problem with blends on a 6.2L/6.5L diesel engine

[Jeffrey S. Brooks Banned Find all posts View Profile Close Jeffrey S. Brooks]

I have been doing biofuels research with an old 6.2L diesel engine for four years. My method is blending gasoline with vegetable oil at 20% gasoline/80% Waste Vegetable Oil (WVO).

I find the STANADYNE DB2 Injection Pumps are failing after about 9 months on the above fuel blend. I believe the problem is one or more seals inside the Injector Pump are failing due to the presence of alcohol in my blend, because in regions were alcohol is not blended into the gasoline, bio-blenders do not tend to have failed injector pumps. In my region alcohol is commonly blended into gasoline at 10-20%, which means my bio-blend includes 2-4% alcohol, which is most probably ethyl, but might be methyl alcohol. At that percentage of alcohol there might be a problem with seals.

1) Does anyone here agree with my conclusions?
2) Does anyone know if there is a rebuild kit for the STANADYNE DB2 Injection Pump that can handle biofuels (alcohols)?
3) It would be very useful to my research if I could rebuild these pumps myself, so that I can see what is going wrong with them. So, does anyone know where I can purchase a repair manual and rebuild kit for this pump?
4) Is anyone here experimenting with bio-fuels on a 6.2L/6.5L diesel engine?

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: problem with blends on a 6.2L/6.5L diesel engine

Jeffrey
That's bad news about the IP.
I'm not familiar with the stanadyne though I see it's a rotary pump.
I've been doing the vege for about 8 years, and starting with 20% ULP.
It was some time later that I found that 20% was much more than what was needed.

Both my Hiaces have rotary style pumps and have not failed, replaced or been rebuilt.
I consider that they've taken a lot of abuse with gallons and gallons of fuel over a long period. There's been no alcohol content to the fuel even when I ran ULP blends.

I'm interested to know just what is going bad on your pumps. Is it seals? Is it caused by corrosion? Have the IP's strainers been cleared?(always the 1st thing to check)

Alcohols are known to attract water but it's no more of a problem than for those using the fuel as it was intended. I'd be surprised if it was a lubricity problem as the 80% vege is more the enough. The seals should be viton and here is an interesting compatibility chart covering wide range of chemicals and their effect on viton.

More specific info on the pump please...

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: problem with blends on a 6.2L/6.5L diesel engine

Geoffrey,

I have a DS-4 in my 6.5L.

I am currently running BIO and straight Vegoil, but intend to add a 3rd tank that will be for a blend.

I have succesfully run a blend of various strengths in my Toyota Surf for the last 2 years.

My plan with the 6.5 is to have a BIO startup tank, a Blend tank for short trips and a Vegoil tank for long trips.

I will keep you updated on my progress.

have you visited the DieselPlace forums - they have everything there is to know about the 6.2/6.5L engines - both wiith Ds-4 and DB-2 pumps

Craig

[Jeffrey S. Brooks Banned Find all posts View Profile Close Jeffrey S. Brooks]

Re: problem with blends on a 6.2L/6.5L diesel engine

Thanks Craig, I posted my inquiry to the Diesel Garage, I will try the Diesel Place next. It would be most useful for resolving my problem to know how much alcohol, if any, is added to gasoline/petrol wherever you are.

How I make my blend of 20% gasoline (petrol) and 80% WVO is I blend them in a tank, then let them settle, then I drain off the sludge before processing, and if there is any water in that sludge, then it is most probably also taking some of the alcohol in the gasoline with it.

I am presently looking into using another solvent for thinning my WVO that does not have ketones or alcohols in it, which tend to be hard on seals and hoses. Gasoline has been my first choice all along, because it takes half as much gasoline as diesel for the same thinning effect, and kerosene (paraffin) is more expensive than gasoline in my region. Also, 20% gasoline lowers the gel point to below 0F (-18c), while still firing up on the first crank without the use of a block heater, like it was a warm day.

