MBZ nozzles, 155 BAR? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• MBZ nozzles, 155 BAR? by autoholic on 22 Sep, 2008 13:23
• I am considering purchasing some 155BAR injectors w/MBZ nozzles for my 1.6TD Samurai. I currently have 135 Bar stock injectors and one of them was popping off kind of funny, resulting in a miss/rough running when cold, Id like to put some new injectors in it.
  Ive heard the MBZ nozzles are a good choice for SVO? Is the spray pattern the same? Should timing be adjusted w/ the higher pop psi?anything else I should consider?
  I should mention that this engine has an NA pump w/ gov mod and 1.9 camplate
  Thanks!
• #1 by burnt_servo on 22 Sep, 2008 13:44
• i've got the merc noizzles in my car set to 2500 psi .
  
  the tip in side the merc nozzle has a flat spot , gilles mentioned that he thought it was to make the 5 cyl merc engine run smooth , i've read that the flat spot was to help prevent the tip from getting clogged .
  
  the flat spot causes a much different spray pattern than the vw nozzles .
  
  with the nozzles i got from prothe , 2500 psi seemed to be the magic number that i got a nice fine mist from when pop testing them . ( yours may be different )
  
  i've got around 4000 km's on the new nozzles now with no problems .
  
  and the higher your pop presure , the more you need to advance your timing ...... and if your running a non standard pop presure you will need to get it roughly timed staticly , then fine tune it with a timing light dymanicly .
• #2 by autoholic on 22 Sep, 2008 14:59
• Thanks,
  I heard the same about the grooves in the MBZ nozzles, that they help keep injector clean. OK so maybe i'll advance the timing a bit, right now it's at 1.05mm, maybe I should just leave it and advance it with the cable to see where I like it, then check it and reset the timing based on that?
  
  Does the different spray  pattern concern you at all, seeing how the prechamber in the MBZ compared toVW is very different, should we be concerned about burning valves or melting pistons or anything nasty like that? Are you monitoring EGT's? if so did they change at all?
  
  Are there any changes to cam timing anyone is doing? I just have been locking the cam at the back with the tool and using feeler gauges to shim either side the same amount, with the crank at TDC of course.
  
  As I mentioned, I'm using an NA pump which is turned up with a couple of minor mods, is it still worth using these injectors with an NA pump? I'm not looking for alot more power, it's running pretty damn well as it is, but I would like to have it run as efficiently as possible, eventually on veg after I break this motor in.
• #3 by autoholic on 22 Sep, 2008 15:01
• A timing light for dynamic timing? what type of timing light do you need to time a diesel? I never heard of that.
• #4 by Smokey Eddy on 22 Sep, 2008 15:17
• yeah me niether
• #5 by jtanguay on 22 Sep, 2008 15:43
• you can get these probes that attach to the injector lines and convert the signal so that a timing light can probe onto.  it triggers the light so you can time it that way.  some say it is a bit earlier than actual injection though...  but much more accurate.  TDI's use this same technology on the no.3 injector so that it can adjust the timing.  but as the injectors wear, unless it is a nice even wear, it will start to run rougher.  new PD's and CR motors control injection much more precisely than with breaking pressure and springs.
• #6 by Mark(The Miser)UK on 22 Sep, 2008 16:27
• Aren't the nozzles pretty  much  pressure independant, other than the higher the pop pressure the finer the spray? So anything with a '0' in its name will do :?
   
  Wasn't the flat sided pintle a means of giving a pre squirt on start-up; a replacment for those nozzles with a very fine drill hole up the middle?
   
  I'm running '315's [flat sided] which I snatched out of  some kind of Ford... They are set to 135 bar ish They do not smoke on startup and no discernable leak off.
  
  All Bosch injectors I've opened up suitable for the TD are made in France. This includes original Quantum ones.
  Mercs use '314's; any difference?
  
  Oh for a book of nozzles :idea:
• #7 by autoholic on 22 Sep, 2008 16:46
• So your using Ford nozzles in the VW? I just wonder if all these different injectors are specifically designed for the shape/configuration of the pre chamber?
  I know I do not want to spray fuel right against the cyl wall for example.
  
  I thought there were alot of people running MBZ nozzles. I Ordered the complete injectors from Volkswaparts, I just want to make sure this will not present any problems before installing them in this new motor.
  
  I guess I should rephrase my question: Which injectors/pop off psi would you use in my situation? 1.6TD, NA pump w/minor mods, SVO after break-in?
  
  The AAZ injectors sound like another good option?
  
  Thanks again.
• #8 by autoholic on 22 Sep, 2008 17:23
• Here is what the vendor mentions about these injectors:  
  "New VW 1.6 or 1.9 Turbo Diesel Injector made with the larger Mercedes Spec Nozzle (part number DN0SD265). 155 Bar Opening Pressure. This is new and not rebuilt. This is a tuning injector for 1.6 Turbodiesels.
  
  The DN0SD265 nozzle has a prespray trough sidecut and is naturally self-cleaning, recommended for use with biodiesel and vegetable oil. Biodiesel is higher viscosity than regular diesel and will flow better in the larger nozzle"
  
  I got em coming, decided to give them a try, I'll let you know how it goes.
• #9 by zukgod1 on 23 Sep, 2008 07:24
• Well I'm running CASE nozzles in my injectors.
  They are huge in comparison to the Merc tips.
  Running a k24 with the pump turned up a bit I could hit 40psi, scary amounts of fuel..
  I posted the flow rates somewhere on here..