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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
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Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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![[*]](./images/onepoint9/default_icon.gif) posted on 5-8-2006 at 02:25 AM |
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Veggy Oil And The Modern Direct Injection Diesel
Ive been asked a couple of times lately, the effects of Veggy Oil and Single-Tank 'Conversions' to Direct Injection type Diesel engines, so I thought
I would put all down here for reference, instead of going over it many times---
Nearly all Post 2000 Diesel vehicles are of this type, There are the odd exceptions but not many...The reasons why the Makers have gone over to Di
type engines are-Cheaper to produce, and an increase in Volumetric Efficiency--Less Pumping-Losses... (basically you can get more power out of the
same capacity engine. However, This comes at a cost-The Di type engine is a lot more tempremental as to its fuelling and timing requirements with
relation to its smoke and other emissions-
-- No Problem though, We, -The Maker Of Your Choice, will chuck a Microprocessor at it, to control all that-- Much Cheaper than all the time and extra
machining of a Pre-Chamber engine, and we can use the Same Engine in the basic model AND the top of the range Sporty Model, Just a few different
Plastic-Covers, and there you go!...All we need to do for the power differences is change Firmware Code in the EEPROMS! Just Perfect, Give that
technician a FAT bonus! ) --
Cheapskates the Makers really--Pile 'em High, Sell 'em Cheap, Stick a DVD in the back and lots of pretty plastic covers on the engine (To Hide The
Truth maybe!)...Pander to the Masses demanding Ever More Power, and clean up the exhaust with cunning electronics and exhaust 'filters' as well as the
weird Cerium based additive 'modules' needing replacement at a cost of Hundreds every year or so......(They LOVE those things!)
To get back on track, Now Ive done my soap-box bit, What does this mean for veggy oil as a replacement 'fuel' for these Direct Injection modern
beasts?
It gets a 'little' technical, but not too bad, Worth plodding on, It is however assumed that the reader knows in principle the operation of the Diesel
Engine.....
As has been described elsewhere, The first small Car Diesel-Engines were Indirect Injection, Meaning the fuel was sprayed by the Injector into a small
Ante-Chamber known as a Pre-Chamber or Swirl-Chamber, normally contained within the Cylinder-Head. This chamber was connected to the main chamber by a
tangentally arranged narrow passage or by small holes as in the case of the Mercedes Pre-Chamber type.
This was needed to be done, as a huge amount of Turbulence is needed to effectively mix the air and diesel-fuel spray in the tiny amount of time to
allow high speed operation and make for a very Progressive Burn, rather than a sudden explosion. If the fuel didnt burn at a controlled and
progressive rate, it was found not to be possible to run the engine at high speeds without major noise and smoke emissions.--Something tolerable with
Trucks in the '30's but Not cars of the '70's and 80's when Diesel Cars started creeping on to the scene.
There are generally Two Types of 'Pre-Chamber' or Indirect Injection engine. The Mercedes System, where a small spherical chamber is connected to the
main chamber by a blind ended tube with several small holes set at right-angles to the piston axis. Contained in this spherical chamber, there is a
'Hot-Spot', formed by a small rod with an enlarged central section. This is in direct line of 'squirt' from the injector and allowed to run at very
high temperatures--Around glowing orange heat This promotes a good vapourisation and ignition of the fuel and a really well controlled progressive +
quiet burn....
The other system, developed by the Combustion Engineers, Ricardo's (Yes, The same guys of the Infamous 'Report'), developed in the '30's and called
the 'Ricardo Comet' design is used by nearly every other car engine maker using IDi technology. This as mentioned earlier is a semi-spherical chamber,
with the Injector at the top, mounted at an angle as to Not direct its spray down the throat of the communicating passage from the main combustion
chamber. This small passage is set at an angle to the sphere, so as air is compressed in the cylinder, it will be forced into the pre-chamber with
some force and at just the right angle to cause the air-mass inside the chamber to swirl at very high velocity, just like a whirl-wind
The lower half of the sphere containing the tangental passage, is made from a special autenitic Stainless-Steel and deliberately allowed to run at
very high temperatures, by reducing its contact area with the actual metal of the cylinder-head into which its pressed (Its outer cercumference has a
recess in it, below the face of the head...)
This promotes excellent mixing and vapourisation of the injected fuel as well as a good progressive burn.
As can be seen, With the IDi system, There is MUCH less likelyhood of Unburned Fuel making it the distance involved to the cylinder-wall, without
first vapourising and burning away.
