oil changes when running on veg oil

andyfb78 · Post by **andyfb78** » Fri Dec 28, 2007 6:24 pm

yeah I agree with doughnuts/biscuits, have had a curry smell from one batch of waste oil....guess where that came from....
Chip shops tend to use palm oil which is too viscous (at ave. UK ambient temp), 'veg-oil' is usually rapeseed or sunflower.

You can use a mix (and as far as I know, it is a mix ie solution, not a colloid so stays mixed). but as mentioned earlier, the as the viscosity goes up the the injectors (designed for diesel viscosity) fail to vapourise the fuel properly, leaving droplets and poor burning, leading to carbon deposits in the cylinder, rings, etc. You will also get waxing in the filter unless you heat the system, and this overloads the fuel pump which in turn wears out more quickly...

I have seen some pumps where the shaft has actually sheared trying to force oil through cold injectors.

You can get replacement injectors/fuel system designed for the different viscosity of veg oil, I believe a company called Elsbett will do this 'engine' conversion, but it's somewhat expensive.

I've spent a while experimenting and replacing parts, studying the theory and talking to diesel engineers (Engineers, not mechanics, no offence, but the guys who design the engines) and I have learnt that twin tank is the only way to make the hassle pay off, without the risk to my (well strictly my girlfriend's - no comment needed) splendid bongo..

I am worried that we may start to see some bad results with the bongo crew merrily adding oil straight to an otherwise unconverted bongo, it's a tough, fairly simple engine so I hope I am wrong.....

Andy

andyfb78 · Post by **andyfb78** » Fri Dec 28, 2007 6:26 pm

posting cross over,

yes I agree, they really should be kept apart as far as possible...

bigdaddycain · Post by **bigdaddycain** » Fri Dec 28, 2007 7:28 pm

The Great Pretender wrote:
B D C did you test the viscosity of diesel only, veg only and mix?

Alas no TGP... It was a very quick unscientific check of the uniform viscosity of a 30% veg 70% diesel mix in a 25 litre container which i'd had stored in the shed for a few weeks.

I was just curious enough to give it a quick timed flow rate check (1 litre from top, then 1 litre from the bottom) without agitating the container previously too much.

The rate was the same from the bottom,as it was for the top...

This would imply to me that if properly mixed originally,the mix stays in that state... (well for a few weeks at the very least)

Which further suggests to me that the same scenario would be true for the contents of the fuel tank.

Its by no means a definitive laboratory test,but i'd say it was indicative of "real" test results.

mikeonb4c · Post by **mikeonb4c** » Fri Dec 28, 2007 7:54 pm

andyfb78 / TGP - thanks for filling me in on the pros and cons of veg oil use. I've yet to take the plunge. I'm only using about 1 tank per month at present so the economics of fitting a kit don't really stack up esp. with so many short runs, even though I like the idea. But if things change, I may come to you for advice on fitting options etc.

andyfb78 · Post by **andyfb78** » Sat Dec 29, 2007 12:24 am

Crikey! I'll do my best to answer any questions, but I don't even pretend to be an expert.
But I'm quite happy to go through what we have done, including tank wise (the biggest tech hurdle). The rest is as per the dieselveg website, which is pretty informative, even though it might appear to be marketing speak...

if I ever get round to washing it, coz it doesn't look like a bongo at the mo, I'll take some pics of the conversion and tank solution, and if I then ever figure out how to post pictures I will do so.....

cheers

Andy

mikeonb4c · Post by **mikeonb4c** » Sat Dec 29, 2007 12:51 am

Thanks Andy - I (and others I reckon) would be v interested to see pictures. We are all also waiting with interest to hear from Torchwood about his fuel heating coil idea works out plus his plan to have a small diesel 'start-up' tank in the engine bay

The Great Pretender · Post by **The Great Pretender** » Sat Dec 29, 2007 1:02 am

mikeonb4c wrote:Thanks Andy - I (and others I reckon) would be v interested to see pictures. We are all also waiting with interest to hear from Torchwood about his fuel heating coil idea works out plus his plan to have a small diesel 'start-up' tank in the engine bay

There are a number home made ways to heat the veg oil to reduce viscosity. The most efficient way is is to use what the c/h industry use in combi boilers a plate to plate heat exchanger.
Do you think a fuel tank next to a hot engine would go down well with the insurance company?

