Thread: Blending

Hey Chev,

I have been reading up on blending at the info pop site recently and am currently running a 20% unleaded/80% WVO blend in Helga. So far the results have been very good with only one small problem on a very hot day that may or may not have been due to the petrol boiling and causing a vapour lock. There were signs this may have been the case and others that it was not so I have no idea what really caused the problem. That has been the only hiccup in 3 weeks running and it occoured in exceptional circumstances anyway.

From what I have read on the infopop site, blending WVO with Diesel CAN cause problems with waxes and " the dreaded White Stuff" dropping out and causing filter blockages and coating tanks and fuel pickups with slime and gunk. It appears to be a random but highly significant problem that many people experience and many have no problems with. It seems to depend on the Diesel people are using which can vary in it composition from refiner to refiner and be itself blended differently depending on the location it is sold in.

The general consensus is that you are SAFER using other substances to cut the WVO with like Kero or unleaded to avoid the problem in the first place. The problem seems to occour more in the colder weather so I would say you should be careful and do tests before using a diesel WVO blend. The problem appears to take some weeks to appear genreally so maybe you should mix up some test bottles and give them a chance sit. Of course the problem with that is that the diesel you buy to do the tests with would want to be the same as what you eventually use in your vehile. If the blend is changed as in winterised, your tests would be meaningless. You would really want to buy say a 200L drum, blend that fuel with the same oil you intended to use and then see if the two are OK and nothing drops out. I would suggest putting some samples in the fridge for good meausre.

As most maunfacturers list blending diesel with Petrol up to 30% to "winterise" the fuel, I would suggest that this may be a better alternative to blending with diesel. Petrol is a lot thinner than Diesel so you will be able to reduce the WVO's viscosity a lot more effectively with the same qty of Petrol than what you could with Diesel anyway.

As the weather is warming up, I am going to try cutting my blend back to 15% petrol and then 10% if that is OK and just vary the ratio according to the weather. 20% may be too much petrol for summer but perfect for winter.

As for coking, I think this is a subjective thing and depends on the engine and the blend you are using. Certainly in theoy a blend that is working properly won't have any ill effects.
As a saftey precaution, I am running a water injecton setup in the belief that this will prevent any coking problems and keep the cylinders and related parts carbon free. Some learned people here have questioned how effective this may be and as I haven't been doing it long or pulled an injector before I started, I don't know the engine condition to start with. If I do later look into the engine and find it clean and carbon free, I won't know if the blend was fine or the water prevented any problems. In any case, as long as everything is OK I happily won't care!

I would try some careful tests with the diesel blend but also give the unleaded a go and see how that works out for you.

Thanks for the advice.

Given that cutting with ULP reduces the viscosity, I see my main problem is then the DI part. The last thing I need are droplets of WVO on the sides of the combustion chamber running down to the ring grooves.

I am wondering if anyone knows if a ULP/WVO blend addresses the DI problem.

Vege, when heated to 80c, is about 4 times the viscocity of diesel. My assumption is that if you make your blend to be closer to that of diesel itself, then the problems with DI would be minimized.
You could try making your blend from diesel, petrol and vege to give the required viscocity.
To measure the relative difference do this:
Suck the heated, blended fuel up a clear length of approx 3mm tubing to a measured point. Time the exact duration for it to exit once released. Compare that with unheated diesel.

To be successful, you should cold filter the vege to at least 5 micron or less......and to get to that stage, you must first remove the fat or else the filter will inevitably block.

I agree with t-bird. If the blend is close enough to diesel viscosity, then the fuel won't hit the cylinder walls because it will be burned in the normal fashion. Also don't forget that when the engine is up to temp there is a lot of heat transfered to the injectors from the head which warms and thins the oil anyway.

I would like to see an experiment to investigate if heating the veg does in fact make any difference to the temp of the oil once it gets as far as the injectors. Obviously heating is good for the filter and pump but I wonder to what degree it ends up affecting the burn.

Perhaps Chev you should look up " blending" on the info pop site and see who is using it in what vehicle to give you some clues to answer the DI question.

