[Vwdiesel] Oil pressure

[LBaird119 at aol.com]

>>Someone give me reasons for the insanity?

  Because!  That's why.  (That's what my Dad always told me anyway!)

  I believe it has a lot to do with VW's (as well as most German and many 
Euro marques) tendency to NOT reengineer everything every two to three 
years just to make you want the new model.
  It's the same basic casting as it was back about '75, when it was gas, 
had a distributor and a fuel pump.  You notice the holes area still 
there for those.  We just use them for a vacuum pump and crank 
vent.  Thus the std. joke of being sure you get the vacuum pump 
timing set correctly.  Although it does have to be one of two positions 
180 apart.
  They didn't keep the cogged int. shaft drive because then the injector 
pump would be slip fit to the belt, unless you added a longer belt and 
another idler.  Franz probably suggested THAT.

> >>Anyone know of a source for the pre-honed int. shaft bearings?

  Most places have them, you just have to be sure which you are 
getting or your hands will be really sore by the time you're done 
hand honing to fit.  Ugh.

> >>What keeps the int.shft bearings from spinning and blocking their own oil 
> 
> >>passage? Just interference fit?  

  Just friction.  That's why the clearance between the shaft and the bearing. 
 :-)
 
> >>Why isn't there a groove in the bearing or
> >>bearing surface on the shaft to distribute the oil pressure around the 
> whole >>shaft? 
> 
  Well, there are none on the cam, none on the rods and only halfway around 
on 4 of the 5 mains.  There is a groove on one of them, to direct oil at the 
vacuum pump gear so even though one is larger than the other and can't
be mixed up, the one CAN be put in backwards.  Make sure the holes 
line up with the holes too.

  '91 ECO PROBABLY has the 36mm gears.  AFIK it's 26mm gears up to 
somewhere from 81 to 84.  Then they went to 30mm by '85 or earlier.  
Then the 36mm came out on a 1.8 Audi.  That's where I got my first two 
applications of it from.  Had to swap drive shafts due to length.  So, I 
presume the 36mm came out on the diesel for the TD, hydraulic head. 
Since it's feeding a turbo, hydraulic lifters and oil squirters.
     Loren