1957 tachometer noise

[Bruce W.]

The tach on my 1957 makes noise. It has been rebuilt and I have a new cable. Tried cable lube and lithium grease but still makes noise??Tried backing off the cable and moving it around but it always comes back. Anybody out there had this problem? Is there a special lube for this? Appreciate some help
Bruce

[Richard M.]

Re: 1957 tachometer noise

Bruce, Since it could be either the instrument or the cable....

I would remove the tachometer and carefully attach a drill to the end of the main shaft. Run the drill up to the RPM that it previously made noise and the result will lead you to which of the 2 may be the problem.

If the tach appears noise-free, you could then remove the cable from the car and use that attached to it to test the assembly. If okay, try bending the cable in the positions as normally installed to emulate the same conditions.

You might want to contact the rebuilder and ask if they tested it for quiet operation throughout the range before all of this testing.

Rich

[Bruce W.]

Re: 1957 tachometer noise

thanks Rich,
Definitely not the tach. Do you think that repos are not using the same size cables? Perhaps causing the cable to vibrate? It is not binding and there is no needle bounce? Appreciate your help.
Bruce

[Richard M.]

Re: 1957 tachometer noise

thanks Rich,
Definitely not the tach. Do you think that repos are not using the same size cables? Perhaps causing the cable to vibrate? It is not binding and there is no needle bounce? Appreciate your help.
Bruce

Bruce, Over the last 5 years or so I've used many reproduction tach and speedo cables. I never noticed a pronounced looseness of any of them. However, there was a stretch of time where the internal cable ends of a few repros were too long causing a bind at the instrument end. I had to grind about 1/16"+ at the end to free them up. One was a tach, other a speedo. I noticed it before actually running the cars, luckily each time, as I had them connected to the instruments but not the drive ends(Gen and Trans). When I checked free operation at the drive ends while finger turning, there was a bind.

What drives your '57 tach, Generator or FI Distributor? I wonder if you have some erratic drive gears causing a cable bounce noise, even if the needle is steady.

If I had your condition, I'd still do a drill driven experiment from the cable drive end to try to emulate the fault.

One other note. Be cautious of using grease on the cable as it can ride up and inside the instrument right into the mechanism. I use CRC Power Lube. Others use Cable-Ease, which I think may be very similar products. The CRC is a foaming liquid, my penetrant of choice for just about everything.

Rich

[Bruce W.]

Re: 1957 tachometer noise

thanks Rich, the tach is driven from the generator. The gears in the drive from the generator are new. Maybe the cable is to long? if it is the cable which it appears to be and doesn't appear to long since there is no noticble bind or bounce. What is the solution. I am very wary of these repo parts. Should I try to find an NOS cable? If so any suggestions on who might have one. do you know what the correct length of the cable should be?
Thank you,
Bruce

[Richard M.]

Re: 1957 tachometer noise

thanks Rich, the tach is driven from the generator. The gears in the drive from the generator are new. Maybe the cable is to long? if it is the cable which it appears to be and doesn't appear to long since there is no noticble bind or bounce. What is the solution. I am very wary of these repo parts. Should I try to find an NOS cable? If so any suggestions on who might have one. do you know what the correct length of the cable should be?
Thank you,
Bruce

Bruce I'd try to nail it down to find absolute root cause before pulling the trigger on NOS cable, that is if you could find one.

When you said you loosened it in your first query post, was that at the tach end or the generator end? The binds I got were at the instrument ends as the cable has a integrated stop flange and it was a tad too long. The threaded clamp pushes on the flange pretty hard if the tip is too long.

If you didn't loosen from the tach end then I'm not sure of the solution without being there and helping. These little gotchas' are always a pain.

Rich

[Bruce W.]

Re: 1957 tachometer noise

Rich, loosened it from the tach. it seems to help temporarily. I didn't want to get under the dash to take out the tach with my bad back but I guess I will have to.
Bruce