Oil Filter Heads

8G740/1H1052 Teclamit/Purolator suspended replaceable element, up to November 1967. Note the bypass valve lower right which opens if the filter becomes blocked.

Various suppliers have conversion kits like this that convert the Purolator/Teclamit filter head to take a spin-on hanging filter. (Thomas Gunderson) The evidence suggests that both the factory spin-on filter heads below will fit the earlier engines as a direct replacement.

12H2244 Teclamit inverted replaceable element, November 1967 to April 1970. Bypass valve no longer fitted, but note the anti-drainback tube now the filter is inverted.

12H3273 inverted spin-on cartridge, March 1970 to September 1973 and February 1974-on with oil cooler hose adapter. No bypass valve, but anti-drainback tube.

12H4405 hanging spin-on cartridge, October 1973 to January 1973. The bypass valve (left) has reappeared.

Inverted spin-on filters need an anti-drainback valve internally to prevent the filter draining when the engine is switched off, which delays oil reaching the bearings on start-up. Hanging filters don't need it, but I'd expect all good spin-ons to have one. Having said that not all do, and some are very poor quality. The valve can be seen through the inlet holes on this Mann 916/1 filter:

Dismantled the valve can be seen to be a cupped disc sandwiched between the end-plate of the filtration medium and the end-cap of the filter: