View Full Version : Blending WVO w/ RUG and Kero??

4th April 2010, 03:40 PM
Does anyone blend in their diesel? I run WVO, but want to get better lubrication in my diesel tank. I have seen 70% WVO 20% Kero 10% RUG. I used this last summer and my lift pump went out on my Cummins. But it does have 100,000 on that pump. But my engine is much louder on diesel than on WVO.

What do you blend and for how long???

4th April 2010, 08:29 PM
Your blending ratio will depend on the lowest temperature you encounter when starting. Here where it's warm all year I use WVO with 30% jet fuel and could probably use less. Opinion seems to be that any blend with more than a few percent of VO will have enough lubricant property.
My 1HZ Landcruiser (precombustion motor) likes the kero/veg blends but I find I can easily use too much RUG and cause detonation and rough running. If kero/jet fuel is not available, look at heating oils, and if they are as thin as Kero they may be a good blending choice. A few percent of RUG can aid starting at lower temps. Keep thinning until your cold startups are about as quick and clean as they are on diesel and you could be OK. Regards, Combustor.

Tony From West Oz
4th April 2010, 11:12 PM
I run WVO, but want to get better lubrication in my diesel tank.

How much better lubrication do you want?
Adding less than 5% WVO to your diesel will improve the lubricity of the fuel way above ULSD and above LSD also.

It sounds like someone has been sprouting the IP manufacturer bulletins to you.


4th April 2010, 11:44 PM
Hi WVOdrvr,

I run a two tank system. In the wvo tank I use 95% WVO and 5% Rug blend.
In the diesel tank I blend in summer 50% WVO, 40%Diesel, 10% Rug. In winter 20% WVO, 70% diesel, 10-15% Rug.

I have stopped the blends now in my start up diesel tank and only add 2-5% wvo to improve the lubrication.

I noticed on the blend when starting from cold carbon deposits were forming on the injectors and glowplugs. There was often a puff of white smoke out of the exhaust which signals unburnt wvo.

I have seen 70% WVO 20% Kero 10% RUG. I used this last summer and my lift pump went out on my Cummins.

I don't know what type of ip you have, but on a blend when you start the engine cold it may add extra strain on the ip if the blend is thicker than normal diesel.

God bless, froggo.

5th April 2010, 01:42 PM
Hi WVOdrvr,

I run a two tank system. In the wvo tank I use 95% WVO and 5% Rug blend.

Do you get vapor lock or anything with the blend? I run 2 FPHE that brings my temp up to 160 to 180 degrees before my lift pump. Will this create pre detonation or vapor lock if I mix RUG??

5th April 2010, 08:55 PM
Hi WVOdrvr,

I run 2x30fphe's and have never had any issues with max 10% Rug during summer.

There is a limit to the amount of Rug you can use so you may need to experiment a bit to find what suits your vehicle.

God bless, froggo.

Jeffrey S. Brooks
7th February 2011, 02:18 AM
I have been running various blends of WVO and unleaded gasoline (RUG/Petrol) since Feb, 2007 on a 1983 Chevy 6.2L diesel with a Stanadyne Rotary DB2 IP. I have started the engine with no difficulty on an 80/20 (WVO/gas (petrol)) mix down to 3F (-16c). I have found that by blending as little as 5% gasoline (petrol) in the summer, and as much as 30% in the winter, the engine starts and runs as if it was running on diesel fuel.

8th February 2011, 11:59 AM
Wth RUG blends I find that cold starts are Ok but restarting when hot can be difficult. The motor will run like a hairy goat for maybe a minute. I believe the RUG is vapourizing in the injector lines etc and doesn't inject nicely till temps normalize downward.
I wonder if the engine compartment being VERY cramped in the Hiace has anything to do with this heat soak issue?

Jeffrey S. Brooks
9th February 2011, 07:52 AM
My engine is almost 30 years old, so it runs a little rough at first on whatever fuel I run on, even 100% diesel fuel. But, I do not have the runs rough hot problem you are reporting.

I doubt seriously if the petrol in your blend is vaporizing in the injector lines, because volitilization is a product of pressure, and the fuel in the injector lines is going to be under high pressure. If you are having a vapor lock problem then it is mostly likely going to occur in the low pressure portion of your fuel supply, which is before the lift pump. And, if that portion is not heated, then you should not be having a vapor lock problem.