My IP rebuilder has been rejecting my injector pumps. I believe it is something he does with everyone who is experimenting with biofuels. I do not think he wants to be bothered with the residues from biofuels, especially when he can get all the injector pumps he wants from the junkyard at low prices here.

Anyway, since he was not going to give me a rebate on my core, I asked him for it back, so that I could see what was wrong with it. He sent me back a bag full of parts that I do not believe came from my injector pump. But, I noticed a red colored seal on the main shaft.

I know from experience that red colored seals tend to be silicone. If there is a silicone seal inside the STANADYNE DB2 Injection Pump, and it is in contact with the fuel, then it is most definitely going to swell in the presence of alcohol, but my alcohol content is only 4%. Nonetheless, I believe at this time that alcohol is the problem. If so, then I will have to find another solvent to use other than gasoline (petrol) with WVO, or add water to my blend prior to settlement to remove the alcohol from the gasoline.

Today I received an email back from my injector pump repair tech. He thinks my blend is still too viscous with 20% petrol in it, and he believes that is my problem. Maybe that is the problem, especially since the last batch was indeed more viscous than usual, because I had added a gallon (4L) of gear oil, which is very viscous, but I had not added more gasoline to thin the blend out more. So, perhaps I just need to add more gas.

I also noticed that even though I settle my fuel blend, and filter down to 1-micron, I am still getting a fair amount of sub-micron particulate settling out after a few days. I noticed when I opened up the dead IP it was coated with a fine coat of free-carbon, which is this sub-micron particulate passing through my filters, so maybe that is the problem.

Any more ideas?

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: problem with blends on a 6.2L/6.5L diesel engine

Jeffrey,

here in australia most of us that blend do so to get the required viscosity for consistent operation. I personally would never start my 6.5L from cold on a blend.

From what i have read the weakest part of these engines is the pump - although the later model DB2's are meant to be bulletproof.

I would suggest you might talk to Kennedy Diesel - they are experts on all of these motor/pump combos.

My plan is to start on BIO all the time and then switch to my blend tank after 2 minutes of idling - the blend will consist of WVO, BIO and ULP - i will not put ethanol based fuel into this mix - although i may be forced to that in the future by the Gov.

The reality is that if i have to use twice as much BIO as ULP/RUG to get to a similar viscosity i am still ahead as my BIO has a cost to me of 40 cents/litre. and ULP here costs around the $1.30 to $1.40 per litre

Craig

[Nuddy Senior Member Find all posts View Profile Close Nuddy]

Re: problem with blends on a 6.2L/6.5L diesel engine

Just appling logic. Apparently alcohol and WVO don't mix. If the petrol has alcohol mixed in, when it is mixed with WVO would the alcohol separate out? If it does separate out would it float on top of the WVO/petrol blend or would it sink to the bottom. If it floats on top then it should stay in the fuel tank unless it is run nearly dry - that is, no problem. If it sinks to the bottom then the fuel pickup should pick up straight alcohol or perhaps a mixture of alcohol and water.
This would of course be detrimental to the IP but wouldn't it also give running problems - that is, would a diesel run on straight alcohol or a mixture of alcohol and water?

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: problem with blends on a 6.2L/6.5L diesel engine

Jeffrey,

Can you advise what your collection/filtering regime entails.

Also what heat mechanism do you have in the truck ? Are you attempting to start the car from cold on the blend ?

Craig

[Jeffrey S. Brooks Banned Find all posts View Profile Close Jeffrey S. Brooks]

Re: problem with blends on a 6.2L/6.5L diesel engine

Just appling logic. Apparently alcohol and WVO don't mix. If the petrol has alcohol mixed in, when it is mixed with WVO would the alcohol separate out? If it does separate out would it float on top of the WVO/petrol blend or would it sink to the bottom. If it floats on top then it should stay in the fuel tank unless it is run nearly dry - that is, no problem. If it sinks to the bottom then the fuel pickup should pick up straight alcohol or perhaps a mixture of alcohol and water.
This would of course be detrimental to the IP but wouldn't it also give running problems - that is, would a diesel run on straight alcohol or a mixture of alcohol and water?