As for viscosity, when I used to do some spray painting I used a viscosicty cup to check how much thinners to mix in the paint to get the right consistancy. These were just a graduated cup with a hole in the bottom. You put the paint in the cup to the appropriate level and then timed how long the paint took to run out the hole. I cannot see why this same cheap disposable device couldn't be use to get an idea of how thin a blend was compared to diesel. As long as long as a sample of diesel and wVO or blend were allowed to equalise temprature, the test should give a good indication.

The point about the fats is very noteworthy as well. It takes surprisingly little to block a filter. For this reason I think it would be a good idea to at least warm a blend before it hits the filter in the vehicle.

ATM I am standing my oil in the original tins and pumping carefully from the top till I see some of the fats in the clear suction tube. This oil is then pumped into one of the 4, 60L drums I use and allowed to resettle for a month or more till that drums turn in the rotation comes up. I then filter this oil into the drum for blending as fuel. As I purposely leave maybe the last 5L in the bottom of the 60L drum, I have had no problems with fats since I started handling the oil this way and filters last a lot of oil.

I believe the Unleaded in a blend also helps with the fats and I am going to try some experiments with some fatty type oil to see what happens.

Originally Posted by David

Perhaps Chev you should look up " blending" on the info pop site and see who is using it in what vehicle to give you some clues to answer the DI question.

Thanks but I have spent ages on the infopop site and opinions vary widely. There are folks blending and swearing by it. The issue I see is the spray pattern initially from a cold blend and whether this leaves deposits on the side. I want to know if a blend will address this. No one seems to cover this issue for DI's.

great info guys, i dabbleb a little myself using ulp to thin my svo but i had bad hot restarting [probably vapourising] so i went back to dino diesel. testing the viscosity i s good but the 3mm tube thing is maybe not so good , think of honey most of it would just stay in the tube. try drlling a small hole,say 3mm[just to copy] in the lid of a coke bottle ,cut the bottom off it, now you can turn it upside down. tip in 500 ml of whatever you want to test and start counting,
make sure ther is a second recepticle inbetween the hole and you new shoes

A few thoughts

The World Famous Dr Pepper Viscosimeter (Pat Pend)Is a good simple viscosimeter which can give some very useful information.

You can not beat Kerosene for thinning WVO/biodiesel.
Unlike ULP which has a very low cetane rating, Kerosene typically has a cetane rating equal to or higher than normal diesel and in fact is routinely used at levels up to 100% as a diesel fuel (#1 diesel) in colder parts of the world.
AvTur/Jet A-1 is also kerosene and if you add a lubricant to it it becomes virtually identical to #1 Diesel. You could theoretically run your car on 98% Jet A-1 with 2% biodiesel to insure satisfactory lubricity.

It has been my experience that if you buy a 200 litre drum of Kerosene they charge about $2 a litre.
If you can find a petrol Station that has a Kerosene Bowser, the Kerosene is similar in price to Diesel Fuel.

Tilly

Originally Posted by tillyfromparadise

If you can find a petrol Station that has a Kerosene Bowser, the Kerosene is similar in price to Diesel Fuel. Tilly

-IF- being the operative word.

Some years ago I had a Kerosene heater I was quite fond of using in the winter but all the older servos around the area that had Kero pumps were rebuilt with modern places where you could do you weekly grocery shopping ( at double the price of the supermarket) or get your favourite Burger meal but not buy something that had been sold forever at servos like Kero. You could buy 20L drums at the hardware but I think you would get more BTU's out of burning the pile of money they charged for it.

I go past an airport every day, wonder if I could buy Jet-A1 off one of the fuel suppliers if they would fill my 20L drums and what the price would be? Last time I looked some years ago, it was about the same as petrol but I have no idea now.
I would give blending with kero a go if I could buy it at a reasonable price and get a reliable supply.

Is there a reccomended blend ratio most people use with Kero such as 20% kero/80% WVO and would there be any advantage to heating the blend or should it be run cold?
I know one of the ideas of blending is no mods to the vehicle but if just plumbing in a fuel heater would help, dosen't seem like much trouble to go to if it had any worthwhile benifits to the pump or injectors.

One should be careful about using kero , Avtur and other non - excised petroleum products as diesel fuel. In this use, they are liable for excise.

Even with excise paid petroleum products, blending with Used Cooking Oil will make all of the blend due for excise.

The excise will be applied at the diesel rate of $0.382 /L

Tony