Tachometer oil

[tanny]

A while back, someone said he replaced the oil in his tach to keep the needle from jumping around. Does anyone remember or know the viscosity of this oil? I thought he said he used gear oil. Thanks, Victor.

[Bambikiller240]

Victor:

I do not remember the post you are refering to, but I would not suggest using oil to lubricate the spindle of the tach. Oil will spread out and attract dust, lint, etc which will further foul the spindle that the needle is attached to. I believe that a grease would be more appropriate, as it will stay in a concentrated area.

Just my $.02

[Zedrally]

If you go down this path, "Moebius" oil for french clocks. Available from Watchmaker Supply houses. While your there buy an oiler or make one using a .5mm piece of wire. Only the minutest amount is required. Just to give you an idea, I have bottle here that was passed down by my father. Size would be about 50ml and he used 5 of that in 40years of wathmaking!

I couldn't suggest grease as the friction would be far to great [sticky].

First plan of action is to clean the movement first, never having stripped a Tach before I can't be of any assistance, however all dirt, old oil etc must be cleaned from the pinon and jewel [if used]. You could use a little carb cleaner for this, work with a fine artist's brush, preferably under magnification.

Welcome to the world of Intrument repair!

MOM

[Bambikiller240]

Originally posted by Zedrally

I couldn't suggest grease as the friction would be far to great [sticky].

You don't use wheel bearing grease, there are many grades of grease. A light weight grease is what I would use.

Moebius oil is good for watch/clock movements, but those items are generally a more "sealed" environment where lint and dust to do not exist to a great extent.

[Zedrally]

I would certainly have to agree to dis-agree wiith you on this. Many Clocks that I have serviced attract lint, dust and the occassional mouse do-da in the most sealed environment.

The Tach mechanism would be more sealed than the average mantle clock.

Having said that a silicone grease would be a suitable alternative,

MOM

[tanny]

From the description that I remember(or maybe don't remember), I thought that the tach had some kind of viscous coupling mechanism using oil that would eventually evaporate or somehow otherwise disappear, resulting in erratic movements. That is the oil I was wondering about. If this is not the way the tach works, please ignore this thread. I haven't had a tach apart so I am ignorant of its inner workings. Thanks, Victor.

[Inf]

Tanny,

I remember seeing a similar post myself. I think Victor Laury posted it? If i'm mistaken, sorry. I can't remember what thread it was in though.

I don't know about there being a viscous coupling inside the tach.

I had a 240Z and 280Z (4 and 3 wire respectively) tach apart a few weeks ago, didn't take as many reference pics as I guess I should have, but here are 2 pics. From what I could tell the movement of the needle was controlled by 2 springs that you can see wrapped around the center spindle

[Inf]

240Z inductive loop 4-wire tach

[Inf]

280Z negative trip 3-wire tach

[tanny]

Pardon my senility, but I'm sure now that what I was thinking of was the fan clutch. Senior moment. Well, I'll just have to take the tach out and mess around with it. I'll have a spare tach shortly, so I can hope that it will work better. Have to go back through the threads and see if I can r&r one of them. From what I read, mine is most likely a 4 wire(73), which in one thread was claimed to be less reliable than the three wire. Thanks everyone, Victor.:stupid: