Go BottomHour meter on 870
 | EdSea
Join Date: Posts: 1 
|
2003-03-27 52013
This may be a dumb question but does the hour meter
(as on my 870) supposedly indicate the time that the tractor runs in clock time? I've had hour meters before on boats and they show how long the ignition has been on. On this diesel tractor I'm not sure what is indicated but it doesn't seem to be simple clock time (e.g. 1.0 on the tractor seems to be closer to 2.0 hours clock time). Possibly it is some algorithm of the the rpm's or something? If it is just a problem with my hour meter I guess I have a lot more hours on the tractor than I realized.
Reply to |
Quote Reply |
Add PhotoHour meter on 870
 | Billy
Join Date: Oct 1999 Posts: 975 Southeast Oklahoma 
 Pics
|
2003-03-27 52016
Ed, I don't know about your 870 but on my 4610 the hour meter doesn't advance unless the engine is running.
Billy ....
Reply to |
Quote Reply |
Add PhotoHour meter on 870
| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley 
|
2003-03-28 52041
I think most hour meters on tractors with mechanical tachs (which is a lot of them) are simple geared counters off the tach drives. That means they run slower at lower rpms. I'd guess most are pretty close to clock time at PTO rpm. Some tachs work from injector line pulses, but the hour counter would still be a function of rpm rather than running time. Maybe there are electric tachs on newer tractors where the hours would be key time rather than running time or rpm's.
Seems odd that many tachs read in hours hours estimatedfrom rpm's, but it makes sense if you consider that the main reason for hour counters is to know when to perform maintenance. Of course, a tractor that spends most of its time lugging around doing loader work at near idle rpm benefits from shorter maintenance intervals, so maybe it doesn't make such good sense.
....
Reply to |
Quote Reply |
Add PhotoHour meter on 870
| BillBass
Join Date: Feb 2002 Posts: 190 North Texas
|
2003-03-28 52042
I agree with Tom. A mechanical hour meter is essentially the same thing as an odometer on a car. It is geared to register 1 "hour" while running at rated PTO rpms. Running at less than rated PTO rpm would result in less than 1 "hour" clocked during a real 1 hour period. That principle probably made sense on tractors used for farm work where tractors are typically run continuously at higher rpms while plowing, cultivating, planting, etc. On compacts, it's probably more of a counter than an hour meter. ....
Reply to |
Quote Reply |
Add PhotoHour meter on 870
| EdSea
Join Date: Posts: 1
|
2003-03-28 52081
Thanks guys, your explanation jives with my experience. And I agree that when used for maintenance intervals (or wear as in a purchase decision) the lower rpm time is understated which is the opposite as to what you would want. I guess one could hook up a conventional hour meter (which is fairly inexpensive) to monitor key time which would be best for the lower rpm work. I guess I should accelerate some of the overdue maintenance considering the "time" is calibrated assuming you run rated rpm mainly which I do less than 1/2 of the time. ....
Reply to |
Quote Reply |
Add PhotoHour meter on 870
| BillBass
Join Date: Feb 2002 Posts: 190 North Texas
|
2003-03-28 52082
I don't know that you need to accelerate maintenance for that reason. I would go by the manual. It is no different than your car. Say you change oil every 5000 miles. Now if you drove exclusively highway during one 5000 mile period and averaged 60 miles/hr, that would be 83 hours engine run time. If,however, the next period of time you drove exclusively city and averaged 30 miles/hr, that would be 167 hours engine run time. In reality, you would average somewhere in between.
....
Reply to |
Quote Reply |
Add PhotoHour meter on 870
| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
|
2003-03-29 52111
Ideal oil change intervals may be complicated to define. Every engine rev creates wear, oil breakdown and oil contamination, so oil should be changed after so many revs. I think counters on some equipment do read in revs. Time also plays a role because oil additives break down over time, so oil should be changed every so often irrespective of use. Chugging around at low rpm and doing light work may mean an engine doesn't get up to operating temperature and fuel combustion isn't complete. That also contaminates the oil and creates a need for shorter oil change intervals.
Not that I think the typical owner has to ponder these things. The rule of thumb of 'by the hour meter or once a year' likely works for almost every owner.
....
Reply to |
Quote Reply |
Add PhotoHour meter on 870
 | DRankin
Join Date: Jan 2000 Posts: 5116 Northern Nevada
Pics
|
2003-03-29 52123
I have one of each type of meter.
On the 4100 it took about 18 months of use to hit 80 hours because the meter only turns a full hour at max RPM.
The BX hit the 80 hour mark in less than 6 months at the same usage rate. ....
Reply to |
Quote Reply |
Add Photo
Go Top
Share This