<VV> Busted Clutch Cables

[kevin nash]

> 
> Message: 3
> Date: Wed, 17 Apr 2013 16:54:30 +0000
> From: Joel McGregor <joel at joelsplace.com>
> Subject: Re: <VV> Busted clutch cables
> To: "virtualvairs at corvair.org" <virtualvairs at corvair.org>
> Message-ID:
> 	<27D1EC0369826D478297DD86D9DE5E2C260DD65F at 2012SBS.joelsplace.local>
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> 
> If it's failing at least 6" from anything I can't see how it's due to the clevis or pulley on a cable this small.  Do the majority of them fail like that?  I've never had one fail that I can remember.  (I shouldn't have said that)
> Any engineers out there that can explain this?
> Joel McGregor
Joel- The most likely possibilities for a cable break between the clevis and pulley are: Rust spots- rust on a cable is bad news, as therust increases the stress on the rest of the good material, and the increased stress helps it rust more in the same spot! Other (unlikely, in my opinion) possibilities are slight hard spots or soft spots in the individual wires, which will cause the wires to stretch unevenly, increasing the stress on some wires and eventually causing breakage. A less than ideal crimp can cause breakage, the usual way is for the cut end of the cable to be a bit tipped over relative to the clevis, again causing higher stress in some of the wires relative to the others, eventually leading to breakage. I've noticed that most have said that the most common breakage is at the end of the cable, and I've heard that from others over the years that have said the same thing, and I'm wondering if the typical late cable break is at the end, and early's it's at the pulleys- all mine, except for one have been at one of the pulleys. Withlates, the cable system is much much simpler, and its easy to see why the crimps then become more important- I noticed that onthe 69's one end of the cable has a spherical ball end, which would appear to eliminate much stress at that end of the cable, as long as it is lubricated. With earlys it sure seems like the cables either last "forever" as in Mark Durham's example or are problematic like mine and othersthat I know. It might be that our different experience has to do with pressure plate differences- all my earlys have had 1500lb pressure plates, and most of the "regular" pressure plates were only 900lbs- almost 70% increase in cable tension(!) assuming equal pivot points, so its easy to see that there might be some differences in reliability there!I'm going back to work on my hydraulic actuated clutch conversion now :<) !!Kevin Nash