I have ran mine on 100% filtered veg for years.... no links but this is what you need to do:
Fit a high flow Facet fuel pump on fuel pipe coming from the tank, then from the facet pump into a 'flat plate heat exchanger' (taken from a scrap combi boiler or buy one off ebay for £40ish). The heat exchanger is also plumbed in to your heater matrix water feed, so heats the veg oil going through it as the coolant gets hot - keeps veg nice and thin all year round. From the heat exchanger into your standard fuel filter that is wrapped with insulation... why insulation... 'cos the filter actually hangs down under the vehicle and is in the direct path of all that lovely 70mph cold air, which makes the oil go thick again in the filter and a bit of performance is lost. Last thing is to take the 'banjo' bolt out of the delivery pipe in the top of the diesel pump and remove the incredibly fine gauze mesh inside the bolt (just pulls out)... this makes a huge difference to the power and responsivenesss of the vehicle - even if youre running on straight diesel.
Then, youre good to go on 100% veg all year round.
Cold starts are fine, as there are your normal 4 glow plugs, plus a huge one in the inlet manifold as well pre start and stays on for a while after its running... so fires up instantly.
The diesel pump is a japenese copy of a bosch on these (zexel?) so will pump chip fat all day... well at least mine has for years.
Thanks for the reply, Would it be ok if I asked you a few more detail questions when I finaly get a van? Where do you attach the heat exchanger? do you bolt it up under the floor? Cheers Adrian P.s Could you give me an Ebay link to the type of heat exchanger I would need?
P.p.s Do you use waste veg oil? If so what technique do you use to filter/de-water it?
I use waste veg from a few sources, some of it I pay 40 per litre for, this has been boiled so all the water has evaporated off, then cooled and filtered down to 1 micron, then put through a centrifuge so all tiny bits are gone.
I also get oil straight from fryers, with this I just pour through an old bed sheet over the top of a drum, then pump out of the drum through some in line filters of varying size down to 10 microns, this is then ready to use in the vehicle. to check for water, get a pan on your cooker nice and hot and drop some of your filtered oil into it, if it sizzles and spits, theres water in the veg oil and best not to use it, if it doesnt then its all good.... to be honest in all the years I've been doing it I've never had issue with water in oil, guess it depends where its from and whats been cooked in it.