My hot end started factory with a nozzle screwed into the Heat block then the throat screws into the other side of heat block this in turn slides into the top heat sink.

This did not work correctly as the PTFE tubing kept burning up to fast,
So I made a few changes.

Started with a nozzle screwed into bottom of the Heat block then the throat /w PTFE liner screws into top of the Heat block .
With an added heat sink Fin the screws onto the Throat then this assemble slides into the Top Heat Sink.

Added Heat sink Fin
RepRap M6 Heatsinks.jpg

Throat with PTFE liner

Throat.jpg

Heat Block
s-l1600-3.jpg
Modified Assemble w/Cooling Fan duct "top Heat Sink above X Axis Carriage.

TL-W3M 2.jpg

Now the Life of the Throat PTFE Tubing is increased greatly even at ABS print Temps.