2014 Bluetec diesel clatter
03-29-2018, 03:18 PM
#26
Even the older diesels have more clatter with some batches of fuel than others. You could be into a batch of low cetane fuel. If so, a bit of cetane improver could tell you if that is your problem. In my old 300D I have had such bad fuel that I had to add a quart of two cycle oil to the tank so I could stand to burn it.
Newer engines squirt a sniff of fuel in early to get the combustion started and then the rest is added. The idea is that the fuel does not light with a bang. With either low cetane or a bad injector spray pattern, yours could be all going off at once, giving the normal diesel bang.
I have found the Gumout Diesel fuel system cleaner to be very effective at reducing the clatter in my old diesel. If I were in your situation I would try it in a tank full.
LOL ....I just noticed The age of this thread.
Newer engines squirt a sniff of fuel in early to get the combustion started and then the rest is added. The idea is that the fuel does not light with a bang. With either low cetane or a bad injector spray pattern, yours could be all going off at once, giving the normal diesel bang.
I have found the Gumout Diesel fuel system cleaner to be very effective at reducing the clatter in my old diesel. If I were in your situation I would try it in a tank full.
LOL ....I just noticed The age of this thread.
Last edited by nelbur; 03-29-2018 at 03:27 PM.
03-29-2018, 07:15 PM
#27
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1922 Ford Model T / no OBD
160k is serious mileage, so don't expect you'll make 1/2 mil without some work on drive-train.
Noise is one of the hardest things to troubleshoot over the Internet, bu at this mileage checking the timing chain stretch would be good idea.
That assuming the swirl flaps have been cleaned and transmission serviced?
What is your present 0-60 acceleration time?
Noise is one of the hardest things to troubleshoot over the Internet, bu at this mileage checking the timing chain stretch would be good idea.
That assuming the swirl flaps have been cleaned and transmission serviced?
What is your present 0-60 acceleration time?
08-23-2019, 12:09 PM
#28
Senior Member
new diesel engine that exhibits more 'diesel knocking' after a few days of use, generally is suffering from poorer ignition characteristics of the current fuel (lower cetane rating) , lower engine or intake air temperatures, or deposits on the fuel injector tips causing poorer fuel injection spray patterns.
A diesel is 'compression ignited', depending on the heat (air temperature) developed during the compression stroke to ignite the fuel.... Fuel injection (a very fine spray--almost a 'fog) is started B4 top dead center and continues during the power stroke until completed. There is a 'time delay' between the start of injection and ignition of the fuel-fog plume. The fuel IS NOT thoroughly mixed with the air-it is contained in a very fuel rich 'plume'. Injection continues as the injected fuel burns in a stationary flame, consuming air on the outside surface of the plume of fuel mist until injection is complete. The time delay between start of injection and ignition of the fuel is used to calculate the 'cetane number.' N-cetane is used as 'the reference' fuel against which to measure the test fuel. The 'cetane number' of purchased diesel is the characteristic used to indicate the Ignition Characteristics of the diesel fuel. It DOES NOT indicate Power production or any other characteristic of the diesel fuel.
The lower the Cetane Rating, the longer the ignition delay, the more fuel is already in the combustion chamber when the fuel ignites, the louder the 'diesel knocking' in a given engine.
Some engines have higher compression ratios, which results in higher air temperatures when fuel injection begins, give shorter 'ignition delays' and lower 'diesel knocking, more power potential, higher burning efficiency, and lower smoke generation.
Some diesel fuels may have 'good' high cetane numbers, but burn with substantial 'smoke.' Smoke generation is primarily caused by molecules more dense and physically bigger than 'N-cetane.' 'Aromatics' are denser and take longer to burn completely and burn with more 'smoke.' Some people are confused by 'smoke generation' of different fuels. More 'smoke' Does Not indicate more power from that fuel. More power comes from injecting more fuel, which burns for a longer time, and generates more smoke.
These 'lower quality diesel fuels' as indicated by lower 'cetane numbers' often will cause 'coke deposits' on the tips of the injectors and result less fine fuel spray, more smoke, lower combustion efficiency, longer ignition delay and more 'diesel knocking.' It only takes tiny amounts of 'coke' to adversely effect the combustion process. Even tiny increases in the Ignition Delay can raise the 'diesel knock' to audible levels.