Consider the Direct Injection type engine. Here, the Combustion chamber is formed in the top or 'Crown' of the piston. Usually it forms a bowl
sometimes with a flat bottom sometimes with a raised bottom Often there is a small ridge of around 1mm around the top of the bowl, an attempt to
contain the combustion 'charge' and promote turbulence during the last few mm of upward piston travel, causing 'Squish' of the air between the head
and piston, forcing the air towards the centre of the chamber. The Inlet-Manifold and valve-tract is often very carefully designed to cause 'tumble'
of the air as its drawn into the cylinder through the open valve, to promote as much Turbulence in the air-mass as possible.
There are NO hot-Spots or anything like that to assist in the vapourisation of the injected fuel, as well as the fact that the piston-bowl runs at a
very much lower temperature than a Pre-Chamber or M.B 'Hot-Spot', as the piston is made of Autothermic Aluminium Alloy and cooled quite effectively by
the cylinder-walls and the lube-oil from underneath, flung up from the crank-pin and connecting-rod...
Being a large open chamber, in comparison to the Swirl Chamber types, with nothing much between the cylinder-wall and the injector there is a Huge
likelyhood even on the best designs and everything perfect that unburned and or partially burned or 'pyrolised' fuel will hit the cylinder-walls
Another factor in favour for us 'Veggies' of the Venerable IDi is the type of Injector used with the IDi system. Generally, this is a 'Pintle' type.
meaning that its rather like a needle-valve, where the needle protrudes slightly from the hole, in the face of the nozzle and during normal operation
the movement of the needle lifting will keep the hole and needle pintle fairly clean of coke (Carbon to us Mortals!)
The Di system generally uses a 'Hole' type injector Usually, up to eight tiny, and I MEAN TINY holes are arranged in the nozzle tip. these are Very
short passages, their inner end is closed off by the nozzle needle when its not actually spraying fuel. They are kept as short as is mechanically
possible to reduce the amount of fuel that will slowly boil off and vapourise due to the heat of combustion just after injection has finished, which
would otherwise raise smoke and emission levels.
Consider the effect that even a minute amount of Carbon build-up would have on this type of injector nozzle...It would completely disrupt the correct
operation of the nozzle, and instead of a very fine spray, one or two holes could literally produce a jet of un-atomised fuel, just like a
water-pistol....
So,--Why should I care if unburned veggy hits the cylinder-walls of my pride and joy...?
Just Two Words....
RING-GUMMING.........
When exposed to heat and oxygen Veggy-Oil will start to break down. It starts to thicken and polymerise and as time goes on, it turns from a sticky
brown 'goo' into a hard black Coke/Carbon material. Just take a look at the frying-pan in your favorite Greasy-Spoon!
Any unburned veggy or partially burned veggy hitting the cylinder-walls will find its way to the Piston-Ring grooves on the next upward stroke of the
piston. This veggy will collect in the gap behind the rings and the small clearances either side of the ring and piston. As time heat and plenty of
oxygen are available, it breaks down and sets solid, sticking the ring in its groove, so it can no longer follow the irregularities of the
cylinder-wall and seal the piston, as it was intended.
This ring gumming is slow and progressive, The speed at which it happens is dependent on Many factors The main ones being the temperature of the
combustion-chamber and the condition of the injector atomisation, but as it progresses, gets faster and faster, at a weirdly logarithmic rate...
This causes loss of compression pressure gradually over weeks/months of use. which contributes to the secondary effect....Often the slow and
progressive slight power loss may not even be noticed, or blamed on other issues, such as blocking filters or the choice of veggy oil or even the
weather (No one wants to admit even to themselves there's something nasty growing in the Crank-Case!)....
(A Diesel Engine relies on the fact that when air is compressed, it gets hot, just like the effect noticed when pumping up a bicycle tyre. It depends
on this heat for the ignition of the fuel. If for some reason there is a loss of air, say, from leaky rings, the peak temperature attained by the air
at the point where the piston is at Top Dead-Centre, A.K.A. Top of the cylinder, the point of maximum compression pressure, the air will be cooler
than intended, thus there is a very real danger of incomplete combustion, or even a complete Misfire, where the veggy wont burn at all, Pale bluish or
White-Smoke in exhaust and maybe an unsteady engine when idling)
Not all the veggy is burned Particularly when cold, so this just adds to the supply of 'Ring-Glue'
As it progresses, the amounts of unburned veggy in the combustion chamber/cylinder, increase where it will pass to the lubrication oil by the
operation of the oil control rings scraping it off the bores. The Oil Scraper/Control rings, being the lowest on the piston are last to be affected,
The Top ring, which is the main sealing ring and subject to the full force of combustion pressure is first to go...
