Bought V6 Direct kit to replace the old heater on my Mendel printer with 3 mm filament. Keep having jams of filament (ABS or PLA) that will not pull back or push out nozzle. I can heat to 200C, remove nozzle, and then tap the filament down into the heater block. If I heat the stainless steel with the block inside, the 3mm filament has a 3.5mm diameter blob on the end that would have been at the heat block zone. The kit does not have teflon tube and did not include any heatsink paste (it is probably 1 year old production). Heat block zone is definitely larger than the ID bore into the heater. Bore at the top of stainless rod is also slightly smaller, which is perhaps why I can't just pull the filament back into my (geared NEMA-17) extruder. It will start and print, first time, but once the print ends and the head cools, I have to do the hot nozzle 'remove and purge' and pull the filament out, before I can start another print. I expected the stainless rod would have constant diameter bore. Suggestions, please!