[Vwdiesel] Injector pressure setting -- ( by Hagar Feel )

[Dana Morphew]

On 5 Dec 2003 at 7:50, H.Hagar wrote:

> Dana Morphew wrote Dec 04 2003. :
> 
> Q:    I'm wondering how accurately you can set the pressure by how it feels. 
> Can you get it within 5 bar? I'm assuming the final setting is somewhat
> important since VW gives a low pressure limit before rebuild.
> 
> A:   Lets deal with 130 bar injectors first.    According to Bentley lower
> limit is 120 bar. So we are shooting at a 10 bar window. (145 psi?)  I say yes
> with a little practice that is possible.

That is a sensitive hand.  Any worries about fuel penetration?
> 
> Is the 120 bar setting the absolute minimum ?  absolutely not.  If you have a
> very tired Rabbit ---- it may work a lot better at say  100 bar. I use the
> setting that works best for a particular engine.For example if there is a very
> tired cylinder , 120 bar may be best. On big diesels each and every cylinder
> is timed and injection volume set  while running, often by using pyrometers.So
> here you may see   " 1  100 bar  # 2  135 bar  etc  you get it . 

Hmmm...my take is you get better atomization with a higher break pressure.  
Better atomization = better and more complete burn.  

That explains
> why those little delights in front of the cardboard box (house)  are working
> so well.All the little tricks are more or less readable in archives. Look for
> hillbilly fine tuning of injection pumps. If you look way off to the right  in
> my first thread  , you will see that I mentioned that a small angle of turn
> makes a lot of difference.From the point of contact with spring to 130 bar is
> only a matter of  a turn or part of a turn.  The indication is acceptable and
> adding shims is explained in Bentley   as to how much increase in relation to
> thickness.I promise to compare using the testpump and post the results.Weather
> is stopping me now , since I do it outside. The first 4 I did --- was not done
> assembling mated parts.  But randomly selected parts out of coffecan  full of
> springs and barrel parts.Will a VW run on four injectors assembled by hand
> only ? bet your sweet ass. Just don't run em too long.    

When I adjusted mine and installed new nozzles, I recall (which may or may 
not be accurate) that a shim size larger would give you about a 5 bar 
increase in break pressure.  I set mine between 135 and 140 with the 1.9 
spec. at 137.

EBay has testers come up for bid fairly often.              
> 
> Sure is some fun                  Hagar.
 
Dana