Tach cable lube - can I extract cable at block end ??

[rogerh113]

Hello,

I am getting periodic tach cable noise (only second time, now), which I can currently fix by shifting the cable a bit in the engine bay.  I would like to lube the cable, and am wondering if there are any issues with disconnecting the engine block  tach cable mount,pulling the cable, and then re-feeding the cable.  Not sure how difficult it is to align the cable with the tach drive on the way back in - seems like this might be the biggest problem.  If anyone has tried this, please let me know.

Thanks -- Roger

[Rodolfo]

better buy a new cable .Around 35 $

[49er]

I have removed the cable at the block end, lubed it and re inserted it into the tach with no problem.
John

[rogerh113]

Thanks, I will go ahead and give the cable lube a shot. 

My hope is to avoid messing behind the dash unless I have to - been there, done that.  If the 5 minute lube does not work, then I can go after the 1 hour knuckle-buster.

Regards -- Roger

[mmizesko]

Roger,

If you know the cable is the source of the noise, then you should be able to disconnect the cable at the block, hold it high above the bay, and drip some ATF down the shaft.  I think you can even remove the core cable inside the housing and thread it back in.  You just need to have it get back to the tach and have it slot back in.  Joe A did this with mine last spring, but it did not fix my howl.

With mine, and many others, the tach howls from within, especially when the weather drops below 50 degrees.  In this case, it makes the most sense to have a tach and speedo shop disassemble it, clean and lube it and replace any bushings inside. (just paid $75 plus freight both ways).

The knuckles stop bleeding in a few hours, and the resulting scars are kind of a badge of honor.

Good luck.

Mike Mizesko
Columbus, OH

[rogerh113]

Hi,

I actually had the tach rebuilt about 30K miles ago (maybe 14 year....) at Palo Alto Speedo.  Hopefully it has not failed in this time.  Since I can shift the cable and the noise is gone, I think it is likely the cable (of course, I replaced the cable when I did the tach rebuild, so I guess it is just a footrace to see what fails first).

Is ATF the recommended lube??  I am surprised that it would work its way down the cable unless you put a bunch in there, and that might ultimately offend the tach at the other end.   I was going to give the cable a light grease with Amsol 2000 Racing Grease (my go-to heavier lube).  I figure that would well lubricate any areas where there was contact between the cable and cable carrier.

Regards -- Roger

[mmizesko]

Roger,

I think Joe wanted a light viscosity to have gravity let it seep down the cable length from the block end.  If the inner cable comes out completely, then a thicker grease would make sense, but I would be worried about getting the inner cable seated again in the back of the tach, if you aren't the dash apart.  Lots of twists and turns.  I can only tell you what we did, but I'm not experienced enough to know what is called for in the technical manual.  Hope that helps???

Mike Mizesko
Columbus, OH

[rogerh113]

Well, my tach cable seems designed not to be separated - could not pull the cable through the sheath.  So I gave it a light atf lube (thank you), and will see how it goes.  No issues during a test drive, but I would not expect it to act up so soon anyways.

Thanks -- Roger

[Rodolfo]

it is a lot about nothing in my opinion : installing a new cable is 20 minutes

[ja17]

Tie a string to the end of the cable before you pull it through the firewall. Then you can use the string to help pull the new cable along the same route to install it.

[rogerh113]

To me, part of the hobby is the repair and maintenance of the parts as well as the car.  A lot of the fun and it develops a more in-depth understanding of my car.  I have to rebuild the cold start valve every 8 years or so, but it is a fun and easy little device that give satisfaction when it is back in the car and running right.  I would no more throw the long-serving tach cable in the land fill without a lube and retest than i would the cold start valve. 

Certainly not an acceptable approach for a mechanic where part longevity is critical, but then I am a hobbyist and I have my own approach that gives me joy.

Regards -- roger

[Garland]

 My tach needle was sometimes bouncing .Determined outer cable core was exposed to moisture due to friction .Removing inner core evidenced rust. Reimsertion to align with the tach head was not possible. Necessitated  disconnect at the tach to engage inner core. Reversed end-to-end inner core while waiting for replacement cable. Tach needle is normal. Car is 1971 280SL 5 speed manual..Ric Garland,north of Montreal.