what speedo cable for KMP #174

steve meltzer · #1 (**permalink**) 06-22-2014, 06:12 PM

My speedo cable, routed into the "reverser" before getting to the speedo head, bit the dust.
Only 2700 easy miles on the car, so losing the cable seems odd. What Ford speedo cable I should get to replace mine? Any thoughts about its early demise? thanx steve
(I think it came from a mid-70's Mustang, but not sure.) Sorry for X-posting. s

Sandwich · #2 (**permalink**) 06-23-2014, 07:41 AM

Steve
What you need to do is go to Auto Zone and buy a universal cable. Just the cable, not the housing. But whats more important, is that the cable you get is wrapped in the opposite direction. I'm guessing you have a Trimec transmission? So what happens is you are now spinning the cable backwards, which wants to unravel the cable. That is why you need to find a cable that is wrapped the opposite way. I have had the same problem, but with the cable I got from Auto Zone, I've now got 30+ thousand miles on my car.

Dave Cindrich

steve meltzer · #3 (**permalink**) 06-23-2014, 08:12 AM

Dave, thanx so much. I have a top-loader, not a Tremec and I thought the converter I have, accounted for the reverse speedo. However, maybe I need the reverse threaded speedo and no converter? Do you have the AutoZone part number that gives me the cable threaded the way I need? What about the length? thanx for your advice and patience. s

GRUF78 · #4 (**permalink**) 06-23-2014, 03:50 PM

Steve,

You may have an original type cable on your car. Normally, the cable gear that goes into the Toploader is made of plastic. Likely the gear stripped out. The cable has a pretty extreme bend in it to make the turn into the reverse gear on the back of the speedo so there is a lot of tension inside the cable due to that 90 degree, short radius bend behind the dash-it put a lot of tension on the speedo gear. My original cable failed at 1500 miles and the gear was the culprit.

Pull the cable at the trans and take a look. It may be as easy as replacing the gear.

JM

steve meltzer · #5 (**permalink**) 06-23-2014, 04:02 PM

thanx for the reply. The gear looks good, but you can seen broken metal inside it's center, which I think is from the speedo cable. I think the sharp turn to the reverser might be the culprit here. Did you try to change routing any? Any other thoughts? thanx so much. Might the cable have come from a mid-70's 'stang? s

mickmate · #6 (**permalink**) 06-24-2014, 04:41 AM

I think you're right with application. If you hold the spiral cable at one end and twist it, it tries to open. If you get a reverse spiral it stays bound together, that's the one you want. The adapter can be a reverser but there is one from Summit that screws the cable in from either end. That can be a reverser or an adapter but either way is a 90 which can be very helpful.

http://www.summitracing.com/parts/atm-990414/overview/
and http://www.summitracing.com/parts/sw...10-f/overview/

I run them out of the trans and do the laziest loop you can. Under the frame rail is OK if it's tied up to the bottom, above is better if it's not kinking it. I pass it through the front of the L panel and the firewall and that keeps it routed fairly straight into the 90 adapter.

FatBoy · #7 (**permalink**) 06-24-2014, 05:36 AM

Do you have the "reverser" on the gearbox or speedo end?

The thread seems to suggest that it is at the speedo end, whereas mine was at the gearbox end. If yours is at the speedo, surely the cable is turning in the right direction and you don't need a reverse wound cable.
The cable is only turning the "wrong" way if you have the reverser at the gearbox end.....or am I missing something?

Paul

mickmate · #8 (**permalink**) 06-25-2014, 04:54 AM

Yep you're missing something. The cable has a spiral to it. If you hold a spiral at one end and twist it one way it tries to open or unravel. If you reverse the twist it tries to get smaller but in the case of a speedo cable it just bottoms on itself and doesn't get any smaller. The manufacturers recommend using the reverser at the speedo end but doing what you did reverses the cable rotation direction.

steve meltzer · #9 (**permalink**) 06-25-2014, 06:13 AM

thanx guys for all of the help. I've only removed the cable from the tailshaft of the tranny and when you look down into the plastic gear (it's fine, BTW) you see bits of speedo wire. However, I haven't had time to pull the other end of the cable from the speedo head. I'm still confused. If I get a "reverse" cable, can I skip using my "reverser" (from Autometer) and go straight to the speedo head. Where do I find sucha reverse wound cable? part number or ??
Sorry i'm so dense. thanx again. s