A diesel is 'compression ignited', depending on the heat (air temperature) developed during the compression stroke to ignite the fuel.... Fuel injection (a very fine spray--almost a 'fog) is started B4 top dead center and continues during the power stroke until completed. There is a 'time delay' between the start of injection and ignition of the fuel-fog plume. The fuel IS NOT thoroughly mixed with the air-it is contained in a very fuel rich 'plume'. Injection continues as the injected fuel burns in a stationary flame, consuming air on the outside surface of the plume of fuel mist until injection is complete. The time delay between start of injection and ignition of the fuel is used to calculate the 'cetane number.' N-cetane is used as 'the reference' fuel against which to measure the test fuel. The 'cetane number' of purchased diesel is the characteristic used to indicate the Ignition Characteristics of the diesel fuel. It DOES NOT indicate Power production or any other characteristic of the diesel fuel.
The lower the Cetane Rating, the longer the ignition delay, the more fuel is already in the combustion chamber when the fuel ignites, the louder the 'diesel knocking' in a given engine.
Some engines have higher compression ratios, which results in higher air temperatures when fuel injection begins, give shorter 'ignition delays' and lower 'diesel knocking, more power potential, higher burning efficiency, and lower smoke generation.
Some diesel fuels may have 'good' high cetane numbers, but burn with substantial 'smoke.' Smoke generation is primarily caused by molecules more dense and physically bigger than 'N-cetane.' 'Aromatics' are denser and take longer to burn completely and burn with more 'smoke.' Some people are confused by 'smoke generation' of different fuels. More 'smoke' Does Not indicate more power from that fuel. More power comes from injecting more fuel, which burns for a longer time, and generates more smoke.
These 'lower quality diesel fuels' as indicated by lower 'cetane numbers' often will cause 'coke deposits' on the tips of the injectors and result less fine fuel spray, more smoke, lower combustion efficiency, longer ignition delay and more 'diesel knocking.' It only takes tiny amounts of 'coke' to adversely effect the combustion process. Even tiny increases in the Ignition Delay can raise the 'diesel knock' to audible levels.
08-23-2019, 03:18 PM
#29
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1922 Ford Model T / no OBD
"compressor ignited" engines run on ether. I my young years I've been active in airplanes models and the most popular size 2.5 CC was run on ether (still have scars on my fingers from properel to prove it).
Diesel is "injection ignited" and it is timed to couple.
Diesel is "injection ignited" and it is timed to couple.
08-23-2019, 05:38 PM
#30
Senior Member
The general tone of the initial message - paraphrasing; just a tiny bit of diesel clatter at 1100 miles; does this engine get noisier with age...
This does not sound like a mechanical issue, but it does scream a payment book issue.
Let me explain, as a former service manager I have found that, generally, when a new owner comes in with a mysterious noise, a subtle change in characteristic or general dissatisfaction of a non descript nature the problem is not with the vehicle, but the payment book. I do not discount any real defects when I state this - those need to be addressed and repaired.
This hypothesis is usually confirmed when the individual states that at XXX dollars per month you should make a better vehicle or for XX,XXXX dollars this Mercedes should not do...
The fact that it was perceived as absolutely silent initially is irrelevant since all diesels make some perceptible noise, period. That they have just become aware of this and only when standing outside is just ridiculous to call this a "clatter".
This does not sound like a mechanical issue, but it does scream a payment book issue.
Let me explain, as a former service manager I have found that, generally, when a new owner comes in with a mysterious noise, a subtle change in characteristic or general dissatisfaction of a non descript nature the problem is not with the vehicle, but the payment book. I do not discount any real defects when I state this - those need to be addressed and repaired.
This hypothesis is usually confirmed when the individual states that at XXX dollars per month you should make a better vehicle or for XX,XXXX dollars this Mercedes should not do...
The fact that it was perceived as absolutely silent initially is irrelevant since all diesels make some perceptible noise, period. That they have just become aware of this and only when standing outside is just ridiculous to call this a "clatter".
