i'm converting a international schoolbus with a v8 engine. i'm considering using an auxilary pump to pump wvo from the heated tank through the racor lfs filter and to the injector pump. is this pump really necessary? the vehicle is already equiped with a mechanical pump much like the one on a gas v8. if necessary does anybody have any seggestions on what pump might be best? i'm also considering using a second filter to really get the oil clean, possibly a paper one. is it necessary to heat this filter to prevent waxing and solidification?

I've been using a 3-micron Racor suction-side filter as a pre-filter for about a decade (only started running BD/svo recently), changing it about annually. In that time the "regular" fuel filters haven't needed changing (they have pressure-drop indicators to tell if they're plugging up). The Racor filter takes out smaller particles than the stock filters, plus removes more water than the sediment bowl. I installed an electric pump on the tank-side of the filter to aid priming, and like the added convenience it provides, compared to hand-priming after filter changes, checking timing, working on the fuel heating lines, etc. The electric pump doesn't interfere with normal running when it's off - no significant resistance even with cold fuel. It's one of the "square", solid-state NAPA fuel pumps, rated at only about 4psi, but pumps a couple gallons/minute unloaded.

is it a stainless steel mesh type? are you using the original fuel pump in the vehicle as well as your primer pump or does the injector pump do all the work?

Shadetree: sorry to take so long to reply, I visited U of I to check out their their SVO/bio-diesel programs. Cool stuff, but it'll be a while 'til anyone is making a living at it. We'll have to wait for market forces to bring petro-diesel up to the Canola level. I'd give it about 2-5 years. Time to start on my Graduate studies. But I digress. You asked "is it a stainless steel mesh type?" - No, it has the disposable canister filter element, and a water trap underneath. It's a common big diesel truck filter.
"are you using the original fuel pump in the vehicle as well as your primer pump" - Yes, without modifications. It draws through the electric pump without any measurable pressure drop, and the electric pump is a low pressure unit, so it won't over-pressurize the mechanical pump. The engine doesn't run any differently when the electric pump is on or off. The Rover uses a Lucas/CAV rotary injector pump. I'm planning to swap in a freshly rebuilt engine this winter and am anxious to see what the old one looks like after running for 6 months on BD/SVO blend. Professor Peterson predicted stuck rings and bearing problems from the SVO, but so much oil is leaking past the rings that this may not happen. On a tighter engine it would. I'm running straight Canola oil in the crankcase. Surprisingly, it's staying totally clean, though it requires adding a quart every 200 miles! I also just got a single-cylinder engine running on BD.

I finally took the time to get the part number for my filter: Racor R26S, on a 200-series mount with water trap, but not the electronic water sensor. It's on the suction side of my '64 Land Rover's fuel pump. I change the filter annually, about 12,000 miles. It's rated as a 2-micron filter. Nothing has malfunctioned with it in 6 months summer/fall useage on BD/SVO, nor in the previous 5 years on dino-D. Racor also makes a similar filter for the pressure side of the fuel pump, but I have no experience with it. I retained the stock filters between the fuel pump and injector pump, which have a pressure drop indicator, but haven't needed to change them since installing the Racor. I think it's a better particulate filter, and definitely has a better water trap. Cost for replacement filters is about $16 at the local diesel truck shop.