Tachometer and Speedometer

[Seangie]

Hey all -

Trying to get my Tach and Speedo running.  Speedo I am not too concerned about but I'd love to have the tach online.

The PO bought autometer instruments in a new panel.  They look nice but after a call today with autometer it looks like I am going to have to buy something like this -
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=129/category_id=105/home_id=59/mode=prod/prd129.htm

He said that the autometer instruments that I have will only work with an ignition type signal and not from the signal from the AC post on the alternator.

My questions is with my 6v92 and Allison 740 is the install of the DSL-2 fairly simple?  Is there already a place to screw in the sending unit? 

Thanks in advance.

-Sean

[Eric]

Can you link or post a photo of your units?? I'm sure there got to be a better way.... Or I hope at least!


Have fun !

Eric

[luvrbus]

Call this  guy 1-800-873-1055 Precision Speed www.precisionspeed.com are you sure the tach doesn't have dip switches to run off the r terminal on the alternator, I prefer the pulse generator my self over the fly wheel sensor or the R driven tach myself

good luck

[Seangie]

Can you link or post a photo of your units

Eric - I'll take some pics when I get out there tomorrow and post them.

are you sure the tach doesn't have dip switches to run off the r terminal on the alternator

Cliff - the only dip switches on the back of the tach are to change between 4/6/8 cylinder.

Funny cause the front of the tach says "Silver Eagle" like they were made for an Eagle bus.

Would it be easier to just buy a different tachometer that works off the R terminal, sell this one and call it done?

Thanks again.  Appreciate the feedback.

-Sean

[Seangie]

Here are some pics from my adventure today -

The model of the Tach is an autometer 1699 - 80001,  I am assuming it is custom and 1699 is the actual model.

Moving on to solutions - I crawled under the bus and found a nice 1.25" threaded hole that is open right under the flywheel.  Good deal.  The challenge I think will be finding a sensor that fits up in there.  The one from Dakota Digital is 2" long but only 3/4" wide.  I need something that is less than 2" long and 1.25" wide or maybe if they make some kind of reducing double threaded nut?  (I am making this up as I go along here )

Does anyone know if they make a sensor specific for the 692 that will give me the signal that I need?

Does anyone have a 5" tachometer lying around that will work on the R stud from the alternator?

Any other suggestions? 

Thanks again!

-Sean

[Seangie]

Also - here are the instructions that I have for the Tach.  Unfortunately no settings to change to read from the r post on the alternator.

-Sean

[TomC]

I have an Isspro tachometer.  I used a signal generator that works off the tach drive coming off the blower.  The only problem I had was the actual drive was not installed.  Don Fairchild installed one for me and it works very well.  I use the Tach and GPS almost exclusively now. Good Luck, TomC

[Ed Hackenbruch]

Do i remember somebody a while back saying that that hole was a drain hole?

[Sam 4106]

Hi Sean,

A "reducing double threaded nut" is called a reducing bushing, available in the plumbing department at hardware stores. That's assuming the hole in the flywheel housing and the sensor are pipe thread.

Good luck, Sam

[luvrbus]

I think he going to waste his money there is no guarantee that tack will work with a magnetic sensor the way I read it it runs of a distributor on a gas engine if it don't read 3000 rpm he has problem there also so many different ohm's on the pickup how does he know what to buy 250 or up to 1200 if it was me I would be looking for a Dixson tach and speedometer lol

good luck

[TomC]

Most all truck use the magnetic pickup off the flywheel-just have to have the magnet to make it work.  Good Luck, TomC

[Sean]

Sean,

I think you will be better off selling the Autometer unit on eBay and then buying a tach that has a universal signal input, so you can just connect it to the R terminal, calibrate, and be done with it.  I'm guessing you can find a 5" tach with universal input for less than a c-note if you shop around, perhaps on that same web site.

That said, if you want to keep the gauge, there are lots of "pulse converter" boxes on the market that can translate the R signal you already have into whatever the tach needs.  For example:
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=127/prd127.htm

That's a few bucks less than the Dakota Digital sender product you linked, and tapping into the R terminal is less work.

You can also roll-your-own out of two $5 integrated circuits and a few discrete components once you calculate the conversion factor; plans are on the Internet if you Google around a bit.  Same goes for the speedo, actually.

HTH,

-The Other Sean
http://OurOdyssey.BlogSpot.com

[Scott & Heather]

Watching this thread too as I'm in the market for a tach as well. Sean (odyssey) it never ceases to amaze me how much electronic stuff you build by hand! Too cool.


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[luvrbus]

I would not use a tach running of the R (relay) terminal off the alternator if you buy a different tach use a pulse generator off the engine not all alternators have a R terminal

[Lin]

To me it always seemed that a tach that reads directly off the engine is best.  That said, I bought one the reads of the alternator on the advice from Precision Speed.  It is adjustable.  They calibrated it before it was shipped based on the pulley measurements, but I did not think it was right so I bought a photo tach for $20. to reset it myself.  It works fine, and that's what really counts.  There are lots of other projects to move on to.