(Just as well the Oil-Control ring is last to go, or the engine could have otherwise end up in a runaway condition where it burns all its lube-oil in
a minute or two and hits revs the makers would never have dreamed possible...The danger to life when driving a vehicle when this happens is better not
even imagined, You CANT SHUT IT DOWN!....although I dont need to imagine it...Its happened many years ago to me....)
This ring gumming is Progressive and Accelerating Process, Thats why its so Insidious!
The Veggy builds up in the engine lube-oil....
There comes a 'Critical Mass' point, (although before this, it can thicken to some extent but without careful testing the amount of contamination
cannot really be assessed),- where the Mineral Lube-oil and the Veggy oil are in the right proportions with the normal engine heat and other forces to
react to form a polymer, and on that fateful day the engine cools after the 'Critical-Mass' has been reached where the lube-oil will set solid, just
like jelly!
-Seen it happen, Very strange stuff is evolved...Same consistancy as Dessert Jelly, with the wobble and shake to boot, but greenish black opaque and
covered in a clear yellow thin oily fluid. It has a slight but weird almost linseed/white spirit type smell too....
Next engine start, you'll not have any oil pressure, and if not noticed, engine destruction will occur within minutes.....
IF the Lube-Oil is changed, then the risk of Polymerisation is removed....For Now...
The Ring-Gumming continues its destructive course, untill the point that there is insufficient compression to attain combustion at all. The outcome
is the engine just will not start, Maybe a tow-start will get it going but it will soon die perminently!
OK, So you keep an eye on the Lube-Oil level....Great, Spiffin, Marvelous!
This will only tell you that incomplete combustion and ring problems have already started, if you see an increase in level....
You could have an engine, maybe not in its first flush of youth or just because of its design, that normally uses a small amount of Lube-Oil anyway,
so the slow dilution with veggy will keep pace with its normal oil use....The lube dilution will then not be noticed, or maybe mistaken that the
engine is no longer using up its lube-oil....The outcome is inevitable....
I hope this will prevent just one engine self-destructing on veggy oil and explains the Importance of a Twin-Tank system for the Modern (and Not so
Modern....) Direct Injection Diesel engine...
If it does, then my efforts are rewarded...
Alastair Bowlie-Evans,
A.K.A, H.C.II, At- Public Information Divn, SWC
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Update for addition of information on the different types of Vegetable-Oil, particularly Soy/Soya based oils, and Fuel Duty issues., 23/2/08
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Soy Oil issues—OR—What IS your WVO...?...
I recently did some testing of my own to confirm the testing done by a German Co, (I forget who) and that was recently posted on this Forum.
Similar to the testing done by the Germans, I was using GM Soy oil, running through brand-new injectors, and new heat-shield washers. The test-engine
was a M.B. OM-602 in my 190D 2.5 These were run for 500 odd miles, consisting of roughly 50/50 motorway and 'commuting'/round town pottering
The Injectors were then removed, dismantled and examined. They were heavily carbonated and both the needle and pintle were gummed, with a
greenish-yellow matte coating. During the use of the vehicle nearing the end-of-test there was also a noticeable amount of smoke when the engine had
been run, but Not fully hot-just 'warm', No excessive smoke on start-up, or when fully hot, and otherwise appeared to function normally....
I did the same using Rape-seed after chemically cleaning the injectors and after a similar mileage again examined the injectors. While there was some
carbon present it was very much less than on the Soy oil, with no gumming or yellowish/greenish deposits/gums of the needle and pintle The odd effect
of smoke on a 'warm' engine was not present at the end-of-test, and has not returned running Rape-seed oil
The engine is in a completely Standard state of tune, no timing alterations or H.E etc...--Not that any mods would help the carbonisation/gumming of
Injectors taking place when using Soy oils anyway.....
Types to stay away from (Particularly if your engine is of the Direct-Injection type) are the Soy oils or Soya-bean oils, (As well as the GM Modified
Soy--The cheapest in the Warehouses....) as these have been proven to cause carbonisation/gums in Injectors and combustion-chambers-
-A Di type Injector cannot tolerate much in the way of contamination before becoming inefficient.....