Maybe your glow plug temperature sensor is bad, so it is not detecting the the glow plugs need to be powered at hot start.

10th February 2011, 08:33 AM
Jeffrey, you might be onto something here with the point about GP's. I made mine manual switched when all the problems with burning them out was frustrating me. Am planning to re-instate the stock set up there. Thanks.
As a test today, I doubled the RUG amount in the tank and it wasnt any worse.
I'm happy to say I've not had any IP failure and this van has had lots of vege put through it in 5 years come May.

12th February 2011, 11:39 AM
No sooner said, then today power drops away after an hours running around town. I pull over and see streams and streams and streams of bubbles in the return line. I've had this before with mixes that have high % of RUG.
Am wondering if there's anything different with the set up that would cause this. Certainly the cramped Hiace engine bay wouldn't help. Another thing could be the plastic fuel tank, being housed inside the van doesnt get any cooling benefit from passing breeze.
Ambient temps now are approx between 25C and 30C.

Jeffrey S. Brooks
13th February 2011, 12:27 AM
I live in southern Arizona, USA, for more than 50 years. Here temperatures commonly rise above 110F (43c), and most drivers drive motor vehicles that run on petrol but never experience vapor lock. This suggests that ambient temperatures and fuel temperatures of 110F (43c) will not cause bubbles in the fuel line of a diesel engine running an 80/20 blend of VO and petrol.

Now, if your auto mobile is vaporizing the petrol in your fuel blend, then you may have a fuel line heater, which is taking the fuel temperature over 110F (43c). However, I suspect that the bubbles that you are observing in your return line are more likely due to an air leak in your fuel line that has to be on the negative pressure side of your lift pump.

Tony From West Oz
13th February 2011, 03:42 AM
I doubt that the problem is vapour lock, unless your blend is going thru a heat exchanger.

Air leaks are often first noticed when using veggie oil as it is much more viscous (even at 80C) than diesel or biodiesel.

Check your hoses for kinks or for degradation and your hose clamps and threaded fittings for tightness.
Check the fuel filter as some filters with inbuilt primer pumps can have air leaks.
Check the filter is on tight.

In a 300D, I have had one of the newer style primer pumps leak air on the suction side of the lift pump which was a real bitch to find, but easy to fix.


13th February 2011, 05:12 PM
Thanks for the ideas.
Clearly vehicles with modern efi are significantly different than diesel injection systems. One notable difference is the returned fuel set up. This would allow fuel to the injector to remain below vaporizing point. When it's returning fuel to the tank, it can then be cooled by the tank itself being exposed to the passing breeze. The fuel injectors in these set ups are in a manner of speaking: fuel cooled.
Most of what gets returned from my Toyota diesel set up is from the IP itself, with a smaller amount from the injectors return rail. This would mean that any excess heat at the injector couldn't effectively be syphoned off by returned fuel.

There's no heat exchangers in my set up.

This phenomena only appears with blends involving RUG, more often with higher ratio and most often when ambient temps are high. A typical scenario will be the bubbles will appear if stuck in heavy traffic during a hot day. Also what can make the issue worse is shutting down the engine for 30 minutes when heat-soak raises fuel temp in the IP, injectors and lines to the prevailing engine temp.

If I were to consider that the fuel was vaporizing in the IP itself then that could easily explain the power loss, after all the IP wouldnt be happy pumping air bubbles. If I were to consider that it was vaporizing in the injector feed lines it could still explain the bubbles because they could be returned via the return rail on the injectors themselves. I reason that the injectors are the hottest part of the system so bubbles are likely to occur there first.

I'm able to observe all this because I have clear nylon return line in view from the drivers' seat. Also when this happens the return temps we are talking is well in excess of 43'C, possibly closer to 50 or 60. Uncomfortably hot to touch.

I'm considering that having the fuel tank inside the van, somewhat of a design flaw because it can't benefit from the normal air cooling of a standard unit. One thought was to put a cooling heat exhanger on the return line to reduce the tanks temp and allow blends to work better.