Yes, alcohol is more hydrophilic than it is lipophilic, so that if one were to put alcohol and vegetable oil together in a container and shake, the two fluids will begin to separate in a few minutes. And, alcohol will not blend readily with gasoline (petrol) either. However, the petroleum industry has found that by adding some other component to a blend of gasoline and alcohol they can force them together.

My guess is, since alcohol is hydrophilic, then it will most probably join with any water that is present in the blend, and if so, then it will precipitate out and settle to the bottom with the water that it joined with.

craigcurtin:
How I make my blend of 20% gasoline (petrol) and 80% WVO is I blend them in an external processing tank, then let them settle for a few hours, then I drain off the sludge that settles to the bottom of the tank before filtering the blend down to 1-micron through a bag filter, and if there is any water in that sludge, then it is most probably also taking some of the alcohol in the gasoline with it. Most of the particulate in my WVO also settles out at this time.

Changes that I plan to make in my process:
I have recently noticed that there is a fair amount of sub-micron particulate that is settling out from my blend after a few days. This suggest to me that I should let my blend settle for more than a few hours, and maybe as much as a few days to reduce this sub-micron particulate.

Also, it is now clear to me that Stanadyne does not offer a bio-fuel friendly rebuild kit for their injector pumps. So, in the short term I am going to locate a source of some solvent that is like gasoline (petrol) but does not contain alcohol or ketones in it. Kerosene and paint thinner come to mind.

Perhaps we could have a write-in campaign with Stanadyne to force them to offer a bio-fuel friendly rebuild kit for their injector pumps. They would have to replace all silicon and buna seals with Viton or Teflon seals.

Corporate Headquarters
Stanadyne Corporation
92 Deerfield Road
Windsor, CT 06095 USA
Phone: 860-525-0821
Fax: 860-683-4500

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: problem with blends on a 6.2L/6.5L diesel engine

What's actually gone bad with the IP. Has it leaked or worn out, or is it a blockage? Can you determine any cause from the parts? Was it rebuilt 9 months ago or a second hand item?

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: problem with blends on a 6.2L/6.5L diesel engine

Geoffrey,

Get onto Dieselplace and also get in touch with Kennedy diesel.

There are a number of people running BIO in their 6.2L/DB2 combos - as such if what you are surmising (in relation to the seals being non alcohol friendly) is true then no one would be able to run BIO in their units.

It sounds like you are trying to take shortcuts with your filtering setup.

Instead of doing what you are try the following

1) Let the oil settle for as long as possible
2) Filter to 1 micron (Cold filtered) prior to blending
3) blend and then let settle - this is the way i do it and i do not find any addition droupout etc in my blending/storage tank.

If you are concerned then "polish" the blend by circulating for a few hours through a 1 micron bag filter.

What fiiltering/heatiing setup do you have in your car ?

Craig

[Jeffrey S. Brooks Banned Find all posts View Profile Close Jeffrey S. Brooks]

Re: problem with blends on a 6.2L/6.5L diesel engine

What's actually gone bad with the IP. Has it leaked or worn out, or is it a blockage? Can you determine any cause from the parts? Was it rebuilt 9 months ago or a second hand item?

tbird650, the symptoms of my 4-5 failed injector pumps has always been the same for the last 4 years. After 6-9 months on my 20/80 petrol/wvo fuel blend is the pump just stops pumping fuel through it. I have disassembled the pumps as much as I can without a manual to figure out the problem, because I find the fuel control solenoid is still working. The first three pumps had the screen plugged with tar-like lacquer. However, removing the tar-like lacquer did not get the pump working again. I beleive the the tar-like lacquer had glued the IP shut. I have since modified my process to eliminate the tar-like lacquer.

The last 2-3 failed IPs had black particulate on the surfaces of the inside of the pump, but the screen was clear. That black particulate is sub-micron, because I bag filter my processed fuel through a 1-micron bag filter.

