Waste Oil Heater Forum - Your definitive source for burning waste oil for heat.

Do becket burner fuel pumps tend do do alright pumping waste oil?
I took my nozzle off yesterday when I was experimenting with a larger one, and noticed a very small amount of what look like microscopic fillings in the threads where it screws in. Very tiny and small amount. Might be from changing nozzles so many times just the thread friction?
The oil is clean and warm to the touch, the bronze sintered filter on the nozzle is spotless, and the pressure output of the pump is just under 100psi where it's always been, so nothing wrong with anything just curious.
I'd think a pump would last forever pumping oil but just wanted a second opinion.

Also I've been running the stock unmodified becket burner and realized that the rumbling noise it makes is the flame backfiring into the burner tube which heats the line, so when I adjust things to run smooth, the backfire no longer heats the line and goes out, so I'll need to heat the fuel line inside the burner tube somehow.

Need some ideas...
I've been running waste oil in my oil furnace in the garage
 It's a becket burner furnace. I'd either start it on diesel then switch to waste oil, or if I left waste oil in it I'd need to warm up the pump and burner to get it to start. It burned very well, no smoke or smell.
However, I started reading about how waste oil burns with a longer flame and may hit the back of the combustion chamber, so i looked inside and yes the combustion chamber was degraded badly at the back.
So, I removed the burner, and tossed the furnace, and built a boiler to install the burner in.

The boiler tank is 12 inches wide, 42 inches deep, and 72 inches high. The fire box inside is 8x8 inches and about 40 inches deep. Flues are 6 square tubes 1.5x1.5 from the rear of fire box up.
It is made from 1/8 inch plate and tubing.

Now the problems...
I need to figure out a combustion chamber of some kind, so the flame burns hotter and cleaner. It runs but the exhaust out chimney is either black from not enough air, or hazy and smelly.

Also, I need a way to heat the fuel line so that I don't have to manually warm it up to start it. I found online that beckett sells a line heater, but it seems small and not enough to keep it hot enough.

I tried the burner with and without the retention head, it doesn't seem to change anything.

Should I try to make a combustion chamber with fire clay? Steel? Ceramic wool? Not sure what would actually last.