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Topic: Engine RPM's look okay? (Read 1702 times) previous topic - next topic

Re: Engine RPM's look okay?

Reply #20 –
Our tach sensor is visible on the top engine bell housing with a wire connected to the end of sensor. No gauges connected to alternator.

Re: Engine RPM's look okay?

Reply #21 –
Update to my attempt to calibrate the new tachometer:
The simplest method is to set the "pulse per revolution" number into the tach, but no one was able to provide me that number. Not Cummins, who told me the chassis manufacturer would know it. Not Foretravel in Nac; who never returned my call. And not MOT, who should know it since they put the tach in last year. The value in the tach is currently set at 120.45, so me "guessing" at a new number and hoping to get close seems unreasonable.
Instead, since I now have the digital photo laser tach, what I did today was set a brick on the accelerator to hold the rpm's up, have the wife point the laser at the crankshaft pulley and live stream video of the display to me at the dash, where I matched the tach dial to the reading on the laser. That seems to have worked, as readings now agree through the range of idle through 2,000 (at least in no-load testing.)
One last question: I'm pointing the laser at the large pulley in the photo below. That is the right one to give me engine RPM, yes?

Re: Engine RPM's look okay?

Reply #22 –
Quote from: Dan & Annie –
One last question: I'm pointing the laser at the large pulley in the photo below. That is the right one to give me engine RPM, yes?
Yes, that is the crankshaft pulley, with the harmonic damper right behind it.  That pulley turns at engine RPM.

Re: Engine RPM's look okay?

Reply #23 –
Quote from: Dan & Annie –

One last question: I'm pointing the laser at the large pulley in the photo below. That is the right one to give me engine RPM, yes?


Yes, the lower pulley is bolted to the crankshaft.

If turning at a different speed that the engine, some REALLY bad things would have happened.