Re: pros and cons of blending veg oil

Anthony,
Great idea.
I have been blending veggie and biodiesel for about 8 years for my wife's cars (she does not want to change switches at particular times in her journeys).
During winter I did a 50:50 veg:bio mix and in summer a 75:25 veg:bio mix.

Since buying a W124 300D, from a friend who used a 85:15 veg:ULP blend for many years, I have changed the proportions to 80:10:10 veg:bio:ULP. As I am low on bio at the moment, the proportions are 90:10 veg:ULP with no issues.

What has been done to the fuel system?
The W124 300D has a small fuel heater installed for countries where sub zero temperatures are likely. It is thermostatically controlled to come on at low (<10 degrees C) to prevent filter plugging from cloudy diesel.
All I have done, is to remove the thermostat and reconnect the fuel heater in-line before the fuel pump, so it is active at all times.
I doubt that this heater would increase the temperature of the fuel by much (+20 deg max) and it does not seem to cause any vapour lock issues with the ULP in the blend.

I hope this is of use to other members,
Tony

Re: pros and cons of blending veg oil

There's a lot of variables to take into account. Things like vehicle set up, type of oil, viscosity, driving habits, etc. What works for one, might not work for others.
There doesn't appear to be the perfect set up either. There's lots to know and lots to learn. This forum has been invaluable for tips, help and how to's.

Summary of some of the things that have happened or what's been learned.

Glow plugs will eventually burn out if fuel is too high viscosity. Also injector nozzles can soot up. It's a "runaway" effect.

Once I had a paper filter burst internally in previous van I had. Set up was heated fuel blend was fed at engine temps. It was a spin on type, Sakura brand.

Plastic tanks can work better for vege possibly because hot fuel returning can be cooled suddenly in a steel tank and HMP fats accumulate.

Looping can solve some of the above in steel tanks but hot fuel is then returning to the IP. ULP doesnt like too much heat. Even diesel doesn't but perhaps to a lesser degree.

IP's don't appreciated being restricted in fuel supply. Less fuel is available to inject plus injection timing is affected, both result in power loss.

Fuel line size needs to be adequate. Larger for heavier oil. Stock would be OK if the viscosity was the same as diesel.

Filter size needs to be big enough to cope. Viscosity has a surprisingly big effect on flow. Go big.

Consider using a gauge on the IP to monitor lift pressure. Also a vacuum gauge on the fuel line. Both are good tools to monitor system health.

The tanks' internal strainer is suspect if you're getting restriction. The HMP fats will not dissolve easily. Even added solvents have little effect. I used hot caustic to clean out the tank when I removed it last year.

Common injector cleaners contain: acetone, toluene, xylene, methanol. Be careful about using excess methanol. It can weaken the bonding in paper based filters.

Adding ULP, diesel etc before filtering speeds up the process greatly. Also encourages any water to fall out.

My van will have bubbles in the return line if the ULP content is very high, more so if loop return. The limit is somewaht higher with return to tank set up.

Sock filters work for on board filtration. The flow is multiple times that of a paper filter. Currently I use 1 or 5 micron. It would also be possible to shorten the sock and have a shorter housing. Filter supply shop says they send them to a sewing shop for cut/sewing to length.

Re: pros and cons of blending veg oil

Yep I'm now running a 9:1 SVO/petrol blend and the only issue I have is clogged filters (discussed elsewhere). I've found waste fuel from garages pretty easy to get, and the staler the better, as the volatiles (aromatics) have evaporated which is what you want, as they'd be the ones that could cause preignition in a diesel engine

Re: pros and cons of blending veg oil

Preignition in a diesel engine?

Re: pros and cons of blending veg oil

Tony, Do you blend in tank or externally ? DO you notice any issues with Lacquers from the ULP ? I remember this was raised a while ago - i know in my Surf i was always getting issues when i blended. I have not done so in the Suburban yet but am seriously considering doing so as most of my driving is city based and it takes too long for the suburban to come upto temp before i can switch over.

Craig

Re: pros and cons of blending veg oil

Craig,
We have had no issues with anything dropping out of the fuel at all. Pre-filters stay clean on our cars.
I pour 45 L of 1 micron cold filtered veggie oil into the tank and follow up with 5 litres of stale petrol to clean the oil off the funnel and to make up the 10% ULP in the blend.

We recently sold the W124 300D, but the 300CD is still running well on the blend. We have 2, mercedes C250 Turbodiesels, which we are not yet using the blend, until I modify the fuel system a little. They are using biodiesel (B100) until then.

Regards.
Tony

Re: pros and cons of blending veg oil

Good one thanks Tony, I might give it a go and see what happens. Have you done any posts about your oil filtering and drying setup ?

Craig

Re: pros and cons of blending veg oil

My oil remains indoors from when it leaves the fryer and is either put back into the original containers, or (at the F&C Shop) into my 60L drums so I do not bother drying the oil. If water can remain in the oil after being at 180°C, it will stay there at 100°C.

My filter setup is that I pump my oil into the bottom of the first of 4, 200 litre drums, the oil from the top of the drum goes into the bottom of the next 200L drum, this repeats for the 3rd drum, whose oil goes to the 4th drum, from which it is decanted into my filter bags, in home brew fermenters. The filtered oil goes into 20 or 25L HDPE chemical drums, which are stored until needed for refueling.
I pour a 20 then a 25 Litre drum into the tank, then rinse the funnel with 5 litres of stale petrol, into the fuel tank.
Then I Drive.
As I use around 50 litres of fuel a week, the 6oo litres of up-flow settling takes about 30 weeks. Most of the fats drop out in this process, but a small amount is still present and coats the liner in the bag filter with a few mm of fat. This layer of fat then becomes the filter, which should be much finer than 1 micron.

I scrape off the fat occasionally, when it starts to get too thick and slows flow too much, and it is a dark brown/dark grey colour from the particles it has filtered from the oil.

This fat is left for Summer, when the liquid from the top is drawn off and passed thru the bag filters, for Summer use. Any remaining fat in the drum is then mixed with sawdust, packed into used milk cartons and used as fuel for our fireplaces in winter. These 'firebricks' provide more heat than a similarly sized piece of hardwood.

I hope this helps,

Tony