GASKET - FAULT FINDING PHOTOGRAPH (1) PHOTOGRAPH (2)   CENTRE BRIDGE BURN   FEATURES:    Note blackening between bores which progress to burn through failure as in second photo. CAUSES:    (a) Inherent distortion of head or block denying lack of clamp between bores. (b) Distortion due to overheating.  GENERAL: Cylinder heads normally distort forming longtitutial low bridge between all bores. Combustion gases escape into the adjacent cylinder and vise versa on the next stroke. This concentrated heat flow burns the fire ring bridge away to point of dramatic power loss. REMEDY:  Follow gasket manufacturer / supplier fitting recommendations and reface head and block as a matter of course. If called for address any cooling inefficiencies. Always fit new cylinder head stretch bolts and strictly follow tightening procedures.      CIRCUMFERENTIAL SHIFT   FEATURES:    Note outward displacement of left hand bore & rupture of top outer gasket edge. CAUSES:    Isolated lack of clamp.  GENERAL: In this example the left hand bore has distorted and shifted outwards due to lack of clamp caused by a sunken liner. Compression gases have then ingressed into the left hand water gallery at which point overheating has taken place. REMEDY: Follow basic procedures ensuring flatness of head and block faces. Where a block has wet liners it is advisable to check liner protrusions against manufacturers specifications. In all cases liners must protrude by the same amount and preferably to the maximum limit. As a general rule liners must protrude by a minimum of 0.002" / 0.05mm or ideally to the manufacturers recommended highest limit.