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Re: [T3] Distributor Questions


On 8 Aug 98, at 20:53, oofacts@earthlink.net wrote:

> OK lets remember, 72 Squareback, dualcarbs...
>
> I need a new clamp. That bolt is welded through it, and I think it's
> backwards. I can't imagine VW wanting a clamp to be stuck in a place so
> impossible to tighten.

Yes, it's a strange arrangement, but once you realize what the right
way to do it must be, it can be done rather easily with a 10mm wrench
stuck down between that shaft and the fan housing..  Don't feel too
bad, on my first encounter with this dilemma in around 1970 I spent
days trying to figure out what VW intended me to do.

I have a good used clamp, cheap.

> Pulled out distrib. loked at shaft. Engine was at TDC 0¡. Drive shaft was
> at an angle, but not quite as extreme as that shown in Bentley.

The angle shown in all the books is not quite right, but it is close.
Was your drive shaft groove offset in the correct direction?  If the
angle was close and the offset was correct, then your drive gear is
installed correctly.  This is good news.

> My cond. is to the LEFT of the vaccuum plate,

It's not clear to me what you mean here.  By "vacuum plate" are you
referring to the vacuum advance diaphram unit?  If so, distributors
up to 71 have the cap mounted just CW from where the green points
wire exits the dist body, 72 and on mount the cap slightly furthur
CW, from the CCW-most of the two mounting bolts for the vacuum unit.
There is no real difference, except that the later version gives more
room for your 10mm wrench to adjust the timing.

> The way my distributor is (Bosch 040) the rotor CANNOT point at the notch
> on the rim if the drive shaft is positioned correctly (with the smaller
> half pointing front and slightly left) and the distributor is inserted
> correspondingly. In this position, the rotor is 180¡ from the notch.But
> there IS a little nub on the back of the rotor. Could this have been some
> sort of indicator/pointer Bosch put on this distributor? Its very
> confusing. Either that or my distributor is completely built backward.

This is not the right dist for any FI type 3.  Since I assume this a
US car, it was originally FI, so someone has changed the dist,
probably when they put in the dual carbs.  I also looked through all
the VW listings and the Porsche listings just to make sure it wasn't
a 914 dist, but I've come up empty.  What's the complete number?
What's the OE number (stamped just under the Bosch number?)

Your dist sounds like it is 180 off.  Is it a FI dist (does it have
the extra trigger points in the bottom?)  Regardless, it could be
rebuilt and turned around.  Without disassembling it I can't tell you
exactly what has been done wrong, if anything.

> I looked at bentley and they
> said to time it at 5¡ BTDC, which on the diagram looked like the third
> notch. BUT my guess was that this was presuming I was using a strobe, and
> that I had FI.

Right, this figure assumes you have the correct dist with vacuum
retard/advance (a 72 only feature) and can only be done with a timing
light.

> So I looked at Muir. Muir said to use 0¡ TDC, and his chart
> makes it out to be the first notch on the left. Not where the bridge
> actually begins, but the first notch in the bridge. Static timed it.

There are two different 4 notch pulleys.  Look at the pictures in
Bentley.  The left notch on the 68-71 version is TDC.  The four
notches on that version are 0, 7.5, 10, 12.5.

On the 72-3 version, I THINK the next to left notch is TDC.  On this
version  I THINK the notches are -5, 0, 5, 7.5.  There is plenty of
confusion on this question.

> Checked the Dwell on the points: 26, not bad for a beginner. But while the
> engine was idling, it began to shake hard (what does this indicate, yes
> lugging, but why when warm and idling?) - not something it usually does
> unless its cold, at which point I give a little steady gas until it goes
> away..

Your dwell should be ~45-50 deg.  Changing the dwell changes the
timing so you have to do the dwell first, then set the timing.  This
is true no matter how you go about setting the timing (timing light
or static.)

> Thought maybe I timed it wrong, so I Futzed with the timing. Keith had told
> me to try 7.5 BTDC which on Muir looks like the 3rd notch in the bridge.
> HEY WAIT A MINUTE. Looked at muir, looked at Bentley. Why does one say
> notch 3 is 5¡ and the other say 7.5¡ Somebody clarify whats what here. And
> when you do, bear in Mind that my chassis is 72, but my crankcase says 73.

What do you mean "crankcase says 73"?  Or is this just what you have
determined fron the engine number stamped in the case.

> Hey, how does one advance and/or retard timing?

Loosen the dist clamp and rotate the dist.  CCW advances the timing,
CW retards it.

> Is before TDC advancing it?

Yes.

> Is ATDC retarding it?

Yes.

> But when I pulled out my sparks, damn they were black. I had a tune-up this
> past March, and I've done a couple 400 mile trips since then, but BROTHER!
> So here's another question. I know that ovetr this time, since I have an
> oil leak I can't trace, which gives my car a bit of a habit, therehave been
> a couple instances early on where I checked the oil after I'd driven it
> some and the oil looked low, on the low mark, so I added a quart. Next
> morning I'd check the oil and it would be well above the high mark. I know
> this isn't good, but will someone tell me why this isn't good?

When you check your oil level you should wait a few minutes for all
the oil to drain back down into the case so you get an accurate
reading.  You also need to do this on level ground.

OTOH, if your plugs are black, it is possible that your dual carb
setup is just running over rich and dumping a lot of extra gas in
your cylinders.  This will result in gas diluting the oil in the case
and increasing the apparent oil level that you read.  It also washes
down the cylinder walls, removing the oil film that lubricates the
rings and causes rapid cylinder wear.

Is it possible that the thermostat has been removed from this engine?
This would make all of these things even worse.

> I think I want new distributor. Should I? Muir says he doesn't like vacuum
> advance, but that's what I have now, actually Vacum-mechanical combined. Do
> I need to have vacuum?

Muir is out of his league here, but it is likely that you aren't
using your vacuum advance.  Vac adv is good for economy, mech adv is
good for power.  If you have both then you can have both advantages.
Carbs require a different vacuum unit, and you probably don't have
the right one.  There may not BE a right one, depending on which dual
carbs you have.  Is there even a place to connect the vac adv on
these carbs?

You should probably forget about the fact that your car is a 72.  The
stock tune-up specs for a 72 are useless to you since your engine is
no longer stock.  What you need to do is find out what the best way
to tune an engine like yours should be.  This is not an easy task and
depends on a lot of factors.  It is clear that you are just starting
up the learning curve and you seem to be going about it well, by
asking lots of good questions.

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

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