air filter

I have a 1980 Mercedes 300sd Turbo diesel with a love craft conversion and around 240k miles. The previous owner ran the car on SVO and keep up with routine maintenance. I was originally running the car on biodiesel with no problems, it was a little slow to start in the mornings, but thats to be expected. I no longer have biodiesel available to me, so I moved to WVO.

I let my WVO settle in 5 gallon cubes for two weeks, pour the top layer through two filters (not sure of micron rating because previous owner gave them to me and didn't know) into a 55 gallon barrel. I then let that oil settle for a week then pump from there into the car. I checked the oil for water (pan test showed little water), it comes from a Vietnamese place that changes their oil twice a week, and put it in a glass and shone a light through it and could detect no particles. The oil, as far as I could tell, was good to go.

About half way through my first tank of WVO I began having starting issues (weather has been typical southern California weather). After the glow plug light turns off, I try to start the car and it tries to turn over, but shows no sign of starting. I hold this for about 30 seconds, stop, turn off the ignition, turn it back on, wait for the glow plug light, then try again. After about another 30 seconds the car, out of no where, fires up and runs fine. I do not know what is causing this problem (my oil, conversion, filters, glow plugs) I have no idea.

Any advice would be great, thank you.