Being aware of it means I can drive around the problem or use less/no RUG when I know there's heavy hauling to do etc. I'm going to try and remember to log the fuel tank temp before and after a run. It might be a good bit of info and a key piece of the puzzle.

13th February 2011, 08:03 PM
I've been using WVO since the late 1970's and along with an engineer mate have done many experiments with blends and believe using rug will in the end cost you a lot of money.

Using rug was designed for stopping gelling in diesel for short period and our Aus antarctic division used it for years, but always had IP failures in the generators which ran 24/7 and seasonally they had to rebuild the IPs of every thing because of the damage done by evaporating rug and subsequent build up of additives within it, which are not designed for diesel systems.. Now they do it differently but I don't know what they do as the bloke I knew involved, has retired. On our boat we use an additive which drops water out and conditions the dino and never get gelling, they may use a version of that.

The best blends are bd or dino at 10%, which I use in winter and have never had an trouble and my hj60 has done well over 500000 and the engine as never been touched.

If you purge your IP and injectors with ATF every time you do a service, you'll have no problems for many years at it takes everything out of the system. If you keep things simple, you'll have years of good motoring with few problems.

I'm a bit worried about my cruiser at the moment, I haven't changed a a throw away filter for more than 3000 klms. In the past it's been between 600-1000. I think after so long, the tank is probably fully coated with VO and so nothing grows and super heating my oil before filtering, seems to remove the brown and white stuff that tends to built up in filters.

Not long and the 12ht cruiser will be on the road, rebuilding the entire thing as we weren't sure how long the engine had done and the cooling system was clogged in places.

Jeffrey S. Brooks
14th February 2011, 01:59 AM
tbird650 I too have a clear return line, which, I agree with you, is a great way to monitor fuel line performance. While I have had leaks in my fuel line, I never see bubbles in my fuel line associated with a hot day in southern Arizona, USA, so I do not seem to have the same problem that you are reporting.

While you say you do not have a heat exchanger in your system, if your return fuel temp is 50 to 60c, then it seems there has to be a heater somewhere in your fuel system. Maybe it is a factory electric heater? And, at those temps petrol in your fuel blend could easily be boiling out, but I do not believe you will have boiling on the possitive pressure side of the fuel system, because boiling is a function of both temperature and pressure, so at high pressures even hot petrol would be liquid. But, at 50 to 60c a fuel blend containing petrol would certainly be causing vapor lock on the negative pressure side in your fuel line.

Interesting findings Alga, when you write "I've been using WVO since the late 1970's and along with an engineer mate have done many experiments with blends and believe using rug will in the end cost you a lot of money."

I have been blending petrol with VO for 4 years. In that time I have had my mechanical problems, but I found the cause was not the petrol in the blend, but the fact that blending petrol with VO can cause lacquer to precipitate out of the VO and collect at the bottom of the fuel tank, and accumulate there and eventually work its way along the fuel line and eventually glue the injector pump and injectors shut, so I am willing to predict that the problems that you observed blending petrol with VO years ago may very well have been the lacquer that I observed.

The solution to the lacquer precipitate was simple. I simply blend petrol with VO and settle the solution before filtering the fuel blend into my fuel tank. This causes the lacquers to be caught in my filtering and trapping system before the fuel gets to the fuel tank.

15th February 2011, 04:17 PM
I've started monitoring and recording the fuel temperatures along with ambient air temps. I've only got 1 gauge but hope to get another sorted shortly. This with allow concurrent recording and offer the bigger picture.
The results so far, are surprising. Stay tuned for the report!
There's no heaters or heat exchangers to heat the fuel of any kind in my system. I do have a small side tank which allows a kind of loop system so that returning fuel can be feed back and aid warm up. This side tank is a kind of header which is vented and relies on there being at least a few inches of fuel in the main tank. I only use for warm up only.

There appears to be two distinct phenomena. None of which cause breakdown but are an inconvenience.
The first is what I have called: the hairy goat syndrome, where an engine will run rough or even stall out for the first minute after hot restart.
The second is bubbles in the fuel when using RUG possibly from heat, causing power loss.

Ambient temps are the hottest on record here at present!

Tony From West Oz
15th February 2011, 11:03 PM
Here is one thing to check;
With a cool engine and a cool daay, crimp the fuel line as near to the veggie blend tank as possible so that fuel will still just flow at idle.
Start the engine and monitor for air in the return line.

