Bench breaking in a 61-261 and noticed something like a lite brown mollases stain down the side of the block in about 3 places on the exhaust (hottest) side of the engine block. The biggest concentration of "stain" seems to be coming from the head gasket area between #3 intake and #4 exhaust. Its not an oil leak 'cuz the stain cannot be removed even with solvent, as if its baked on.
Compression checks at 163 to 169# with nothing strange noted, spark plugs look good, head bolts torqued to specs, vacuum holds good and steady @20 inches, valve cover gasket does not leak, engine runs smooth in all rpms, no oil in the coolant and no coolant in the oil. Looking really close at the "active area", you can see minute bubbles developing then a minute clear drip of something going down the side of the block.
Had the head magged during teardown and no cracks. found. Could it be the head gasket filler material breaking down in all the heat. Don't know if this symptom is a precusor to something more terrible to come, or not to worry. Thanks for your insight
to between #3 intake and #4 exhaust ports.
