replace fuel line for biodiesel?

[nekto]

I'm going to start running biodiesel in my 81 1.6 diesel caddy... Does anybody know whether or not the stock fuel lines / seals n such are made with the newer kind of rubber that can stand up to the solvent properties of biodiesel?

if not, are there any kits that I can buy to replace the necessary fuel lines, etc?

If anybody has any pointers on how to lift the 81 caddy, or add a turbo, i'm all ears on that too!

,Matt from AZ

[mortskeg]

Matt, welcome to the forum!
The stock rubber fuel hoses on the pickup are not biodiesel compatable, with the low pressure fuel return lines (the ones that connect all the injectors) the most susepable. You'll probably want to change out your hoses with viton or similar if you plan on running B100 (100% biodiesel) but you probably won't have any problems with the stock tubes running B10 or B20. I have made about a B10 mix with no problems. You can actually run the b100 with your original fuel hoses, just keep an eye on them and replace them when they become soft/ squishy sticky before they burst.

I think there was a company in Eugene, Oregon that was selling a complete viton swap kit but to me it seemed overpriced. I know that the stuff is spendy but you might be able to find some at an industrial hose supply place. I'm still on the lookout for my vehicle so let us know what you find.

I've also thought about raiding the wreckers and getting some fuel line out of a TDI vw as they have compatable fuel lines but don't know how the fit would be. Run a search for "lift" and "turbo" with Darth Garry as the author as he has done both to his "truckdoza" Hope this helps.
:cheers:

[racerman]

http://www.greaseworks.org/biodiesel
here is the site for the homemade fuel friendly line

[ajrn]

http://www.greaseworks.org/index.php?module=pncommerce&func=itemview&ItemID=12

Uh oh, fuel pump seal (viton) replacements..

Although I do agree, at least initially, the swelling would STOP, not start leaks...

I'd like to hear more from the "B100" crowd, about what has failed, or what they replaced, with anticipation of failure...

AJ RN

[ajrn]

I've found an '82--

Anyone know how much and what size(s) of fuel line I'll need..?

I agree, the kit is a little pricey, and they won't give diameters or feet needed, you can buy their kit, or.... Don't... Seems to be pretty much their answer.. :up_yours:

I like Mort's idea of using urethane tubing.. I'm going to pitch it on the biodiesel forums, and see if there's reason NOT to do that..

AJ RN

[mortskeg]

I got this idea from 'sharkey' on the vwdiesel forum. I bought 5' of 5/16" and 4' of 1/4". I think I had about a foot or so of each left. Stuff seems to be working good. :)

[ajrn]

This is going to sound like a total n00b question... And it is, as I haven't even picked the truck up yet.. :0

Where are all the places I'll need to replace?

I'm assuming there's a junction between the tank sender, and a metal line that runs underneath the truck. And another junction between the other end of the metal line, and the fuel injection pump. Then individual lines that feed the cylinders coming off of there..

I'm sure I've 'oversimplified' but are there 'hidden' places to worry about??

:i_dont_kn

Whoops! forgot the return lines!

Are 1/4" and 5/16" line ALL I'll need?


AJ RN

[mortskeg]

I'm assuming there's a junction between the tank sender, and a metal line that runs underneath the truck. And another junction between the other end of the metal line, and the fuel injection pump. Correct, though on the engine end it just runs from the feed pipe to the filter, a hard plasic vw fuel line gets it to the pump from there.
Then individual lines that feed the cylinders coming off of there..These are actually steel and are 'good to go'
Whoops! forgot the return lines!It (metal line) runs parrallel to the feed line and is the same diameter IIRC
I'm sure I've 'oversimplified' but are there 'hidden' places to worry about??You need small diameter (1/8"?) between the injectors and the injector- pump return. 2' would be plenty. Also the big diameter fuel filler-tank pipe but I don't know where to get that one.

I used the 1/4" pipe between the injection pump and metal return line. All other large diameter I used the 5/16" (tank-feed line, feed line-filter, returnline-tank).

BTW these sizes have metric equivelents printed on the tube (8mm & 6mm?) which is what was probably orig used.

Hope this helps.

[asav8tor]

On the fuel injectors, the last injector to the right has one port capped off. Around 1987 the cap started leaking. I put a 1" length of Radio Controlled airplane silicone fuel line on the port and put a machine screw in the end to cap it off. It got a little soft where the diesel fuel touched the inside of the tubing but the part on the port and the machine screw maintained a good grip until I replaced it this year. All of the short hoses interconnecting the injectors were starting to leak ( I can't believe VW would use a hose that doesn't last at least 25 years ), so I replaced them all with R/C silicone fuel line. You can see the diesel bubbling through the lines as the engine runs. The silicone fuel line is NOT intended for diesel and they do make another model airplane fuel line that is. Some of it is black and another type is see through. The silicone lines get a little soft after diesel runs through them so it is important to get the length right the first time. The line will last and maintain a good grip UNLESS you try to shorten it after running the engine. Another point, get the lenght correct so the lines do not touch other things. Example, a line slightly too long would rub against the metal lines from the injector pump and eventually rub a hole in the silicone tubing from engine vibration. Too short and you risk kinking the line at the port fitting.

[mortskeg]

Yeah this tygon stuff I used between the injectors has almost the same feel as RC fuel line but it is B100 compatable. Infact I got it at Parkrose if you know that place. I used a 1" section of the tygon on the last injector, plugged it with a plastic pin (the center section of the plastic clip that holds the grill on the pickup, I had extras) and secured it with a small zip tie. Been working great.

Around 1987 the cap started leaking.You've been VW'n for a long time. :D

I put a 1" length of Radio Controlled airplane silicone fuel line ....What are you flying? I have a junky uproar 40 that I haven't taken up since I moved down here.

http://img.photobucket.com/albums/v400/glen_ekstrom/newpaint.jpg

Are you still running the silicone line with good luck? (has it been there since 87?)
:cheers:

[asav8tor]

Haven't flown RCs for a long long time. Currently flying a MD80 full scale. Sometimes out of PDX . The RC fuel line I used for the cap on the last injector lasted from 87 to 2005. When I changed everything over to RC fuel line I replaced the capped line with a new one. I would prefer to use diesel clear RC fuel line but I didn't have any on hand.

I am seriously considering the VO conversion. Thinking a 40+ gal tank and 2000+ mile range. :thumbs_up

[ajrn]

Hey--

Found a 'local' (about an hour away) seller of tygon tubing.. They do online sales-- so I thought I'd pass on the link..

http://www.usplastic.com/catalog/product.asp?catalog_name=usplastic&category_name=7510&product_id=26053&cookie%5Ftest=1

Of course, this keeps me from loosing the link before I get to Lima.. :rolleyes:

So, I'm looking at buying 10' of 1/8" 1/4" and 5/16"?? If anyone else wants to buy some, I think I'll have plenty of extra! :thumbs_up

AJ RN