No political agendas. I'm just trying to get some information out about LSDF, biodiesel and their potential effects on IPs so that we don't inadvertently kill our IPs. For grins, I've got a Robert Bosch inline injection pump book on order to try and determine the locations of the seals and o-rings in these IPs.
FWIW, at lunch yesterday, I stopped off at Central Texas Diesel Injection Service (CTDIS) to ask a few questions about their experiences with bio-fueled (SVO and Biodiesel) vehicles. I found out some interesting things...
In the last year CTDIS has serviced two vehicles which had experienced IP failures that they attributed directly to the use of biodiesel. One was an International-powered school bus, the other, a late model Mercedes-Benz (I didn't find out if it was a CDI or IDI engine). The bus was making a x-country trip and supposedly had a fresh engine and, I assume, a fresh IP as well. The owner of CTDIS said that he had never seen a new IP as badly worn as the one from that bus. He attributed the failure to a lack of acceptable lubricity in the biofuel. The Mercedes was not dissasembled and no autopsy was performed. It returned to the dealer for a replacement pump.
As far as CTDIS knew, they had not worked on any straight SVO powered engines yet.
At this point, CTDIS recommends using Stanadyne Performance formula to make up for the lack of lubricity in low-sulphur diesel and an assumed lack of lubricity in biodiesel.
Regarding my question on rubber in IP and other fuel system components....
Most, if not all currently produced diesel IP have viton seals and o-rings. Older Bosch IPs, such as those on the 615, 616, 617 and possibly some 60X engines have seals made from Buna-N.
Based on this knowledge, I did some research on Buna-N, or
nitrile, and discovered this:
Buna N or Nitrile, is a copolymer of butadiene and acrylonitrile. Acrylonitrile content is varied in commercial products from 18% to 48%. As the nitrile content increases, resistance to petroleum base oils and hydrocarbon fuels increases, but low temperature flexibility decreases. Due to its excellent resistance to petroleum products, and its ability to be compounded for service over a temperature range of -65 to + 275 degrees F (- 54 to +135 degrees C), Nitrile is the most widely used etastomer in the seal industry today. Most military rubber specifications for fuel and oil resistant MS and AN 0-rings require nitrile base compounds. It should be mentioned, however, that to obtain good resistance to low temperature with nitrile compounding, it is almost always necessary to sacrifice some high temperature fuel and oil resistance. Nitrile compounds are superior to most elastomers with regard to compression set or cold flow, tear and abrasion resistance. Inherently, they do possess good resistance to ozone, sunlight or weather but this can be substantially improved through compounding. However, since ozone and weather resistance are not always built in, seals from nitrile bases should not be stored near electric motors or other equipment which may generate ozone, or in direct sunlight.
Nitrile Is Recommended for:
General purpose sealing.
Petroleum oils and fluids.
Cold Water.
Silicone greases and oils
Di-ester base lubricants (MIL-L-7808).
Ethylene glycol base fluids (Hydrolubes)
Nitrile is not recommended for:
Halogenated hydrocarbons (carbon tetrachloride, trichloroethylene)
Nitro hydrocarbons (nitrobenzene, aniline)
Phosphate ester hydraulic fluids (Skydrol, Fyrquel, Pydraul).
Ketones (MEK, acetone)
Strong Acids Ozone
Automotive brake fluid.
Source:
Scientific Instrument Services, Inc.