Is it time for a gasoline engine tractor?

[GManBart]

They are all Onan Gensets powered by turbo Cummins Diesels...

Our typical rating is 150 kW Standby and 125 Prime.

These are used for emergency power for medical facilities and go from stop to speed with load in 6 to 8 seconds... not exactly optimal for any engine... most have 20 to 25 years in service and I would hope for many more but they are now under the Bay Area Air Quality Management District which has plans to sunset older units... and collects an annual fee to remain operational...

Many diesel standby systems don't have ANY rating for continuous duty because they aren't designed for it. The systems you're dealing with are already prime/continuous rated to start with.

You said: "There is no difference in design/build only on how it is used." That simply isn't true as a blanket statement. Big systems designed for continuous duty that may be the case. Smaller systems designed for standby duty it definitely isn't the case.

 

[ultrarunner]

I'm going from memory... the last one I purchased was in December of 1995.

In addition to meeting the Hospital requirements I was also severely limited by the local city requirements which were very restrictive as to minimizing fuel stored, location, security, etc.

I don't doubt that you are right...

To investigate further I would need to pull out my build binders from Onan to recall of exactly what was specified...

One site I had a 1000 gallon fuel tank and the city changed it to 180 gallons... saying I could bring in more fuel if needed... never could understand how that would work in an Earthquake... especially since that side is designated as a level II to receive injured...

I did establish a protocol where the city corporation yard would take on the responsibility to keep me fueled if disaster was declared...

So far the longest single run time has been 9 hours...

After Loma Prieta our sister facility was 8 days straight on standby power.

 

[Redneck in training]

Sure you can run them "continuous" at pto speed, what you "can't" do is pull "full power" out of the pto on a continuous basis...

Well you can, but it will drastically shorten the engine life...

SR

It all depends. If the cooling system is designed right you could run them at PTO and full power. The wear depends mainly on median piston speed. In other words how far and how fast the piston travels over unit of time. That is load independent.

 

[Sawyer Rob]

It all depends. If the cooling system is designed right you could run them at PTO and full power. The wear depends mainly on median piston speed. In other words how far and how fast the piston travels over unit of time. That is load independent.

Take away the "if's", we are talking about tractors here, as we buy them, NOT something designed a specific way for a specific purpose.

I've read it right in tractor manuals, to NOT pull more than 80% full rated power out of the tractors pto for more than 30 minutes continuous. That's another way of saying "duty cycle" for the tractor...

This is in reference to running pto powered tools, like grinders, generators and the such.

I always de-rate the pto power on my tractors by 20% or so, when I'm running anything off the pto that pulls BIG power out, for a length of time...

SR

 

[sd455dan]

Gee- sometimes I'm glad I have a (cheap) chinese tractor- since the hp ratings are arrived at by operating the engine @ rated power for 12 hours straight...
Don't recall any 30 minute owners manual limitation on either of my tractors pto run time @ rated power?..?

Mowing large fields over grown with Tanzi that was over the tractor hoods in 95 degree weather, in the highest gear that could be pulled without continually bogging the tractors engines for hours on end had to be running @ rated pto power .
Pretty sure there are others who work their tractors even harder with no ill effects?
Anyone else have that reference on the pto use??

That is interesting, I thought diesel tractors were all rated for continuous duty use.

 

[Sawyer Rob]

The REAL question is, has there ever been a china tractor that could actually run 12 hours straight?? ha ha ha

SR

 

[sd455dan]

The REAL question is, has there ever been a china tractor that could actually run 12 hours straight?? ha ha ha

SR

it is running just as nicely as the JD 550G and much quieter than my Ford 3000 :thumbsup:
and yes on several occasions it has run an 85" tiller for over 12 hrs straight with just operators taking turns and stopping to refill the fuel tank .

Back to the PTO running @ rated power

So there must be some bummed out new tractor owners out there.
Once they discover the warranty has been voided after mowing a field or running a large pto genset...

 

[Kubota 2350]

The REAL question is, has there ever been a china tractor that could actually run 12 hours straight?? ha ha ha

SR

That's funny!! :laughing::laughing:

 

[sd455dan]

That's funny!! :laughing::laughing:

You won't be laughing if the Kubota or JDs warranty is voided by using it for hours at rated power...
maybe you should check your manual...:laughing:

 

[daugen]

If the load does not exceed the ability of the cooling system to take out the heat, isn't that the tipping point?
On a hot day we all watch the temp meter. Control the heat, control the life of your engine, assuming other variables within line.
I'd like to see a modern tractor mfg deny an engine claim for damage caused during routine farming. Good way to kill your reputation.
Not supposed to fail in the first place assuming no abuse. It's what is considered abuse that gets interesting.

I'm curious if any current gas engines are being made with a heavy iron blocks like diesels? Iron sucks up heat, radiates it nicely and supposedly does that better than aluminum. But heck, aren't Porsche and Ferrari engines aluminum with steel bores? With likely some super exotic coating on the piston walls.
Why not do that for tractors? Get the cooling right to pull the heat out of the engine and why shouldn't a gas engine last almost forever?

Makes me wonder what the most reliable automotive gas engines are and how to convert them to other use. What four cylinder engine comes to mind?

If the engine won't fail, then aren't we really concerned mostly over fuel burn? Then let the most efficient engine win.