D-Jet injector diameter

[corsachili]

Does anyone know about the apparent difference in the diameter or D-Jet fuel injectors? Some have a cap on them and some don't, but past that, the actual diameter of the shaft that fits inside the intake manifold seems to vary as well.

 

[Malc]

I think originally they came with a kind of plastic "boot" which shielded the nozzle and valve tip. They tend to go brittle with age and break. They are on more modern Bosch injectors too, like the ones from an L jet or motronic system.
I have run injectors with and without the boots, it doesn't appear to make any difference.

The injectors "sit on" a seal rather than sealing on the injector shaft so I don't think the diameter is that critical. However it shouldn't vary that much I would of thought.

 

[bengal taiga]

DJet injector variances

I agree with Sir Malc. Expect for minor manufacturing variances, all of the blue bosch injectors are dimensionally the same.

None of my original "blue" injectors had plastic caps on them. Newer ones and even other used injectors have had the plastic cap or cover on them. I do not have one in front of me, but I recall some of the plastic caps were barely pressed on while others took a fair amount of effort to remove them.

Injectors, for the most part, are quite durable. Water seems to be the biggest enemy because it may cause rust and impede the injector's plunger action. This is followed by crap in the fuel or combustion byproducts that can cause the injector not to function or may mess up the spray orifice, making the injector inefficient. The other common enemy is mishandling. If you inadvertently manage to drop an injector on its pintle/tapered needle - good bye injector. When blue injectors seemed more abundant and inexpensive, I found out how easy they are to break. Suffice it to say, the needles are brittle and can be bent or broken with the same force you use to adjust the gap on a sparkplug.

If you look at the pictures (http://sdsefi.com/injectors.htm) you will note the "o-ring" over the base of the injector tip. In my experience, the "o-ring" fits over the base without regard to the plastic cap. I haven't looked at the injectors on my D-jet for quite a while, but I would not be surprised if only a few injectors still had the plastic "protective" hats on.

HTH.

 

[psychrunner]

fuel type?

I know the "what grade to run" question has been tossed around quite a bit, but what do those with the csi injectors think best to use - Premium unleaded or is the regular unleaded fine?
Thanks
Randy

 

[BonitaCS]

The bore diameter for the injector is 14mm (for the o ring to seal against). For my 1.3 conversion I bored the intake manifolds out about .2" so the sides of the o rings will seal properly against the sides of the c bore. I'm also making a custom rail with brackets that will bolt to existing injector retainer tapped holes. TMI?

Scott

 

[corsachili]

D-Jet injector diameter update

Thankfully I have someone who remembers stuff that I don't. The problem was not the diameter of the injector nozzle, it was the pintel cap that was installed. The guy that cleaned, bench tested and returned them to me did a fine job, and installed the only Pintel caps that he had available. Those caps ended up being too big for the intake manifold. Now, you can run the injectors without the pintel caps but you then need a different O-ring, which is much harder to find.