WHAT I'VE DONE TO GET MY 1999 JEEP CHEROKEE 2.5 DIESEL RUNNING ON 100% VEGOIL:
First off, I am talking about running on standard vegoil bought from the supermarket,
or in bulk from a cash-n-carry. I am not taking about not recycled vegoil or bio-diesel,
although similar, these have seperate issue that are not covered here.
Running on vegoil poses some problems for diesel engines only because vegoil is a lot
thicker than mineral diesel, and pushing thick vegoil through injection systems and into
the combustion chamber requires some adaptations on vehicles which are optimsed to run
on thin mineral diesel. The key factor to note is that when heated to 80 degrees vegoil
has the same viscocity (i.e. is as thin) as mineral diesel. So, once the diesel engine
is warmed up, you can use a simple coolant-water heat-exchanger to heat the vegoil to
80 degress. The vehicle then runs exactly as it would on mineral diesel. The problem is
how do you get the engine started on vegoil? Some vehicles are better setup than others
to push cold vegoil through the injection system. The pre-2001 VM diesel engined Jeep is
probably the second best vehicle (after old Mercedes) at coping with cold vegoil.
Reason Why pre-2001 VM diesel Jeeps can cope with cold veg-oil well are:
1. The Injection pump is a Bosch VP36 series which is good for pumping cold vegoil.
2. It has heater fitted to the Fuel Filter.
3. Glowplugs remain on for "afterheating" by default.
4. It is indirect Injection (so unburnt vegoil contamintion of sump oil is minimal).
Because of the Jeep VM Diesel's advantages, and so long as all the injection
system components are in good working order, you can just poor 50% vegoil
into the tank and drive off with no problems during the summer. Some even claim
to run a 100% in summer, and maybe they do, but during the winter months there is
no chance your Jeep will start on 100% vegoil without some modifications.
I have nothing against peple doing a 50/50 mix, personally I wanted to be 100%
carbon neutral, so making some modifications was the only way to go for me.
Before embarking on my conversion I had lengthy discussions with Stephan Helbig in
Germany. Germans are way ahead in terms of vegoil as fuel use, they've been doing
it for years. Stephan Helbig is Germany's leading light on vegoil conversion, he
wrote the book "The Edge Of Veg" that can be found in my references at the end.
Stephan advised three things to help starting on cold vegoil: Wider fuel lines,
longer glow plugs, and increased injector pressure.
So, this is the modifications I made (COST £460 inc labour):
1. Fit wider fuel intake line, 10mm.
PARTS £10, FITTING £30
2. Fit new longer glowplugs (Bosch Duraterm: 0250-202-103)
PARTS £15 Each, FITTING myself.
3. Fit heat exchanger. (http://www.biotuning.co.uk/
PARTS £80, FITTING £50
4. Get injectors serviced and increase injector pressure by 20 bar to 170 bar each.
(when re-fitting serviced injectors get a Jeep Dealer to do it as they will have to
program the MSA to expect a new number one injector: pre 97 jeeps need to have their
timing manually advanced instead)
SERVICING £20 EACH, FITTING £150.
If you think fitting new injectors would be easier the part numbers are
(Bosch: Num1 Injector=0432-217-249 £180, Others 3 Injectors=0986-430-249 £30
prices from http://www.vmdieselspecialist.co.uk
Three very important things you need to note when using vegoil as a fuel are:
1. Don't run at high rev's for the first couple of minutes from cold, basically
keep under 2000 rpm until the coolant is upto 80 degrees (or your pump will break
2. Change you fuel filter after 300 miles of running on veg oil (veg oil cleans
out a lot more gunk than diesel, this gunk could block a filter).
3. Ensure oil changes are done frequently, at least every 5000 miles.
(any vegoil seeped into the sump is not a good lubricant)
RUNNING IN WINTER:
Running 100% in winter is done by many people, but it will take three 20 second
pre-startup key-turns to get going on the coldest days. Many people do mix in a
small amount of mineral diesel though.
Here is Stepahn Helbig book (Stephan is Germany's leading light on SVO)The Edge of Veg:
These websites are also very good:http://www.dieselveg.com/http://www.vegetableoildiesel.co.uk/forum/http://www.elsbett.com/engl/
NOTE ON BUGS:
I've not had this problem but Diesel fuel is prone to bacterial infection, vegoil is more
prone than diesel and these little bligthers can block your fuel filter.
Some of this "Q-CIDE FP" Fuel Disinfectant will kill them off.http://www.fueltreatment.co.uk/products.htm
NOTE ON PUMP SEALS:
There is some debate as to whether the main seal in fuel pump of a Jeep is made of Viton.
Non Viton seals can degrade when you use bio-diesel because it has methanol in it.
This is not a problem when using SVO, but is one to be aware of people do mention it.
Currently the UK tax law is the first 2500 ltrs of vegoil you use is tax free.
After that you have to register as a "producer" with HMCE, via a a EX10 form, and pay 27p per litre.
HERE's THE PICTURES:
It should smell like someone having a BBQ, or the light frying of chips.