8V71 RPM gage connections, Need help planning connections.

[Gary LaBombard]

Hello again,

I am still sitting in front of my computer it seems for weeks now but I am getting closer to getting back to work on my Eagle, I hope!  What I am questioning here is I was told by Jack verbally how to shift my bus, (Yep, don't know how to do it yet correctly).  Anyhow, he kept mentioning the RPM's and I don't have a gage on my bus, only the speedometer and not sure if that even works correctly yet.  By Jacks instructions it is really quite advantageous to have those RPM's perfect and shifting will be a near breeze or easier, especially downshifting I hope.

I have a  4 speed, 8V71 engine.  My alternator is not gear driven but I believe I remember over the past 5 years now that you can connect up a RPM gage directly off the engine.  There is enough port holes in the front of the engine facing the front of the bus anyhow.  Well, you DD mechanical inclined guys and Sonnie your involved here too, where can I connect up the RPM gage directly off my engine and where can I get the parts needed completely to do so that are needed, (Gage, plates, gaskets, cables needed).  Will the gage be calibrated out of the box or is this another learning curve to have the gage work correctly and accurately??  Is this one of those $1,000 projects??

Thanks for the input and any information ahead of time you offer to help me decide.

See you guys in Charlotte in a couple of days. 

Gary

[Dreamscape]

Hi Gary,

I will be following this thread closely because I'm in the same spot as you for our Eagle.

Guess they didn't feel it was important enough to use them back then, dunno.

Happy Trails,

Paul

[luvrbus]

Gary, these guys have any  part you need  and will help with all your needs for installing    www.precisionspeed.com   if you need the tach drive  gear and cover I have one for the front  good luck

[Catskinner!]

Gary

Call me, I have what you need.

This is the tachometer and sending unit that goes on

the front of the block.

Catskinner!
Sonnie Gray
72 0/5 Eagle 3406 Cat
Pottsboro, Texas

[eaglelover15]

Gary, you can run the tach off the blower or aux drive on the back of the engine if the front drive doesn't work for you but either way you will need a tach drive. I have some 8v71s in equipment and the tach drive is different on all 3     

[TomC]

For the most accurate tachometer- most 2 strokers will have a mechanical tach drive-usually off the blower.  Mine is on the left side of the engine off the blower near the back of the engine.  I then bought a 3000rpm tack with the electric generator that mounts into the mechanical tach drive from ISSPRO.  To run the wire from the engine to the dash, I bought 5 different colored 50ft extension cords, plastic wrapped them together, and ran them the length of the bus (a bit of a job, but now I have extra wires running the length of the bus).  It was simple to program-the generator said how many poles it was, and you just flipped the switches on the back of the tachometer as stated in the instructions.  The actual drive generator has two wires that go to the tachometer, then there is a ground, a ignition power source and a light kit to illuminate the tach at night with your dash lights.  I just mounted mine independently on top of the dash with a gauge mounting kit.  Even though I have an automatic, it is nice to know what you're turning, then you can keep it in the most economical rpm range (1600-1800 for the 71 series; 1500-1700 on the 92 series; 1400-1600 on electronic 4 strokes).  Good Luck, TomC

[mikelutestanski]

Hello;     Another solution which requires some work is to use the R terminal of the generator which is half voltage but is also a pulse waveform and by knowing the gear ratio of the generator to the engine you can correctly figure the engine RPMs . The table shipped with the unit tells you how to compute the ratios and with the answer set the dip switches properly to get the right reading..
   Precision speed has had those in stock but don't know if they still carry the items .     
     Happy Bussin   mike

[tomhamrick]

I use the Isspro (sp?) attached to the R terminal of my Eagle 10 and it works great! Bought it several years ago from International Bus Parts in Florida.
Tom Hamrick

[Bob Gil]

KO now ya-ll have about blown my mind!  What little I had.

I was trying to figure not where to look and what to look for the pick up for the Tac and other insterments on mine since the wires have burn't. 

From this line of remarks it could be any where.  I guess I don't have a R terminal on my alternator it is not there so I will se what i can find with the remainds of wires comeing out of it.

I found the sending units for the water temp on each of the heads but the wires are real short not much left of them at least on one side anyway.

O well I have the tail lights about ready to mount then to the wiring.

[Brian Diehl]

Another option is to screw in a magnetic pickup sender in the flywheel housing.  I did that with my 6v92 and ran the sensor with two wires from a programable tachometer at the front.  I just had to tell the tach the number of pulses per second (I think 120 it was).  Worked excellent until I put in my new powertrain.