Adding tach

[User811780]

I’m looking to add a tachometer to my 6 cylinder 81 f150. I know I need the printed board along with the new tachometer. Can anyone tell me if this cluster would be correct?

https://www.ebay.com/itm/256477093465?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4mEIirhIRDW&sssrc=4429486&ssuid=&var=&widget_ver=artemis&media=COPY

[viven44]

Not sure if it would work.

Looks like a diesel tach based on the documentation here

https://www.garysgaragemahal.com/tachometers.html

That speedometer connector also looks different than usual. Not sure why.

[grumpin]

Pretty sure it's not a diesel tach., no red lines and the cluster would say Diesel Fuel Only.

My guess is it's out of a medium duty Ford truck. Maybe with a big six.

https://www.ebay.com/itm/374633111339

Edit, added link.

[Rockhauler]

Took a couple quick pictures of dashes in my 2 trucks and front and back of a spare dash I have kicking around, these are Trucks sold in Canada so KM are the larger numbers on speedometer..

Not sure which year this extra dash if from.




My 1986 F150 standard trany dash


My 1985 F250 diesel dash


Paul

[ArdWrknTrk]

Those are great photos, Paul!  
Perhaps Gary can add them to document non-USA clusters?

Clusters are modular.
You can swap an mph speedo for kph, or add a tach.
Clusters with tripmeter have a hole for the reset button (stalk) to poke through the lens.
It's the same tach for 6 or 8 cylinder. There's just one terminal on the back that needs to be grounded to make the change.
This should all be well documented by Gary -somewhere- on the site.

[Gary Lewis]

I don't know if that one will work or not, but I think it will.  The ID# on that flex circuit is F3HF 10C956-A.  The F3 tells me that the circuit was designed in 1993 and the HF says for a medium duty truck.  In fact, this search shows several hits that say it came from a 1993 - 95 F800.  And those clusters have been known to work in our trucks.

So it should work - assuming the target truck has gauges and not idiot lights.  The trucks with gauges have an 18-pin connector to the cluster and the trucks with idiot lights have a 14-pin connector.  So this cluster would not plug into the harness on a truck with idiot lights.

[Ford F834]

Unfortunately this instrument cluster won’t help you…

As Gary mentioned, this is from a 1990’s medium heavy truck. The 3,500 rpm tachometers are all for DIESEL applications. They get their signal from pulses generated at the flywheel teeth. Some have little toggles that need to be set according to which transmission the truck uses. These will not work in a gasoline truck using ignition pulses.

Second issue is that the speedometer is electric, not cable driven.

If your truck is a 1981, it should use the red circuit film. Green was 1980 only. Check the ordering of the indicator lights at the top of your bezel. The circuit film corresponds to that.

For gas engine pickups, Ford only offered 6,000 rpm tachometers. For Medium heavy trucks, there was a gas 4,000 rpm tach (80/81 only very rare) and a 4,500 rpm GAS tach with no yellow/red zones on the gauge face. These are still uncommon but not as rare as the 4,000 rpm one. However, buyer beware, the later gas 4,500 rpm units have only 3 terminals on the back instead of 4, and the posts won’t fit. I haven’t messed with one, but I also don’t think they will work with a 6 cylinder, since isolating or grounding that 4th post is how you get the same tach to read correctly with both 6 cylinder and 8 cylinder engines.

So if you find a 4,500 rpm tach, make sure that it has 4 posts on the back, and that it does not have red/yellow zones. That one is for the 6.9 IDI diesel. It will kill the ignition on a gas truck!

If you want any more gory details ping me, I have a bit of obsession with special tachs.

[Gary Lewis]

Thanks, Jonathan!  That helps a BUNCH!  

[viven44]

I was just going off the 3500 RPM limit.. but agreed I thought it would have said Diesel Fuel only.

I think the OP is better off buying a gasoline cluster and in my experience its better to buy an older cluster locally and test the tach with some alligator probes (power, ground, tach signal) before buying. I have bought clusters online for the tach but the tach didn't work or wasn't accurate.

[Ford F834]

There are two designs of tachometer… the integral circuit type from 85/86 that has an “open” exposed circuit board, and non-integral circuit type from 80-84 with a “closed” case covering the internals. General consensus is that non-integral circuit type tachs have a lot more problems and are more sensitive to sticking when cold. They also tend to develop problems when not used for long periods of time. Given the choice, I would recommend looking for an integral circuit design tach.

[Ford F834]

Oh, wait… somewhere there is a really good website with comprehensive information on this stuff 😎


https://www.garysgaragemahal.com/tachometers.html

[User811780]

Thanks for all the replies, I’ll do some eBay shopping and see if I can find one that will work.

[Gary Lewis]

I think I've seen that website.  

[User811780]

I give up, anyone want to do some shopping for me and point me in the right direction to a gauge cluster that would work with my setup???

[BigBrother-84]

First, do you need the automatic transmission indicator?
There are plenty, with or without this indicator, on ebay.


I used the eBay criteria«1980-81 f-series bronco cluster tach» and got multiple results.  Would say around 250$.
Just be sure to avoid « diesel » or « 1980 » units.
1981 to 1986, gasoline truck or Bronco, should work.  Red printed circuit behind.

[User811780]

I don’t need the indicator, Any certain RPM I should look for?

[ArdWrknTrk]

If you read the linked page you'll see you want a 4 or 6K tach, and NOT a 4,500 rpm one.

Diesel tachs do not have a coil trigger to work with. 💡

[BigBrother-84]

I think a majority of used available gasoline clusters w/tach are 6000rpm model.

That’s the one I installed in Big Bro (the truck didn’t have).

Since Big Bro is geared as a farm tractor (or a battle tank), I rarely reach 3200rpm.

[ArdWrknTrk]

Yeah, well how many do you think were* Windsor's and 460's v/s how many 300's, which would use the 4k tach??? 🤔

*damn phone... 😖

[BigBrother-84]

In fact, each time I drive Big Bro on a highway, I am wondering about what Bullnose engine needs a 6000rpm tach.  Really?