Best Diesel RPM's??

[FBH44]

Have a Perkins AD3.152 diesel, 16 years old, 152 CID, and I use it mainly for small chores, moving things, some light bush-hogging. I know its not a JD, but should I be operating a small diesel like this it 1500 - 1700 RPM's?? I see many tach's for this size diesel have a green range around 1700 RPM's. Thanks.

 

[JDemaris]

Depends what "best" means to you. Long stroke diesels tend to run the most efficient at the peak of their torque-curve. That's usually 1800-2200 RPM.

 

[FBH44]

Thanks, I'm referring to getting the longest longevity, freedom from glazing, engine long life.

 

[Tx Jim]

I think getting engine to operating temp and keeping it there is more important than rpm's as long as engine isn't lugged at low rpm.

 

[gtx1967jewison]

Kubota 3 cylinders of the 25-30 hp range run at 3600 governed speed....

 

[buickanddeere]

You will never run it enough to ever see the wear difference between 1500 and 2200rpm. You will never save enough fuel to save a Jerry can full a year.
The low rpm stories are for 24/7 prime power applications in marine propulsion, power generation and irrigation.
The engine should not be heavily loaded when below the rpm that peak torque is measured at. Guessing 1600-1700rpm? Peak HP is probably around 2000-2300rpm?
There is more wear to engine and drivetrain when the engine is lugging.
What does the operator"s manual say?

 

[LarrySTN]

The AD3.152 engine is very well built. My father bought a MF135 diesel more than 40 years ago, and the engine has held up remarkably well. While I am a john deere fan the small JD engines never were as reliable as the AD3.152. If you keep the oil, coolant and filters changed as recommended, you will not hurt the engine whatever rpm you use. The most fuel effecient according to Nebraska Tractor test is about 1700. They"re a bullet proof engine.

 

[Indiana Ken]

(quoted from post at 07:07:24 01/30/14) Thanks, I'm referring to getting the longest longevity, freedom from glazing, engine long life.

I have not heard of cylinder glazing - but would like to learn more about it. From these posts it seems to be related to speed. What confuses me is if it is on the cylinder then shouldn't we be concerned about piston speed and not so much crankshaft RPM.

Average piston speed is given by: PS (feet/minute) = 0.166 x stroke (inches) x RPM.

Example 1) My 4000 Ford has a stroke of 3.6 inches and a maximum no load RPM of 2430. For piston speed we have, PS = 0.166 x 3.6 x 2430 = 1452 feet per minute.

Example 2) On January 7, 2014 on HP Vs CU. IN. B-manic posted about a Wurtsila - Sulzer RTA 96 14 cylinder engine. It has a stroke of 18 feet and operates at 100 RPM. For piston we have, PS = 0.166 x 18 x 12 x 100 = 3586 feet per minute.

One engine runs fast, pistons go slow, another engine runs slow, pistons go fast. I would think an engine should simply be run fast enough for the load such that it is not lugging.

 

[buickanddeere]

Worrying about a non issue. As long as the engine is loaded and up to 180-195F coolant temp.glazing is not going to occur. A diesel idling at light load and low coolant temps may glaze. Most often an issue with those who have no idea what a block heater is . And they let a cold engine idle for 5-30 minutes to "warm up".