which injectors should I go with?

Aug 2, 2019
Wilmington, North Carolina
My old 3B blew up and I got a new one, although it has higher Kms. My old 3B had the injectors rebuilt 60k miles ago so i figured I'd go ahead and swap them but they don't look nearly as good as the ones I pulled out of my new engine. I don't know much about injectors/how to tell when one is dirty or running improperly, which ones should I put back in my new engine? Stay with the ones that were in it or pit in my "rebuilt" injectors from my old engine.

First off here is a side by side, on the left is the "rebuilt" injector from my blown up motor, on the right is from my new greasy engine. All the injectors look the same on each engine.

Heres a picture of the threads down into the engine on the new motor, pretty clean. These injectors were easy to take out. All looked like this

Here is one from my old blown up engine, every single plug looked like this or worse... very hard to take out, had to struggle the entire way thru from all the crap in the threads.

and then also this melted injector, cool. this one came from the new engine I got, took whatever was melted off with a screwdriver and it looks perfectly fine again, just like the rest of them.


My question is... were these injectors running properly? The ones that were pulled out of the new engine I got just seemed to be cleaner aswell as not just totally covered in black, what would cause this? My engine blowing up or the injectors weren't rebuilt properly, orrrrr? Really just curious on which ones I should use in my up coming running engine. Thanks!


Waiting for Barn Time
Jan 11, 2015
Visual is not as good as physical test. Take it to diesel shop. They usually have a tester. Cheaper than buying on. Need to know if injector opening pressure and spray pattern is to FSM spec.


Jan 9, 2008
Moronville, ME
That shrapnel on the one injector scares me. Do you have access to a borescope you can stick down the injector hole and inspect the precombustion chamber? I would be worried that is part of the pre-combustion chamber that was stuck to the injector. You don't want to drop a pre-cup. You're going to have a bad day if that happens. If that was my engine I would pull the head and inspect things before sticking it in the vehicle.
Mar 10, 2019
melbourne, Oz
x2 what ceylon said.
just take them to a shop, they will replace the nozzles with correct ones and re calibrate them with calibrated and well maintained pressure pop testers. They have the full gamut of 20 odd sizes of shims to set the proper pop. The whole injector should come back looking new.

Hard to tell from pics but the new nozzle should have a very fine sharp point, not blunt.

My local diesel mechanic wire wheels them shiny satin. He says to paint the holder or they shall rust, with epoxy enamel or urethane clear (not the nozzle or threaded areas which connect with the fuel line olive holders). Put a bit of anti -sieze on the injector thread only, so you can get them out again in the future 100,000kms without grief.

Make sure you have no burs from pvo (from over tightening) on your olive ends, use red scotchbrite carefully if you do and clean meticulously. Do not over tighten, just enough to stop diesel leaking, they are a good design. If you still have a leak, undo the olive fitting, clean and try again rather than over tighten. The main torquing is the nozzle to port. The aluminium washers are very soft, don't over tighten them or you may damage your hard return line.

The nozzles have very fine tolerances and do not like dust and dirt. If you pull one apart, and feel the actual needle slide down the nozzle you get an idea of how close a fit it is, this is where the diesel gets atomized.

Clean the ports with a vacuum with a tube fitting carefully, better to suck it out than fall in. Maybe a bit of brake clean and brush, but be careful. The d mechanic said the fat brass washer is the most important, the little horse shoe washer cups upwards. It is best practice to be super anal with diesel injectors.

The cost is worth 100,000kms for sure, to set and forget. It is good to know a diesel mechanic you like. There is some dodgy ones out there too, who fit the incorrect nozzles and grind springs to save on shims on ebay.

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