twin tank disco 300tdi HELP

[bigM]

Hi to all,
been lurking around here a few weeks and found many answers to many questions/problems and hope someone can help with another!
Run a Disco 300tdi p plate.Have dabbled with svo over the past year in various mixes but now decided to twin tank(after starting/running probs over winter)Ive collected bits and bobs ie FPHE,Heated filter,Pollak valve.Gonna use a jerry can for aux tank to get started (started as in buy a better tank later on)Have a supply of wvo too!
Couple of questions tho..
1. fuel system as it stands ,is .. main tank--lift pump--filter--i.p--return to tank.
Veggie systen woul be..main tank--lift pump?--heated filter--FPHE---pollak--i.p--return to heated filter BUT if i do this and have diesel in aux tank...how do i get the diesel to the other filter etc without aid of the lift pump?Is the injection pump enough to draw the fuel through?or do i need another pump too?OR am i stoopid and missing sumfink??
2. Are the standard fuel lines from main tank ok to keep in place for the veg up to the engine bay or should i strip out and start with new hoses alltogether.
3.Before i start cutting things up and getting to point of no return...whats the inside diameter of coolant hoses/fuel lines?
ANY ADVICE WELCOME

[terence]

changover fuel supply before the heat exchanger and filter.

that way the filter and HE get flushed with diesel on shutdown.

one lift pump will then be sufficient.

[bigM]

HI Terence,
Yes I thought about that way but wasnt sure the oil would be very hot before it got to the injectors as it would firstly be flowing straight through the HE as opposed to initially sitting in it for a few minutes while engine warms up and secondly it has further to travel
Also worried that would leave a lot of veggie to purge at end of day?

[terence]

why are you worried , just time it correctly, the veggy is being returned to its tank anyway.

if you dont put the flush in front of filter, your filter will clog will cold veggy and fats and she'll either run poorly or wont start at all.

a useful tip use blue redex in your veggy tank. and clear polythene windows in your fuel lines, a stop watch to time it , allows you to see when its been flushed.

saves hours of cold start cock ups. ASK me how i know

[Nathaniel]

Use a separate filter for the oil - cuts purge times.

Also a separate HE for diesel/veg will cut the purge time too

I didn't bother with a HE on the diesel side.

Technically (with a bosch IP) you don't need a HE at all...

All you need to ensure is you have pure diesel at the injectors when you shut the engine down in prep for a coldstart.

The High pressure lines can take longest to purge - just because your injection pump is returning diesel from the return side doesn't mean the injectors have diesel - something to watch.

[bigM]

Yes,thats what i was trying to achieve basically.Only trouble is that the lft pump is the first port of call once the fuel leaves the tank and before it gets to the filter.
So could i re-route and have the oil go from MAIN TANK--- Heated filter--HE--Pollak --lift pump then IP
And Diesel go from AUX TANK ---filter--Pollak--lift pump then IP ?????
My concern was this might be too much of a suck for the lift pump!!

[terence]

you lot believe in making life complicated.

one filter, one lift pump.

time the purge.

simple

FFS.

[bigM]

yeah Terence but id have the return to aux tank with the dino in it...wouldnt I ??