[oldtrk 40]

Hello all
Have to weld GM marinev8 block that was damaged do to freezing. Theres a chunk of the block below the exhaust manilfold that was pushed out aprx. 2.5 by 4" Have welded cast before mostly with ni rod ,. Its a hit or miss sometimes.
Am leaniong more towards brazing or silicon bronze . My biggest concern is not so much the welding but the stress es set up by the welding process . Read the article that jody has written up about cast iron , lots of info there .
Whats the best way to tackle this job ??
Thanks Larry

[brokeitagain]

being an engine block it, pitch it out in the scrap pile, cylinder wall distortion, cam bore distortion, main bearing bearing web distortion could have happened to that block, its not a one of a kind casting and replacements are available

[paul_s]

When I was a kid, my Dad got a Army surplus generator that was powered by a 4 cyl Jeep engine. It was used on construction of the Yukon highway and the block had cracked due to a freeze up and it had been welded. It also came with a new block covered in cosmolene (sp?) so that the engine could be rebuilt if the weld failed. The original engine is still good at my brother's farm in PA. I don't know the extent of the weld but I remember seeing some weld where the block met the head.

[Superiorwelding]

Personally I would with nickel rod. I have had great success with this stick rod, although it is quite expensive.
I would agree with replacing the block, except I am sure you were contracted to weld it and it would be a lot of work to transfer all the parts/rebuild.
To quote Jody from his website....
"I tig weld on A/C with A/C balance control maxed out and use Aluminum Bronze filler metal
Its strong, it flows really well on A/C, dilution is low, and shrinkage stress is low so it does not tend to crack other areas next to the weld.
This method works great for tractor and farm equipment and machinery, But may not work as well when you have a lot of thermal cycles like on an engine.
For that type of application My choice would be to stick weld using a nickel rod also known as Ni Rod. (the Ni is pronounced like"eye" with an N)
Sometimes the flux on the stick electrode can help dissolve some of the excess carbon."
Welding cast iron is a gamble no matter which way you slice it. I tell my customers they have a 50% chance of success.
-Jonathan

[brokeitagain]

being an auto tech for 20 years and building several of my own race engines, and knowing boats are simply expensive to work on, because hey if ya got a boat you got money to sink, (not my philosophy but boat techs and shops see it this way),a replacement block and following proper winterizing procedures will be the best route for the owner, the parts and labor to replace the block will be a lot less than welding that block, finding out it didn't hold after its assembled and running, removing the engine rebuilding it once again and no longer having problems, seems a shorter road to go to just replace the block.
im willing to bet replacing the block is cheaper and faster that pulling the engine twice

[oldtrk 40]

It sounds like bottom line is ,The engine is going to be able to run without problems after the repair is made , I did mention this to him . how do we know the freeze up did not do more internal damage that is not visible ??
Thermal changes from normal oper4ting conditions something to consider also
No charge for him ,this is freebe .
Thanks
Larry

[Bill Beauregard]

Due to a massive breakdown in communication, I and my two sons share responsibility for diluted anti freeze in a newly rebuilt 427 Chevy Tall Block. Yeah the good kind with big journal forged crank, serious cam, extra piston height, extra oil control ring, and everything else to make it a fire breather. I don't know who to kill, maybe me. The crack visible was where you describe. My engine builder was going to send it to be stitched, a process that leaves an appendix scar. This is said to be the most dependable repair. Once dismantled it proved to be damaged internally. I searched at length to find a donor block, bought it, and then found several more.
Which block do you need? Mine had been out of production 25 years, most donors had gone to power monster trucks and puller trucks. Those that hadn't belonged to people who knew how scarce they are, and how sought after.

[Bill Beauregard]

I wouldn't attempt it. Find a specialist, pay then pray. Or bite the bullet, find a rebuild able block. In my case it cost 1500 to buy then bore and reassemble with my components. Do the honorable thing, don't patch it with JB Weld and sell it! That ain't fair unless the buyer knows.

[Otto Nobedder]

Larry,

If it's a freebie for a friend, and he's aware of the risks, why not go for it? Especially if he's doing the hard bits... pulling and stripping the block.

Jody's recommendations (in Jonathan's post) are always solid.

As long as he knows there's "no promises" and holds you harmless if it fails, you have nothing to lose but time, and valuable experience to gain.

Steve S

[AKweldshop]

Do you have a quick pic????

[TamJeff]

Sometimes it is better if it is a non-critical section to put a coupon patch over the entire area and weld around that instead of chasing porosity or cracks.