[Vwdiesel] biodiesel requiring a rebuilt injection pump on an '84 Rabbit

[Will Taygan]

The new rebuild kits from Bosch use Viton.  I've run B100 for years
without a pump problem in the 1981 1.6NA pickup *BUT* my pump was
rebuilt by the PO in the late 90's so maybe it's got viton already!

Now the aged return line did blow after the first month, I haven't
switched to viton, but replace my rubber fuel hoses every 2 years.
Yeah, I probably should change them, but viton is pricey.

Will.

On Mon, 2006-03-20 at 14:32 -0600, Bryan K. Walton wrote:
> Hi everybody,
> 
> I have a question for the list concerning the effects of biodiesel (in
> high % blends) on the injection pumps of A1s (my case -- 1984 Rabbit).
> 
> I purchased this rabbit in December of 2005. It has approximately
> 121,000 miles on it. I've been running B20 in it so far. A few months
> ago, I had a mechanic upgrade the fuel lines to viton lines in
> preparation for me raising my concentration of biodiesel. I've
> purchased a new fuel filter and have planned to up my percentage of
> biodiesel to B60 sometime in April (and then go to B100 in June).
> Today, I read something on the Frybrid mailing list that made me halt
> my plans. Here is the link, to that thread:
> http://www.frybrid.com/forum/showthread.php?t=3571 In this thread,
> Chris Goodwin, owner of Frybrid, states that when running biodiesel,
> "early VW products will need a rebuilt Injection pump or they will
> leak at the advance plate, then at the face seal, the biodiesel will
> turn the cam belt to mush and the engine will bend valves and need 
> rebuilding."
> 
> I can handle a leaking fuel line, but rebuilding an injection pump is 
> frightening! And I don't even want to think about having to rebuild my
> engine. What is the story here? 
> 
> Would Chris's scenario happen slowly enough that I could fix the
> injection pump before there was engine damage? Or are we talking about
> something that would happen almost immediately?  What symptoms would I
> see if Chris's scenario started happening to my IP?  Is there anyway I
> can determine what the seals are made of on my IP, short of waiting for
> disaster to strike?
>  
> Any VW owners out there (with circa 1984 diesels) running biodiesel
> in high blends that can speak to this and their personal experiences?
> 
> Thanks in advance,
> Bryan
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