Biodiesel and rubber - PeachParts Mercedes-Benz Forum

cavaliers16 · #1 10-04-2006, 06:23 PM

What did you guys do to get your cars ready for biodiesel? I know it eats rubber fuel lines and that they have to be replaced with Viton ones. Did you have to make any modifications to the IP workings or o-rings? I've heard that over time these parts will disintegrate

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Old300D · #2 10-04-2006, 06:34 PM

Quote:

Originally Posted by cavaliers16

What did you guys do to get your cars ready for biodiesel? I know it eats rubber fuel lines and that they have to be replaced with Viton ones. Did you have to make any modifications to the IP workings or o-rings? I've heard that over time these parts will disintegrate

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No modifications to IPs. I replaced the old rubber lines with Viton because my filters were plugging with disintegrating rubber. Now they aren't. I've got more than 20k miles on homebrewed B100 now.

cavaliers16 · #3 10-04-2006, 06:38 PM

Where do you get the lye and methanol (I assume it's cheaper in bulk)? I'd like to make the car a biodiesel and wvo burner.

Old300D · #4 10-04-2006, 08:29 PM

Quote:

Originally Posted by cavaliers16

Where do you get the lye and methanol (I assume it's cheaper in bulk)? I'd like to make the car a biodiesel and wvo burner.

Methanol comes from a local dragstrip. The lye (KOH) can be purchased on line, or a local chemical supply. A friend of mine has a commercial license and buys in bulk - we split 100lb containers for a cost of $1.20 a pound.

dieselmania · #5 10-04-2006, 09:35 PM

How many rubber fuel hoses are there on a 124 with 603 turbo? I know there are the ones under the hood, but are there more at the tank or along the underside? And where do you get the Viton ones?

I recently replaced the return lines with OEM from the dealer, would they be rubber or Viton?

Thanks

#6 10-04-2006, 09:56 PM

I did not replace all of the rubber lines on Margaret when I used B100 for 7,000 miles. I replaced the lines between the injectors, the incoming line and the 'cigar' return line. Realize that these lines are exposed to hours of heat cycling which breaks them down. Biodiesel goes right through hoses in this condition. The lines at the tank are not exposed the extremes that the ones at the engine see. I still have the old lines on at the tank. Now this is not to sa that it will be the same for everyone, but that is how it worked for me. I Never needed to replace the lines on my E300. Heat and age are the enimies to the life of the rubber lines.

dieselmania · #7 10-04-2006, 10:11 PM

nate, when you replaced the return lines between the injectors did you use rubber or viton?

redassag00 · #8 10-04-2006, 11:47 PM

I replaced all my fuel lines with new OE Mercedes Hose, either made by Cohline or whatever. I cant justify the cost of the Viton if I have to replace the hoses every 2-3 years.

The SDL will start with a B30 blend, I already have changed lots of fuel lines on her.

Lostyankee · #9 10-05-2006, 12:35 AM

I've been told that all new rubber hoses rated for fuel will tolerate biodiesel because they are made to handle ethanol blends. I believe the cutoff date was mid 80's but any hose that old should be replaced.

#10 10-05-2006, 12:15 PM

Quote:

Originally Posted by dieselmania

nate, when you replaced the return lines between the injectors did you use rubber or viton?

I have used Viton and Urethane.

Old300D · #11 10-05-2006, 01:49 PM

Quote:

Originally Posted by redassag00

I cant justify the cost of the Viton if I have to replace the hoses every 2-3 years.

And why would you do that? My lines are 2 years old now, with no signs of brittleness or aging.

Rashakor · #12 10-05-2006, 03:18 PM

Well the problem with B100 is really not with rubber.

Rubber problem pops when you add heat to the mix. As mentionned above. Regular modern diesel fuel line have actually no problem from biod if they are not under heat stress.

Get Viton for the return lines. and regular rubber for eveywhere else!

redassag00 · #13 10-05-2006, 03:40 PM

Quote:

Originally Posted by Old300D

And why would you do that? My lines are 2 years old now, with no signs of brittleness or aging.

That was the discussed interval here on the site, which I mean for regular rubber, i.e. 2 or 3 dollars for conventional rubber hose. Not viton.

Old300D · #14 10-05-2006, 04:11 PM

Quote:

Originally Posted by redassag00

That was the discussed interval here on the site, which I mean for regular rubber, i.e. 2 or 3 dollars for conventional rubber hose. Not viton.

I misunderstood you, I thought you had to replace Viton. I've had too much crap from the insides of nitrile line plug my filters, so that's why I got away from standard "rubber' lines. It's nice that Viton holds up over time so well.

dieselmania · #15 10-05-2006, 08:25 PM

ok, where can I get Viton return lines?