Tach cable lube

[RobertGary1]

I just got my tach back from overhaul and now it shakes below 2,000 rpm. Overhauler suggests lubing the cable although the timing seems suspicious 

Do you lube the ends or pull it through? Is it lithium grease?

The cable in no way looks rounded off. 

[PT20J]

I lubed the cable in my 1978 M20J by removing the connection at the back of the tachometer and pulling the core out. I cleaned it off and used graphite speedometer cable lube from an auto parts store. 

Skip

[A64Pilot]

Often times the cable itself can be completely removed from its sheath by pulling it out, usually from the engine side, it can be then cleaned off with mineral spirits and relubricated. Lithium should be fine in my opinion.

‘I see that I am a slow typer.

‘Oh, and on edit, jumpy readings at slow speed is actually very commonly the cable needing lubricating.

Used to be very common on older cars that had cables for their speedometers 

Edited September 19, 2021 by A64Pilot

[RobertGary1]

[PT20J]

@A64Pilot has a good point that it might be easier to remove the cable core from the engine end. Either way should work. I did mine from the cockpit because I was replacing a tach that read high and the cable was disconnected anyway.

[1980Mooney]

10 hours ago, RobertGary1 said:

When I watch the video on an iPhone it appears that there is so much vibration that the entire panel is blurry. But at the sale time you are at only 950 rpm (on the ground I assume).  Is that some sort of video conversion artifact or do you have a lot of vibration?  

Edited September 20, 2021 by 1980Mooney

[1980Mooney]

51 minutes ago, 1980Mooney said:

When I watch the video on an iPhone it appears that there is so much vibration that the entire panel is blurry. But at the sale time you are at only 950 rpm (on the ground I assume).  Is that some sort of video conversion artifact or do you have a lot of vibration?  

And if I try to watch it on my desktop computer it just says:

Sorry!

We could not locate the item you are trying to view.

[RobertGary1]

1 hour ago, 1980Mooney said:

When I watch the video on an iPhone it appears that there is so much vibration that the entire panel is blurry. But at the sale time you are at only 950 rpm (on the ground I assume).  Is that some sort of video conversion artifact or do you have a lot of vibration?  

I shot it on iPhone and it looks like that on my phone too for some reason 

[RobertGary1]

2 hours ago, PT20J said:

@A64Pilot has a good point that it might be easier to remove the cable core from the engine end. Either way should work. I did mine from the cockpit because I was replacing a tach that read high and the cable was disconnected anyway.

The tach is out. When I tried superficially to grab it it didn’t want to pull out but I’ll pull harder. 

[RLCarter]

1 hour ago, RobertGary1 said:

The tach is out. When I tried superficially to grab it it didn’t want to pull out but I’ll pull harder. 

Not sure about aircraft but on most speedo or tach cables the inner cable will only come out in one direction. I would try from the other end before anything 

[RobertGary1]

So somehow it working. 
I tried to pull the cable from the sheath. No joy. I pulled from the instrument side and it’s certainly held in there. Went to pull it from the engine side but the nut is interfered by the vacuum pump. Not having my pump wrench I tried a Hail Mary and just lubed the instrument side snd test run jt. It worked great!

So either that dab of lube on the tip of the cable worked or the overhaul shop really did find an issue; fixed it but didn’t want to admit it.