Log splitter engine speeds?

[Mastermind]

I have a Husky splitter I bought last year at tractor supply co. It's a pretty good tool, a heck of alot better than using the old wood maul. I've got a question about engine speed for you gurus here. It won't run at say 3/4 throttle, it vibrates down to about 1/4 throttle. For most of my splitting it still has plenty of pressure, but is it ok to run it like this, or well it damage the engine, or something. I can run it wide open, it will stay at that setting, but it sure seems crazy to run it at full throttle all day, some thoughts here?

 

[builder1101]

any rpm will give you the same pressure.
more rpm will pump more oil
and these tiny engines make all their HP at the 1/2 or 3/4 mark....

reason i ditched my briggs and mounted a 1500cc toyota....

putt putt's all day, whisper quiet, double mufflers.

i think it does better, doesn't guzzle the gas for RPM's to make hp....

 

[Rookie1]

You may not want to but it was designed to run full throttle. It wont hurt anything but a little fuel consumption. Any splitter I use I run full.

 

[toyfarm]

I've always ran my splitters from 1/3 to half throttle unless splittin' some gnarly wood then she goes up around full throttle mark! As said before, engine was designed run wide open throttle. It will be ok any where between idle and WOT. You decide, it won't hurt it

 

[matt9923]

Do the pumps have a certain rpm range? I could make my 5hp pull, its barley moving to me?

 

[ericjeeper]

Pump was designed to be ran at 3600 rpms. Might as well run the engine there to maximize your time. Fuel is cheap.

 

[Wood Doctor]

I've always ran my splitters from 1/3 to half throttle unless splittin' some gnarly wood then she goes up around full throttle mark! As said before, engine was designed run wide open throttle. It will be ok any where between idle and WOT. You decide, it won't hurt it

+1. Best advice I have seen in years. That is exactly what I do. Why make the engine beat its brains out and waste fuel when you don't have to most of the time?

 

[Mastermind]

Thanks for the replies, I was only concerned that the engine life may be shortened by the low rpm under load, ie piston slap or something. I don't know much about small engines, and thank you guys for your help. Oh and as far as tighting up the throttle, I can't see any way, just a rivet holding a lever, but I,m pretty sure someyhing can be done.

 

[AKKAMAAN]

Most older heavy equipment, with large diesel engines, I have seen, had that "hr meter", that counted one hour for running 1 hour at, lets say 1800 rpm's. If engine run's for 1 hour at 900 rpms (1/2), it would only count 0.5 hr on the counter. So when the counter showed 1 000 hrs, the engine had turned EDITED to be: 1 000 by 1800 by 60= 108000 000 revolutions. This is a way to count the lifetime useage of diesel engines, drive lines, pumps etc on this piece of equipment.

I think the point with this way of measuring hrs, is to keep track of wear and when to schedule maintenance. This system also tells me that you can't expect more than a certain amount of revolutions out of a engine crankshaft.

Even if you optimize maintenance, operation conditions, and run engine at optimized RPM and torque output (Power) I would say "RPL"="Revolutions Per Lifetime", is limited as the life expectancy of an engine.

Running at a fixed, optimized (a little above max torque output), rpm will benefit lower fuel consumption (CO2 footprint and $$) and also give more life out of the engine. Also if engine bogs down a little from load, torque will increase. But be careful, running an engine at the same fixed rpm for many 1000's of hours, can get expensive if you one day want to raise rpm to "the double".

However, diesel engines are so different in charcteristics, they do not bog down for load the same way as gas engines, due to a sophisticated fuel and rpm governor system.

I think, with small gas engines, like Honda and Briggs, used on logsplitters, it would benefit total economy better, if engine idles when no power is needed (CV in neutral), and then have a auto throttle system, that raise the rpm to a fixed setting (just above max torque mark) when the CV is moved a little, and pump starts creating pressure.

Most engines with NO aircharge (turbo etc), have max torque at about 60-70% of max rpm (and max power at 90-95% of max rpm).

This is the philosophy I have teached over the years....opcorn:

Here is a good article about car engine, torque and power

 

[toyfarm]

QUOTE"Most older heavy equipment, with large diesel engines, I have seen, had that "hr meter", that counted one hour for running 1 hour at, lets say 1800 rpm's. If engine run's for 1 hour at 900 rpms (1/2), it would only count 0.5 hr on the counter. So when the counter showed 1 000 hrs, the engine had turned 1 000 by 1650= 1 650 000 revolutions. This is a way to count the lifetime useage of diesel engines, drive lines, pumps etc on this piece of equipment."QUOTE

If that were the case, they would be called revolution meters! An hour meter is just that, whenever it's energized it keeps track of time, non-energized = no change in time!

