# Ford 3000 Tach ?



## Hightech1953 (Dec 30, 2018)

Installed new proofmeter cluster, tach cable and 12v alternator kit. I thought the tach was probably not that accurate so I ran the tractor with the PTO engaged. Used a hand held digital tach on the PTO shaft to see what the proofmeter tach would show at 540 rpms at the PTO shaft . It was 2400 rpm at the proofmeter tach and 540 at the PTO . Still had plenty of throttle left. That is a pretty big difference . At 1800 on the proofmeter the PTO shaft was turning at 440 RPM. I did not think it would be that far off !! Any one else experience this problem ?


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## Ultradog (Feb 27, 2005)

Hightech1953 said:


> Installed new proofmeter cluster, tach cable and 12v alternator kit. I thought the tach was probably not that accurate so I ran the tractor with the PTO engaged. Used a hand held digital tach on the PTO shaft to see what the proofmeter tach would show at 540 rpms at the PTO shaft . It was 2400 rpm at the proofmeter tach and 540 at the PTO . Still had plenty of throttle left. That is a pretty big difference . At 1800 on the proofmeter the PTO shaft was turning at 440 RPM. I did not think it would be that far off !! Any one else experience this problem ?




I have heard those alternators don't provide a real accurate reading.
Some guys have changed the pully on the alternator to get a more accurate reading.
I have never used that style of conversion but you might think about that.
It's kind of too late now but there is another way to do a conversion on those tractors.
It depends on the year of your tractor.
In late 68 (I think)
Ford did away with the screw in frost plugs. From then on they used a more modern press in frost plug.
If you have the later style block you can convert them to a 1976 and later tach drive.
Remove the large soft plug under the oil filter and pull the oil pump drive gear that drives off the cam. The newer drive gear has a square hole in the top. You can kinda see it in the photo.
Then you














buy the later style angle drive to run the tach. Photo.
Mind you, the old/new style tachs spin opposite of each other - ie, left hand/right hand.
And you must use the temp sender from a 76 and later tractor.
I have done it this way a few times and use a cheap 10-SI alternator from Napa and make my own brackets.
Price is a wee bit more than the kit you bought but the tachs are dead on.
If your engine has the old style plugs you can not do it this way.


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## Hightech1953 (Dec 30, 2018)

Ultradog said:


> I have heard those alternators don't provide a real accurate reading.
> Some guys have changed the pully on the alternator to get a more accurate reading.
> I have never used that style of conversion but you might think about that.
> It's kind of too late now but there is another way to do a conversion on those tractors.
> ...


Looks like mine is a no go !!


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## Hacke (Feb 22, 2011)

You could put a larger pulley on the alternator, but that may result in low chargíng at idle and poor cooling.

You did not get what you paid for, contact the seller.


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## Ultradog (Feb 27, 2005)

Hacke said:


> You could put a larger pulley on the alternator, but that may result in low chargíng at idle and poor cooling.
> 
> You did not get what you paid for, contact the seller.


Fwiw,
It more likely to be your tach than the alternator.
The tach drive is a direct, gear drive and does not vary relative to engine rpm whereas the tach operates on a couple of cheesy magnets and could be off a bit.
I would try the larger pulley first.
And I wouldn't be too concerned about charging issues at low speeds with a bigger pully.
Those are about a 60 amp alternator after all.
Hitech, is your tractor a gas or diesel model? Either way, consider this:
If gas it's only using about 4 amps to power the coil and energize the gages. A diesel is only using maybe one amp to energize the gages - if that much.
Even at low idle it should provide enough power to recharge the battery, power the coil, gages, lights, etc and a guy has to spin it up to 1200 rpm or so to do any useful with it.
Hacke, 
I assume you mean alternator cooling?
I might be concerned about alternator cooling if you had a dead short somewhere and it was putting out 40 or 50 amps for an hour or two. She'd get hot then for sure.
But changing the rpms/cooling by 10 or 20% won't cause a problem on a low amp useage situation.


