[T3] Generator ... Again

Jim Adney jadney at vwtype3.org
Tue Sep 18 21:10:02 PDT 2012


I'm sending this message to everyone, because there may be other 
'67-early '68 owners out there who encounter the same problem.

On 3 Sep 2012 at 7:12, Max Welton wrote:

> Well, here I go again. On my way home from work yesterday in the 68,
> the charge light came one. It flickered lightly at first, then came on
> more insistently. It still isn't fully "on", but she isn't charging. I
> happened to be logging engine data (Megasquirt) and was able to see
> the main buss voltage go from its usual 13.6 to ~12 volts. I had no
> problem driving home on the battery (about 40 minutes). 

Max sent me his generator to work over and I got it today in good 
shape. Seeing it reminded me that we were talking about one of those 
early 12 V generators that came with the plugin connectors in the 
black plastic surround.

That's the same version of generator that I had on my '68. It turns 
out that I went thru this exact same problem. At that time I was new 
to Type 3s, and I didn't have the resources I have now. Here's the 
rest of the story:

VW & Bosch changed from the plugin generator at the end of May '68; 
after that all the generators came with screw terminals. I hadn't 
realized that this was a mid year change. The 2 versions use 
different brushes. I don't have any of the early brushes here, but 
I'll try to get some tomorrow. IIRC, I fixed mine by filing down the 
brushes that were sold to me, which were probably the late version, 
and were too long.   

When the brushes are too long, the brush spring pushes sideways more 
than downward, so the brush tends to hang up and not press down 
against the commutator. That causes arcing, and roughens the 
commutator.

This commutator will clean up nicely and I'll either install the 
correct brushes, or brushes that I've modified to work.

So the moral of the story is that not all 12 V Type 3 generator 
brushes are the same, and no one is likely to sell you the right ones 
if you have one of the early generators with the plugin connectors. I 
didn't find ANY brand other than Bosch who listed a different brush 
for these early generators, so it's unlikely that you'd find anyone 
who could actually sell you the right part.

BTW, Max, there was more dirt in this generator than I'd expect to 
see from just one year's use, and it appears to be more black and 
oily than I'd expect from even dirty cooling air. Any chance you've 
changed something that might cause oil to blow out the rear of the 
crank and onto the fan, like install carbs on a '72-3 engine?

The telltale sign would be carbs on an engine that has a breather box 
with 2 plastic caps, rather than just 1.

If so, you should look into changing the breather so that you don't 
get pressure buildup in the crankcase.

This is a problem that happens to LOTS of people who convert late 
engines to carbs.

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




More information about the type3-vwtype3.org mailing list