 

[AKKAMAAN]

QUOTE"Most older heavy equipment, with large diesel engines, I have seen, had that "hr meter", that counted one hour for running 1 hour at, lets say 1800 rpm's. If engine run's for 1 hour at 900 rpms (1/2), it would only count 0.5 hr on the counter. So when the counter showed 1 000 hrs, the engine had turned 1 000 by 1650= 1 650 000 revolutions. This is a way to count the lifetime useage of diesel engines, drive lines, pumps etc on this piece of equipment."QUOTE

If that were the case, they would be called revolution meters! An hour meter is just that, whenever it's energized it keeps track of time, non-energized = no change in time!

Agree! Revolution meter!! Thanks toyfarm!!

 

[AKKAMAAN]

Do the pumps have a certain rpm range? I could make my 5hp pull, its barley moving to me?

Most pumps are more flow efficient at higher rpm's, internal leakage-% is higher on slow rpm's....but there is a upper limit too, when mechancal friction start increase rapidly. That's why there is "manufacturers recommendations" for operational rpm's....

 

[toyfarm]

Tried to REP ya but says i passed too much out lately!

 

[msvold]

Interesting

Interesting discussion. I was under the impression that the manufacturer paired the engine with the splitter with the intention of running at WOT. The owners manual (SPEECO) states under starting instructions to:
1) 25 Ton, 28 Ton and 34 Ton Models with 10.5 h.p. Engine
a) Move the throttle lever to “FAST”. Always operate the engine with throttle lever in the “FAST” position

 

[toyfarm]

Interesting discussion. I was under the impression that the manufacturer paired the engine with the splitter with the intention of running at WOT. The owners manual (SPEECO) states under starting instructions to:
1) 25 Ton, 28 Ton and 34 Ton Models with 10.5 h.p. Engine
a) Move the throttle lever to “FAST”. Always operate the engine with throttle lever in the “FAST” position

Could you imagine writing a manual that explains to everyone when they need to change the throttle? Much easier to write "fast" than to have cousin Eddie bring back to store and say " i had it half throttle and it was a small 30" piece of hedge that only had four limbs coming out of it, I just don't understand why it won't split"

 

[matt9923]

Most pumps are more flow efficient at higher rpm's, internal leakage-% is higher on slow rpm's....but there is a upper limit too, when mechancal friction start increase rapidly. That's why there is "manufacturers recommendations" for operational rpm's....

My splitter has a fixed throttle, its not running anywhere near wot. I left it cause I'm not sure if my small pump has a max rpm rating? Couldn't find any specs on it.

Maybe I can bring it up and see what happens? or put an adjustable throttle on it or an auto like you suggested....

 

[AKKAMAAN]

Interesting discussion. I was under the impression that the manufacturer paired the engine with the splitter with the intention of running at WOT. The owners manual (SPEECO) states under starting instructions to:
1) 25 Ton, 28 Ton and 34 Ton Models with 10.5 h.p. Engine
a) Move the throttle lever to “FAST”. Always operate the engine with throttle lever in the “FAST” position

Sure they do but they also want GOOD specs on the paper...the engine can be a little undersized (or pump undersized)...

For fuel econmy and wear on engine I would rather have an oversized engine running a larger pump on lower rpm's to get my reuired flow and cycle speed...instead of beating the heck out of a smaller engine/pump combo at max top rpm's....

Isn't this how we discuss with our cars/rv's/pu trucks, especially when we are hauling trailers....????

But as I said before...these small engines have already low fuel consumption and are cheap to replace...so it might not be such a big deal....

 

[Kong]

For me this is a real no brainer. Run them at about 3/4 throttle and if they sized the engine right to the rest of the splitter's parts that should give you all the power you need while not running the hell and all out of the engine. Its also probably about the point where you get your best fuel economy but way more important than that the thing will probably be reasonably quiet at about that point too. Quiet counts for a lot in my book.

Yeah, gas is cheap* - right now - but that doesn't mean I've got any reason to be wasting any of it I don't have to.

Cheapest gas I ever bought was in 1962 somewhere in south Georgia, it was $0.11 per gallon. In those days regular sold for around $0.17 nearly everywhere so eleven cents was really a good deal, I believe it cost us about a buck and a half to fill up the old Chevy.

 

[triptester]

The majority of the small engines used on splitters are designed to run at full throttle. When added strain is put on the engine rpms drop slightly to the engines maximum torque range.
Most of these engines are also splash lubricated. They don't lube as well at low rpms.

 

[Ol' Brian]

For me this is a real no brainer. Run them at about 3/4 throttle and if they sized the engine right to the rest of the splitter's parts that should give you all the power you need while not running the hell and all out of the engine. Its also probably about the point where you get your best fuel economy but way more important than that the thing will probably be reasonably quiet at about that point too. Quiet counts for a lot in my book.

Yeah, gas is cheap* - right now - but that doesn't mean I've got any reason to be wasting any of it I don't have to.

:agree2: 100%

That's exactly my way of thinking also. And, after 9 years of this, the 5hp Briggs on my splitter isn't complaining yet.