Tachometer Advice Needed

[david lewis]

Several forum participants recommend that I install a tachometer for my Universal 25M diesel. I concur with their recommendation but I wonder what is involved. All my past experience is with outboard auxiliaries on smaller sailboats. There is no place for a tach on my instrument panel. Should I replace the whole panel and if so who is a source for this item?Also on a gas engine a tach is easy as you can inductively pick up the voltage from the spark plug firing. What is used on a diesel? I assume a magnet mounted on the engine shaft and a magnetic transducer?Any advice will be most welcome.Regardsdave

 

[R.W.Landau]

tach

David,You may want to post this in the Diesel engine forum to get Gordon's input.r.w.landau

 

[Brian Pickton of BeneteauOwners.net]

tachs

Jan.7,2000Dear David,On most diesels tachometers measure the alternator's AC output frequency before rectification. The alternator will have a tachometer connection usually in the form of a spade connector next to the field terminal spade connection on the end of the housing. If in doubt on how to do the wiring any competent diesel mechanic or electrical worker familiar with diesel alternators should be able to give guidance. Take a look at the hardware available for power boats which sometimes mount a remote tach in its own housing in case you don't want to attempt a whole new instrument panel. Sorry, I don't have source for instrument panels but your engine manufacturer should be able to help you out there.Brian Pickton of BeneteauOwners.netAboard the Legend, Rodney Bay, St. Lucia

 

[david lewis]

Tachs vs. alternator frequency

That is a surprise to me. it just seems logical that the best way to pick up crankshaft speed is directly off the crankshaft either optically or magnetically. ALternator speed is a function of pulley size and belt condition. I dug around on Torresen's web site and found they offer the panels for sale so I'll pursue that avenue.Thanks,d

 

[R.W.Landau]

good luck

Dave,Tell us what you did, when you make the decision.r.w.landau