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On 28 Nov 97, Ben R Lowry wrote:
> Since I didn't how to fix it, I got a distributor off of my friends dune
> buggy (we are going to overhaul the engine on the dune buggy anyway), and
> poppped it in(after reseting the timing of course) and it worked fine.
> It is neither vacuum advance nor a 009, like the original. Will this
> cause problems? Does an auto-tranny need a vacuum advance distributor?
> Where are the numbers to verify what type a distributor is? (It's a
> Bosch)
The vacuum advance is no more necessary on an AT car than on an MT
car. Still, the vacuum advance coupled with mech advance is a very
good thing. It allows your total advance to be a function of 2
variables [engine rpm and load] while the mech adv dist is a
single variable device. In the end, the vacuum advance will give you
2-4 mpg better gas mileage, because it allows more advance at crusing
speed than you would dare to use in the absence of something that
sensed load.
Here's the situation: You're cruising at 65 mph. With the OE dist
you have about 28 deg of mech adv and 10 deg of vac adv for a total
of about 38 deg. Now the books will all tell you that that is way
too much, but what they haven't mentioned is that they are all
talking about full-throttle all out competition. You're at about 1/4
throttle and the adv is fine. But now you need to pass, your speed
doesn't change much, but you've gone to full load and the vac adv has
dropped to zero and everythings fine.
If you have the mech adv only dist you MUST set it to stay below the
critical 32-34 deg max total adv, because when you're cruising with
it and decide to pass, it won't change the advance one bit.
In the end the vac part of the vac/mech adv distributors allows you
to take advantage of the fact that your engine can tolerate lots more
advance when its load is low.
> The peice wich broke, did screw out, so I'm guessing I can get a new
> peice, but I don't know the name of it. It looked like a half peanut
> shell, and held one(or two?) ball bearings in it. When it broke, it
> allowed the cover plate(is that the right term?) to move around, thus
> changing the gap.
The piece which broke is part of the breaker plate assembly. This is
the part which consists of two plates, one stationary and the other
rotatable on which the breaker points mount. The vac adv diaphram
causes the rotation of the movable plate. Your "halp peanut" is not
separately available, but the whole breaker plate assy is, and yours
is probably SHOT. With the dist out it is easy to remove and look
over. You will probably be dismayed at the wear in the center where
the two plates mate.
This assy is available from Bosch or VW as a replacement part for
about $35. As it is just about the only thing that will ever wear
out on one of these distributors it is well worth it.
BTW, the early FI T3 AT distributors have just about the fastest
advance curves around. I don't think you can come close to it
with a 009.
Jim
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Melissa Kepner Jim Adney
Laura Kepner-Adney
jadney@vwtype3.org
Madison, Wisconsin
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