An Indirect Injection engine with its Pintle-Injector has the advantage that it doesnt get quite as hot, (But still quite hot enough according to my
findings...) and is almost ‘self-cleaning’ in its operation, Unlike the ‘Hole’ type used with a Di engine....
The problem with this type of oil is it breaks down at the temperatures seen at injector nozzles, 250-300 deg.C and without Oxygen being present. It
'polymerises' caused by the temperatures causing the long-chain molecules 'cross-linking'--Basically just like Linseed oil, It dries, but unlike
Linseed it 'polymerises' without the presence of air, just the heat is enough. Rape-seed oil is much more resistant to this effect
This 'damage' happens mainly during the cooling down of the engine, when there is a high % of Soy-oil in the system, and during times of low fuel flow
through the injectors
It has been speculated, that a percentage of std. Diesel fuel blended with the Soy oil can reduce the effects of this polymerisation/carbonisation. I
have neither confirmed or tested this theory.—A job for Summer-time I think!
There is a definite difference in the exhaust smell of Soy oils and Rape-oils.
Soy (To me,) smells of a BarBQ on fire, a burnt sort of meaty smell, while Rape smells of a fresh chip-pan cooking, and not a 'burnt' smell....
If you plan to use WVO (Waste-Veggy Oil) the only indicator that you may have as to the type of oil you are collecting, is the containers you are
collecting it in, if they are supplied by the chippy etc, These are often the same ones the oil came in when new, the old oil being re-filled into the
empty containers for disposal after use--But-This isnt always the case....
Unfortunately, not all containers from all suppliers say exactly what type of oil they contain, and those that do only in the 'small-print' like on
the KTC bottle-in-box stuff, if its just called 'Pure Vegetable-Oil'....
Currently, (as of June last year 07) The current Road Fuel Duty situation allows the 'private use' by Individuals of up to 2500 Litres per year of
BioDiesel (By fiscal definition.....) without the need to register and pay Duty to
the HMRC--If in doubt, Post a Q in the HMRC thread for up to date information
[Edited on 23-2-2008 by High Compression II]
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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Pav
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Location: West Midlands, UK
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| posted on 5-8-2006 at 10:14 AM |
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I agree totay twin tank on my frontera so far so good
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norite
Posting Freak
Posts: 1178
Registered: 1-8-2006
Location: The North East
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Mood: On the veg and loving every mile of it...
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| posted on 5-8-2006 at 10:42 AM |
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You know, this is so flipping stupid coming from the vehicle manufacturers. Surely they *must* know something about what diesel engines were supposed
to run on in the first place. I don't understand why they can't make their modern CDi or HDi engines and injectors tolerant of veggie oil in the first
place, or at least offer this as an optional extra.
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
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Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 5-8-2006 at 11:31 PM |
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Edited thread to add this unfortunate tale of Lube-Polymerisation. Its been copied from the thread,
POLYMERISATION.
Hi All,
I've just read High Compression II's post on ring gumming etc, and thought I'd copy a post I left on the Toyota Landcruiser Owners Club web site.
I drive a 1991 80 Series Toyota Landcruiser. She has a 4.2 TD, and any further info is in the post.
Hi All,
I thought I’d share my experience with you as it may save some of you who run on veg oil some money!
I converted my 80 series about 2 years ago to run on veg oil. I bought a kit from DieselVeg, and fitted an OEM auxiliary tank and dual filler. I also
adapted the kit by fitting a second fuel filter, and having the return line switch between tanks instead of it looping back to the pump ala
DieselVeg.
I initially ran on new veg oil, and then switched to used oil that I filter to 1 micron. I’ve had a few problems. The fuel pump started leaking, and
all the seals were replaced. I’ve had diesel bug twice, and I suspect that the pump is leaking again, but I’ve yet to find the leak! Generally I’ve
been very pleased with the conversion, and apart from the problems with filtering the oil in winter it all works well. The latest batch of oil I have
seems to have a little water held in suspension, and I’m seriously thinking of going down the centrifuge route to clean the oil.
As advised by DieselVeg, I change the oil on a regular basis, to avoid any potential problems with Polymerisation. This is generally about every 3
months (3500 miles).
I recently had 4 months off work, and didn’t do many long distance miles. I returned to work recently, and on my way home ( 200 mile round trip) I
felt that the car was a little sluggish when overtaking, but I’d been working all night, was not thinking straight, and put it down to the oil not
being as clean as I’d like.