FatBoy · #10 (**permalink**) 06-25-2014, 07:41 AM

Quote:

Originally Posted by mickmate

Yep you're missing something. The cable has a spiral to it. If you hold a spiral at one end and twist it one way it tries to open or unravel. If you reverse the twist it tries to get smaller but in the case of a speedo cable it just bottoms on itself and doesn't get any smaller. The manufacturers recommend using the reverser at the speedo end but doing what you did reverses the cable rotation direction.

What do you take me for Nick?

That bit I'm fully aware of.

The point I was making is that depending on which end of the cable the "reverser" is located will dictate whether you need a standard or reverse wound cable. If the reverser is on the gearbox, then the cable will spin in reverse rotation, as was the case with my Contemporary. If, on the other hand, the reverser is at the speedo end of the cable, the cable will spin in the conventional direction and a standard wound cable will be required.

Paul

steve meltzer · #11 (**permalink**) 06-25-2014, 08:00 AM

My reverser is attatched to the speedo head, NOT the gearbox. So, I'll need a conventionally wound cable, right? However, if I used a reverse wound cable, won't I be able to ditch the reverser, which, as I recall, puts an unwanted kink the speedo cable. thanx. s

cobrakiwi · #12 (**permalink**) 06-25-2014, 08:10 AM

You will still need to use the reverse adapter.
You may need a longer cable to make the bend out of the gear box a larger radius.

FatBoy · #13 (**permalink**) 06-25-2014, 09:09 AM

Quote:

Originally Posted by steve meltzer

My reverser is attatched to the speedo head, NOT the gearbox. So, I'll need a conventionally wound cable, right? However, if I used a reverse wound cable, won't I be able to ditch the reverser, which, as I recall, puts an unwanted kink the speedo cable. thanx. s

That would be a very useful cable that somehow changes the direction of rotation somewhere along its length.

The "reverse wind" on the cable is simply the direction of the twist in the individual wires that make up the cable core. The cable needs to be driven in a direction that tightens the twist rather than attempts to unwind it. Therefore, if you have a reverser on the gearbox end, the cable will be driven in the opposite direction, so you need a cable core that is twisted in the opposite direction to prevent it being unwound in use.

Make sense?

Paul

maurice19 · #14 (**permalink**) 06-25-2014, 09:22 AM

Steve,

You can eliminate the external reverser, if you want, by changing the gear in the trans that looks good now to another gear that has opposite turn threads.
That will reverse the spin, but a lot of work to remove the trans and replace the gear.

Per Kirkham`s info, I did that before the trans was installed and it works fine.

Maurice

Ps, my trans is the tko 600

steve meltzer · #15 (**permalink**) 06-25-2014, 09:25 AM

now all of this is starting to make sense to me. i was thinking about a longer cable to straighten out those tight radii. i called a local speedo shop and quoted me about $12/foot to make a cable and said that it didn't matter how it was wound. thanx. s

steve meltzer · #16 (**permalink**) 07-14-2014, 07:05 AM

Sorry it's taken so long to wrap this up. Here's the denouement. I re-routed the cable from Kirkham's near center of the car location to one just to the right (as you sit in the car!) of the puke tank. This seems to take the route of the least bends and widest radii. I then ordered a custom hard case cable from the guy recommended by Autometer, maker of my speedo. His name is Roger, Speedometer Services, Milwaukee, 414-463-6660. It would have been cheaper to get a stock speedo from one of the Mustang or Ford parts purveyor, but I got a cable, hardened case, and built to my specs. Roger knows these cables and tranny setups very well. I'm really pleased with the fit, tho' I haven't had a chance to try it out. (see my posts about oil leaks I'm chasing on the FE section of CC) Thanx for all of your help.

steve

BTW: Roger at the Speedo shop totally "poo-pooed" any belief of some cables being wound opposite the others. The "reverser" sold by many (mine's from Autometer) is, of course, required for the reverse sweep speedo of our cars. steve