About 2 years ago I purchased a 1976 Mercedes 300D with the intention of one day running it on 100% vegetable oil.
Why?
Well, there are environmental benefits of burning veg oil rather than petro-diesel. Petro-diesel is a fuel that was laid down tens of millions of years ago. Burning it is releasing all the stored CO2 into today's atmosphere at a far greater rate than plants took to make it. Veg oil, whether in Biodiesel form, straight vegetable oil (SVO), waste vegetable oil (WVO) or used cooking oil (UCO) forms, is a renewable resource and its CO2 output fom combustion is theoretically balanced with the plant's intake from the atmosphere. In other words, veg oil is a "green" fuel with a much reduced impact on our atmosphere.
I don't wish to post too much detail on these fuels here on this blog. A quick search using words like: biodiesel, WVO, SVO, bio-fuels will produce plenty of reading matter on the subject. A good, quick reference to biofuels is http://www.nrel.gov/docs/fy00osti/25876.pdf
For those unfamiliar with Benzs, my 300D is a model W123. Technical details are as follows: -
(All technical data reproduced with kind permission of Carfolio.com
Reproduction free under the terms and spirit of the GNU GPL)
Code: OM 617 D 30 / 617.91
Manufacturer: Mercedes-Benz
Type: 5 cylinders SOHC
10 valves total
2 valves per cylinder
Main bearings: 6
Bore x stroke: 91.00mm × 92.40mm
Bore / stroke ratio: 0.98
Displacement: 3005 cc 183.37 cu in
Compression: 21.00:1
Fuel system: Bosch diesel inj.
Aspiration: Normal D.
Catalytic Converter: N
Max. output: 81.1 PS (80.0 bhp) (59.7 kW)@4000 rpm
Max. torque: 171.0 Nm (126 lbft) (17.4 kgm)@2400 rpm
Coolant: Water
Specific output: 26.6 bhp/litre
Specific torque: 56.91 Nm/litre
Performance
Top speed: 148 km/h (Yeah, right, they're dreaming...!)
Power to weight: 55.36 bhp/ton
Chassis
Engine location: Front
Engine alignment: Longitudinal
Steering: recirculating ball PAS
Suspension front: I.W.CS.
Suspension rear: I.STA.CS.
Brakes: Disks front/Disks rear
Transmission: 4 spd Auto
Drive: RWD
Top gear ratio: 1
Final drive ratio: 3.46
Why a 300D Benz?
The W123 model Mercedes Benz is widely considered as the most bullet-proof and reliable Benz models ever made. Around the world, stories of these cars reaching 500,000km are commonplace. A million km on the clock hardly raises an eyebrow. All W123s are a tribute to Mercedes Benz engineering, and their diesel engines in particular, are legendary.
More so than their petrol (gasoline) counterparts, the diesel W123 models hold sway as being even more long-lived. The Bosch in-line injection pump that feeds the 5 cylinders is just as tough. Moreover, unlike most other diesel injection pumps which rely heavily on the diesel fuel itself for lubrication , the Bosch pump is lubricated by sump oil from the engine. Therefore it is not as prone to the effects of low-sulphur fuel as most pumps are these days. It has a reputation as being particularly resistant to the effects of bio-fuels on newer fuel system elastomers, seals, and metals.
Watch my week by week progress on the conversion of this vehicle to use used cooking oil as a fuel!
Cheers
OZTayls
27 comments:
Hi, read with interest your conversion. I have an OM 617 912 Mercedes engine in my 40ft 1934 Norwegian yacht and seem to have a diesel leak from the throttle lever from the IP, govenor? I see you mentioned that the IP is oil lubed, not from the diesel?? Any ideas on how to solve this leak.. it's too heavy to let go, esp in a boat... Cheers
Hi Conan
It sounds like a seal that needs replacing. Any diesel mechanic should be able to repair it quite easily. However, IP's require a specialist's attention, and therefore I wouldn't fiddle with it myself!
