Where does clog happen? Is it between the nozzle and the heat break?

It is either in between the nozzle and heat break, or in the heat break. I’ll have to experiment a few more times when I get home, but one time removing the nozzle did not fix the clog, while another time removing the nozzle did fix it.

Did you try cold pulls and do you have a picture of filament end?

Cold pulls, warm pulls, and shoving filament in until the clog clears. All clear it for a while until it eventually clogs again.

How do you identify a clog? Is it just clicking noise from extruder?

Gradual increase in frequency of ticking noise coming from extruder motor (Bowden setup) and decrease of filament extruded until eventual complete clog.

How do you fix a clog? By replacing nozzle?

See above, either pulling it out or pushing it through.

How hot is your extruder motor and stepper driver? Do you have a cooling fan on steper driver? Have you ever adjusted stepper driver vref?

I will have to check temps when I get home. There is no cooler on the extruder. I have not adjusted the Vref (had to look that up), but I originally tried tuning the stepper rotation distance before I knew there was a clogging problem.

Did you tighten the nozzle while heated? Did you try tightening more (don’t brake it)?

At this point the hot end has been disassembled, cleaned and reassembled probably close to 50 times in the last 2 weeks. It’s been done cold while disassembled, hot on the printer, after the nozzle has been torched from cleaning, you name it. Both nozzle and heat break are as tight as they can be.

Is extruder fan working properly?

Yup

What retraction settings do you use?

The printer clogs even outside of prints, so retraction is not an issue.

Does your bowden tube have any play at both ends?

Nope

Why dont you PID tune your hotend (its important especially after upgrading hotend)? Did you try printing at higher temp like 210-220C?

I had not heard of PID tuning until reading comments today. I might look into it when I get home, but as I’ve said other places I don’t think heat is an issue as reported idle temps are same as the build plate and clogs are able to be fixed by pushing filament through the heated nozzle. Also, filament still oozes from the hot end while clogged. I’ve tried printing at recommended temp, as well as far below and far above recommended, doesn’t change anything.

Did you try extruding without hotend (like disconnecting bowden tube and running filament trough extruder)?

Yes, but not enough to “test” it - what I’ll try is disconnecting the heat block, leaving the heat break attached to the printer, heat the nozzle, then try running ~1m of filament through the (cold) heat break. I’ll have to report back in a few hours when I get home.