Engine hours?

Usually it is just hours. In an auto engine, and hour spend isling can be far worse than a road mile. In piston aircraft, engine hours are measured two different ways. There are "engine hours" which is simply the hours that the engine has been running, and "tach hours". One "tach hour" is one hour at full RPM. One hour at 50% RPM would be measured as .5 "tach hour".

Vaughn

On my MF 135 farm tractor, the hourmeter is driven by cable through the tach, so "hours" varies with engine speed. i.e. an hour at 1000 RPM takes longer to accumulate than an hour at 1800RPM. I think it is standardized at something like 1500 RPM so it all averages out and the accumulated time on the meter is more or less accurate.

John

----- Original Message ----- From: "Diamond Jim" Newsgroups: alt.engineering,alt.mechanical.engineering,rec.crafts.metalworking Sent: Tuesday, October 26, 2004 6:40 AM Subject: Engine hours?

Depends on the meter. ie, my tractor has a mechanical tachometer driven hourmeter, so slower or faster speed makes a difference. My welder has an electric meter that just counts time, so speed makes no difference.

Jim,

I have a 2001 F550 Powerstroke diesel, with a PTO that runs a versalift

38' insulated manlift. It runs about 1050RPM with the PTO engaged. There is an hour meter with the PTO controls, to keep track of engine hours only when the PTO is engaged.

Don

Jim,

I have a 2001 F550 Powerstroke diesel, with a PTO that runs a versalift

38' insulated manlift. It runs about 1050RPM with the PTO engaged. There is an hour meter with the PTO controls, to keep track of engine hours only when the PTO is engaged.

Don