This is something I thought would reduce reliance on powered valves by using 1 way valves and fuel pumps.

andyfb78 · Post by **andyfb78** » Sat Dec 29, 2007 12:53 pm

The diesel veg kit is basically:
-a plate type fluid/fluid heat exchanger, sized for your vehicle.
-two solenoid switch over valves (one for feed, one for purge)
-a top up electric heater (built into the valve) this is what you pay for really, from ATG in Deutschland......
-electrickery (standard double make relay, and an adjustable timer relay for the purge control)
-control switch
-buzzer thangy
-loads of hose
-and a plastic tank (I opted out of this and made my own to fit under the sliding door).
plenty of info on their site if you wanna create your own, and they'll sell the bits separately should you wish.

mikeonb4c · Post by **mikeonb4c** » Sat Dec 29, 2007 2:12 pm

Diesel tank in the engine compartment. Yes I wonder about that too. maybe Torchwood might drop in and comment. Not sure that a sensibly sited diesel tank in that area necessarily represents a serious hazard, but with insurance companies perception is everything.

-and a plastic tank (I opted out of this and made my own to fit under the sliding door).

I'd love to see a picture of that. One of the things about conversions is that you may end up with a tank taking up space inside the vehicle, and I wouldn't want that.

The Great Pretender · Post by **The Great Pretender** » Sat Dec 29, 2007 7:30 pm

This site has 100's of tanks to fit most vans and campers unfortunatly at the moment it is being revamped so you need to send for a catologue.

http://www.caktanks.co.uk/index.html

Towsure do marine fuel tanks very cheap.

http://www.towsure.com/category/6496-Tempo_Fuel_Tanks

Mike at Wheelquick is waxoiling my Bongo tomorrow so im hoping to check it out underneath for tank space.

neepboy · Post by **neepboy** » Sun Dec 30, 2007 6:24 pm

Ive heard thro the pajero forum that 1 ltr of white spirit added to 20 ltrs of veg oil mixed well and left for a week results in a mix that is within 4% viscosity of derv. straight svo is 26% more viscous than derv.
hopes this helps

The Great Pretender · Post by **The Great Pretender** » Sun Dec 30, 2007 9:56 pm

neepboy wrote:Ive heard thro the pajero forum that 1 ltr of white spirit added to 20 ltrs of veg oil mixed well and left for a week results in a mix that is within 4% viscosity of derv. straight svo is 26% more viscous than derv.
hopes this helps

Cant comment on the amount of viscosity reduction, but yes it does thin it.
Be aware though white spirit is banned as a road fuel.

brorabongo · Post by **brorabongo** » Sun Dec 30, 2007 10:28 pm

The Great Pretender wrote:
Cant comment on the amount of viscosity reduction, but yes it does thin it.
Be aware though white spirit is banned as a road fuel.

Is white spirit ok due to not being Kerosene based? as seen here:-
http://www.youtube.com/watch?v=GOFbsaNeZps

Plus remember this was filmed before the tax change on veg oil use.

The Great Pretender · Post by **The Great Pretender** » Sun Dec 30, 2007 11:16 pm

Very misleading video, just get some used oil, strain it through a j cloth, add white spirit and any diesel car will run on it, SCARY.

They are correct, it will run, wont last though.

I have been trying to look up white spirit as a banned substance but hav'nt been able to find it. It seems that on this very rare occasion I may and I restate may be wrong.

The definitive site IMHO for all things vegtable or bio is......................

http://www.vegetableoildiesel.co.uk/forum/index.php

bigdaddycain · Post by **bigdaddycain** » Mon Dec 31, 2007 12:11 am

That schematic you posted seemed familiar T.G.P....

Nice to eventually meet up with you today and discuss the various systems on offer

It's certainly food for thought....

oil changes when running on veg oil

veg oil viscosity

Re: veg oil viscosity

Re: veg oil viscosity