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True hours

Posted: Wed Sep 07, 2016 7:04 am
by jazo
Hi, few years ago when I purchased my 1394 it had 6368 hrs on the clock, I fitted a electronic hour meter under the dash to compare clocks,I have never left the key on and the genuine clock works fine. I now have 6698 hrs on the main clock and the electronic clock reads 538 hrs. So that's 330 hrs compared to 538 true hrs. With this that suggests my tractor has done around 10900 hrs if the main clock has always worked and has not had a broken cable. Does anyone know what the 90/94 series clocks are calibrated to? The work my tractor does has a good mix of flat out on the road and alot of 540 pto work

RE: True hours

Posted: Wed Sep 07, 2016 8:19 am
by march12
Hi, if i am correct, true working hours ar mechanical(engine hours) multiplide 1.8 if avarage workink engine rpm are 1600revs per min.

RE: True hours

Posted: Wed Sep 07, 2016 5:04 pm
by case-ih1594
Hi, I don't think the engine 'hours' are the same as 'time' hours.

As march12 has said they are based on one 'engine hour' being at a set rpm (1600 was suggested). The hour clocks on older tractors stated this on the face - something like "hours based on 1600rpm". In other words an hour would pass twice as quickly at 3200rpm, or twice as slowly at 800rpm.

Posted: Wed Sep 07, 2016 6:12 pm
by broadsword
Took some finding - knew I`d asked this before. ... t=1412+rpm


Posted: Wed Sep 07, 2016 8:17 pm
by JamesF
It reads hours above 1412 rpm

Posted: Wed Sep 07, 2016 11:20 pm
by jazo
I see some tractors of the same age with electronic clocks always seem to have done more hours