Hi Oz,
I found your blog quite by accident but i'm so glad I did. I too bought a 1977 300D two years ago with an intent to manufacture my own bio-diesel however I didnt really consider running it on SVO. Your conversion sounds like a great idea and I'm pretty keen to give it a go on my own car, just have to get the money together and get my husband out to the shed!
I hope you will be available to answer any questions I may have in the future.
Rebecca,
Goulburn, NSW, Australia.
Hi Rebecca
Thanks for your email! Yes, do it because not only is it so easy to do, you will save a fortune in fuel. I'll be posting an update shortly, so check back soon. I've added a small electric fuel heater before the injection pump, which I'll show you how to make it from commonly available plumbing parts! I'll also show you how to make a cheap and easy to manage filter system for filtering your oil. I've also added some insulation to keep the heat in the fuel lines! Again, a no-brainer to install.
Your 300D is ideal for running on veg oil. Compared to a lot of other vehicles it is very tolerant of SVO/WVO.
Cheers and good luck!
Bruce Taylor
http://oztayls.blogspot.com/
G'Day Bruce,
After reading your blog about how you prepared the 300D to use cotton seed oil it started the wheels turning.
I have converted a Hilux Surf (Diesel) to use cotton seed oil by adding a heat exchanger, a changeover valve, an extra filter, mounted a 120Y fuel tank,(complete with filler)in the old girl and sourced a good supply of cotton seed oil.
I'm almost ready to go but I don't know what I have to do to the oil before I can us it.
So I'm using the second tank (with the heat exchanger turned off) as an additional diesel tank.
So I guess I would like to find out how you prepare the cotton seed oil for use in the Benz and what I need to do to it before I can use it..
Hope you can help me with this end of the project Bruce and I'll be looking forward to hearing from you...
All the best for Christmas,
and have a happy New Year.
Frankie,
SE Qld
Hi Frankie, thanks for your question. The really great thing about using unmodified oil for fuel is that it requires very little processing. I always chuckle when I read about the people who mess around with biodiesel and the hassles they have! All I do is filter it through a 5micron bag filter an it's ready to go into the tank. The bags have a ring at the top and I just sit mine in a plastic home brew drum and let the oil drain out the tap into a carboy.
You can buy the bag filters on eBay or locally from MONARCH INDUSTRIAL PRODUCTS - AUSTRALIAN OFFICE
Postal Address: P.O. Box 5411, Brendale, Queensland 4500 - Australia
Phone : +61 (0) 7 3298 5000 Fax No: +61 (0) 7 3298 5011
Hi. I'm using your fuel line schematic to set up my '87 300D on veg oil. Question: you said you stopped up the venturi inside the banjo nut on the return from the IP (it is mounted to the filter housing). What do you mean by that? Are you preventing fluel from going into the filter (stopping the center hole of the bolt?
Today I ran on WVO for first time but air locks kept shutting it down. Still working...
Hi Kevin. Yes, this is important. With this fuel system design, the only function of that 3-way banjo bolt is to route the excess oil back to the tank. If you don't stop up the venturi you will find it very difficult to prime the system, because air will keep leaking in. Once it's stopped up (use a metal epoxy) so as to prevent any flow in/out of the fuel filter via this fitting, then priming is easy. Of course fuel is still going through the filter before it reaches the injectors via the other in/out ports!
Well done... you're almost there!
Cheers, Bruce
Hi Oz,
I stopped up the return venturi on the banjo nut on the filter. I think that solved the return issue and I was able to prime. But now I have another problemo. When I switch to veg, it runs only for about 1 minute and slowly stops. When I switch back to petrol diesel, it immediately runs normally. Sêems like its not getting the correct fuel flow on veg. I'm using a small 10 micron Racor filter for the veg (measures about 3" x 3"). Oh what is the matter?
OK, it could be one of 3 things. This exact same thing has happened to others, including me, at some point or another, so you are not alone!
1. You are either getting fuel starvation, or
2. There is air in your oil circuit, or
3. There is an air leak somewhere in the oil circuit.
Fuel starvation can be caused by some filters which are too restrictive. I haven't used the Racor elements, so I can't comment. I use Fleetguard and they work fine. Check the tank side. Have you opened the breather on the tank? Check the fuel pick up is not blocked. I had to remove the screen on fuel pick up line. If you are filtering to 5micron or less, this shouldn't be a problem for the Racor.
