Diesel Injectors New or Rebuilt (non-CRI)https://www.baileysdiesel.com/wp-content/uploads/2017/06/RD28-0681HBP.png 600 600 Nick Lopez Nick Lopez https://secure.gravatar.com/avatar/79000040f508166b7894f5425ea98ae7?s=96&d=mm&r=g
Diesel Injectors: New or Rebuilt (non-CRI)
The question of which Diesel Injectors new or rebuilt has come up many times and it did again during our episode of Ask Mattie B Live (on our Facebook page at 1230 Thursday) This post relates to Non Common Rail Injectors – specifically those found in a 1Hz engine (105 series landcruiser).
So – New or Rebuilt?
Not yet – let me explain how they work first:
How to these injectors work:
These older injectors are VERY basic in comparison to a common rail injector. In essence, they’re not that much more complicated than a garden hose! Basically these older units work on the same principle only difference being is that they have an ‘opening pressure’ that basically dictates the pressure that the injector will open at. This is controlled by a spring and the tension or pre-load its set at.
When the pump injectors, the injection pressure rises, lifting the nozzle needle off its seat. The fuel then comes past this seat, hits the ‘pintle’ at the end and then deflects out. The pintle is the little bit you can see sticking out of the nozzle.
Ok – so what goes wrong?
There’s really only basically 2 issues:
- Spring tension drops as the spring gets slightly tired, which in turn lowers the opening pressure and in extreme circumstances, can result in secondary injection creating much higher EGT’s.
- The Pintle on the end of the nozzle needle becomes eroded and therefore doesn’t atomise the fuel correctly.
- In very rare cases, you also get high pressure erosion on the high pressure sealing surfaces.
Get to the point! Diesel injectors new or rebuilt?
From my point of view, this is what we do as a part of the rebuild process here at Baileys Diesel Group (very common across the whole industry).
- 100% replacement of nozzles:
These are a low cost product which is the high wearing part and therefore not worth trying to cheap out on the repair, just simply replace with a brand new genuine unit
- Reset the opening pressure:
The springs do ‘settle’ a little throughout their life, so we re-shim them to get the original tension back up so they perform as new
- lapping of the high pressure sealing surface:
This is probably the only part that we do differently, at BDG we use a precision lapping table to get the high pressure sealing surfaces flat and very smooth in order to maximise the amount of injection pressure getting from the pump to the outlet of the nozzle.
So as you can see from all that, the injectors are in effect (well all the parts that matter at least) as new – or even slightly better.
Therefore there really is no difference between Diesel Injectors new or rebuilt unit with these non Common Rail Injectors.