Adding a Tachometer

[labbe001]

I just purchased and earlier model JD 450B and as it turns out, most all of the gauges are busted out. From what I can tell, this machine didn’t come with a tachometer. I would like to add one as some of the adjustment procedures in the manual call to run the machine at a certain RPM. My question is, how difficult is it to add a tachometer to a machine that didn’t come with one? Are there provisions on the engine side to accept a tach cable and where would I look to find that?

[B Town]

The tach drive is near the right rear near the cylinder head. Very near the valve cover. And if I remember it is vertically oriented.

Online deere parts catalog. Here is a link.

https://partscatalog.deere.com/jdrc/sid ... gId/241913

[Jim B]

There is a drive gear (shown with the camshaft) the threads into the rear of the camshaft. The mating gear and housing (shown with the tach) are mounted vertically in the flywheel housing plate, in line with the rear of the camshaft. If the adapter is not in the flywheel housing plate, I am not sure the drive gear will be in the camshaft. You might be able to look in the hole and see with a horoscope or mirror. If it is not in the camshaft, you will have to pull the engine to install it.

[labbe001]

Going from the description…I would assume the hole that the tach gear would go into is the same hole that item #6 in the below link would screw in to?
https://partscatalog.deere.com/jdrc/sid ... pgId/20364

As it turns out, my machine doesn’t have this hole in it. There is no hole anywhere on the top of the flywheel housing. I think it’s safe to say my machine doesn’t have the provisions to install a tachometer.
Is there a way to adjust the engine clutch without using a tach? The procedure in the manual describes setting the endgine at a certain rpm but without a tach, I’m unable to do so.

[Al Swearengen]

Going from the description…I would assume the hole that the tach gear would go into is the same hole that item #6 in the below link would screw in to?
https://partscatalog.deere.com/jdrc/sid ... pgId/20364

As it turns out, my machine doesn’t have this hole in it. There is no hole anywhere on the top of the flywheel housing. I think it’s safe to say my machine doesn’t have the provisions to install a tachometer.
Is there a way to adjust the engine clutch without using a tach? The procedure in the manual describes setting the endgine at a certain rpm but without a tach, I’m unable to do so.

Maybe something like this???

https://www.amazon.com/Digital-Tachomet ... slink=true

[Al Swearengen]

https://www.tractorbynet.com/forums/thr ... pm.177544/

[NWJD fan]

Tiny Tach makes a tach for Diesel engine applications that clamps a sensor on one of the fuel lines from the injection pump to the injectors that senses pressure pulses in the line and converts that into a digital read out RPM

[Hurlbutt]

On my old Ford with the Navastar 7.3l IDI the alternator provides pulses that are used to determine the RPM which is common practice in the automotive industry. There is a lead which is tied to only one winding to give a single pulse per revolution and these are used to derive engine RPM. The pulley ratios have to match what the tac is calibrated for. I believe there are units which are field calibrated.
These guys, https: //autohackguys.com/installing-diesel-tach/ , likely use inertia sensors like phones use to count your walking steps to monitor engine vibrations so there is no wiring.
There is an option of adding a sensor to the flywheel / bell housing area to monitor the rotation of the crank. My little Chinese tractor has a sensor on the flywheel but it could be on the front pulley. I'd be inclined to add a sensor like this (https://www.ebay.com/itm/184795083476?h ... SwLwdgh3UC) to drive an electronic tac. As I recall, there is a hole drilled into the flywheel which the sensor "sees". A multi lobed wheel or star cluld be added to the vibration dampener to provide something for the sensor to monitor.
https://www.aliexpress.com/item/3256802 ... 2052%21sea lists a $25 3000 RPM tac and a sensor for about $13 that I was looking at last night for my with Chinese tractor that is in the process of over haul. It supposedly is water proof and suitable for boats. Maybe the lens doesn't leak.