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Discussion in 'Electronics Q&A' started by Marc Rainaldo, Apr 3, 2021.
back new tachometer
I hooked up with 12v on ignition with a 24-12V victron reducer.
In coming weekend I will hook up original with resistor.
I will order the zener diode and other resistors so that I can try everything.
I think pulse settings will be from 8P what i can read in the manual. Manual attached in post 21
These are just the wrong type of tach's, you could try just connecting them up and try the settings and see if one of the A-E settings. You might get lucky or might not. Not the answer you want to hear but the manual only talks about pully ratios and not pulses. Pully ratios can equal pulses but its a guess
These are a type of tach that will work with your sender. https://www.aetnaengineering.com/model-8905r-lcd-tachometer/
Or as the manual states, take the alternator to a shop and maybe they can add the tach output before the regulator circuit. If they screw up you might be buying new alternators.
I think I bought the wrong model. When I read the specs from your link with the 0-7000 rpm meter you can adjust for 4P.
Your senders operate at 4 pulses per revolution, IF your sender is taken off of the blower shaft (top back of engine), if it is on the crankshaft pulley it is 8 pulses.
If the manual you posted is correct, your tach's are not set by pulses, they are set by pulley ratio, page 4 table.
If you want the tach's to be accurate, and they need to be highly accurate on 92's, I would return your tach's and get the right ones.
Yes gonna do that. Hope they will take them back. I let you know the results. Thanks for your effort
attached is the manual from the model that is the good one.
To be sure can you check for me if it’s oké for the 6V92?
In the manual they speak about gasoline’s 4 stroke engines. Or can we just say they are good from the 4P adjustment option?
Lol, I know but I think tomorrow the shop ain’t happy so when they order the new ones I have to be sure...
I don't know what to tell you, except if you want the right tach, you need to order the right tach. I know for a fact that the Aetna Engineering works great and was the defacto standard for many years, still is for the older boats like ours.
ofcourse I want the right tach as you can see in photo dashboard a different tachometer is not that nice.
In the time we post I also had contact with Veethree. The guy there send me following that makes me doubt of it will work with the product change:
The 65129F tachometer is for gasoline inboards and stern drives (4 to 8 cylinders) and outboard engine (4 to 12 magnetic pole alternators). On inboards and stern drive engines the signal would be coming from negative side of the starting coil, tachometer output on an electronic ignition, or tachometer output on a distributor cap. Not all of those sources are compatible especially if using not OEM components. On outboard engines the signal would come from the rectifier which converts the AC power from the alternator/stator to DC power to charge the battery.
Technical Support Representative
Veethree Electronics & Marine LLC
Received answer from Veethree:
Unfortunately the only other tachometer would be in our Heavy Duty line which does not look like the Lido line. The tachometer is 82301 or 82301E. it is driven by a 8 pulse per revolution sensor which would be inserted into the take-off, this is where older engines would have had a mechanical cable for a mechanically driven tachometer. The adjustment would be for the ratio of the take-off of .5, 1, or 2. Here is a picture of the tachometer.
Looking for another solution.
In my previous post you can see the tachometer that would work. Unfortunately it don’t matches the rest of the gauges.
On my port engine there is a second alternator for 12V service battery. That alternator has a W connector.. is that possible for the tachometer I have ? If so I can build an extra alternator on starboard engine and problem fixed with the tachometer I have
Since you have the tach's already and an alternator with the w output on it, it can't hurt to try it out. I think you are going to have a hard time getting that type of tach reading correctly though. That type of pickup isn't really used on Detroit's, their pulley system isn't typical as it is only there for the alternator. Hopefully that ratio is supported by the tach, but I think you will find one end of the range isn't going to match very well.
While these only partially match you gauges, they are the correct tach to have with Detroit's. Good Luck!
First of all I want to thank you for all your effort. Couple days ago my knowledge with tachometers was simple and I thought it was an easy thing to change. I couldn’t sleep last night and start reading and thinking.
You referred me to your thread about the emu-1 and when i first read it, it was a bit acabadabra. I didn’t knew what a emu-1 was. I found out that the Emu-1 is a converter from signals to NMEA2000. Then it all make sense. Definitely will the emu-1 be on my list.
For now I have to deal with my tachometer I just bought.
The design is very important for me because I spent two weeks making a carbon dashboard. It was the first time ever I worked with carbon. I did a lot of testing and finally I have a own made carbon dash.
The gauges you recommend me I don’t like the design. If no other option are available I would place the old gauges back. These are a bit bigger and to place that I have to saw bigger holes in my carbon. Or buy 2 i70s and 2 emu-1 would be very nice. Unfortunately with that last option it would cost me around €2500. Pffff very nice but a lot of money.
I am waiting for the Veethree guy if the 4Pulse from the 2:1 gearing off of the blower cam will work on the gauge that has the same design with a 4P adjustment option. If he says that I would might work then I buy 1 to test, if I go to the tachoshop and change my 2 alternator meters and the 4P gauge won’t work I can’t go and change them back again for the alternator version. And ofcourse I have to check my engines is the sensor is placed at the blower.
Thanks again, learned a lot.
Marc, my point in referring you to the clamp circuit was not suggest that you switch to the EMU-1, but to suggest that, that circuit might help you out in all of this. As far as which tach to use, thats your call, I think I have gone as far as I can in all of this and you just need to make a decision as what direction to go in. You have many options and perhaps some experimenting to do, but it sounds like the easiest course of action is to put back your original tachs. Good Luck.
Went to our boat to measure pulley ratio from the extra alternator but that didn’t matched my adjustments options on my new tachometer.
then I searched for the sensor. The sensor is mechanic and leads to the engine synchronizer. On that unit I found the sensors that produce electronic output. Unfortunately no product number on that sensor and the manual of the synchronizer pointed that the senders showed in the picture of the manual were not from them.
Meanwhile I had contact with a guy from VDO-Marine products. They have a tachometer, white and with chrome rings that would match perfectly with my other new gauges.
For some reason he remembered a colleague from him having a Swa Ray too. 5 min. later that colleague ringed me and he had excactly the same glenndeling synchronizer on his Sea Ray 420DA and did the same thing as I do now.
He gave me the tachometer number that I needed.
And he gave me the link for the chrome ring.
Unfortunately it’s a 3 weeks delivery time but that’s worth waiting.
Apart from the light color they will match pretty good I hope.
When everything is installed I come back with the results.