Page 1 of 5 12345 LastLast
Results 1 to 10 of 43

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

  1. #1
    Join Date
    Jan 2009
    Location
    Prescott, AZ, USA
    Posts
    273

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

    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?

  2. #2
    Join Date
    Apr 2006
    Location
    New Zealand
    Posts
    621

    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...

  3. #3
    Join Date
    Jan 2008
    Location
    Sydney
    Posts
    829

    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
    Holden Suburban K2500 1998 6.5L Turbo GM engine
    210,000KMs (90,000 on new crate motor)

    Currently 2 tanks in and working - 90 litre BIO tank and main tank of 160L WVO

    30 plate FPHE in Engine bay and Helton Dual coil in rear
    Walbro FRB-5 pusher pumps x 2

    50,000KM on Veg and 10,000Km on B100

  4. #4
    Join Date
    Jan 2009
    Location
    Prescott, AZ, USA
    Posts
    273

    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?

  5. #5
    Join Date
    Jan 2008
    Location
    Sydney
    Posts
    829

    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
    Holden Suburban K2500 1998 6.5L Turbo GM engine
    210,000KMs (90,000 on new crate motor)

    Currently 2 tanks in and working - 90 litre BIO tank and main tank of 160L WVO

    30 plate FPHE in Engine bay and Helton Dual coil in rear
    Walbro FRB-5 pusher pumps x 2

    50,000KM on Veg and 10,000Km on B100

  6. #6
    Join Date
    Dec 2007
    Location
    Lake Macquarie (just south of Newcastle) NSW
    Posts
    1,363

    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?

  7. #7
    Join Date
    Jan 2008
    Location
    Sydney
    Posts
    829

    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
    Holden Suburban K2500 1998 6.5L Turbo GM engine
    210,000KMs (90,000 on new crate motor)

    Currently 2 tanks in and working - 90 litre BIO tank and main tank of 160L WVO

    30 plate FPHE in Engine bay and Helton Dual coil in rear
    Walbro FRB-5 pusher pumps x 2

    50,000KM on Veg and 10,000Km on B100

  8. #8
    Join Date
    Jan 2009
    Location
    Prescott, AZ, USA
    Posts
    273

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

    Quote Originally Posted by Nuddy View Post
    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
    Last edited by Jeffrey S. Brooks; 1st April 2011 at 11:45 AM.

  9. #9
    Join Date
    Apr 2006
    Location
    New Zealand
    Posts
    621

    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?

  10. #10
    Join Date
    Jan 2008
    Location
    Sydney
    Posts
    829

    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
    Holden Suburban K2500 1998 6.5L Turbo GM engine
    210,000KMs (90,000 on new crate motor)

    Currently 2 tanks in and working - 90 litre BIO tank and main tank of 160L WVO

    30 plate FPHE in Engine bay and Helton Dual coil in rear
    Walbro FRB-5 pusher pumps x 2

    50,000KM on Veg and 10,000Km on B100

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •