240D - One Injector is Different
 

My '81 240D appears to have one injector different than the rest (see pic). You can see the difference in the bodies, although the overal height is the same. The different injector is a bosch injector, which I think was an original on these cars. Does anyone recognize the other three? They say NA30X on the injector. Are these some aftermarket ones?

The bodies of the NA30X injectors all unscrewed with some application of torque. That Bosch one will not come apart. I actually ruined a breaker bar trying to get it apart. I may just have buy a new injector.

The reason I am doing this job was to install new Monark nozzles. Bought a pop tester and having lots of fun!

I just looked on the body of that "different" injector and see that it says 135 BAR, which is the injector that the turbo diesels are supposed to have, not my 240D, which is supposed to have a 115 BAR injector. So it looks like someone swapped an injector from the wrong car.

However....the pop pressure tested this injector to pop within 10 psig of the others, so does it really make any difference? Maybe they put a weaker spring in the body, or removed the shim to get the pressure lower. So as long as it pops at the correct pressure and as long as the bottom of the injector goes the same distance into the engine, does it really make a difference?

No.

Google shows the NA30X to be a
FUEL INJECTOR, BOSCH REMANFACTURED


http://store.impartsol.com/fuelinbosrem1.html

Yes, it appears that the NA33X is an updated version of the NA30X, which is for the 115 BAR injectors for the older non-turbo diesels. The NA34X is the updated injector for the NA31X (135 BAR), which is used on the turbo models.
All of these appear to be Bosch injectors.

The rebuilt info of the Injectors with the X number is right.

There are 2 different types of Injector Bodies that can be used; as you have pictured. However, all of the parts that go with that Injector must stay with that Injector as the internal parts are also a different size.
It is actually a good idea to keep all the parts from each Injector seperate from the others anyway as it makes it slightly easier when it comes time to Pop Test them.

As long as the 2 different bodied Injectors are set to the same Pop Pressure and with the same Spray Nozzles they can be used on the Engine.

For getting the Injector Apart, put top part of the Injector in a vice (Aluminum or Copper Jaw Covers if you do not want to mark them up) and heat the Injector Nut with a Propane Torch.
After that use your new Breaker Bar (1/2 inch drive) and Socket on the Nut and brace youself and give a quick tug on the Breaker Bar.
It is also OK to use an Impact Wrench on them when taking them apart.