Motor Hour Meter Question

[Ray Bowles]

How are the motor hours that are recorded by the hour meter calculated? Is it simply by total hours run or does the RPM rate influence it. Do hours run at 1500 RPM count the same as hours run at 3000 RPM?
Thanks, Ray

 

[nick8489]

Works off ignition so RPM irrelevent

 

[RAD]

Any time 12 volt is applied to the hour meter it starts counting.....some are wired so when the key switch is on there's power to the meter and on my diesel its set up so that when the engine is running a fuel pressure switch completes the circuit and 12 volts is applied to my hour meter and other gauges

 

[Joe]

It's like an electric clock, it only runs when there is power.

 

[Bill Roosa]

To answer the question, it does not account for the RPM and does not need to. The difference in oil contamination, air moved through the air cleaner, coolant lube concentration, ect are not that much effected by engine RPM. The assumption is that you will not be idling for the entire period and that a "normal" engine usage will result in some higher RPM session and some lower RPM session. The average being what the manufactures use for calculating "hours between changes".
Did you ever wonder how the hours between changes of the various filters/fluids can be simple multiples of each other and they are all "round" numbers and not "145.3 hours” type numbers? There are safety factors built in and you are always changing before there is an actual need to change.
Designed by geniuses to be run by idiots.