Originally Posted by colcreate
Better to drill from the outside.
Center pop the coach bolt head and put a pilot drill in about 20mm deep. Then increase drill size in stages to the thread diameter. If you are careful you will be surprised how easy it is to do. Once the head is gone you should be able to remove the engine and then deal with the remaining shank of the coach bolt.
Also if trying the grinding option, rather than grinding use 1mm thick slitting discs on your angle grinder, they are wickedly quick at slicing through stainless, believe me I have had some experience in this!
Always use them edge on and never be tempted to use the face of the disc to grind.
As above ,drill the head off and punch it throu !!