been welded is much stronger than the cast iron parts. As a result when they are cutting it down it can A. dull thier tools significantly B. damage ther tools and/or your block when cuttign metals of vastly different hardnesses

just a though.

Suck it up and pay your fine....Fee.....New block and tuition on a lesson hard earned..;)

I ahve not heard form dad yet today, he suppose to talk to some buddie to see if any of them have any other solutions. check back later tonight..


Thanks

puder


your right about the part that was welded hardening much more than before welding. if the part is pre heated and post heated though, than the hardening won't be nearly as bad in the heat affected zone and will be much stonger than if not pre heated at all. the area that was welded will become brittle and easier to crack espically if the part is allowed to cool down too fast. cast iron doesn't harden nearly as much as some stainless and high carbon steels do as far as machining is concerned after welding on them though.

Fran