The next day, I was planning an ATF and engine oil change, and took the car for a drive to warm the oil. About 1 minute down the road, I thought the
engine was a little clattery. I pulled over, wound the window down, and was greeted by a range of intermittent noises not pleasing to the ear. I
immediately turned back home, and noticing that I had no oil pressure, shut the engine down. I pulled out the dipstick which was bone dry. I walked
home and returned with some oil. The oil filler cap had thick jelly deposits and the warning bells were now at klaxon level. The car started instantly
with full oil pressure and I drove home.
So far…………………….
I’ve flushed the engine twice.
I removed the rocker cover, and cleaned the jelly like polymerised oil from all the nooks and crannies. The cam shaft was undamaged.
The turbo was sent off to Turbo Technics and was a write off due to oil starvation. Part of the casting was cracked (age related), and I’ve bought a
reconditioned unit.
I dropped the sump, and recovered about a litre of polymerised jelly from the sump. I’ve cleaned as much muck out as I can from below, and have
removed all six big end bearings. All were fine apart from number 4 (from front) which was scored and has left a slight ridge on the journal. This
should polish off. I had replaced the bearings about six months ago.
I’ve done a compression test. The manual states this must be done when the engine is hot, so it’s difficult to relate the test to their figures. All
showed signs of wear, number one being the worst in terms of initial pressure readings. The manual recommends adding a small amount of oil to the
cylinder, and a further test. I don’t have the figures with me, but some showed an increase of about 80 psi, one increased by about 280 psi.
I’m no mechanic, but having spoken to the 4X4 garage who do my MOT’s, and lent me the compression tester, it is a strong possibility that while I was
off work, the engine was not getting up to temp before I switched over to veg oil. The rings have either gummed up, or are worn enough for the higher
viscosity veg oil to enter the sump. It has also been suggested by Julian (ELCO List) and the garage, that over fuelling could be a problem. This is
backed up by the black smoke on acceleration. I am going to take the head off and replace the rings. I will also send of the injectors for a service.
Any recommendations?
I had hoped to be able to take off the ladder frame that holds the main bearings in place to inspect the bearings for damage. I don’t think I can
remove the frame with the engine in situ, and so my dilemma now is whether to remove the engine in order to have a look at the main bearings, or do as
both the 4X4 garage and my mechanic neighbour have said, and leave them alone. Their rational is as follows:
a) The engine was designed for operation in parts of the world where mechanical abuse is likely to be high.
b) The oil feed to the main bearings is greater than the big ends, and seeing as the cam, and 5 out of six bearings are okay, the chances of the main
bearings being damaged are small.
Any advice from people who have physically changed their own main bearings would be much appreciated.
I’m normally fairly diligent at checking the oil, etc but this time I didn’t. If I’d pulled the dipstick and checked the oil, none of this would’ve
happened. I could kick myself.
So that’s my story so far. I hope that this will be of use to someone, and prevent a similar occurrence.
Regards, Ian.
[Edited on 28-3-2008 by High Compression II]
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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HMRC-00
Member
Posts: 209
Registered: 10-6-2006
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| posted on 6-8-2006 at 12:18 AM |
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well HC II dont cars have to be disposable now they are fully computerised?
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CHIP
Posting Freak
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| posted on 6-8-2006 at 12:23 AM |
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My cars were generally disposable before I got them 
SVOLOCH
Vegetable oil powered through Andorra, Belgium, England, France, Luxembourg, Netherlands, Scotland, and Spain.
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HMRC-00
Member
Posts: 209
Registered: 10-6-2006
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| posted on 6-8-2006 at 12:43 AM |
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yes CHIP.........'were'....................wont be for much longer....................
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DjDemonD
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Registered: 3-12-2005
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| posted on 6-8-2006 at 11:12 PM |
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Excellent explanation of the differences and of the causes and effects of ring gumming... really informative and well written... but
can you explain why the two tank system will reduce this effect... as far as I can see from the article written here ring gumming might occur in a DI
engine due to unburned VO collecting in the piston rings and is an effect produced by differences in the injection method. But how is having this VO
heated and supplied from a second tank going to make any difference, is it less likely to be unburned if it is injected with lower viscosity and
already carrying some heat with it?
