Has anyone ever told you...... - Page 3 - PeachParts Mercedes-Benz Forum

Brian Carlton · #31 12-24-2006, 11:00 PM

Quote:

Originally Posted by Knightrider966

I can only report from my observations. I've got both a 1983 E300D and a 1982 E240D and I know the E240D makes a bit more noise because of the sound of the engine sucking in a lot of air goes right through the air filter and housing and seems to amplify out the plastic intake hose. My E300D is quieter and sounds a little more like a clack clack clack without the air huffing into the motor. On the 240, the air makes one 90 degree turn into the engine and in my 300 the air goes first through one 90 degree turn, then a 180 degree turn and finally into the engine through the turbo at another 90 degree turn. Even my roomate can tell when I come home which car I'm driving by the sound of the engine when I pull into the driveway.

As Forced mentioned, the model designations are incorrect.

But, with your cited examples, I fully agree.

If you take two vehicles with identical injectors and prechambers and cylinder configurations such as a 617 and a 616, the 617 should produce less noise due to the convoluted intake tract.

But, variables in injectors, prechambers, and timing between the engines will usually take precedence over any intake variables. If this were not the situation, every single 616 would create more racket than the 617. We already know that this is not the case.

Brian Carlton · #32 12-24-2006, 11:15 PM

Quote:

Originally Posted by Knightrider966

I can only report from my observations. I've got both a 1983 E300D and a 1982 E240D and I know the E240D makes a bit more noise because of the sound of the engine sucking in a lot of air goes right through the air filter and housing and seems to amplify out the plastic intake hose. My E300D is quieter and sounds a little more like a clack clack clack without the air huffing into the motor. On the 240, the air makes one 90 degree turn into the engine and in my 300 the air goes first through one 90 degree turn, then a 180 degree turn and finally into the engine through the turbo at another 90 degree turn. Even my roomate can tell when I come home which car I'm driving by the sound of the engine when I pull into the driveway.

As I'm pondering the injection noise situation, what intrigues me about both of these engines is the "clack....clack....clack" sound. This can easily be heard and almost counted. Therefore, it's occurring at about 1/2 engine speed............6 times per second. With the sound occurring at this frequency, it would appear that a single cylinder is making the noise. If all cylinders produced equal injection noise, the frequency would be 5X this rate for an OM617 and a person couldn't discern the "clack....clack....clack". The speed of 300 times per second would prevent this.

So, I continue to be intrigued with the injection event. Clearly it must not be equivalent in all cylinders..........

Knightrider966 · #33 12-24-2006, 11:30 PM

Well, in my engines the clacking noise seems to be consistent and rapid in all cyliders. I had a lot of engine and fuel system work recently performed, but i'm sure there are differences in compression between cylinders. I would think that this could alter the sound somewhat. I guess you could say that if I could slow down the RPM's until you could hear every cylinder, they would sound pretty much the same. A mechanic's stethoscope doesn't reveal any big differences between cylinders. I think the 240 sounds louder to me because the intake manifold is kinda like an echo chamber. I do notice the engine making more noise on fossil fuels though.

Brian Carlton · #34 12-24-2006, 11:34 PM

Quote:

Originally Posted by Knightrider966

Well, in my engines the clacking noise seems to be consistent and rapid in all cyliders. I had a lot of engine and fuel system work recently performed, but i'm sure there are differences in compression between cylinders. I would think that this could alter the sound somewhat. I guess you could say that if I could slow down the RPM's until you could hear every cylinder, they would sound pretty much the same. A mechanic's stethoscope doesn't reveal any big differences between cylinders. I think the 240 sounds louder to me because the intake manifold is kinda like an echo chamber. I do notice the engine making more noise on fossil fuels though.

If you can hear the "clack...clack...clack", then you're listening to a single cylinder. If all the cylinders make the same noise, the speed of the clacking would be 24 times per second on the 240. You wouldn't be able to discern this noise.

Knightrider966 · #35 12-24-2006, 11:50 PM

Yeah, I guess you would describe it best as a rattling sound. Your right, a clacking would be like nailing and I know mine is not doing that! I think my terminology is different.