Different nozzles for my engine - what are the effects?

Hello.

I've asked something similar before, but I'd like to ask for your advice again because I haven't received any specific information.

The "AEL" engine block was used by VOLVO in two different versions.
What I know is that the crankshaft is different (at least the stub or the mounting point for the timing wheel), and that there have also been changes to the fuel injection system (possibly also more internal components - but there is no information available about those).

The most important difference is likely the motor control unit. The newer model uses an "MSA15.8", while the older one uses an "MSA15.7" – these are completely different control units (with different shapes, connectors, etc.), and I also assume the software is different.
I assume the reason for the change, or the upgrade, was related to environmental concerns. Personally, it seems like the newer generation of engines produces less soot, but that's purely a subjective impression. The old AEl is already quite smoky.

Regarding my issue, my car received a new engine block in 2005. Only the block was replaced; everything else was rebuilt. In a Volvo specialist workshop (which, however, doesn't necessarily have to be a positive thing, see below).
Now I know for sure that the newer engine generation has different fuel injectors, at least that's what I found online:

[code]
"Until 1999: 'DSLA 150 P 502' => 5 pieces (MSA 15.7, spray angle 150°) - Opening pressure: 190 BAR."
FROM 1999 "DSLA 93 P 838" => 5 pieces (MSA 15.8, spray angle 160°) - Opening pressure 191 BAR.
Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

My basic idea is that I'm now using the "newer" engine block with the older injectors. I would have assumed that the injection angle needs to match the piston design, which is what I was told here before. Now I've gone through various spare parts catalogs, and I haven't been able to find any specific information indicating whether the pistons are different.

May I ask you again what your theoretical perspective is on this?

The fact is, this engine has been running like this for approximately 220,000 km, and if the injectors weren't working correctly, it wouldn't have lasted this long, right? However, this summer, the exhaust muffler was replaced, and at that time, the head gasket on one cylinder (NHG) cracked in three places, and only on that one cylinder. I then repaired the damage and noticed that the workshop had forgotten to install the sealing ring when they replaced the cylinder head. When I had the head on the workbench, I saw that the injector protruded much further in. The engine rebuilder also said that this could be the reason.

To put it simply, if I'm going to repair the nozzles, what types of nozzles should I buy? And what factors determine the correct injection angle? Or is it possible that both injection angles would be correct for the block?

I'm looking forward to it.
"Thank you."

best regards, uwe

Hello Uwe,

Quote:

And what does it depend on, to determine which injection angle is the right one?

from the piston bowl and the position of the injector in the cylinder head.

If everything has been working perfectly so far, I would leave the combination as it is.

Best regards, Rainer.

Thank you for the response!

From your sentence, I understand that you would also assume that the damage to the cylinder head gasket is due to the missing gasket, which is quite thick. The nozzle was clearly visible and protruded too far into the combustion chamber.

The injectors are old, really old. I would have liked to replace them right away when I had the head off. However, the engine specialist inspected them and checked the spray pattern, and he said that even with 450,000 km (I assume they've never been replaced), they are okay. So, there's no need for action in that case either.
"It's not that I want to do anything, the car drives perfectly as it is, it gets under 6 liters per 100km and produces very little soot."

"Thank you!!"

Sure, here's the translation:

"Hello."

I'm just an amateur electronics enthusiast, but wouldn't it be possible that the new high-performance tips are slightly longer and therefore have a 160° angle, while the shorter ones have a 150° angle?

"It's not necessarily that much, 5 degrees per side..."
That would explain why the shape of the pistons hasn't changed. I can only speculate about the advantages of the new configuration, possibly in terms of emissions.

Hello.

Thank you for the information.

I've discovered something else. I have the data sheets for both engines, and they are the same in almost every way – except for the compression ratio.

In the older engine, the compression ratio is 19.5:1, while in the newer engine, it is 20.5:1.

"But does it really have such a big impact? Supposedly not. I had the head skimmed slightly before installing the new gasket, so the compression probably isn't 100% accurate anymore. However, according to..." A diesel engine mechanic might not be that bad - after all, it's still running.

The question now is really which nozzles I can use - based on my findings, I'm almost convinced that both will work. Therefore, I would be inclined to choose the "newer" nozzles when exchanging them, as it would likely be an improvement.

It probably has nothing to do with the fuel injection pump, because someone, quite cleverly, once thought that the fuel injection pump also needs to be compatible. That tells me that there's only one part number for both engines, so they must be identical.

"Thank you."
Best regards,