DjDemonD
1999 Astra 1.7TD estate on SVO 100% twin tank - now sold
2000 Omega 2.5td 6-pot to SVO twin tank - now deconverted but did 30k on 100% SVO - DEAD INJECTION PUMP
1992 Mercedes 300D single tank now full return single tank, done 3000 miles on 90% SVO (summer) - problems solved after replacement fuel tank and
lines - DIFFERENTIAL FAILED BEING BROKEN PARTS MANY PARTS AVAILABLE
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HMRC-00
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| posted on 7-8-2006 at 12:24 AM |
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Hi Dj think you have got it in 1. If the viscosity is the same, it is heated.
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
Member Is Offline
Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 7-8-2006 at 11:08 AM |
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| Quote: | Originally posted by DjDemonD
Excellent explanation of the differences and of the causes and effects of ring gumming... really informative and well written... but
can you explain why the two tank system will reduce this effect... as far as I can see from the article written here ring gumming might occur in a DI
engine due to unburned VO collecting in the piston rings and is an effect produced by differences in the injection method. But how is having this VO
heated and supplied from a second tank going to make any difference, is it less likely to be unburned if it is injected with lower viscosity and
already carrying some heat with it? |
Its NOT the viscosity At The IP which is the issue....
Its the TEMPERATURE of the Combustion Chamber....
The Engine MUST be at Full Operating Temperature, BEFORE CHANGEOVER to Veggy to minimise the possibility of Unburned Fuel situation. The Injectors
should be changed if worn/well used too...
The Veggy Injected, will be at Whatever Temperature the Injector is at....This is worth remembering.....
Heated veggy will VERY quickly cool on its way to the Injector as the flow is very small to an injector The sheer Mass of metal that is the
fuel-injector/Cylinder-head will be unaffected by a tiny amount of hot veggy entering it. Veggy has half the specific heat capacity of Water....
If the engine is cold, so will be the veggy injected...Nothing much will change this, apart from getting the cylinder-head and therefore the Injectors
HOT!....
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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Darren
Posting Freak
Posts: 1180
Registered: 11-2-2005
Location: SouthEast UK
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| posted on 15-8-2006 at 12:17 PM |
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There are a number of German companies supplying good quality single tank conversions for modern direct injection engines.
As HCII states the main problem is cold starting. The engine has to be in good health and modifications are made to increase the combustion chamber
temperature for cold starts. Having the glow plugs glow for and extended period can help a lot as can fitting a heater to pre heat the engine coolant
for 1/2 hour + before starting. Modifications to the injectors are also required for rotary pump tdi engines. The only company to offer a DIY kit is
Elsbett and that is only for the volkswagen audi group tdi vehicles and a Renault dti engine. Their kits come with some warnings. Watch lube oil
level closely and stop running SVO immediately an increase is noticed (then identify the engine problem), try to keep engine rpm over 2000 when ever
possible. Turn off engine rather than leaving it ticking over when not driving (even long waits at traffic lights - also recomended in vehcile owners
manual for fuel saving reasons). Use a coolant pre heater before cold starting (altough Elsbett have said this is unecessary in UK temperatures).
Halve the oil change interval and use a vegetable oil based lube oil - Plantomot (from what I hear Biomot is very similar if not identical). Avoid
short journeys whenever possible......
All this having been said I know of numerous (hundreds) of Elsbett single tank Tdi conversions - very few have had problems. Not changing oil at the
right intervals, converting a vehicle that has been 'chipped' for performance, high milage engines that were converted and had problems from engine
component wear (not unusual on diesel)
From what I have heard the other German single tank DI conversions are more technically advanced (and expensive!!!) Also Elsbett are about to
introduce a kit for the Pumpe Duse VW TDi which will use an ECU remap. I imagine (and have heard) these will provide better SVO combustion than with
the rotary pump Tdi engines Elsbett kits.
Fuel quality is VERY important all companies require DIN standard fuel oil. If you want to fuel with used cooking oil you should either be very
careful with your fuel quality - use only lightly cooked oil and be careful to remove water and particles watch for the oil viscosity as the
temerature starts to fall- or use a twin tank system
I was working with a company which fits Elsbett equipment - but no longer.... I'd recommend their technology above a twin tank if your situation
suits.
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
Member Is Offline
Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 17-8-2006 at 03:18 PM |
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Hi Darren!-
Good addition to the thread....
I am aware that Elsbett and others supply single-tank for some Di and modern systems, but I tend to err on the side of caution when dealing with the
Di type, as I know you are too...
I thought that you were an Elsbett Agent? (Ive actually recommended a few guys more local to you than me contact you for the Elsbett kit over the last
year or so. I would have taken on and supplied their kits But they require you NOT to supply Any Other equipment apart from theirs....:mad
What happened?
