The International Cessna^® 170 Association

Asking for a friend.....

“My Mitchell tachometer failed and I removed it. The local instrument shop had too many problems with Mitchell so they no longer carry them and supplied me with Superior Labs tach which costs twice as much...”

With regard to installation, it looks like all one would have to do is to remount the tach and reconnect the cable, taking care to properly seat the cable end into the fitting in the back of the tach. The engine only has 440 hours since overhaul when the cable should have been properly lubed.

1) Should the cable be relubed now?
2) If do, what is the proper lube for smooth low temp operation?
3) Are there any installation tricks to make it easier when reaching up under the panel and connecting the cable?

My right arm and hand somewhat screwed up by a temporary orthopedic problem so this is going to be a challenge.

Personally, my choice would be a brand-new cable if I installed a new tach... but if it was working properly before... it should be fine now as well. Dry graphite is what is often recommended for lube. Put on some rubber gloves and work the graphite into the spun-wire cable and reinsert it into the housing.

If your cable is sufficiently long, it may be possible to insert the cable threaded/knurled end onto the tach before mounting the tach, but the cable-end is “keyed” and will only fit onto the tach one way and isn’t difficult. (Been a couple years since I did this and I’ve slept since then.)

Keystone Instruments recommends petroleum jelly as a tack cable lube.

Here's what the Service Manual says:Apparently the reason for only lubing the lower two thirds is that you do not want the lubricant to wick its way into the tachometer. Luberplate 110 is readily available. I can't find ST-640 speedometer grease. Some car guys recommend Kable-Ease.

Thanks to both of you.

I called the Mitchell factory and they recommend the use of Lucas Red’N Tacky Lithium grease for the cable and remarked that its good for low temps as well.

https://lucasoil.com/products/grease/red-n-tacky-grease