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## Hacke (Feb 22, 2011)

The alternator and cluster are new and there should not be a need to make changes in order to make them work properly. Buying today's aftermarket parts is a bit risky.

The first measurement shows 2400/540 = 4.4, the second gives 1800/440 = 4.1 so there is a "slippage" in the tachometer.
A larger pulley will not fix that, but maybe there will be less slippage with lower alternator speed, and if you choose one that gives a proper reading at 1800 rpm, it should work fine.


Yes, I ment cooling the alternator, maybe it is not that big of a deal. The regulator parts do not like heat, but the engine radiator fan is pretty strong and helps a bit.

They say that alternators starts charging at very low speed. Of course they do better than a generator, but you cannot go too low. They are individuals and the only way to know is to try.


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## Hightech1953 (Dec 30, 2018)

It is a diesel . 
The main reason I was checking was for the PTO speed was when using the bush hog. Didn't want to be lugging the engine. So knowing 2400 rpm = 540 pto rpm I can live with that for now. The only implements I have that use the pto are a bush hog , rototiller and spreader.


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## Ultradog (Feb 27, 2005)

I haven't had a tach or even a wiring harness on my 3000 D for about 6 years now.
Well, I have but every time I get one on it I steal it back off to put on another tractor to get it sold. All I have is an oil pressure gage as I do like to keep track of that. I do a lot of bush hogging and just spin the engine up to about 3/4 throttle.
The 540 speed is not a magic number. It's just an approximate guide.
I do understand a guy's frustration in buying new parts and having them not work right though.
Makes you want to take a knout to someone.


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## RC Wells (Dec 26, 2008)

Consider a Tinytach for reference RPM. Inexpensive, installs with a pulse sensor on one of the diesel injection lines, and can be installed out of the way but still easy to read. www.tinytach.com

But, these Ford diesels are much more flexible and forgiving than the newer engines if you are off a few RPM's. Just do not lug them.


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## Bob Smith (Aug 28, 2017)

Hightech1953 said:


> Installed new proofmeter cluster, tach cable and 12v alternator kit. I thought the tach was probably not that accurate so I ran the tractor with the PTO engaged. Used a hand held digital tach on the PTO shaft to see what the proofmeter tach would show at 540 rpms at the PTO shaft . It was 2400 rpm at the proofmeter tach and 540 at the PTO . Still had plenty of throttle left. That is a pretty big difference . At 1800 on the proofmeter the PTO shaft was turning at 440 RPM. I did not think it would be that far off !! Any one else experience this problem ?


I also installed a new aftermarket cluster, alternator kit, & tach cable on my 1970 3000 diesel with the same result. I used a calibration tachometer (from work) and checked the actual engine RPMs against the new tach indicated RPM. They were off about the same as yours. I considered replacing the alternator gear with a bigger one, but after doing the math (correctly I hope), I would have had to change from the original 3 or 3-1/2" (I would have to look at my notes) gear to a huge one. I think it would have to be 4-1/2" or 5" to get the tach to be accurate. Instead, I made a chart so I would know what RPM I was actually running. Then, I decided to see if I could make the tachometer more accurate. I took it apart, could not find any adjustment or anything. Put it back together. Well, after fiddling with it (gently I thought), it is now just whacky, and I can't fix it. I really don't need the tach for bushhogging and such, but it would be nice to keep track of tractor running hours for maintenance purposes and just to be OCD. I may look into Ultradog's suggestion. Sounds like the best solution for me. From his post, I assume I would have to get a counterclockwise tach rather than the clockwise tach I have now. I don't know why the aftermarket cluster tach doesn't work with the alternator kit. I assume the alternator tach drive gearing doesn't put out the correct RPM or the cluster tach is just not accurate. If I hadn't of waited so long after purchasing the cluster and alternator (alsost a year) to install them, I would have probably sent the cluster back for an exchange.


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## Hacke (Feb 22, 2011)

Sad about the tachometer. It is a small comfort, but you are not alone in the curiosity community.

I suppose the alternator has a gear box like this:
https://www.aidtractor.com/part/1100-0545

You could change the gears to correct the speed.


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