[T3] odd issue RPM hangs.

William Jahn willjahn975 at gmail.com
Mon Oct 14 19:14:48 PDT 2019


I'm not sure. I wouldn't say it's so loose that it actually rattles yet
it's pretty easy to remove it and easy to turn it either way . In my mind
when the RPM's pick up if it does in fact move it would advance the spark
and it might stay there yet it might retard the spark. Since the dist
rotates CW the wheel would rotate CCW.

 I can't explain why on earth one day I had the engine fully warmed up and
set the timing just below 5* BTDC and checked it several times and set the
RPM to 1000 and it was still there.The next day I check engine warm  and
the timing was on TDC , I didn't change it and the I could not move the
dist. I  then drove it to warm it up then changed it back to just below 5*
BTDC . For some odd reason it seemed to have better pickup at TDC it didn't
ping any more at either setting.

 I could not find one issue with the dist and still I lubed the weights
again. I rev the engine and see it advances yet instead of dropping back to
where I set the timing it goes a bit retarded then comes back to where I
timed it.

 Since I was having this odd hanging idle I decided to check the timing and
dropped the idle to 850 RPM and saw it was 7.5 * and if I opened the
throttle and release it it would either drop right back to 7.5 yet most of
the time it would hang higher and slowly drop down and the throttle was
closed so I thought it's the timing. I was surprised at 7.5 it didn't ping
and since it pinged at 5* why not at 7.5 so 7.5 had to be a false.

 I can't imagine why I cannot set the timing and have it read the same each
time, it should and it always did. Each time I warm it up then drop the RPM
to 850 and set it then bring the RPM back to 1000 and the timing stays it
does not advance between 850 & 1000  and it's never the same the next time.

 This is the only car in my entire life than didn't have points or that I
changed from points and never had one issue. I used to set this engine with
points .018 gap and static time it and checked with a light it was right at
5* BTDC I must be missing the point of it having to be warmed up it's not
like it's 30 degrees here I can see the point of making sure the AAR is
closed so the RPM is at it's lowest . I used to just start the car and plug
the AAR and set the timing and it was fine .

 Now it's turned into a nightmare. Nothing makes sense. This is why I felt
going back to points even if it's just for the sake of ruling out the
Pertronick! as a possible issue it would be well worth my time and effort.
I even checked to see if the rotor snaps back and it does yet here's the
glitch . the rotor has just enough play it that wedge that fits the dist
slot If I move it to the left and release I can move it a bit move to the
left or CCW , why because it's not a snug fit . No it will not move on it's
own it takes a bit of force , if I remove the rotor and just turn the dist
shaft I can't move it CCW at all. Yet the force it takes to turn the rotor
is about 50 times as hard as turning the pertronix wheel about the same
amount.

 I realize anyone reading this must think I've completely lost my mind and
wouldn't blame them yet this is not my imagination , trust me I have tried
everything and just cannot get the timing to remain where I set it. This
pertronix wheel has 4 magnets and they are far from weak and everything
around them is magnetic other than the aluminum fixture it is riveted to,
one would think and being logical would reason since the 4 magnets are
closest to the dist shaft that will keep the wheel from rotating , I very
well may be. I have no idea what the magnetic force is when they pass the
pickup or sensor. As far as pertronix is concerned after a few calls I was
told the wheel should not move at all and to use pipe sealant  tape , good
luck trying to get that crap to stay. I used to have a dwell meter yet
never used it simply because it's not going to fix point contact pit and
valley that happens and even though it was an expensive Mac tools dwell
tack in it's day it didn't work for long $85 right down the drain. Sure
while it worked the tach was nice.

 I'm just going to pull the pertronix out and put in points and see what
happens , I already have the condenser mounted in the proper most
impossible place to get at without removing the distributor it's an old
Bosch condenser not the new garbage. Even so the points I've used in the
past no matter how good they were grew a pit and peak so I'd change them.
If this does not solve this insane issue then at least I know I have ruled
out  the pertronix.

On Mon, Oct 14, 2019 at 5:54 PM Jim Adney <jadney at vwtype3.org> wrote:

> On 14 Oct 2019 at 14:54, William Jahn wrote:
>
> > I noticed what I think the issue I have is. On the Pertronix the
> > magnetic ring on the dist point lobe is not a tight fit, If I hold the
> > shaft I can rotate that ring close to 1/16" on the points cam and even
> > though the rotor sits down on that ring I can still move it and this
> > would advance and retard the timing in the same manner
>
> It can be moved, but it's probably snug, not loose. Whereever you
> leave it, it will stay there. So it does not contribute to the
> advance.
>
> If it did move, it would still not move in proportion to rpm or
> vacuum, so its effect would not be predictable.
>
> If it's really loose, that would result in erratic timing, which
> would be a problem. If that is the case, you should be able to see
> the timing jump around with a timing light. I think that's extremely
> unlikely.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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