Why exactly is towing severe?

[Graham Piccinini]

Originally Posted By: BigCahuna
So after reading all the posts it must mean excessive idling is the best possible way to operate your motor. At idle the motor is running at low speed just enough to circulate the oil. It's given just enough fuel to keep it running, so no dilution. Internal parts are hardly making contact, just barely moving. And you get the best mileage per gallon. But some will say it's also severe service.,,,


Here is an idea.
1) Change oil in your car and save a small sample of new oil.
2) Start the car with new oil and full tank of gas.
3) Let it idle until it runs out of gas.
4) Now take a sample of the oil that has ZERO miles on it, but about 30 hours of idling (assuming 15 gallon tank and 1/2 gallon per hour fuel consumption.)
5) Send both samples for a UOA and then come back and post the results.

I bet the results will speak for themselves as far as metals and fuel dilution numbers, and you will never again say that idling is not severe service.

 

[Graham Piccinini]

Or even a better idea - let the engine idle with that oil for 150 hours. That will be an equivalent of a regular 5k OCI (35mph average speed × 150 hours = 5250 miles.) Then compare the UOA to a normal driving 5k OCI. You will see severely elevated levels of metals in oil and higher fuel dilution numbers, also TBN will be lower on the idling sample.

 

[Linctex]

Originally Posted By: BigCahuna
So after reading all the posts it must mean excessive idling is the best possible way to operate your motor. At idle the motor is running at low speed just enough to circulate the oil.


No, not at all.

I think the best (magical?) RPM is 1800.

You need some splashing that idle can't give... you also need good coolant flow from the water pump.

I know of a 1800rpm Kubota diesel generator with over 23,000 hours on it!
At 60 mph, that's the equiv of 1,400,000 ... and it's never been rebuilt.

I know of other engines in similar fashion - like irrigation engines that run all summer for 30 years straight.

 

[claluja]

Idle oil temp: 130 degrees
Operating oil temp: 200 degrees

. . . . For one of my engines

 

[BrocLuno]

Originally Posted By: BigCahuna
So after reading all the posts it must mean excessive idling is the best possible way to operate your motor. At idle the motor is running at low speed just enough to circulate the oil. It's given just enough fuel to keep it running, so no dilution. Internal parts are hardly making contact, just barely moving. And you get the best mileage per gallon. But some will say it's also severe service.,,,


Actually it's not running fast enough to circulate the oil... Only a small portion of the engine is serviced by pumped oil. Cylinder walls, piston skirts, cams, lifters, timing chains, distributor drives, and the like are serviced by sling oil or splash oil. You need to be turning 1,500 with warm oil to have enough sling oil off the crank to get to a lot of these parts.

The best long cycle is about 1,900 rpm and a light load. Just what a lot of engines do on cruise on the freeway

 

[64bawagon]

Class 8 trucks pull huge, high profile loads all over the world day in and day out and can run over a million miles between rebuilds, its all about having the right equipment for the job. If your constantly running 80-90% throttle then you didnt choose right.

 

[Shannow]

Originally Posted By: Vlad_the_Russian

Originally Posted By: BigCahuna
So after reading all the posts it must mean excessive idling is the best possible way to operate your motor. At idle the motor is running at low speed just enough to circulate the oil. It's given just enough fuel to keep it running, so no dilution. Internal parts are hardly making contact, just barely moving. And you get the best mileage per gallon. But some will say it's also severe service.,,,


Here is an idea.
1) Change oil in your car and save a small sample of new oil.
2) Start the car with new oil and full tank of gas.
3) Let it idle until it runs out of gas.
4) Now take a sample of the oil that has ZERO miles on it, but about 30 hours of idling (assuming 15 gallon tank and 1/2 gallon per hour fuel consumption.)
5) Send both samples for a UOA and then come back and post the results.

I bet the results will speak for themselves as far as metals and fuel dilution numbers, and you will never again say that idling is not severe service.


Bought my Colorado with 4,600km on it 100+ something hours of operation, 30+ hours of idling, and 38% oil life left on the oil change indicator.

Went another 5,800km on that remaining 38% because my driving style was different. one 900km road trip I didn't lose a percent.

Idling is sever service...no load, and fuel dilution.
Towing heavy loads is severe service, high temperatures and lots of blowby gasses.

Just because they are diametrically different doesn't support the strawman case presented by BC.

 

[Cujet]

Originally Posted By: BigCahuna
So after reading all the posts it must mean excessive idling is the best possible way to operate your motor. At idle the motor is running at low speed just enough to circulate the oil. It's given just enough fuel to keep it running, so no dilution. Internal parts are hardly making contact, just barely moving. And you get the best mileage per gallon. But some will say it's also severe service.,,,


My old girlfriend used the very same logic. I would say something like: "you look nice today" and she would immediately respond with something like "you mean I did not look good yesterday? "

Such a hasty conclusion ignores all sorts of other factors. Including items like pumping losses, design RPM, efficiency curves, low cylinder pressures and poor ring sealing and on and on.

 

[dnewton3]

Despite the fear mongering by the OEM, and panic stricken folks here on BITOG, I contend there really isn't much that is truly "severe".

Are things "different" as to the inputs of towing something? Surely yes. More load makes for more stress. But more does not mean destructive or abusive. The fact is that most equipment is made for a maximum condition, and to last some predetermined amount of cycles. Anything less than that is easier on the system.

Of all the UOAs I've seen (which is a LOT of them), it's rare to see towing really make for truly heinous results.

Recently last fall, I towed my RV trailer out to SD and back. The headwinds were brutal; the EGTs were at or near max for three of the four travel days. And yet my UOA showed only a slight uptick in Fe wear, and all metals were "normal" relative to the wear rates expected. Despite the hard use and "severe" conditions, the engine performed just as expected with no undue wear. All this on dino HDEO and a Wix filter. A few years before that, I ran a shorter OCI with very little towing; the UOA showed wear rates were completely "normal". So despite how easy or hard the Dmax engine was worked, it pretty much did what it was asked to do with no shift in it's behavior.

A few years ago, I had my wife drive the Villager for 15k miles on ST dino oil and a MC filter. True soccer-mom type use; short trips, hot summer, cold winter, lots of stop/go driving, etc. Pulled the UOA and cut open the filter. Totally normal wear rates and nothing out of the ordinary in the filter. "Severe"service OCI was 3k miles; yet we went 5x that distance on inexpensive lube and a normal filter. Despite the "severe" use, the wear rates were totally normal and in-line with all other Villagers that saw far easier service. Then I ran a long trip; mostly highway, which is about as easy on an engine as you can get. The easy service was no "better" than average wear data. In short, hard service and easy service didn't really make any difference in wear rates.

As long as the mechanical systems are intact and working per OEM design (air filtration, cooling system, etc) and as long as you use spec'd items (meeting OEM intent; but not necessarily OEM branded), there's no reason to think "severe" is anything but over-blown malarkey.




Typically, regardless of how the equipment is used, it tends to perform to an average wear rate, despite how "easy" or "severe" the inputs are.