Author Topic: Carbon issues  (Read 19636 times)

Shadow

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Carbon issues
« on: December 17, 2007, 02:14:01 AM »
I'm running my 6/1 on WVO,but I'm having trouble with carbon after about 4 days of running. I have made some corrections so it may get better. I heat the oil via engine coolant to about 160 degrees then have an injection line heater so oil is hot going in. I just added the line heater so this might correct it.
            When I pull the head off,the exhaust valve is carboned up as well as the top of the piston is fairly black and baked on, as well as a bit of a black ridge in top of  cylinder.
           I've tried the water injection method for a day or so, didnt seem to help much. I've running with the compression knob turned in(some people say you need higher compression for veg.oil) that didnt seem to make much diff.
         Next I'll try the Acetone mixture with the oil, see if that helps. I wonder what would happen if I used Lacquer thinner instead of Acetone? The ingrediants of Lacquer thinner are, Toluene, methyl ethyl ketone, methanol,and acetone. But its $15.00 a gal, compared to $28.00 gal for Acetone.
    Next question How much of a role would my exhaust system be playing in this ?  I have 2 inch pipe coming out of the engine with a sharp 90 degree elbow going straight up 3 feet then a more gradual 90 following the ceiling over to the outer wall about 6 feet, then through the wall and another 90 along the outside wall for about 2 feet into a Ford  pickup muffler then out of the muffler to another gradual 90 downspout.Total exhaust sytem is about 15 feet of 2 inch pipe but lots of turns. Is exhaust better to rise up out of the engine or down?  Straight out is not an option the way my shed is set up but I could go straight up through the ceiling or down to just above the floor then straight out. Or Maybe exhaust is not the problem.
               I am current oiling the valves and rocker arms with a veg-oil-2 cycle oil mixture just a shot a couple times a day. I think I'll make a felt washer setup on the valve stems so the absorb oil but dont let it get sucked in the valve guides.  ???
       

dieseldave

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Re: Carbon issues
« Reply #1 on: December 17, 2007, 04:02:53 AM »

  Are you putting a decent load on the unit. No load will always cause a carbon problem.

  You also mentioned 160 degree coolant heating the veg oil. Unit would benifit by running around 200F. 8)

  It appears that your unit is a indirect compression head,judging by the compression change over knob.

Shadow

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Re: Carbon issues
« Reply #2 on: December 17, 2007, 04:32:21 AM »
i think it's loaded fairly decent , it's a ST 5 gen that puts 240 volt into a Rectifier/charger that charges a 48 volt battery bank. When I flip the breaker to start the load it drops the engine rpms by about 30, it runs around 650 empty and 620 loaded. Mind you as the battery bank comes up so do the rpms but not significantly.
      The 160 temp is about what the oil temp is, I try to keep the engine temp around 180-190. I use a Taco pump to circulate water around my oil tanks.
  Yes, I think they consider these indirect injection. I've tried it with knob screwed in and screwed out dident seem to make a difference. I think the higher compression would be the best, but if the higher compression is distorting the swirl of the injector then maybe its not helping. According to the Lister books the knob should be turned out to run. Which means lower compression.

rcavictim

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Forget additives, heat the injector.
« Reply #3 on: December 17, 2007, 05:32:13 AM »
I had a problem with fuel system seals and leaks after I mixed some acetone into my heavy oil/diesel fuel mixture on my VW 4-cylinder diesel power plant.  I had another problem as well. It appears that the acetone in the fuel caused vapor bubbles in my fuel heater designed to bring heavy oil to thin viscocity before it hits the IP.  There was a continuous stream of bubbles entering the pump which caused real havoc with running as you can imagine.

I recommend that you not add any light hydrocarbons to thin the veg oil.  You might try what I did on my one cylinder JD175A with excellent results on really thick oil (not veggie).  Place an electric heating element on the injector itself and heat it up to 300-350 degrees F (I operated mine at a continuous 400 degrees F).  Preheat the oil to 160 F with the engine coolant to allow it to flow easily through the IP.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

jimdunne

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Re: Carbon issues
« Reply #4 on: December 17, 2007, 07:27:02 AM »
RCA, that just is not so-too many engines out there are running using pure acetone to help with carbon issues, etc.

Read http://biodiesel.infopop.cc/eve/forums/a/tpc/f/159605551/m/2411025012 , it has a lot of suggestions.

http://www.pureenergysystems.com/news/2005/03/17/6900069_Acetone/ is the best info for acetone that I know of.

Also, my guess is; you have an IP/seal leak which allows air in.

There is a lot of info on the web about VW diesel engines, and other older diesel engines that frequently have trouble with wvo, biodiesel, etc, because of rubber lines, seals, and parts. May not happen in one month, and may not happen in one year-but it will eventually. Not because of acetone.

Someone earlier wrote about the cost of adding acetone; it costs 2 to 10 cents per gallon of treatment depending on how much you use and how much you pay for it, and if it is free fuel you are using, it is a very inexpensive solution to a problem.

