I'm currently in a debate with a "welder" who had welded a guys mounting points on his block due to cracking. His customers (after only one month) block ripped the bolts out of the repaired area, and he refused to pay for what happened. This is where I stepped in.
From what it looks like (and what I've been told), he used a TIG-pulse welding configuration and laid pass after pass, only letting the block air cool to room temperature. He cut out 1/4 inch of material to weld the crack at its root, so there was at the very least 1/4 of material welded onto this (it looks like it was ground down as well). The block was not sent through a hot isostatic process, nor was it put in an oven prior to, or even after (he could have even used vermiculite...) doing any and all of his passes.
This engine weighs approximately 300lbs and in a FWD configuration, has a lot of torque and engine movement. I feel this weld was not done to an acceptable standard whatsoever, and he should be back charged for his shoddy workmanship. I feel that his work is the direct cause of the malfunction of the rear engine mount (leading it to be ripped out of the block), as this has NEVER happened on any block that has not had to have been repaired.
From what I've been told from several veteran welders, is that the block should have been replaced in the first place. If a repair WAS attempted, MAPP/Propain gas torch and special filler metals are preferred over TIG because higher tensile strength can be achived. The block should have been prepped properly (HIP, heat oven cooling).
Your opinions on the matter, along with references to sources of information would be very appreciated.