[Vwdiesel] Injector testing/new nozzles

[Shawn Wright]

On 14 Nov 2004 at 1:43, LBaird119 at aol.com <LBaird119 at aol.com> wrote:

> > For those who have done this before, what is the consensus with injector 
> > nozzle replacement? Can I just install new nozzles &heat shields and 
> > leave it at the that? Or is testing the break pressure, etc. necessary? ie: 
> > do 
> > the springs and shims wear over time so that break pressures drop, even 
> > with new nozzles? 
> > Those who have tested pressures: how often are worn injectors still out of 
> > spec with new nozzles?
> > 
> 
>   The biggest thing about testing them is to "clear" them out and 
> get a good spray.  It usually seems to take a couple, fast, way 
> over the top gushes from the tester to get a good pattern.  I suppose 
> they'd clear in the car too.
>   When you do new nozzles you nearly always need a little #400 
> wet/dry sandpaper, oil and a flat surface like a drill press table or 
> a piece of glass.  The upper body, and both sides of the intermediate 
> piece need "ground" smooth again.  There will be ridges showing on 
> the upper body and the smoothest side of the intermediate piece.  You 
> need to sand off 90% of those ridges and make sure the double 
> ringed sided of the intermediate piece is flat and smooth as well.  
> Rinse everything in diesel, brakleen or WD-40 and make sure you 
> have diesel, atf or at least WD saturating the nozzle's pintle and 
> hole.
>   I brakleen and blow off the body halves and use a dab of antisieze
> on the threads, well above the mating surface.
>   The little that you sand off nearly always puts the break pressure 
> right in the "new" specs.  :-)

Loren,

Thanks for this detailed account. It's been a few years since I took one apart, so now 
I guess I'll have to practice on my spare TD injectors to get familiar with the above 
procedure. I don't recall any ridges, but I probably didn't know where to look. Has 
anyone tried installed TD injectors on an NA? If the nozzles really are the same, then 
what are the differences in the injector body? Or is it just springs/shims to increase 
the break pressure to the TD spec? Do the valves on the pump body need to match 
the break pressure of the injectors?

--
Shawn Wright
I.T. Manager
Shawnigan Lake School