Ran water a lot for about 100,000 miles,mainly towing, and it is tough to regulate on a 200 HP diesel, let alone a 6 HP diesel!! That is why I don't run it any  more.

Have been adding 16 oz of pure acetone per 100 gallons of biodiesel, vegoil, and/or yellow-green diesel for about  30,000 miles in my newest Duramax, and find it makes for smoother running, better mileage, and the elimination of all "hiccups".

And as far as the older engines, Listeroids, etc, that run the really low-grade waste fuels are concerned, there is no comparison. This soul will just not run them  without it.
 

rcavictim

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Re: Carbon issues
« Reply #5 on: December 17, 2007, 08:31:29 AM »
RCA, that just is not so-too many engines out there are running using pure acetone to help with carbon issues, etc.
 



jimdunne,

Glad to meet an expert on my own physical plant consisting of several diesel gensets and as many fuel storage and delivery systems who knows it better than the fellow that put it together, maintains and nurses it all.

Funny with this intimate knowledge of my setup you don`t know that my engines or any of their associated seals and hoses have never been exposed to vegoil or biodiesel.

I am not saying that someone else may not have good results with acetone.  In my own experience so far it has caused real problems.  One was that it suddenly caused the fuel in one of my supply tanks to have vapor pressure for the first time and this caused an oily mess all over the floor as it literally pushed oil uphill and out a open pipe while I was somewhere else. It revealed a plumbing error oversight on my part which has since been corrected, but it is true it caused a large oily mess.  All the spin on filters associated with tanks that had acetone added developed mating flange gasket seal dripping rate leaks at the same time noticed weeks after the acetone treatment.  These seals had been dry while in service for a year and more prior to the addition of the acetone.  I have not seen any IP leakage.

In my statement I carefully chose my words as ` It appears that the acetone in the fuel caused vapor bubbles...`

My air or fuel vapor bubbles on the VW plant may be pinhole line leakage, but it may also be vapor bubbles caused by the line suction and high temperature within the fuel heating stage.  I will be able to determine the actual cause in time as the added acetone clears the system.  In the meantime I shall not be adding anything `experimental` to my fuel.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

jimdunne

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Re: Carbon issues
« Reply #6 on: December 17, 2007, 12:41:26 PM »
Wonderful post, RCAVictim.

Let me just say that I first ran ULO in a diesel engine in 1958.  It was an IH 6 cylinder which was started on gasoline and once warm, changed over to a kerosene/ULO mix. Since then, have more hours operating equipment, vehicles, and airplanes than I care to think about, and yes, a fair amount of it was using alternative fuels.

Have used heating, treating, and diluting for alternative fuels for a long time, and the same rules apply no matter which fuels (hydrocarbons) are used. Yes, the applications vary. No, since you are comfortable that you know about your engine(s), and obviously, fuels, will not detail my humble rules, processes, and  formulae. Am certain they would not help you in any manner, anyway.

Have also had about as many issues with hoses and fittings cobbled together as anyone, and most of those were from my own failure to follow good practices.It is always so much fun to blame others though, isn't it?
 
You state that I am an expert on your own physical plant. I assure you, I am not, and have no desire to ever even look at it. And, the day when you and I are intimate will be one cold day in He**.

Let me write this in a clear way: Acetone in ratios of 1/250 to 1/1200 (1-5 ounces per 10 gallons of fuel) mixed in fuel does not cause vapor bubbles.

Please continue, I will not respond further to dampen your joy in being a victim (again).







rcavictim

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Re: Carbon issues
« Reply #7 on: December 17, 2007, 03:54:38 PM »
Shadow,

I would recommend NOT using laquer thinner as a fuel additive until it is known for sure that this stuff will not eat seals and hoses.

The many sharp bends in your exhaust system are not friendly to the engine.  Replace those which absolutely cannot be avoided entirely with large radius sweeping bends which means forget cast angle plumbing fittings.  If you must use the plumbing pipe with threaded ends and couplings format it is possible to have black iron pipe bent nicely in a radius with a hydraulic pipe bender like on I recently purchased on sale from Princess Auto.  It does a really slick job with virtually no crush at the bend with this type of pipe.

Exhaust pointed at the ground instead of up into the air is going to make a black sooty mess of the ground and everything alse in the near vivinity of the exhaust outlet. Ask me how i know.   :(    If this is not a problem I don`t see any operational issues with it.  The downhill will help keep condensation out of your engine.
« Last Edit: December 17, 2007, 03:57:12 PM by rcavictim »
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

Doug

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Re: Carbon issues
« Reply #8 on: December 17, 2007, 04:00:09 PM »
A good mufler shop can bend up pipe too worth considering.

One can also look for other materials such as EMT or thin wall elecltrical conduit because it was made to be easily shaped and bent. ( Please note if you are going to use something like EMT or Pipe from other sources you need to consider how safe well suported and leak proof things will be
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dieseldave

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Re: Carbon issues
« Reply #9 on: December 18, 2007, 03:49:04 AM »
Iv'e seen a lot of photos on this site of members installations with the exhaust pipe(s) pointing upwards.  This is not a good idea,as 'wet stacking' can occur with light loads.

