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

[James Hansen]

He's just referring to leakage at the front seal.
diesel, bio, or otherwise leaks at the front seal, then slowly eats up 
the T-belt.  when this happens, the timing goes off, and the pistons tap 
the valves back into the head.

If you are completely oblivious to things mechanical, then this type of 
thing can happen, yes.  If you pay attention, then a fuel leak would not 
go undetected.  Now that you know about it, I would assume you would pay 
attention :-)
Main cause of pump leakage at the input shaft is generally from a too 
tight t-belt.  biodiesel *may* harm this seal, but it's an easy 
replacement to a moderate DIY'er if indeed it is only the seal, not 
bushing wear from a tight timing belt that caused the seal to pop in the 
first place.

-James
> 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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