Vehicle & Technical > Defender

Veg Oil conversion

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Suvvey:
At some point next year I am looking to do a dual tank veg oil conversion on my 200tdi Defender to hopefully run on WVO. I priced all the componants up that I want for the system that I think best suits me and I'm quite happy that I know what I need and where it goes in the circuit but was hoping someone may have some examples of what they have done? Especially on a 200tdi as the only guys I know with converted Landys are using 300tdi's, I know there should be no difference in the componants needed but would be interested to see how it was fitted into your engine bay.

Only question I have with the system itself is where to fit the heat exchanger. I know it should be as close to the injection pump as possible but if it is fitted after the lifter pump then both diesel and wvo will be heated. This may not be a problem if I knew it would always run on oil when up to temp but wanted to be able to run it on both fuels just as easily.

Saffy:
mines 300tdi dual tank in 110. Modified 90 tank under driver seat area, this is the derv tank, the original rear tank is the SVO tank.  System consists of twin tanks both with independent standard sized filters, electrical solenoid type fuel selection valve, electrical solenoid fuel RETURN valve. 3 way switch (DERV, SVO and PURGE), plate type heat exhanger plumbed into the coolant line.

RUNNING ON DERV:
DERV TANK >>>>DERV FILTER>>>FUEL VALVE>>>>>LIFT PUMP>>>INJECTION PUMP>>>>RETURN VALVE>>>>>>DERV TANK

RUNNING ON SVO:
SVO TANK>>>>>SVO FILTER>>>FUEL VALVE>>>>HEAT EXHANGER>>>>LIFT PUMP>>>INJECTION PUMP>>>RETURN VALVE>>>SVO TANK

RUNNING PURGE (30 SECONDS to purge the fuel ONLY the fuel system of remaining SVO only, DIESEL with it beign returned to SVO tank):
DERV TANK >>>DERV FILTER>>>>FUEL VALVE>>>>LIFT PUMP>>>>INJECTION PUMP>>>> RETURN VALVE >>>> SVO TANK


Important to purge so that the derv tank doesn't get x amount of pure SVO returned to it every switch over, slowly contaminating it.
After purge it needs least a mile or a good few minutes running at high revs  or so to make sure SVO is burned out of the cylinders (when exhaust stops smelling of chips!). The subject is touchy but personally I do not want my TDI to ideally have ANY percentage of svo/wvo in the cylinders on cold start as that in my opinion (and others if you research) will lead to coking and slippery slop of ruining the engine.

This setup needs the lift pump replumbed and it no longer pushes fuel thru either filter but now sucks, so important not to use bleed nipple on filter as it draws in air!. A weak/old lift pump may struggle to pull thick cold SVO, so perfromance will be down (top speed/ lack of power on hills). When performance dips in cold weather it's time to not be using 100% SVO and use a derv/svo mix.

Would be nice to valve the coolant line of the heat exchanger so it can be isolated because I have had issues when running derv in both tanks and the diesel getting heated so much after several hours running that it effects the performance power/mpg (has only happened twice on long trips).
Recommend proper LR filters and not mess around with crappy inline mesh/paper filters. Recommend carrying a couple spare filters in truck.
 
For me the teething problems after setup where mostly borne from bad joints/mating between different fuel lines... hoses get crushed or leak or draw in air.

Recommend separate return and fuel selection solenoid valves because the all in one valves can't be set in purge arrangement.
Do not cut corner and take easy route of looping/teeing the return line... it means the system will not flush svo out on chang over unless you running for 10's miles - rubbish situation. Return the fuel line properly and the flush is quick and pretty clean.
Recommend an alarm on the curtosey lamp circuit which sounds if yuo open door with and truck still in SVO/WVO... a reminder to flush the system. Before fitting alarm I have forgotten to switch over fuel and flush long enough and when it's 100% svo in the winter and your camped in middle of woods ...it aint gonna start!

Suvvey:
Cheers for that. I have to admit that I'd totally forgotten that the Derv filter is after and not before the lifter pump :oops:. I wanted to keep the derv filter just for derv so will probably replumb the lifter pump as you have said.

Planning on having a heated filter for the WVO as well as another heat exchanger closer to the pump. From what you've said have you put yours before the lifter pump so that just the aux tanks fuel is heated and not both? I have read some reports that heating of your derv can help performance and MPG but personally I don't like the idea. Maybe a little heat in cold weather but seeing as you are trying to get the oil as hot as possible it doesn't seem wise to put the derv through the same route :?

