(800) 853-2651
SHOP NOW

Diesel engine wive's tales?

P

Prawn Farmer

Member
Discussion brought up about operating diesel engine at less than fast idle or rated RPM's will cause glazing and was hard on hydraulic pumps? We were talking about ag/heavy equipment diesels rather than truck engines. Combines being hydrostatic- sure - for the threshing load, but, as long as engine gets up to operating temps and doesn't cold stack why does it matter?
 
Engine should not be operated so slow and so heavily loaded that it is lugging. There are so operators out there that think they are "saving " the engine on rpm alone And not thinking of continuous max combustion chamber pressure and max crank torque.
Power will be rougher with higher peak impulses wih an engine making 100HP at 1400rpm vs. 100HP at 1800rpm.
Turbo engines do need some rpm to build boost.
Operating the engine at less than what ever peak torque is measured at is usually not a good idea.
Cooling system is moving less air and coolant at reduced rpms . Overheating can be a factor.
Odds are you will never live long enough or own the engine long enough to see any extended engine life advantages of 1400rpm operation instead of 1800rpm. Fuel consumption , yes, no or maybe......
 
I was always taught that running the engine at about 75% rpm was a good compromise and you could always add more throttle if you heard it bogging down?
 
Depends on what you mean by "less than fast idle or rated RPM". Rated RPM is usually somewhere in the lower 2000s. Peak torque range is usually in the mid to high teens. On both of my tractors 1900 RPM is just ahead of the peak torque bulge. That's where I pull them. Fuel savings are noticeable. Check the Nebraska test ratings. John Deere has been, for a number of years, running their drawbar tests at both the rated RPM, like 2100. And then running at a lesser RPM. Usually 1900, but lately they've brought that down to 1750. Take a look at those numbers.
 
Any RPM well above idle that does not heavily lug the engine is fine, you do not have to run it at rated RPM.
 
(quoted from post at 19:20:03 11/01/13)
So just what is glazing any hoo, what does it look like and is it painful? Does anyone know?
Click to expand...

Glazing refers to the cylinder liners getting a glaze coating on them. This can lead to excessive oil consumption.
 
A lot depends on the manufacturer of the engine too. The dealer that sold my brother his 9270 case new told him you can lug that engine at 1600 rpms all day and do less damage than full throttle, and the fuel savings was significant. The 504 case engine can take it too if you don't lug it much. I'm not sure it would work good on some others with less cubic inches tho.
 

I don't really know why but any hydraulically operated equipment like an excavator is supposed to be run at fairly high RPMs or it is hard on the Hydraulics more so than the motor.
 
Diesels are made to work, so are hydraulics. Depending on the engine, some diesels will glaze up so bad that you won't be able to rev them up. Others will slobber like a pig with a cold. I was told not to let my Cat 3204 idle for long periods cause it would glaze up but the newer Cat engines were OK to idle. That said, you never see a semi at slow idle when the drivers sleeping in the cold. They always rev them up to prevent glazing and/or slobbering. Whether heavy equipment or a truck, they're still basically the same engine. The engine will more efficient at higher RPM's as well.

When running equipment like a skid steer, it is hard on the hydrostatics to run them at a low throttle.
 
The piece of equipment I"ve got that started this question is a T250 Bobcat that I run between 1250 and 1500 rpm"s and I"ve noticed some minor blue smoke. Engine only has 2700 hours on it and it was suggested to me that I could be starting to glaze the cylinder walls. I do get the hydraulics and engine up to temps and let it idle a few minutes before shutdown to let the turbo cool down a bit. In the 5 years I"ve owned it I"ve used Shell 10w-40 Rotel in it.
 
Hello prawn farmer,

Idling a diesel is a NO NO! Main reason they will eventually start using oil. Glazed liners is one of the results of prolonged idling.

Guido
 
You must log in or register to reply here.

Similar threads

D
Toro Dingo 320D engine
Replies
3
Views
575
David R Inman
D
N
Two engines making oil?
Replies
15
Views
1K
timcasbolt
timcasbolt
N
4000D Injection Pump Trials and Tribulations
Replies
5
Views
916
DONMYEIL
D
guido
Diesel Engine Idle Tool
Replies
1
Views
705
BCnT
B
P
4020 diesel engine surge
Replies
7
Views
11K
htoliver
H
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top