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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fatattack
Junior Member
Posts: 91
Registered: 10-7-2006
Location: london
Member Is Offline
Mood: impotent rage
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| posted on 17-8-2006 at 05:00 PM |
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As the main problem with di engines seems to be incomplete combustion (pump issues notwithstanding), has anyone considered fitting an on-board
hydrogen/brown's gas generator. This is, as far as i am aware, the only after-market device that consistently shows large improvements in economy and
emissions. The ones on the market dont seem too sophisticated as the amount of gas produced is constant no matter what the throttle, but still get
big improvements. Surely there is someone cunning enough on this forum to develop one with a computer chip, an exhaust sensor, and a variable current
input/gas output? I'm sure they would make a mint - I'd invest in it. And it could solve the problems of unburnt svo and coking.
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
Member Is Offline
Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 18-8-2006 at 12:12 AM |
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The use of LPG has for some years been done on diesels to improve mpg/power. I guess such a system Should improve the Di Intolerance to veggy when
cold, but extensive testing would need to be done and on various makes/types of engine to confirm its effectiveness....
It also would increase the cost of the conversion by several hundred pounds...Something that would put many off the idea maybe...
Problem is, the Huge amount of electrical power needed to produce any usable quantities of gas. Note the electric welder needed in most Online
examples of Browns gas experiments....
(An electric welder can supply 200A at around 50V in some cases, This is around 10KW, over ten times the power your average heavy-duty car Alternator
produces.....)
An alternative maybe--
This--http://quanthomme.free.fr/pantone/realisations/FrancePMC5.htm
All in French, but is using the exhaust heat to catalise a mixture of water and hydrocarbons to generate a gas which allegedly runs an engine...
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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fatattack
Junior Member
Posts: 91
Registered: 10-7-2006
Location: london
Member Is Offline
Mood: impotent rage
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| posted on 20-8-2006 at 04:08 PM |
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I dont think a fitted hydrogen/browns generator will use much electricity. Remember "usable" in this context is a tiny amount just to affect the
combustion characteristics - not as a fuel in itself. Presumably this works because of the wide limits of flammability, and probably some other fancy
science affecting combustion (maybe pushing equilibrium, perhaps creating some useful intermediate radicals, etc etc). Methane has a similar effect,
but less so than hydrogen, and lpg less than methane, but still useful. I think methane lacing has been used for oil-fired turbines for this effect.
As the tests for hydrogen generators show significant improvements in mpg, it must be assumed that the extra efficiency that it provides the
combustion must well outweigh the electrical drain on the engine.
I imagine a good hydrogenerator might cost a few hundred bob, but if you get an extra 30% mpg as well as safely using svo, it might be attractive.
Definitly agree about the testing. I think there is good potential if developed beyond the sophistication of currently available products.
I think the french site is based on the same principle as coal gas, ie heat complex hydrocarbons with water and get carbon monoxide, hydrogen,
methane, methanol, and other light hydrocarbons. This might be a way of getting petrol cars to run on fat. I think i asked something similar on
infopop a while ago but the replies basically said that the reaction needs to be tightly controlled so not feasable. But the french site seems to
contradict this.
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Kangooist
Newbie
Posts: 0
Registered: 26-8-2006
Location: Panamà
Member Is Offline
Mood: wondering
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| posted on 26-8-2006 at 05:47 AM |
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Hey Friends,
Another newbie here. I'm also kinda new at the Internet and the way these things are formatted. How does one find the Archives? No, I'm not
joking.
Thanks
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Kangooist
Newbie
Posts: 0
Registered: 26-8-2006
Location: Panamà
Member Is Offline
Mood: wondering
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| posted on 27-8-2006 at 02:21 PM |
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So, I found the archives. I didn't find a list of various cars that are convertible to WVO:
I am presently in the USA. I am inserting that so those who know how to see where a message is coming from won't call me a liar. But, in Panama,
yes, down by the famous canal of the same name, I own a small fleet of Renault Kangoos. they are 1.9liter diesels. The oldest is 2001 and the newest
is 2005. The gas petrol and diesel prices there are almost always the same as in California, or just a bit above USA averages, but down from Europe's
and UK's as I understand. I know not whether they are direct inject or not, nor am I where I can find the pump to look at it. I asked my guy there to
look and he couldn't locate it. I did find an article in German on the net talking about Kangoos, but I am limited to English and Español.
So, Does anyone know abouit Kangoos? I am told that they are available on your island, but maybe not in diesel.
