One biodieseler's experience

[XJCoupe]

I've been using biodiesel for a few months now. While I'm far from an expert on either making it or long-term effects on vehicles, I thought I'd share my experience for the sake of those who are considering it.

I'm the second owner of my '81 Caddy (Pickup) 1.6D. I bought it in Sep. 2004 from my manager, who put about 260k on it. It's been well maintained, and no major mechanincal work has been done. (The head gasket has been replaced a couple times, but no head work was done.)

After about a tank and half on petrodiesel, I dumped in a half-tank of homebrew biodiesel to make B50. In retrospect, it would have been good to drive it longer on petrodiesel to establish a longer baseline. Though I've worked on my own vehicles for several years, I'm new to diesels.

The first fuel filter clogged after about 35 miles on B50. No biggie — I had a spare in the truck, thanks to the suggestion of other biodieselers. The following problems were considerably less pleasant to deal with. The engine would starve for fuel under heavy acceleration, and also started acting like it was out of fuel with about a quarter tank left (gauge is accurate). In both cases, there were a lot of air bubbles in the fuel line to the injection pump.

Both problems were solved by replacing the in-tank filter screen and
all of the fuel hoses. I want to emphasize that neither of these problems are inherent problems with the vehicle, which is almost a quarter-century old. There's also nothing inherently wrong with running biodiesel in an older VW, though you need to be prepared for some additional work.

After many years and many miles, grunge built up in the tank, which biodiesel dissolved and deposited on the screen. The fuel hoses, which were probably original, became permeated with biodiesel, causing air to be drawn through them because of the filter screen restriction and the vacuum of the injection pump.

I dropped the tank, took care of some surface rust on it, replaced the $5 filter screen, and then installed $75-worth of Viton fuel hoses, which are resistant to biodiesel. I purchased the hose kit from greaseworks.org and was happy with the product and customer service. (No affiliation.) I had some trouble with air bubbles in the fuel line. It's important to clamp the Viton hose carefully, as it's not as elastic as standard rubber hose. I was concerned about the security of some of the return hoses, so I clamped them with small clamps from an overpriced assortment that I bought at AutoZone. The tank and fuel lines work was a bit of a pain, but worth it, since I'm planning to keep the truck, and continue to run biodiesel.

Note that there is a biodiesel-susceptible shaft seal in the injection pump. I obtained a Viton replacement for about $20, but haven't installed it, since it's not leaking. (Used flourescent dye to be sure.) That's not gonna be fun, when it does go.

In the meantime, another fuel filter clogged. I think the crud is now cleared out of the system. From that point, I was pretty pleased with the results of running B50. The exhaust smell is less pungent, the engine runs a little more smoothly, and power and economy seem comparable.

This past Virginia winter was colder than usual, and I didn't have any trouble with gelling in the single digits (F) on B50 with a double-dose of Power Service fuel conditioner. At those temps, though, B100 is not 100% liquid.

Now that it's warming up, I'm moving toward B100 with each fillup. I did some other work on the truck, unrelated to biodiesel, that helps starting and running. That includes rebuilt injectors (the originals had 260k+ on them), new glow plugs, setting the timing, setting the load screw (aka "smoke screw") and a new battery.

I'm a newer member in a small informal biodiesel co-op. We make enough fuel for ourselves by collecting waste vegetable oil from local restaurants. The two guys that kicked things off collected a bunch of used equipment, like storage tanks, pumps, etc, to make it affordable. We get about 35 US gallons per batch. The process is well documented elsewhere, though it's not difficult once set up. I think some of the biggest impediments are setting up the equipment to be convenient to use, keeping the operation safe, and disposing of byproducts and the grunge that's in WVO.

To sum up, running biodiesel has worked well for me overall. I suggest making sure your VW diesel is running well before mixing in biodiesel. In particular, timing should be set and injectors should be in good shape. Be prepared to replace a couple fuel filters, the fuel hoses, the pump seal and the tank filter screen if you want to run high concentrations (>B20). Easing in with B10 or B20 would probably be better than B50.

Cheers!

[Fatmobile]

You should have a vacuum gauge on your fuel line.
It will warn you before your filter is clogged or fuel is gelled.

[jkeiffer_gearhead]

what kind of reading would it give you before and after it is clogged?

[Charlie B]

Before I got my first diesel that I planned on running on wvo, no biodiesel nearby and I don't trust myself enough to start playing with chemicals, I did a lot of research. I found my viton hose at Mcmaster.com very reasonably. Have bought cheap inline fuel filters because thats what I read should be done. Their small so I only have a couple left of the dozen I bought. I think I have been running enough straight oil that my system seems to be cleaning itself out. Just as soon as I get that pump shaft seal replaced, I managed to get it out.
What I did for clamping the thin walled viton was cut a 1/2" length of vynyl tubing and slid that like a collar over the viton and metal return line, giving the clamp more to clamp to. Try 3/8" id fits snuggly. The other major thing I did was have Greaseworks rebuild a set of injectors to run vegoil, matter of bumping up the breaking point. Seems to run nicely, or will once I get the seal replaced.

[jkeiffer_gearhead]

where did you get the viton seal for the injection pump?

[Fatmobile]

what kind of reading would it give you before and after it is clogged?

The vacuum gauge can read anywhere from 0 to 5.
I start to worry when it gets over 5 and do something about it if it hits 7.
It could probably hit 10 and you wouldn't notice it without a gauge.

[Guest]

and you place the vacuum guage after the fuel filter i suppose?

[XJCoupe]

jkeiffer_gearhead,

A friend got the specs on the Viton injection pump seal and ordered them (don't know where from). They came in a bag of two, so he sold me his extra. Here's what's on the bag:

Brand: Harwal ("Serving America's Power Transmission Industry")
ID: 17mm
OD: 28mm
Width: 7mm
Lip type: ADL
Material: Viton

Hope that helps...

[Fatmobile]

Click on the www at the bottom of my posts.
I think a picture of my vacuum gauge connection is at the bottom of the fuel temp sensor page.
I connect it to the banjo bolt on the front of the pump, which IS after the fuel filter... to answer your question.

[jkeiffer_gearhead]

thanks I just looked up the website for the Viton seal and I should have a price quote by the end of the day, the website is www.harwal.com
I hope this isnt a competitor to jack, this place only sells rubber and rubber like seals

[Charlie B]

Have found source for viton seal, am finding out style of seal. Will get back with you all and let you know what I find out.

[Fatmobile]

I think all the new bosch seals are biodiesel safe but can't confirm it.

[jkeiffer_gearhead]

HARWAL

Justin,

The following item:

17 x 28 x 07ADL VITON $12.41 ea. Minimum 4 pcs

Let me know!

Regards,

Rob Andreoletti
HARWAL

[Charlie B]

I got a qoute from Floridabearings.com for $9.96 +del for 17x28x7 viton double lip encased metal. I've ordered one and will let you know when it gets here more info.

[shaskill]

Have had great 2000 miles running 50% well filtered Soya oil and 45 cetane. Now I have a bad leak at the throttle body seal I guess it is called. I presume it means pump removal and anyone know where to get the Viton replacement seal? I presume it is not the shaft seal that was referred to in posts?