A small amount of air in the circuit can also cause the problem you described. Prime vigorously. Make sure you've switched it over to veg. Then grab hold of the pump and really work it up and down for about 30-60 seconds.
Go over all your plumbing to ensure it is airtight and that there are no leaks. I did mine twice before I got it right.
Try by-passing the Racor filter by installing one of those cheap see-though diesel fuel filters. If your car runs OK with this, then the Racor filter is the problem.
Hi Oz.
Thanks for those details. I'm trying your suggestions. I'm extremely exasperated and feel like giving up. When I get an airlock, takes me abt 1 hr of on/off cranking and battery jumped to another runnig car to start again. I open the compression nuts on the injectors abt 3/4 turn to watch for fuel. Before I got the airlock today, I had switched veg lines to go thru heated and the small course filter and to the veg valwe. Preheated the engine and switched to veg. Ran abt 30 seconds and died out. Soon as i switched to diesel it would run fine again. But then I got an airlock again and I still cranking. (The '87 doesn't have a hand primer.) If I knew someone in Houston to finish this project, I'd roll it to them.
Hi Oz,
Finally got running on SVO! I had mistakenly routed the fuel lines around the valves incorrectly and was getting starvation. DUH. Now running fine. I need to have a better way to purge the fuel lines. I'll try to find a hand pump to install on or near the IP.
Thanks mucho for your help!
Kevin
Hi Kevin, good work. Glad to hear you got it sorted. I have been unable to reply to your questions because Google had problems and I was unable to log in.
I know what you mean about priming. I would like to replace my Delphi filter with the one that has a built in primer button. That might be better.... :) Cheers, Bruce
Hi Bruce,
Test drove on the highway at 65mph today. Man! Ain't it great to see the diesel gauge stop moving!
One coolant question: For routing coolant, I used a T at the heater as you described, but don't know where to tap the other point. I tapped the small line that feeds water into the radiator (on passenger side). But the water does not circulate thru my heater. I'm doing something wrong. Can you give more details about both ends of the taps? (BTW, flattened a 3/4 copper pipe and molded it around the veg filter for a heater.)
Kevin
Hi Kevin, Where you see the EXIT hose from the heater, (which is a 2 port valve operated by your heater controls, and which feeds into one exit hose) just tap into that. So what you then have is a loop from the tee off from your engine on the LHS, to the tee into the hose that goes to the radiator on the other side. In between, you obviously have the heat exchanger. The coolant in this loop heats fast because it bypasses the radiator until the thermostat opens. Cheers, Bruce
Gidday Bruce,
I have a diagram for UVO conversion on my site under http://www.snotta.com/uvopictures.php - it also shows the pollak valve and fuel heaters althought not the same as your one. I can understand if you don't approve this comment - just wanted to let you know. Regards Ken.
Hi Ken, Thanks for that. Hey, no problem. This blog is not for gain and if it helps people to do their conversions to veg oil, that's what it's about, and the planet benefits too.
Basically I have a looped system very similar to your diagram. I also have two heaters now. The second being a home made electric one based on heating from diesel glow plugs which is just before the Injection Pump. I'm achieving 90degC in the lines to the injectors.
What I've found with a closed loop design is that it works great once its primed and if it totally air tight, but priming can be tricky. If you ever get an air leak, the closed looped system can't expel the air. The "return to tank" system mimicks the original fuel system which is very forgiving in this respect, and it's self priming even when only partially primed. I don't want to take the oil return all the way back to the tank so I'm thinking of installing a catch tank in the engine bay to achieve the same result.
Gidday Kevin,
Yeah I find the loop circuit can be a bit of fun, but I find the easiest way of removing air is to open the throttle full bore, it may starve for a little while but it certainly removes all the air. I have had it on mine when I have forgotten to fill up my 10 litre diesel tank and driven down road and have it run out (while warming up) and having to flick over to UVO straight away and floor the hell out of it and wait for the uvo to come through and fire back into life, lots of fun when you have a couple of cars up your a**.
