Who said Aetna Engineering tachometers were the best?

[Barking Sands]

Well...thanks for the recommendation. During the course of learning about alternators, W signals, various ways to generate a tachometer signal and using various gauges I learned several things.

1) you can keep your original tach and drive an W signal tach using a hall effect sensor and the Dakota tach adapter for about $120 (eliminating the fussy alternator signal)

2) an inexpensive hall effect coupled with a Dakota adapter will drive nearly any tachometer. W signal, flywheel tooth mag pick up, gas/ignition/, etc.

3) the Aetna tach gauges are indeed the best

After the last video I posted, several people praised the Aetna equipment. I took a chance on eBay and purchased a well used gauge (no sensor) for $125. Bench tested it using the test set up and compared it to an optical/contact tach to test for accuracy. The readings between the two were spot on. So its out with the Jegs and in with the Aetna. Very happy with the final configuration and learned a ton along the way. Just thought I would pass along the findings.

 

[Mischief Managed]

I have those on my boat and they are excellent. They are more sensitive to transient voltage spikes in the input signal than my ZF Mathers Micro Commander engine synchronizer and helped me find a bad bearing in the automatic timing advance unit in one of my engines. The only issue I have with them is that the instructions are incorrect for the dip switch settings for a CAT 3208.

 

[Barking Sands]

I have those on my boat and they are excellent. They are more sensitive to transient voltage spikes in the input signal than my ZF Mathers Micro Commander engine synchronizer and helped me find a bad bearing in the automatic timing advance unit in one of my engines. The only issue I have with them is that the instructions are incorrect for the dip switch settings for a CAT 3208.

That's great Mischief. Definitely a helpful tool when its that accurate. After having an intermittent analog tach coming off the alternator I am excited to install this one along with the hall effect sensor. Its dead accurate and responsive as can be. And actually testing on the bench gives me a bunch of confidence.

On the upper helm I added a new Faria analog tach for general feedback.

 

[Mischief Managed]

That's great Mischief. Definitely a helpful tool when its that accurate. After having an intermittent analog tach coming off the alternator I am excited to install this one along with the hall effect sensor. Its dead accurate and responsive as can be. And actually testing on the bench gives me a bunch of confidence.

On the upper helm I added a new Faria analog tach for general feedback.

Since you clearly have a solid understanding of this kind of technology, I highly recommend that you invest in a Hantek oscilloscope/function generator/DMM, if you don't already have one or something similar...



In this situation, the scope lets you easily test the hall effect sender, and the function generator lets you test the tach. They are reasonably priced, compact, well-equipped with probes etc., and well-made.

 

[Barking Sands]

Since you clearly have a solid understanding of this kind of technology, I highly recommend that you invest in a Hantek oscilloscope/function generator/DMM, if you don't already have one or something similar...



In this situation, the scope lets you easily test the hall effect sender, and the function generator lets you test the tach. They are reasonably priced, compact, well-equipped with probes etc., and well-made.

Great idea. When I first started trying to find out about tach signals I actually bought a cheap stand alone function generator in hopes of testing various tachs I had laying around. But its so cheap the instructions where terrible and I could not get it to work. There are several instances I could have used a scope and a few others I could have used the signal generator. I checked out the Hantek you mentioned and have the 2D72 model saved in my basket for now. I will do some more research and purchase one soon. Thanks for the tip, much appreciated.

One thing to note. In the other video I posted about adapting a hall effect sensor signal with 2 magnets to a W signal tach by way of the Dakota Tach adapter...the Dakota adapter has a function generator built in at one particular frequency. I cant remember what frequency/rpm it is but it basically generates say a 1000 rpm signal. That way you can adapt other settings on the Dakota adapter and the gauge settings until the tach reads 1000 rpm without having to run the engine. Very handy little tool for $99. I am using the Dakota tach adapter to modify the signal output from the same hall effect sensor that drive both tachs. The lower helm digital Jegs (soon to be swapped for the better Aetna unit) does not need any modification of the signal except to set the gauge setting dip switches to the frequency of the hall effect output. The upper helm analog Faria can not be adjusted on the gauge into the range of the hall effect sensors output with 2 magnets on the balancer. So the Dakota adapter is used to bridge that gap currently.

There are many tachometer brands, models and types out there. Its really too bad so little detail is available for many. Even new ones rarely come with much details. Obviously the Aetna has a very wide ranging input scale and all the details needed. Some of the Chinese made ones also come with full setting details. But others are still very vague and are set using "pots" instead of dip switches or internal programming via a bluetooth app. That's another small lesson learned. if you have a tach that is set with a "pot" its not likely it will be very accurate through the full range of rpm.