ddalme"My engine (TAMD40B Volvo) manual says to change oil every 100 hrs., filter every other oil change. It has a tachometer with an digital hour meter encased inside it. I also have a separate hobbs type hour meter wired to the motor. When the tach hour meter shows a 100 hr interval, the hobbs hour meter will show 200 or more hours on it. My mechanic says that the volvo meter is measuring the RPM and run time (working/load time) and that is what I should go with for the oil change. So thats what I do. Sounds good, wouldn't think they would have done that back in '83. 1750+ on the hobbs meter and 755+ on the Volvo meter. Go figure."
I have both Hobbs and Volvo hour meters. I had TMD40s, that had only the Hobbs. I upgraded to TAMD41 that came with a meter in the tach. I connected that to the ignition wire that had previously been connected to the Hobbs meter, and it records time that the ignition is on, not according to the rpm of the engine.
How are yours connected? Since I have both, could I connect mine as yours are connected? Could you change yours over to the way mine are connected?
Yours certainly have implications on engine longevity. This is something you may want to change before you sell. Or not!