I'm wondering what the plate exchanger outputs the heated oil at, as I would have thought it would have been close to 80 odd degrees and that would be fine running through the Merc, I gather the reason for the extra heaters is so you can change over sooner? Cheers Ken
Hi guys,
The flat plate exchangers are VERY efficient and easily output 80degC (close to 99% effiency). The problem is that this heat is often applied BEFORE the filter to prevent the filter plugging. Thereafter the heat disipates rapidly from the oil on its way through the filter, through the Pollak valve and then through the lift pump and IP. It definitely requires a heat boost before the IP, so another heat exchanger or electric heater is needed there.
Flooring the pedal doesn't work for me. I find the closed loop retains the air so I have to prime the air out of the loop.
Hi Bruce,
Have been running my '87 300D MB on SVO for about 4k miles. All is well except that recently it was running very rough--as if one or more cylinders were missing--and it finally stopped dead and left me roadside. Seems like my injectors may be stopped up. What's up? Car has 240k miles. Are the injectors gummed up? Worn out? I don't think there's any problem with fuel filtering. THis is an engine problem. I plan to remove the injectors. SHould I replace them? THanks for any tips!!
Kevin
Hi Kevin, the most common issue people have is the filters plugging, but the engine running rough prior to stopping seems to indicate your injectors are blocked. Filtration is extremely important. Some vegetable oils polymerise easily and a filter just prior to the lift pump on the injector is a must-have. I think an injector service is now on the cards for you. While it was running rough, I would have recommended a diesel purge treatment (http://www.dieselgiant.com/injectorcleaning.htm), but I think it's too late for that now. CLet me know how things go. Cheers, Bruce
Bruce, Reporting on my '87 300D Benz...
Running great on SVO! I found out that my earlier roughness in engine performance was either from poor filtration or an old IP. My IP died a natural death at 240k and was replaced. (The German mechanic told me that the veg oil did not contribute to its failure and that he looked inside it and saw no gumming. He approves of a veg-oil system!)
Anyway, I filter WVO to .5 micron and then put it in my tank. I'm smiling a lot, because diesel is $4 now!
Have had much interest abt veg oil. Fun stuff.
How is ur '87 doing? I'm wondering if I need to analyze the crank case oil for any veg residue.
Kevin
Hi Kevin, thanks for the update on your 87 300D and the thumbs up from your mechanic:) My 76 W123 300D is still going great on 100% Veg oil. It's done over 70,000km on veg now. The 1993 W124 300D is still running very well on a 50/50 veg oil/diesel blend, without problems.
Provided you perform regular oil changes every 5000km and you use a good quality "rated for diesel" lube oil, I wouldn't be concerned about any veg oil residues in the crank case. Proper lube oils for diesel engines have good quality detergents and dispersants that manage the soot and the blow-by fuel that inevitably gets past the rings into the crankcase. The high compression of diesel engines means that more fuel makes it into the crank case, and this and the soot accumulation are the principal reasons for maintaining a rigorous servicing regime for diesel engines.
I'm also of the opinion that a diesel purge procedure for the entire fuel system every 12 months is good practise, irrespective of the km you do. Infact, I would probably be inclined to do it more often if you only do low km.
Once again, thanks for the feedback!
"The 1993 W124 300D is still running very well on a 50/50 veg oil/diesel blend, without problems."
Hi
Just wondering why you haven't converted this Merc to SVO ??
Stuart
G'day Stuart. Well, I really must get this updated, because there has been a lot of water under the bridge. In fact, the W124 300D is an awesome veg-runner. I have not needed to convert this car at all as it runs VERY well on 100% SVO UVO WVO veg-oil with only a very minor tweak that costs nothing. I'll add this explanation shortly!
I just bought a 1984 300d and was wondering if this was a good choice for wvo or svo?
Hi Matt, Oh yes, your car is the same model W123, just newer! It's probably the single most common car running on veggie :)
A good forum for help with your car is this one.
http://www.biofuelsforum.com/#australian_svo_straight_vegetable_oil_wco_waste_cooking_oil
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