Ticking/knocking/nailing on WVO

[vibraphone321]

The rabbit is running great on diesel, smooth, quiet, no noises. But when I switch to WVO (two tank heated system, switching at 165f) I get some clattering. Its noticeable at idle, pretty bad at low speeds under a load (taking off in 1st and 2nd gear), and then goes away completely in higher gears. When I switch back to diesel the sound goes away completely as well (in all gears). I put about 1/2 oz of Sea Foam in the WVO filter to see if it would clear things out and it did or about 10 miles, but now the sound is back - although not as bad as before the Sea Foam. It has been in the 30f's here lately, but like I said, I have been letting it warm up - and the WVO gauge is showing temps between 120-150f.

Is this anything to worry about?

I have read that WVO effectively retards timing because of the way it burns and that people are advancing timing to make up for it. Would something like this explain the noise? I like the timing where it is for everything else - good mileage/power, smoothness, cold starting.

What about pulling the cold start on WVO to advance the timing a bit? I read something about that, but haven't tested it yet.

Thanks in advance.

[Fatmobile]

Mine is more clacky on wegy also.

I figured it is either fuel that explodes quicker (higher cetane) or it is causing the injectors to spray differently.
Because it quits at higher RPMs leans more toward timing.

That pinging can be a good indicator of where the injection is in relation to TDC.
If we could make it so the noise would continue throughout the range the curve would be correct.
We could just back the static timing off a little to reduce the noise and be happy at all RPMs.

But then diesel might run like hell, all retarded with white smoke or low power.

[vibraphone321]

Thanks Fatmobile. Is your happy medium leaving it how it is? Running well on diesel and a little noise on WVO in low gears?

[Fatmobile]

Yeah, I usually run as advanced as I can.
So how it runs/sounds on vegy is kinda what limits the setting.