The first 3-4 replacement IPs were rebuilds. The last pump was a pull from a junker extracted 9 months ago.

craigcurtin:
How I make my blend of 20% gasoline (petrol) and 80% WVO is; I select settled WVO from a restaurant, I then blend it with gasoline (petrol) in an external processing tank at 20%, agitate the solution by driving around (my WVO fuel processing system is mobile), then I let the solution settle for a few hours, then I drain off the sludge that settles to the bottom of the processing tank before filtering the solution down to 1-micron through a bag filter, and if there is any water in that sludge, then it is most probably also taking some of the alcohol in the gasoline with it. Most of the particulate in my WVO also settles out at this time. I have calculated the alcohol content cannot be more than 4% of my blend.

It is my belief that the sludge that I drain off contains most of the water in the WVO. My evidence is I have a water sensor in my fuel line. It never indicates water present in my fuel. I have a 5-micron filter in my fuel line, which contains hydrosorb. So far that filter has not plugged since I have employed the above processing method. I believe I can safely conclude that my processing method eliminates water and most of the particulate.

Now, most people who are terrified by the idea of recycling waste vegetable oil to make diesel fuel will be convinced that obviously the cause of my injector pump failures is making fuel out of recycled vegetable oil. And, most people who are terrified by the idea of adding gasoline (petrol) to a diesel engine will be convinced that obviously the cause of my injector pump failures is the gasoline.

Changes that I plan to make in my process:
I have recently noticed that there is a fair amount of sub-micron particulate that is settling out from my blend after a few days. This sub-micron particulate could be the cause of my injector pump failures, and not the presence of alcohol at 2-4% of the blend. This suggests to me that I should let my blend settle for more than a few hours, and maybe as much as a few days to reduce this sub-micron particulate.
 But, it would be nice to know how well the Stanadyne DB2 diesel injector pumps do with particle loads below 1-micron.

Another conclusion is the alcohol present in the gasoline at 10-20%, which becomes 2-4% of the blend, is the cause of my premature injector pump failures. The solution is to find a readily available solvent that has similar characteristics and price to gasoline, but does not contain alcohol.

Gasoline has been my first choice as a solvent all along, because it takes half as much gasoline as diesel for the same thinning effect, and kerosene (paraffin) is more expensive than gasoline in my region. Also, 20% gasoline lowers the gel point to below 0F (-18c), while still firing up on the first crank without the use of a block heater, like it was a warm day. I am presently looking at paint thinner or kerosene as possible blend solvents.

It would be nice to know that the rebuild kits for Stanadyne DB2 diesel injector pumps were biodiesel friendly; however, I have found no definite evidence that Stanadyne has modified their rebuild kit, and my persistent problems with failing recently rebuilt Stanadyne DB2 diesel injector pumps tells me that Stanadyne has not modified their rebuild kit.

I have read on other biofuels forums that a lot of people have been having trouble burning biofuels on Stanadyne injector pumps. Since it is now clear that Stanadyne does not offer a bio-fuel friendly rebuild kit for their injector pumps, then perhaps we could have a write-in campaign with Stanadyne to force them to offer a bio-fuel friendly rebuild kit for their injector pumps. They would have to replace all silicon and buna seals with Viton or Teflon seals.



Corporate Headquarters

Stanadyne Corporation

92 Deerfield Road

Windsor, CT 06095 USA

Phone: 860-525-0821

Fax: 860-683-4500

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: problem with blends on a 6.2L/6.5L diesel engine

Geoffrey,

You seem to have this idea in your head that the seals are the problem - however you stated that last time it was the internals of the pump that were gunged up ?

If the seals were gone/going wouldn't that lead to the inability of the IP to provide pressure to the Injectors as well as fuel leaking out of the pump ?

Why do you want to filter "mobile" - why do you want to speed the process up by mixing with RUG/ULP prior to filtering step ?

I do not see anything in your system is that dewatering your oil ? other than belnding with Petrol and hopefully that doing it for you - highly doubtful this would be the case for suspended water

What heating system do you have in your car ?