  Always point them down.

draganof

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Re: Carbon issues
« Reply #10 on: December 18, 2007, 04:18:10 AM »
Iv'e seen a lot of photos on this site of members installations with the exhaust pipe(s) pointing upwards.  This is not a good idea,as 'wet stacking' can occur with light loads.

  Always point them down.

Now I may be wrong on this but my 38 yrs of working with diesel generators says wet stacking occurs during light loading of a diesel regardless of the orientation of the exhaust. Point it straight up and you will cover a wider area with the droplets. Point it straight down and you could collect it in a bucket and sell it as a roof sealer. :D
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joeblack5

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Re: Carbon issues
« Reply #11 on: February 15, 2008, 02:08:22 PM »
hello everybody,

I searched this and other forums but have not found enough data yet.

I am running a GM90 DI on cleaned WVO, soybean, with a load of 2KW . I am having coking problem after 30 hours of use. ( 3 days of 10 hours each) Every day I remove the injector and clean the nozzle outside of the injector and check the spray pattern on diesel injector tester. It shows good.

I preheat the oil before the injection pump and after that have resistance heater of 90 Watts around the injector line. The coupling on the injector is about 215 Fahrenheit measured with  a thermocouple . I drilled a dimple in the injector coupling to insert the thermocoule with some heat compound to get a reliable measurement .Also wheni put a drop of water on the coupling it bubbles up to steam, so I think the measurement is reasonable accurate.
The outside of the injector feels hotter then the block.
The engine has a thermostat that has 85 degree celsius on it , about 190 Fahrenheit. It is setup in a bypass mode, that means that the waterpump water does not force the water through the engine. 

The cooling system is piped into the floor heat in series with the main boiler. The water pump is the main circulator

I have a 16 ft ( 7 ft and 9 ft) exhaust heat exchanger made of 2" electrical entrance conduit and 3" schedule 40 gray PVC pipe around it with rubber reducers ( furenco's ??) The cool water out of the floor heating goes in this exhaust heat exchanger and then in to the cooling bypass loop of the engine.
The heat exchanger is set up on a slight drop so that condensation does not flow back into the engine. I can touch the exhaust after
7 foot and after the next 10 foot section it is about the same temperature as the cool input water.
It works well.

I have measured the electrical conversion efficiency with soybean oil number as Joules / Kgram and KWH on the output . It comes out to 32 to 35 % very good also.
The output is measured through a volt and Amp meter and also an old KWH meter, disc style out of a mobile home, very convenieint .

The 120 VAC is fed into a 48 Volt battery charger and from there in an Outback Grid tie inverter back in to the grid. There are a lot of losses in the set up, mainly in the battery charger that gets hot.   At a 2KW generator output  I convert about 1.3 KW back into the grid.

My main problem at this moment is the coking. I pulled the head and removed the coke, mainly hard build up. Mostly build up under 120 degrees at the same location where the 3 holes of the injector spray.
The coking is against the cylinder head , on top of the cylinder and inside the cavity of the piston.
I fear that at some moment the piston would slam against the head and damage the bearing and connecting rod.

I have lowered the injector 0.020 more inside the piston cavity by usinga thinner copper washer under the injector in the hope that the carbon build up would be more inside the piston bowl and less between the piston and the cylinder head.

I would like to know what I do wrong, also is this coke build up normal for 30 Hours of running time?
I woud like to post pictures of my setup and coking problem over her but have not figured out how, please advise.

 





 

jimdunne

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Re: Carbon issues
« Reply #12 on: February 15, 2008, 02:40:36 PM »
Try some Power Service Arctic Express® Biodiesel Antigel, and their Diesel Kleen® +Cetane Boost®. Also if you use propane injection; it will stop the issue definitely.

I also use pure acetone, and with your issues, if you use 5 OZ/ten gallons of fuel, it will make a huge difference in coking.

The heat sounds about right, so you have some real yukkies in your "fuel"!! The DI does not help at all, either.

You might use some pellon for another filter stage, and that should help, also.


mike90045

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Re: Carbon issues
« Reply #13 on: February 15, 2008, 08:49:51 PM »

I am running a GM90 DI on cleaned WVO, soybean, with a load of 2KW . I am having coking problem after 30 hours of use. ( 3 days of 10 hours each) Every day I remove the injector and clean the nozzle outside of the injector and check the spray pattern on diesel injector tester. It shows good.
 

Have you processed the oil to remove the glycerin ?  Oil burns, glycerin is goo.

SCOTT

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Re: Carbon issues
« Reply #14 on: February 15, 2008, 09:01:47 PM »



Have you processed the oil to remove the glycerin ? Oil burns, glycerin is goo.

It is my understanding that glycerin is created once the catalyst methanol/lye mix is added during the manufacture of biodiesel.  Glycerin is created only when transesterification occurs.   

If this is incorrect someone whith a chemistry back ground will correct the above statement.

Scott
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