If the amount of air increases, you have an air leak.

Just wanting to eliminate this as a possible cause of the bubbles.


16th February 2011, 09:01 AM
Hi Tbird,

I am with Tony here as I have been suffering from a little air leaks for quite some time (all fixed now - car runs beautifully). As suggested before, vapour lock does occur in petrol fuel injected motors very occasionally. manufacturers get around this by placing the fuel pump in the fuel tank or someother cool place and limiting the length of fuel line that is exposed to the heat of the engine. I flew light aircraft for quite a while and certain engines are prone to vapour lock only after they are stopped on a really hot day and tried to restart within half an hour or so of shutdown. once started though, I have never seen vapour lock cause rough running.

I would be really surprised if the volatiles in the fuel are evaporating inside the fuel pump or on the pressure side of the pump. the additional pressure should stop any evaporation. if however the volatiles were evaporating AFTER exiting the fuel pump in the return line (this being attached or very close to the engine block) I wouldnt be surprised. This would not affect your running though.

My money is on an air leak. without reading every single post, (I am not sure if you have already tried this or others have suggested it) replace all fuel lines with that clear cheap nylon hose sold at brunnings and see where your bubbles start.

My understanding is that a diesel engine should not run as hot as a petrol engine.

I had some issues that I traced back to the manual lift pump on the filter assembly. replaced the assembly and viola.

16th February 2011, 03:19 PM
This is quite embarrassing as I have been here for a while now.


What is RUG?? :confused::o:o

16th February 2011, 05:58 PM
RUG is an acronym for Regular Unleaded Gasoline (http://www.acronymfinder.com/Regular-Unleaded-Gasoline-(RUG).html).

I'm certain there's no air leaks in my system. If there were, I'd surely see it in my transparent nylon return line.

One interesting piece of the puzzle is that petrol starts to boil (http://www.engineeringtoolbox.com/fuels-boiling-point-d_936.html) at 37'C at atmospheric pressure. There's said to be a number of compounds to petrol, some being quite volatile, which accounts for the variation in the figure.

The fuel temp monitoring is proceeding well. It's a shame I can't immediately test fuels with differing degrees of blend. With a bit of time, I'll have an interesting picture of the factors involved.

One thought was that if petrol, being part of a blend, can vaporize in a enclosed fuel line, pump, etc, then why not re-condense back to total liquid again? This may explain why cold start is perfect.

16th February 2011, 07:39 PM
This is quite embarrassing as I have been here for a while now.


What is RUG?? :confused::o:o

For some reason we're calling it RUG in this thread, whereas we it's normally referred to as ULP in Australia. I suspect this thread is accommodating our overseas contributor/s..


16th February 2011, 09:44 PM
For some reason we're calling it RUG in this thread, whereas we it's normally referred to as ULP in Australia. I suspect this thread is accommodating our overseas contributor/s..


Thanks Tim! :cool:

When I read this (following) I freaked out a bit! :eek:

RUG is an acronym for Regular Unleaded Gasoline (http://www.acronymfinder.com/Regular-Unleaded-Gasoline-%28RUG%29.html).

No offense to the bird! ;)

17th February 2011, 12:31 AM
Hi Tbird,

Just thought of something, why don't you try to heat a SMALL amount over a heat source (not a flame!!!!) and see what temp it actually starts to boil at? it would be a good comparison for your temperature logging that you are doing.

Another thought just occured to me as I am writing this, have you checked your fuel cap / tank breather? maybe the rough running when its hot coincides with a bit more fuel burnt and then fuel starvation because the partial vacuum in the tank is making the IP work harder (if your breather is not functioning)?

It might be worth installing clear fuel lines everywhere though to see if the bubbles are forming before your IP regardless. You havent got an exhaust leak that is blowing on a fuel line anywhere? hopefully your exhaust and fuel lines are well separated though.

I will still be surprised if a vapour lock occurs when the engine is running. from my experience they usually only cause extreme difficulty when starting.

It is an interesting conundrum.

Jeffrey S. Brooks
17th February 2011, 06:33 AM
What is RUG?? :confused::o:oRUG means "Regular Unleaded Gasoline" (petrol)