Also how much has the flow of coolant to your heater matrix been disrupted since fitting your heat exchanger? Defender heaters really don't have enough spare heat to go sharing it with anything else :roll:

Saffy:

--- Quote from: Suvvey on December 02, 2009, 23:05:51 ---Cheers for that. I have to admit that I'd totally forgotten that the Derv filter is after and not before the lifter pump :oops:. I wanted to keep the derv filter just for derv so will probably replumb the lifter pump as you have said.

Planning on having a heated filter for the WVO as well as another heat exchanger closer to the pump. From what you've said have you put yours before the lifter pump so that just the aux tanks fuel is heated and not both? I have read some reports that heating of your derv can help performance and MPG but personally I don't like the idea. Maybe a little heat in cold weather but seeing as you are trying to get the oil as hot as possible it doesn't seem wise to put the derv through the same route :?

Also how much has the flow of coolant to your heater matrix been disrupted since fitting your heat exchanger? Defender heaters really don't have enough spare heat to go sharing it with anything else :roll:

--- End quote ---
Bare in mind the heat exchanger does nothing needful other than once things are warmed up it gives the LIFT pump an easier time. The excess fuel returned from the IP is 'hot' from the HE because it doesn't stick around in the IP long enough and will gradually warms up the fuel in the tank and this again will give the lift pump an easier time with the lower viscosity warm oil. The heat exchanger doesn't actually have any value beyond that as the injection pump internals and therefore the fuel passing into it will become the same temperature as that big lump of metal that the IP is made of. It's been described elsewhere to imagine a teaspoon of very hot veg oil being tipped on a stone cold cast iron frying pan... that oil will take on the pans temp soon as it hits it, so the sip of fuel that actually passes though the injection pump takes on the temperature of the 'warmed'  working pump internals i.e if it's hotter oil entering it will cool down to the IP temp, if it's colder oil entering it will be warmed to working temp of the I.P.
So in theory if the lift pump was man enough to pump thick stone cold SVO (which I reality it can to a large degree) then you do not really need a heatchanger. Again this is a subject of debate and I am just relaying the thinking that I latched on to because it seems logical.

That said, a filter heat exchanger is good idea and I suspect in real world it's all you would need. THe best arrangement would be a coolant heated HE passing through a fuel tank so switch over when the tank of fuel is up to temp. That is a popular method in the USA, if you research their setups the HE is usually in or at the fuel tank and they have insulated coolant pipes running from rear up to engine bay (that's the bit I don't fancy!).

Yes only the SVO fuel passes though the heat exchanger on mine.
No, never noticed any difference in heat matrix output. I originally installed the heat exchanger in parallel to the heat matrix, meaning it had T pieces in inlet and outlet hoses, this is a common arrangement in conversions on other vehciles. BUT... later realised that the landrover heat system is ALWAYS passing coolant though the heater matrix regardless of cabin control. Whereas other vehicles often control the flow of coolant thru matirx via the cabin heater settings so a parallel connection is needed if driver turns heat to' cold'. So on hind sight it is much better to put the plate HE in series on one line of the heater matrix in landrover installations because the flow is always there regardless of hot/cold setting and you end up using less joints, cutting less pipework and therefore less potential failure points.

Infrared temperature probe/sensor is good tool to buy/borrow (maplins sell em) when setting up an install as you can point and click at various areas and get an idea of temperature around the engine bay and system. You can see the IP pump external casting showing pretty much the same temp as the coolant hoses. You can check the H.E temp in relation to  coolant hoses, input fuel line compared to outlet of H.E etc etc.

The standard 'hard' fuel lines are pain to mate to, they also become soft when hot oil is passing through, not normally a problem but if you got a joint on one that uses a compression clip it can crush the pipe and cause problems that are right pain to find cause of.

Suvvey:

--- Quote from: Tanglefoot on December 03, 2009, 00:33:19 ---Bare in mind the heat exchanger does nothing needful other than once things are warmed up it gives the LIFT pump an easier time.
--- End quote ---
 :-k

Most of the research I've done on this and people I have spoken to are quite adamant that the oil needs to be as hot as possible to ensure proper combustion, prevent coking of the cylinders,  seepage of the unburnt vegetable oil into to sump as well as premature pump failure.

I did think about fitting a 90 tank or something similar out of sight under the truck but have decided (at the moment) to go for a 50lt removable tank in the boot for the wvo because I wanted to keep the derv side of things as original as possible, to help to keep the fuel warmer. Also because this is my daily ride and it's daily job is running me the 6 miles to work and back therefore not getting time to warm up enough for the switch over to wvo :roll: So would like to keep the same range on deisel that I already have. Besides 50 lt should give me over 350 miles of cheap/free motoring and a couple of jerry cans will almost double it again. Also keeping oil rather than derv in the boot seemed the least smelly option :lol: That being said I would be interested in any pics you might have of your 90 tank set up. Do you fill it from under the drivers seat?

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