GEMO tach cable - which end is which ?????

[rogerh113]

Hello,

I have a squealing tachometer cable (hopefully), and got a GEMO cable to replace it.  The cable is obviously not 'symmetrical' in that one end has a fixed plastic sleeve (~ 4 inches long) just after the fixing 'nut' and the cable is packed with grease, while the other end has no plastic sleeve and is not packed with grease.  I am thinking that the sleeve end with grease attaches to the tach, and the other end goes to the drive on the front of the block.  I figure you would not want the less flexible, greasy bit pointed down into the block, but then I've been wrong more than a few times before....

Can someone tell me the correct orientation for the cable?  Evidently you can get it in backwards, and of course there are no instructions (not even in German....).

thanks -- Roger

[WRe]

Hi Roger,
I've send an email to Gemo and asked for the correct orientation but I haven't got an answer up to now. But if you look at the pictures on their web side you'll find similar cables which shows the plastic/grease sleeve side near the tachometer.
...WRe

[rogerh113]

Thanks.  Everything I can think of points to that orientation, but too bad they don't just come out and say it.  It could be that the stiffness of the plastic sleeve would cause the cable to hit the hood if installed at the block side (not a whole lot of height clearance), but I am not in an experimental mood.....

regards -- Roger

[rogerh113]

Plastic shield is on the tach side of the cable.   After about only 10 minutes I can with difficulty reach up in there and feel the cable at the tach.  Of course I can only do it with my left arm all twisted around, and can't see anything up there.  Did loosen the fixing nut a bit, so if the cable goes in straight through the mystic firewall hole, then it might turn out to be a simple (blind) job.  Will try to tackle the rest of it tomorrow.....

[lurtch]

Hi Roger,
 
Just want to add my 2 cents:

 I had the same screeching tach symptom last summer. I knew it couldn't be the drive cable because I changed that years ago. The fellow at Overseas Speedometer Repair told me that the 50 year old grease in the tach bearings dries up and the sound is probably coming from the dry bearing race in the meter movement.

Larry in Santa Rosa (moved from Menlo Park)

[Mike Hughes]

Just to back up what Larry said, a few years ago my 230SL tacho started to screech.  I removed it and the speedo and sent both to Palo Alto Speedometer for service.  They came back a couple of weeks later looking and operating like new at a very reasonable charge.

You are ahead of the game in one respect - you have already acquired a new tacho cable.  To maintain their repair warranty in effect Palo Alto strongly recommended replacing both the tacho and speedo cables when reinstalling my instruments.

I might mention that screwing the new cables to the back of the instruments is so much more easily accomplished while you are reinstalling your instruments in the dash than when they are already fixed in place  ;^)

[Pawel66]

My two cents: I had a screeching tacho two summers ago. Starting at 2500rpm it was producing terrible noise. I obviously went to forum to search for possible causes, but I also bought a cable as it seemed quite obvious to me, so the forum search was just to confirm I needed the cable.

Then I found the info on the forum, sorry, do not remember whose post it was: when the tacho makes noise, touch it with your finger and feel if it vibrates. If it does - it is quite certain that the tacho needs an overhaul rather than a new cable.

So was the case.

[rogerh113]

Well, all buttoned up before I saw these posts.   Weather is bad, so I will remain in suspense for a couple of days.

I did have the tach rebuilt at PA Speedo quite a few years ago.  Hard to accept that I have had the car sooooo long (about 25 years)  that I am having to replace / repair the same parts for a second time.

It does seem that there is a good mechanical connection between the cable and the meter body.  Hard to imagine that if the cable was vibrating big time that the vibration would not be transferred to the body of the tach (and it would vibrate).  I will have to cross my fingers. 

[rogerh113]

Just as a follow up. turns out it was indeed the cable rather than the tach.  Went for a 30 minute drive today (after all the rain), and it was delightfully flawless.  One forgets how stunning the 113 is.....

[clunker]

Just for reference, the attached pic shows what I understand is the agreed correct orientation