Any info I can get would be useful. I will be travelling in mid October and would like to purchase a kit for conversion of one of them for when I get
back there.
Thanks for any help available including links to someone who sells kits.
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W.B.
Junior Member
Posts: 14
Registered: 31-8-2006
Member Is Offline
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| posted on 4-9-2006 at 03:15 AM |
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just wondering what people can do short of taking apart or replacing the parts to fix coking.
any chemicals that could help?
-Wb
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
Member Is Offline
Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 9-9-2006 at 12:15 AM |
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| Quote: | Originally posted by W.B.
just wondering what people can do short of taking apart or replacing the parts to fix coking.
any chemicals that could help?
-Wb |
No, Not that I know of--Imagine trying to clean that fry-pan at your greasy-spoon without actually being allowed to touch it with any implements Hard
baked on solid coke like that can only usually be shifted by caustic soda, but I wouldnt put an ally piston in there as the caustic will eat that
too.....
Best not let it happen in the first place!--Just follow the rules of Not running cold Di engines on veggy oil!
If its happened already, its an engine strip and probable re-piston/re-bore to cure the fault--Doubt if youll get the rings out of the pistons without
damaging the ring-grooves too much....
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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kielderman
Junior Member
Posts: 60
Registered: 15-9-2007
Location: kielder
Member Is Offline
Mood: optimistic
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| posted on 16-9-2007 at 12:57 PM |
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yes
well written accurate knowledge based
all the things you should be told by those ? how to web sites
so much easier to understand now
thank you
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
Member Is Offline
Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 16-9-2007 at 04:59 PM |
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| Quote: | Originally posted by kielderman
well written accurate knowledge based
all the things you should be told by those ? how to web sites
so much easier to understand now
thank you |
Glad that you found it useful...
It can be very difficult without the aid of pictures or actually showing someone, to get the issues across without mis-understandings...
I just tell it how I see it....
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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fester123
Junior Member
Posts: 2
Registered: 16-11-2007
Location: chester
Member Is Offline
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| posted on 16-11-2007 at 08:13 PM |
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i have a new 57 plate tx4 black cab it had 5k on when i converted it to a 2 tank system from smartveg
The cab ran great for about 2000 miles then some very strange noises came from the engine bay???
i was told it was diesel knock?? so we change the engine oil and filters and it was great for a few hours then the noise came back so we filled the
tank with normal diesel and it is running ok at the moment .
but we want to put it back on veg oil has anybody got any ideas what this could be or any help welcome
the engine is a 2.7 crd chrysler engine help please
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gboy
Posting Freak
Posts: 1240
Registered: 15-2-2007
Location: westcountry tra la la
Member Is Offline
Mood: sensational bordering on supernova
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| posted on 16-11-2007 at 10:35 PM |
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Has the injection timing been advanced?
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High Compression II
Veggy Veteran
Posts: 7522
Registered: 9-11-2004
Location: Swansea South Wales
Member Is Offline
Mood: "No Ma'am, --I'm Not a Greenie, I'm an Engineer....."
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| posted on 16-11-2007 at 11:04 PM |
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As its a Taxi, Do you do the 'Normal' Taxi thing of letting it idle for Long periods....?
I have known a Skoda used in this way to completley coke up and polymerise the oil, wreck the turbo and score the bores....
On Veggy, The Cardinal Rule--The engine MUST Do Work, Not Idle....
If you HAVE to idle for more than say 2 minutes Real-Time, Do so on Diesel Only!
During idling combustion-chambers will cool to low levels where incomplete combustion can occur......
www.doctordiesel.co.uk
"The 21st Century is when it all changes....
--And you've got to be ready...."
BEWARE OF CVS COMMODITIES OR ANYONE CALLED VERNON SCHOFIELD OR STEVE SMITH, TRADING OIL --pm me for reasons why...
"As for testing, know now that
only mechanisms built by bunglers require testing.
Properly-built machines work properly." --E.E. 'Doc' Smith.
Mercedes-Benz W123 300TD Berlin Taxi Beige, 1985, 258K miles total, 2500 miles on 100% BioDiesel so far,
Cost-a-plenty, Guzzles BioDiesel extravagantly, and I love it like an old dog....
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fester123
Junior Member
Posts: 2
Registered: 16-11-2007
Location: chester
Member Is Offline
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| posted on 16-11-2007 at 11:05 PM |
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no timing left as it was from new
my email address is keyghost@ntlworld.com
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