A mechanic is breaking down my engine (85 140 VRO)<br />for a rebuild. Tnere is 1 small chunk (and several minute fragments) of metal missing on top side of the water jacket facing the cylinder side but not touching the cylinder sleeve.<br />Is this caused by the aluminum becoming porous? Is this one of the reasons why a former mechanic refused to work on a looper- but only a crossflow.<br />(he did mention that these engines had a tendecy for the aluminum to become porous after a period of time) This new mechanic said this may be a problem when they plane the head to make it level. Is it possible to patch the area before the plane it? Needless to say, the mechanic made it clear that the ports must be inspected and x-rayed by the machine shop to see if the engine is salvageable. I'm hoping I made the correct decision to rebuild this engine. Do I need to be <br />so concerned?