[Vwdiesel] cold start shaft reseal in car Re: pump still leaks

Andrew .Libby libbybapa at gmail.com
Wed Sep 16 21:34:47 PDT 2009

Perhaps I didn't explain that very well.  The cold start shaft is the stop
for the dynamic timing piston.  Without it present and just the blank cap in
place, the piston will move farther when at rest (static timing).  Because
the dynamic advance overcomes the cold start effect entirely by 1500 rpms or
so, your cruising timing is unaffected (99% of your driving).  Your idle is
retarded which is the reason for your rougher cold idle.  As you said,
without moving the pump everything works pretty much the same as it ever
has.  But my point was that you have changed the static timing point.  What
that means in real life terms is that unless you take a baseline reading
using a dial indicator (or strobe light with diesel pulse adapter) neither
you, nor anyone else will be able to time that pump properly using a dial
indicator.  Without a baseline, if your pump timing ever gets disturbed, you
will need to time it by ear, or re-install the cold start lever.  Not a big
deal, but something to be aware of.

I was also pointing out that the cold start lever had to be installed on the
far side of the pump because the pump rotates clockwise.

I certainly could not get by without a cold start mechanism as I often see
wintertime sub-zero F temps here in Flagstaff, Arizona but your northwest
low altitude cold temps are much milder than here.


On Wed, Sep 16, 2009 at 8:45 PM, <decker at toledotel.com> wrote:

> Hi Andrew;
>    I'm not a Bosch pump expert and your statement might be true but in my
> case by the seat of my pants I couldn't notice any difference. It was a true
> 50 mpg car before and a true 50 mpg car after the removal of the cold start
> shaft. The Dasher station wagon has a 5 spd, an Audi exhaust manifold with a
> 50 mm opening and a 2 inch exhaust pipe from there with a 16 inch turbo
> style muffler. It is bored 1mm over but nothing else that would improve
> performance or mileage
>   My cold start lever seals started leaking in my 1981 1.6 Dasher diesel
> wagon at least two years ago perhaps more and I don't remember how much I
> took out of the pump. I do know that I took out the cold start shaft and
> replaced the cover with a solid one from the other side of a dead pump. I
> might have installed something from that off side hole. I did that without
> loosening or moving the pump. The car started just like before and ran just
> like before. It doesn't idle as well cold and perhaps if one lived in very
> cold country one would want the cold start lever functional. The Dasher has
> a 5 speed from a Quantum turbo diesel and it loves it. It will run down the
> freeway at 70 with room to spare. I made a run to Portland OR yesterday and
> ran 155 miles mostly on the freeway at 65 to 70. It took 3 .1 gallons when I
> got home to Toledo WA. I never felt a difference in the engine when I took
> the cold start shaft out and it runs like a stripe now. Since I took the
> cold start shaft out besides many thousands of miles around here it has been
> to Arizona twice, Canada twice, Texas once, California probably 20 or 30
> times and still gets 50 mpg unless I flog it into a headwind which knocks me
> down a few mpg. In a month I will be leaving on a trip with stops in
> Kentucky, Maryland, Indiana, Minnesota and home. You just don't need the
> cold start shaft in there.
> Brian Decker

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