[T3] Distributer placement/Timing

[Jim Adney]

On 13 Jan 2014 at 10:30, rheorojo at F wrote:

> Is this an issue (improperly seated distributor)that would result in
> the timing drifting out within 50-100 miles? I've had a similar issue
> where, I time the car (73 sqbk auto) and within 50-100 miles it's out
> buy 4-5 degrees. The distributer clamp was deformed some so I have
> replaced it. 

No, improper seating won't cause drift, although it can cause sudden 
dramatic changes in the timing, changes that are usually large enough 
to stop the engine.

General drifting, always in the direction toward greater dwell, are 
almost always caused by wear of the rubbing block on the ignition 
points. A certain amount of wear is normal and expected, but the 
rubbing block should wear a bit then settle in and become relatively 
stable.  

The points cam should be cleaned and re-lubricated at every tuneup. 
If you don't do this, the grease picks up grit which wears both the 
rubbing block and the steel cam. Make sure to clean all the dirty 
grease off both the cam AND the rubbing block each time, before 
applying a smear of fresh grease.

One of the important things I do in a dist rebuild is grind down wear 
paths in the cam. These won't happen if you keep your cam nicely 
lubricated, but over 40 years, most dists have seen fairly long 
periods of neglect that leave them in bad shape.

If I get the dist clamp with a dist for a rebuild, I'll also 
straighten it. They are usually deformed by people who think more is 
better when tightening them. They only need to be snug, just enough 
to keep the dist from turning by hand. That turns out to take very 
little tightness.  

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