Hour Meters - How do they work?

swampdog · Jun 20, 2009

I've noticed that on several pieces of equipment, including on a new Kubota and an older Cat loader, that the hour meter counts time differently than I do.

Do hour meters count actual hours that the machines are running? Or are they tied to engine RPMs. If the machine is running at less than full working RPM or just idling, would it then take longer for an hour to show on the meter?

JonesBros · Jun 20, 2009

Every tenth is 6 minutes on an hour meter. Older machinery sends power to the hourmeter with the key on, to the newer ones work only with the engine running.

I've seen no difference in running wide open than idling with how many hours is counted.

DPete · Jun 20, 2009

The older cat hour meters that were mechanically driven off of the fuel pump counted rpm hours so if you ran at 1/2 throttle for one hour it would clock less than the hour. The newer ones are on an oil pressure switch and clock hour for hour time no matter what the rpm if the engine is running

hvy 1ton · Jun 20, 2009

DPete said:
The older cat hour meters that were mechanically driven off of the fuel pump counted rpm hours so if you ran at 1/2 throttle for one hour it would clock less than the hour. The newer ones are on an oil pressure switch and clock hour for hour time no matter what the rpm if the engine is running

So if you run a new engine low on oil, it gets less hours... :lmao

swampdog · Jun 20, 2009

DPete said:
The older cat hour meters that were mechanically driven off of the fuel pump counted rpm hours so if you ran at 1/2 throttle for one hour it would clock less than the hour. The newer ones are on an oil pressure switch and clock hour for hour time no matter what the rpm if the engine is running

The Cat in question is a 1979 966C loader. Do you know if this is one of the "older machines" that counts RPM hours?

If so, the hour meter likely works fine as the machine is idling quite a lot on the work it's doing now. At least partly because of the turbo cool down times, It idles between loads. It logs about five hours in a ten hour day. (I also wonder how much fuel is used up with five hours idling on a 3406???)

Speedpup · Jun 21, 2009

may be a better meater would be an RPM meter like they have in outboard motors. They tell you how many hours in each rpm range via a computer download.

dieselfuelonly · Jun 21, 2009

Always wondered how those work. Thanks.

AtlasRob · Jun 21, 2009

swampdog said:
The Cat in question is a 1979 966C loader. Do you know if this is one of the "older machines" that counts RPM hours?

I would say yes. I say this as I remember in the late 70's hearing the story of operators paid by the hour meter :bash they got around the problem by removing the clock and loosing

the pin that ran it then bolting it back up.
Everybody on site knew the machines had been working as they seen um moving. So how come at the end of the week no hours were recorded :beatsme
They got paid the same hours as everybody else

irwin · Jun 21, 2009

I had an older J.Deere tractor that ran the hour meter off the RPM's, I'd use it for 5 hours and it would show about three and a half hours. The Kubota I have now is like a clock ie: one hour = one hour

gggraham · Jun 22, 2009

Any hour meter I have seen an hour is an hour no matter what speed the engine was running. Some older machine just ran off the key, newer ones ran only if engine was running. Some of the machines now have a mechanical or digital hour meter you can look at but the only true hour meter we go by is ECU time. Plug the laptop in and see actual hours, how many were at full throttle, half throttle...the load on the engine. Volvo's log a lot of data. Big brother watching for sure....aren't computers wonderful..hahaha

OCR · Jun 22, 2009

hvy 1ton said:
So if you run a new engine low on oil, it gets less hours... :lmao

Good one... :lmao

OCR

Andy512 · Jun 22, 2009

Some stand alone meters are tied to the alternator R terminal to time only when engine is running. Most new equipment has this function integrated into the control systems.

municipaltruck · May 21, 2011

I have a freight liner dealer who is trying to tell me that the freight liner hours still work based on rpms and that the hour meter will run faster or slower depending how revved the engine is, this does not sound right to me but the number of hours has an affect on the warranty so I am wondering if anyone knows whether this is right?

Abscraperguy · May 21, 2011

The Deere tractors up to the 40 series (early 1980's) had a mechanical hour meter. When running at RPM's over 1600 it counted full hours and under that just a percentage. And then they switched to electrical for the 50 series. If the key was on it counted hours.

mitch504 · May 21, 2011

municipaltruck said:
I have a freight liner dealer who is trying to tell me that the freight liner hours still work based on rpms and that the hour meter will run faster or slower depending how revved the engine is, this does not sound right to me but the number of hours has an affect on the warranty so I am wondering if anyone knows whether this is right?

If the truck is new enough to have a warranty, it does not have a mechanical tach and hourmeter. Hours will be hours to it's electronic hourmeter, and if you want great accuracy they can pull ECU hours.

GWS · May 27, 2011

I have often pondered the issue of mechanical hour meters vs actual hours on a machine. For me, the issue is what are the wear hours on it? If the engine and the machine are operated at half the rated rpm, wouldn't you want it to reflect only half the hour readings? This is of course is based on the wear on the machine. I would think the wear on the engine and other parts would be less than if it were running all day at full rpm's. So the question is, even if the hour meter is not showing actual clock hours it has run, wouldn't it still be reflecting a closer indication of the amount of wear on the machine?

RangerJake72 · Jun 2, 2011

I know the hour meter in my Deere 650J runs hour for hour, whether I'm running it at idle for morning check, cranked up on a fire or idling on a fire scene, the hours clock out the same as real time

watglen · Jun 2, 2011

When i was a kid and mechanical hourmeters were the order of the day, a tractor engine was well on its way to a rebuild at 3000 hrs. Then electric hourmeters came into fashion, and tractors were hitting 10000 hrs all of a sudden. Of course, it was sold as a massive improvement in engine building techniques, new materials and oil etc. "These tractors are so good you can get 10000 hrs without touching it" was the pitch. Until i figured out how, i was amazed.

Hour Meters - How do they work?

swampdog

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JonesBros

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DPete

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hvy 1ton

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swampdog

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Speedpup

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dieselfuelonly

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AtlasRob

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irwin

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gggraham

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OCR

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municipaltruck

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Abscraperguy

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