Do you start and stop on this blend ? i.e. leave the blend in the IP all the time - rather than flushing with Dino/BIO ?

Craig

[tbird650 Senior Member Find all posts View Profile Close tbird650]

Re: problem with blends on a 6.2L/6.5L diesel engine

Did a search on stanadyne. It appears they are of simmilar type to Lucas/CAV which have the reputation to be risky on veg.
Here's also a great thread with interesting info on the IP on veg. May well be that you've already found it?
No doubt there's ways and means you can extend the useful life of an IP.
Can you manage any pics of the parts? I for one would like to see what we're puzzling over.

[Jeffrey S. Brooks Banned Find all posts View Profile Close Jeffrey S. Brooks]

Re: problem with blends on a 6.2L/6.5L diesel engine

Geoffrey, You seem to have this idea in your head that the seals are the problem - however you stated that last time it was the internals of the pump that were gunged up ? If the seals were gone/going wouldn't that lead to the inability of the IP to provide pressure to the Injectors as well as fuel leaking out of the pump ?

Yes, craigcurtin my injector pump tech made the same conclusion from my message to him. However, if you download the seal kit from Stanadyne you will find there are a boat load of seals inside their DB2 IP. All you need is one seal that is related to pressurizing the fuel to fail. So, no, there has not once been a sign of fuel leakage from my replaced injector pumps. However, in every case the pump has failed to pump fuel through it at all. Not even a dribble.

Why do you want to filter "mobile" - why do you want to speed the process up by mixing with RUG/ULP prior to filtering step ?

I am a field archaeolgist, which means I have to be mobile to make a living, therefore my WVO processing system has to be mobile, and why my WVO processing has to be relatively fast.

I do not see anything in your system is that dewatering your oil ? other than belnding with Petrol and hopefully that doing it for you - highly doubtful this would be the case for suspended water

Well, craigcurtin, that is how much you know about adding gasoline to WVO. Try doing it sometime. One of the things that does not seem to be well understood by my bio-fuels colleagues is I am a blender, and I am observant of my process, and I have observed that when I add a solvent, such as gasoline (petrol), to WVO it causes various contaminants in that WVO, such as: water, animal fat, and particulate, to rapidly precipitate out of solution. I have observed that most (90%) of that contamination precipitates out of solution in just a few hours, which means one does not have to spend weeks settling or up-flow processing WVO, one need only add a solvent, wait a few hours or days, then filter the solution. I am just learning that if I let my solution settle for 12-48 hours instead of 3 hours, then most of the sub-micron particles will precipitate out of solution as well.

It is my belief that the sludge that I drain off contains most of the water in the WVO. My evidence is I have a water sensor in my fuel line. It never indicates water present in my fuel. I have a 5-micron filter in my fuel line, which contains hydrosorb. So far that filter has not plugged since I have employed the above processing method. I believe I can safely conclude that my processing method eliminates water and most of the particulate.

What heating system do you have in your car?

I am a blender, therefore my fuel does not need heating.

Do you start and stop on this blend ? i.e. leave the blend in the IP all the time - rather than flushing with Dino/BIO ?

Craig

This is actually a good topic. Yes, I have a two-tank system that I installed in my van. No, I do not switch fuels at start-up and shut-down. Therefore my IP is sitting with my blend in it all of the time. If I switch over to petroleum diesel at shut-down, then my IP would not have the blend in it, which might solve the problem, if alcohol in the fuel blend at 2-4% of the solution is causing damage to internal seals in the IP. However, at present I am not doing a lot of traveling, so if I started up and shut down with diesel fuel, then there would hardly be time to run on my blend. A two-tank system is best for long haul, and useless for short trips. From experiments I have done it takes about 5 minutes once fuels have been switched for the new fuel to enter the injector pump. On the other hand, if all I need to do is get petroleum diesel through my IP to flush out my blend, then I could rig something that does that a lot quicker. I will ponder your excellent suggestion today.

