It is my understanding and belief that the oil filters were NOT painted on the engine. First off if painted on the engine the filter would be effectively cemented onto the block making it difficult to remove. That would not be a smart production procedure . Second it would be extremely hard to get a consistent no drip finish on the surface of the filter all the way around the filter the way the engine blocks were quickly and sometimes sparingly painted. We have many stories of these filters being smuggled out of the plants in lunch boxes . It is may understanding they were painted block color (a different time and place) for the purpose of distinguishing them from regular service parts sold to the public in the event of employee theft etc. I have seen some of these block colored filters with the lower crimped lip closest to the block unpainted on some filters (not all) which would also indicate it being painted separately. I am not sure if that is what i am seeing in the black and white photo posted before or not. Most of the assemblyline black filters I have seen had various stamps on them . Not all the same and a few without. Many of the stamped filters when screwed onto a engine would be in a unlikely position if they had to be stamped on the engine. I haven't seen any 66 ones unfortunately but the many 67-69 ones I have seen were consistent with the 65 ones I have seen in paint coverage etc. Of course the 67 -60 big block ones I have seen although block color had to be painted at another time since the oil filter adapter on a BB is not painted. I am confident the 65 BB filters were black also.This helps explain the earlier cars also . Just some of my opinions based on observations . Bob
"if painted on the engine the filter would be effectively cemented onto the block making it difficult to remove."
-- No way paint could be sprayed up under there without wasting A LOT of time.
"it would be extremely hard to get a consistent no drip finish on the surface of the filter all the way around the filter"
-- Not even a concern. Drips and runs would be the norm, and acceptable but not preferred.
"blocks were quickly and sometimes sparingly painted."
-- Always true! I'll bet 15 to 30 seconds max! Paint was expensive. Used as sparingly as possible.
"We have many stories of these filters being smuggled out of the plants in lunch boxes...I have seen some of these block colored filters with the lower crimped lip closest to the block unpainted"
-- It would be sensible for Assembly-Line filters from the manufacturer to be ordered and supplied to Ford, with a light coat of engine color coating, to prevent rust, and specified in the purchase order to have NO
PAINT near the rubber gasket end. This engine color base coat would save Ford money because it would take less paint to cover the filter as the engine was being sprayed after filter installation.
"for the purpose of distinguishing them from regular service parts sold to the public in the event of employee theft etc."
-- Either way, if 1000 were stolen, 1000 would never be caught if they ever successfully left the plant with them.
"Many of the stamped filters when screwed onto a engine would be in a unlikely position if they had to be stamped on the engine"
-- There would be absolutely NO reason for filters to have any markings after painting the engine. My suggestion is that ALL filters with stamped markings were
as supplied from the filter manufacturer and NOT as
they were after the engines were painted.