Stewart Warner Tach Issues

[357456]

Anyone experiencing tach problems? At first it started to slow in opperation and now it just reads half of what it should.
I talked to an old speedo shop near me and they said there is really nothing you can do to prevent it's eventual failure. They called SW and they were told. There are no parts for this tach. Because SW has abandon the circuit in this tach. They consider it to be a poor design.
The new tach looks a little different. SW #82170.
They used to be a great company. I guess it is just like all businesses that get bought and sold a multiple of times. Their quality goes away.

You could retro your old on new movement but........$$$

 

[X Ray]

You can try this...on the back side of the tachometer is a cover ...it covers the adjustment screw for changing the tachometer for 4,6 and 8 cylinder engines. The 6 cylinder setting is pictured....good luck.

 

[357456]

4,6,8

I did try that Rick. Thanks!
I just wanted other owners to know what they could be in store for. And what their options are. I hope no one else has or gets this problem.
I've got a new #82170 on the way like below till I figure out best course of action with the original. It least one close to the original is available.

 

[gordyzx9r]

Are you sure it's the tachometer? It could be a faulty ignition module.

I have a GNX style dash with Stewart Warner gauges in my GN. The tachometer started failing at 2K RPM and would go to 0 RPM. I went through hell tracking the problem down.

Stewart Warner no longer has a tech department, you get referred to the tech department of their distributors nowadays. That pissed me off so I spent a day on the phone tracking down someone of importance in Stewart Warner to help me out and they sent me 2 8K RPM tachs and one 10K RPM tach for free.

Eventually, I just ripped out the whole cluster and sent it to Lauderdale Speedometer and Compass to get looked at and they told me the original tachometer was fine.

Eventually, someone told me that if the ignition module is going bad it could cause that problem. Funny thing was, it wouldn't do that to the Autometer tach I tested or a cheap tach I got from Auto Zone. Once I changed out the ignition module...the problem went away.

 

[Bob Smith]

Our local Buick club had a meeting yesterday at D&M Restorations. We had a GNX there and asked them specifically about the Stewart Warner gauges and tach in the GNX and they it can be repaired. They don't work on the regular Grand National dashes & gauges, but will repair the Stewart Warner stuff. Here is a link to their site:Classic Car Carpet | Car Clock Repair | Guage Repair | Speedometer | D and M Restoration

I hope this helps.

 

[357456]

Sw # 82170

I switched my module out with a new one that I had on hand. No difference in the old tach's symptoms.

I drove over to a local speedo shop. Not all tachs will work in this ignition system. As we discovered. They gave me some advise about tachs.

Most speedo shops will transplant your tachs face on a new movement. Watch what you get into here. With this change you will have to compromise the scale. Unless it has exactly the same degree of sweep.

Some shops say they will repair it. What will you get back? And how much will it cost you?

I don't know about the rest of you. I'm finding it hard to get ANYTHING done right the first time through in today's service industry

On the speedo shop's advise I bought a new 82170. It works fine. For how long who knows? I have two of the orginal type GNX style tachs now. One I sent out and will let you know what I get back from that shop.

Good luck!

 

[357456]

Well after many months I finally got a functing Tach back from the "guage shop" I sent it to. Wow! Hard to get anything done these days on a timely or quality basis. I ended up doing all the leg work for this damn slow shop. After much tugging and pulling in countless phone calls. I ended up getting the 82170 with my original Tach's face. They tried using (and selling me on) a VDO retrofit. First off, the VDO didn't and doesn't have the same degree of sweep or scale as the Stewart. Warner. Second, the VDO wouldn't pick up the Buick's ignition pulse.

So there you go. Be careful out there!