[craigcurtin Senior Member Find all posts View Profile Close craigcurtin]

Re: problem with blends on a 6.2L/6.5L diesel engine

Yes, craigcurtin my injector pump tech made the same conclusion from my message to him. However, if you download the seal kit from Stanadyne you will find there are a boat load of seals inside their DB2 IP. All you need is one seal that is related to pressurizing the fuel to fail. So, no, there has not once been a sign of fuel leakage from my replaced injector pumps. However, in every case the pump has failed to pump fuel through it at all. Not even a dribble.
I am a field archaeolgist, which means I have to be mobile to make a living, therefore my WVO processing system has to be mobile, and why my WVO processing has to be relatively fast.
Well, craigcurtin, that is how much you know about adding gasoline to WVO. Try doing it sometime. One of the things that does not seem to be well understood by my bio-fuels colleagues is I am a blender, and I am observant of my process, and I have observed that when I add a solvent, such as gasoline (petrol), to WVO it causes various contaminants in that WVO, such as: water, animal fat, and particulate, to rapidly precipitate out of solution. I have observed that most (90%) of that contamination precipitates out of solution in just a few hours, which means one does not have to spend weeks settling or up-flow processing WVO, one need only add a solvent, wait a few hours or days, then filter the solution. I am just learning that if I let my solution settle for 12-48 hours instead of 3 hours, then most of the sub-micron particles will precipitate out of solution as well.

It is my belief that the sludge that I drain off contains most of the water in the WVO. My evidence is I have a water sensor in my fuel line. It never indicates water present in my fuel. I have a 5-micron filter in my fuel line, which contains hydrosorb. So far that filter has not plugged since I have employed the above processing method. I believe I can safely conclude that my processing method eliminates water and most of the particulate.
I am a blender, therefore my fuel does not need heating.
This is actually a good topic. Yes, I have a two-tank system that I installed in my van. No, I do not switch fuels at start-up and shut-down. Therefore my IP is sitting with my blend in it all of the time. If I switch over to petroleum diesel at shut-down, then my IP would not have the blend in it, which might solve the problem, if alcohol in the fuel blend at 2-4% of the solution is causing damage to internal seals in the IP. However, at present I am not doing a lot of traveling, so if I started up and shut down with diesel fuel, then there would hardly be time to run on my blend. A two-tank system is best for long haul, and useless for short trips. From experiments I have done it takes about 5 minutes once fuels have been switched for the new fuel to enter the injector pump. On the other hand, if all I need to do is get petroleum diesel through my IP to flush out my blend, then I could rig something that does that a lot quicker. I will ponder your excellent suggestion today.

Geoff - i too do blend so i understand many of things you are saying. If i can draw some conclusions/inferences from what you have said

1) You are an archaeologists and therefore mobile - i would assume form that that you collect oil from a number of sources - how can you be sure of the quality of this oil ? _ it may be worth your while to do a HPT before blending too see how wet the oil is

2) obviously if you are truly mobile then one would assume that only minimal settling of the fuel is happening i.e it is being sloshed and remixed all the time in the vehicle

3) Why not make a 50 litre batch processor that would filter, polish and dewater all in one - 3 tanks in the back of your car - collection tank - whatever size was appropriate, filtering/dewatering/polishing tank and a 3rd tank for blending a storage

If you had these as 3 60 litre drums in the back of your UTE you would be able to have 180 litres on the go at any time. If you wanted more capacity then have the collection tank custom made or a 44 gallon drum.

Rig up a FPHE to the filtering dewatering drum, a gear pump or a good pump like a mallory 4140 to push through a series of filters for polishing, and a vacuum setup to lower the presssure and promote boiling off of any water at a lower temperature.

For the sake of $100 i would seriously look at adding a FPHE into your truck to give the pumps a fighting chance - as well as a way to flush out with either bio or diesel at the end of a trip.

I would also look at a number of the additives available to stop many of the issues you are describing.

I also remember one of the guys on Dieselplace giving his IP a "spa" treatment - he hooked up a can with 1/2 ATF and 1/2 BIO - routed the feed and return lines to it and let the engine run until the fuel was all gone.

Craig