Tiny Tach addon for Mr Komatsu Dozer

[GuglioLS]

I picked up one of those Tiny Tach's that Rich provided a link to in one of Roy's Foton threads, then installed it on my Dozer. Before doing that I did some testing on my Jinma to see how well the Jinma and Tiny tach correlated. See the results below.....




No doubt I was impressed, both the tiny tach and the accuracy of the Jinma tach exceeded my expectations. It's more than just a tach and hour meter, it's got 2 service reminders, a job timer as well as a max RPM indicator. I can recommend it - 5 stars in my book.

Now that I'm convinced it works, time to install it on the Dozer which has no tach.

Larry

[GuglioLS]

First was to sand all the paint off then install the transducer onto an accessible fuel injector line, then mount the tach to the dash. After making sure the device works properly, I painted over the transducer and injector line per the manufacturers recommendation:



It runs off 12 volts, but the dozer is 24, so I had to make a 24 to 12 volt regulated power supply. No pics of that so as not to bore you.

Larry

[GuglioLS]

The below pics describe and show all the features of the tiny tach. I like it.... allot:




I think the last "toy" the Dozer needs now is an oil pressure gauge.

Larry

[Rich Waugh]

Great write-up and pics Larry, thanks! I definitely gotta get one of those now.

A question: Do you have to tell it how many cylinders the engine has? It would seem to me that you would since it counts pulses from one injector line and...wait - each injector only fires once per every two revolutions so I guess not. Okay, I answered my own question - pretty elegant solution to a tach for a diesel, actually.

I see the total running hours are not resettable - that's gonna mean there aren't going to be any used ones on the market, probably. Of course, a guy who can toss of a 24 to 12v regulated power supply on demand can probably figure a hack for that...

If they added one little chip in that thing it could tell you how much to charge for a job, based on your hourly rate, too. That'll be the next version, huh?

Thanks again for doing my field testing, buddy!

Rich

[GuglioLS]

Hey Rich,

Your right that it doesn't matter how many cylinders the engine has. It just multiplies injector pulses from the transducer times 2 for RPM's. It works on any diesel no matter how many cylinders. The 24 to 12 volt regulator was simple. I just used an LM340T 12 volt DC regulator chip mounted inside a little project box, then tucked it behind the dash.

Larry

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[Rich Waugh]

Sure, nothing at all to the regulated power supply - as long as you understand all about "internal current limiting", "safe-area compensation" and "series-pass transistors" and shit like that - which I don't. I don't know why the schematic shows a couple of capacitors bridged around it and nobody mentions them, either. I suppose you EE/genius types just automagically understand all that stuff, but I'm just pretty damn proud that I even know that those are capacitors. :-)

I'm really glad I know someone who actually understands all this voodoo stuff. When vacuum tubes went the way of the Tyrannosaurs I got left behind somehow. Used to be I could actually fix a TV but now I can barely manage to *play* a radio. Alvin Toffler had me in mind, I think. :-)

Rich