Tuesday, February 19, 2008

Gasoline and Vegetable Oil Blends

I've had a few phone calls from Alaska folks really really wanting a cheap and easy solution to running vegetable oil. Most recently was a plan to run 90% raw Canola oil, straight from the farmer's press, which would be "treated" with 10% gasoline.

Here's the response I wrote:
Hmmm. It's my belief that if it were cheap and easy everyone would be doing it. My first thoughts are "There's no such thing as a free lunch" and "You get what you pay for."

Blending straight vegetable oil with gasoline (or diesel) and burning it directly in your diesel vehicle should be considered *very* experimental. Of course biodiesel folks often get nervous about running heated SVO, and the 2-tank heated veg folks can get skittish about running those unheated vegoil blends.

The closest I've gotten to blending is the time that I left my vegoil in the injection pump overnight (I forgot to purge). I did get the 81 VW pickup started at about 40 degrees - and it didn't cause any noticeable harm to the system - but it kicked and bucked quite a bit while thick black smoke poured out until it warmed up. I try to avoid running cold oil in a cold engine.

I do know of one guy who runs unheated 100% SVO in a early 80s VW pickup down in Moose Pass (or was it Cooper Landing?). He told me he just ran it in the summer months, and it worked well for him.

For the internet fanatics, "Diesel Secret Energy" is the most famous of the blending "miracles." They add their secret formula (mostly petroleum aromatics similar to paint thinner), some gas and some diesel, whip it up and call it good. The only person I know of in Alaska that bought the stuff, decided after he mixed it up that he wasn't about to put it into his tank.

Blending, however, does happen successfully. Probably the most economically significant Alaskan example is the big WWII era generators out in Dutch Harbor at the Unisea fish plant. There they blend in fish oil, in a 50-50 ratio. Of course those are old, tolerant engines.

As far as passenger vehicles go, all the studies I've read say that unheated vegoil in an unheated engine will cause bad things: ring/cylinder varnishing, injector coking. The older 1980s studies say this happens more with blends above 20% vegetable oil.

If you're planning on running unheated SVO or an unheated blend in an older, more tolerant engine, you just might get away with it. Be sure to test your crankcase oil, or at least change it often, as vegetable oil will polymerize and thicken your motor oil.

Needless to say, I do not recommend running unheated blends. But if you insist, tell us how it goes!

Veg On!

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