Fuel Injectors: Spray Angle Differences Explained

Hello,

There are two versions of the TDI engine used in the Volvo. Volvo calls it the D5252t, while VAG calls it the AEL. The engines are only slightly different - I noticed that the crankshaft is different (the timing belt pulley at the bottom was different) - and the timing belt cover is also different. I'm not aware of any other differences, but they are likely very minimal.

Now, a new engine block has been installed in my car - I'm quite certain that the old components (injectors?) were also reused. I've now read that, at least with Volvo, the injectors are also changed during an engine replacement - see below. This is also related to the MSA (presumably a specific system or component) in this case.

Okay, so I'm not really sure about the difference - the question I have is: which nozzles should I install in my injector bodies? Does the spray angle matter? Or should it match the MSA (which I already have)? Or should it match the engine (which I have the new one for)?


Nozzles, DSLA 150 P 502 (MSA 15.7, spray angle 150°)
Nozzles, DSLA 93 P 838 (MSA 15.8, spray angle 160°)

I would also appreciate any tips on which nozzles to buy. The first time I replaced them, I bought original Bosch nozzles, and that worked fine. However, there are also "cheaper" options available, and I'm wondering if it's worth considering them.
Thank you for the tips.
best regards, uwe

For the MSA (Measurement System Analysis), the injection angle doesn't make a difference; it would only matter if the hole size were also changed.

I suspect that, along with the MSA change, the emission standard was probably also improved. This usually happened through changes in the shape of the recesses in the pistons and a change in the compression ratio. That's exactly where a modified injection angle would also make sense. Therefore, the nozzles used must be the ones that are compatible with the engine/pistons.

Stay away from cheap nozzles; based on experience, they only cause problems due to large variations in output between nozzles. With nozzles like that, it's almost like winning the lottery if you manage to get a set where the variations between nozzles are less than 10%...

Thanks for the information. I'll check the spare parts catalog to see if the piston has a different part number.
That means I now have the wrong nozzles, because the workshop reinstalled the "old" ones. At least, I don't assume that they are included with a replacement engine...

Sure, here's the translation:

"thx"
Sure, here is the translation of the text from German to English:

"Hello"

Hey Roorback,
I still have a 15.8 D5252T engine block lying around; let me know if you ever need to measure anything on the piston bowls.
I also once tried new injectors with DSLA150P502 AEL inserts, but I didn't notice any difference. The only thing was that my onboard computer (BC) was giving some pretty wild readings, with consumption figures that were sometimes absurdly low.
However, the NHG (National Hydraulic Group) of the donor nozzle holder was also defective.

Thanks for the information. Yes, I actually have 15.7mm pistons here - I could measure them. I saw something on the Volvo forum from an engine control unit specialist who says that the injectors are linked to the engine control unit, and that something was apparently changed in the control unit, which explains the different angle. I'm a bit confused now, but I'll see what happens.

I have some used nozzle sets here from various butcher shops - all of them are old. A friend once borrowed a set to test his 2000 model (msa15.), so they are definitely the wrong nozzles for the wrong engine and wrong control unit - and that also worked...

Best regards,

The part number for the piston depends on the engine number; above a certain engine number, a different piston is used.
What is different, of course, cannot be said.

Great - now I have two opinions, which doesn't make the decision any easier. I think I'll just order the ones that are currently installed - the car actually runs really well with them.


Regards,

PS: I always assume that the injectors are not part of a new engine. Or does anyone see it differently? If the injectors were part of the engine, then firstly they wouldn't be old, and secondly they would be a proper fit (at least with the hardware).!?

roorback wrote:

P.S.: I always assume that the nozzles are not part of a new engine. Or does anyone see it differently?

No, nozzles are add-on parts and are never included by default.

Okay, YOU'RE WELCOME!

What do you do in a situation like that? It will never fit together perfectly again... Of course, a Volvo workshop doesn't know anything about that either - they only know that you can order a part according to the ETK (Electronic Teile Katalog) and replace it...
But - I think I'm just worrying too much. The best thing to do is probably to leave it as it is. The odometer reads 430,000 km... on the nozzles...

Best regards,

Hello.

Let's go back to the piston theory for a moment. If the incorrect nozzles or angles are no longer injecting properly into the bottom of the piston, that's not ideal, right? What could happen in the worst-case scenario?
The question is whether the nozzle holder is compatible with the new nozzles. The opening pressure may also be different, and the hole size may be different. Apparently, there is also a different valve pressure (VP) for the nozzles.

Damn, I think I'm worrying too much – the engine has already run for over 100,000 kilometers.

Best regards,

"Can you please use punctuation marks like ! or ? without spaces before them, as is customary in German? "

Hello, diesel mechanics.

I can't quite understand the criticism, but I'm trying to write in a way that everyone can understand, even though I'm a foreigner. We've had this discussion before, but only here. In all the other forums, there's no criticism like this; in fact, I could often learn a few things from some of you Germans - most people write in all lowercase, don't use greetings, and don't say "thank you" or "please."

I will try.

Best regards,

Quote:

I can't quite understand the criticism

.
Dann erkläre ich Dir meinen Hinweis. Hier ist und soll kein Forum sein, wo man alles klein, alles gross schreibt, 20 Millionen Rechtschreibfehler in jedem Satz sind und diese ohne Satzzeichen oder endlosen ! und ? Chains end.
I don't demand perfect sentences (and I include myself in that, as I don't always succeed either), but I do ask that people put in some effort. It might also be helpful to reread your own contributions.

Overall, your writing is quite good, but unfortunately, it lacks some reflection.

Best regards, Rainer.