Factory Tach

[390mach1 49]

Is there anyway to rebuild a factory tach? my tech always seems to jump to 1,000 RPM I have it all tore apart and cant seem to see any place to adjust.

[69RavenConv 286]

They can be cleaned and lubricated, and bent parts can be straightened. Some folks replace the works with aftermarket works. Keep in mind the factory tach doesn't work like an aftermarket tach and they can be easily fried if excessive current is drawn through them.  Good luck.

[Alan_Mac 48]

Tachman restores original Tachs.  I had Redline replace mine with modern (VDO) internals.     

Edited February 16, 2017 by 69RavenConv

[Raven R code 281]

+1 for the tachman.

[1969_Mach1 333]

To be blunt, sorry, the tach is finished.  The movement usually wears out.  Have it retrofit is the best option since new parts are not available, except for maybe a transister, diode, etc.

 

Tachmans's mood is hit and miss.  Catch him on a bad day and you'll be sorry.  I purchased a Speedometer from him.  It reeked of cigarettes.  The odor punched me in the face when I opened the box.  I had to leave it in my backyard for a week before installing it.  Then the odometer jammed up at one tenth of a mile.  He rudely blamed it on my NEW OEM speedo cable being installed wrong and didn't offer to even look at the speedo.  Pissed off I purchased a different speedometer from Perogie's.  I later disassembled the odometer from Tachman's speedo and found the problem.   I will never use Tachman again.

 

I'd try Rocketman's Classic Cougar Innovations or Redline Gauge Works.

[390mach1 49]

Thanks guys as always I love the feed back! finally getting my butt in gear to finish the car as a buddy is getting married and wants to drive a few stops on the power tour.

[1969_Mach1 333]

Adam, from what his personality seems to be, you're right, you probably pissed him off.  I had also been warned of his moods years earlier when I was trying to find someplace to repair a factory tach.  I avoided him then.  But later when I needed a speedo I thought what could go wrong with that simple transaction.

[danno 128]

I wonder what the problem is with the tach?  If it is just the wires, they can be re-wound. I might be able to help with that, as I am employed as an electrical engineer at a place that winds coils all the time.  It is simply a matter of determining the number of turns and rewinding it. 

[Midlife 814]

I wonder what the problem is with the tach?  If it is just the wires, they can be re-wound. I might be able to help with that, as I am employed as an electrical engineer at a place that winds coils all the time.  It is simply a matter of determining the number of turns and rewinding it. 

There's two basic areas of failures with Ford tachs.  On the input side is a transformer; if it breaks, then current can't pass through the tach on to the coil, which happens a fair amount of time.  The second area of failure is in the gauge mechanism itself.  When that fails, the car can still run with the tach hooked up. 

[390mach1 49]

I'm not sure how to check I as I currently don't have the tach hooked up and its acting like this. is there anything I can check? 

[Alan_Mac 48]

As midlife said, the two wires pass through current for the ignition system.  Use a voltmeter to check continuity through the tach.  

[1969_Mach1 333]

If you are determined on keeping it original you can try Rocketman's Classic Cougar Innovations.  Once when I tried to fix a tach that would stick at 1500 RPM or sometimes not work at all, Rocketman had used step down transformers and circuit boards he had removed from tachs he had retrofit.  In the end, I tinkered with it for several weeks and it wasn't either of those items.  The movements are extremely sensitive and wear and get sticky.

 

If I were in that situation again, I would send it Rocketman or Redline Gauge Works and have it retrofit.  Rocketman is probably less expensive and you'll talk to the person that is doing the work.

[danno 128]

There's two basic areas of failures with Ford tachs.  On the input side is a transformer; if it breaks, then current can't pass through the tach on to the coil, which happens a fair amount of time.  The second area of failure is in the gauge mechanism itself.  When that fails, the car can still run with the tach hooked up. 

Yes, the rewinding of the transformer is what I think is possible. It is usually just knowing the number of turns and measuring the wire size. I measured mine at 1.7 ohms, but that is only the start.