[hal101]

that sound that a diesel motor makes you know that ratel or nock

if your gas e motor made that sound it would go to the shop to get rebuilt

but a diesel motor makes that sound all of its life and everything is good

what could make that noise and not do damage ?

[drtracer58]

Injectors .....

[hal101]

Originally Posted by drtracer58

Injectors .....

nope i dont think so remember gas motors have injectors to

[tstroud]

It is heat and pressure induced ignition. It's called detonation (bad)in a gas engine but that is the way a diesel engine works.
Diesel engines are built much heavier than gas engines so it does not damage them.
A lot of the new computer controlled diesels do not knock loudly anymore.

[hal101]

the diesel ignites as it is injected in the hot compressed air so i dont think that is detonation

[tstroud]

Correct.
In a diesel engine it is not detonation, it is normal ignition.
In a gas engine it is detonation, not normal ignition.

[mrennie]

Some "official" terms for those that care.

Compression ignition engine = runs on diesel fuel, and that fuel ignites because the pressure and heat of compression is sufficient to light it off.

Spark ignition engine = runs on gasoline, and during normal combustion the fuel ignites when the spark plug fires. Abnormal combustion (detonation or pre-ignition) occurs anytime the fuel lights off from something other than the spark plug firing.

I have a little Kubota tractor with a 3 cyl diesel and man is it loud and "rattley" when it starts cold...

[dataway]

Hehehe ... yeah, been starting my Kubota BX2200 in about zero degree temps lately.... acts like it's going to come out of the tractor for the first five seconds. Block heater helps.

[brad900]

The noise is from the rapid ignition of diesel causing a shock wave

[STEELCITYFIREBIRD]

Woodpeckers in the crankcase.

[Will]

Originally Posted by STEELCITYFIREBIRD

Woodpeckers in the crankcase.

How many woodpeckerpower does your diesel have? 🤣

[STEELCITYFIREBIRD]

Originally Posted by Will

How many woodpeckerpower does your diesel have? ��

How many peckerpower does your wood have?

[Formulajones]

Originally Posted by tstroud

A lot of the new computer controlled diesels do not knock loudly anymore.

Yep, they are actually pretty quiet now.

["QUICK-SILVER"]

Originally Posted by hal101

the diesel ignites as it is injected in the hot compressed air so i dont think that is detonation

Diesel fuel has to get hot enough to 'self ignite'. Fuel gets injected on the intake stroke, then the fuel/air mix gets hot enough to ignite on the compression stroke. Typically lighting off before the piston reaches TDC (making the knock sound), then cointinuing to burn and push the piston down.

Much tougher parts than what comes in the average gas engine.

A somewhat local Olds drag racer, use to convert the Olds diesel engines to gas for his hot rods. He ran with the big dogs at the track with junk yard engines. Kind of like the turbo LS bunch is doing now.

Clay

[Bobalong]

Originally Posted by dataway

Hehehe ... yeah, been starting my Kubota BX2200 in about zero degree temps lately.... acts like it's going to come out of the tractor for the first five seconds. Block heater helps.

Synthetic motor oil helps too. 5 or 10W30 synthetic will flow when conventional oil flows like cold honey. When it's REALLY cold outside.

[Schurkey]

Originally Posted by "QUICK-SILVER"

Fuel gets injected on the intake stroke, then the fuel/air mix gets hot enough to ignite on the compression stroke.

Fuel is injected before TDC on the compression stroke, the amount of advance is somewhat analogous to spark advance on a gasoline/spark ignition engine. The cylinder is already pressurized and hot from compression when the fuel is added. The fuel begins to burn instantly.

The fuel is NOT sprayed into the cylinder during the intake stroke.

[tstroud]

Right. The diesel fuel ignites as soon as it is injected. The injectors are timed, similar to spark plugs in a gas engine.

[tstroud]

Of course now there is direct injected gas engines. I'm not sure when the injectors fire on them.

[hal101]

Originally Posted by Schurkey

Fuel is injected before TDC on the compression stroke, the amount of advance is somewhat analogous to spark advance on a gasoline/spark ignition engine. The cylinder is already pressurized and hot from compression when the fuel is added. The fuel begins to burn instantly.

The fuel is NOT sprayed into the cylinder during the intake stroke.

thank you

[hal101]

Originally Posted by tstroud

Right. The diesel fuel ignites as soon as it is injected. The injectors are timed, similar to spark plugs in a gas engine.

yes thank you