[T3] engine miss, solved?!

[Keith Park]

I hate those cans too!  Anyone know the difference between a 917and an 813?
I have one of those too.
With the 2056 supertuned, everything must be right or it wont run properly.
As Ray Greenwood has said, the factory set them up 
Rich so small issues would be hidden and not felt as readily, but with
mine... they can!

Keith

Topnotch Restorations
topnotch at nycap.rr.com
http://www.topnotchresto.com
71 Squareback  “Hothe”
65 Notchback  “El Baja Rojo”
93 RX7  “Redstur”
13 Subaru Outback "Blendin"

-----Original Message-----
From: type3-vwtype3.org <type3-vwtype3.org-bounces at lists.vwtype3.org> On
Behalf Of Jim Adney
Sent: Thursday, May 20, 2021 12:58 PM
To: type3 at vwtype3.org
Subject: Re: [T3] engine miss, solved?!

On 19 May 2021 at 22:15, Keith Park wrote:

> Recently the retard side of the advance can had a vacuum leak and 
> wasn't working properly, It did move but it DID leak.  The hose was a 
> bit loose on the nipple too.

I hate those dual advance/retard vacuum cans. They are fragile and the
retard sides are always failing, but this usually makes it impossible to do
a correct tuneup. Those cans are also frightfully expensive, IF you can find
the right one at all. Part of that tuneup requires that you test the retard
by pulling off the retard hose and verifying that the timing advances by
some significant amount. If it doesn't you can't set the timing properly.

Small leaks in the diaphram won't hurt anything; they get washed out by the
suction from the intake, but I'd be worried that a small leak was about to
become a large one. I've never caught a retard diaphram leak when it was
small; by the time I see them they are HUGE.

> I think it was Jim that mentioned that one screw for the can needs to 
> be the shorter one otherwise its awfully close to the points spring, which
is hot.

Yes, that was me. I'm always careful about the screws in our distributors. 
Bosch used about 4 different length screws, and they are different for good
reasons. [BTW, if the screws that hold the FI trigger points in place are
too long, they can short out the trigger points the same way. You can only
see this if you install the trigger points before you install the points
plate, so you can look down there to verify that the screw isn't sticking in
beyond the inside of the distributor body.]

> I cant say for sure it was touching, or intermittently touching but 
> that does change with RPM, advance etc.  Ah HA!  Put the correct screw 
> in, set the timing, now I have a higher idle so I was able to adjust 
> it down, it was now running too RICH.  no more missing

Sounds good!

> Cant say for sure it was that little too long screw, or routing of the 
> plug wires, or a connection I wiggled, but that screw was definitely 
> asking for trouble and a good example of why to just send your dizzy 
> to Jim to have it rebuilt, its those little tiny details that he 
> remembers and that matter so much.

Thanks for the compliment. I've rebuilt a LOT of distributors over the past
50 years, so eventually the important points start to sink in.  ;-)  

I know I'm as likely to jump into the deep end looking for the cause of a
problem, but I also know that the simple solutions are usually the best and
always the quickest and cheapest.

--
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************

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