Angle drive and cable installation tricks or advice?

[Jonathan]

So I gave my speedometer another chance for redemption. No luck. The needle fluttered for a few hundred yards and then settled back to zero where it stayed. This after a new angle drive, nut, and lower cable.

What I don't seem to be able to get the hang of is keeping everything connected properly, aligned to each other, and the right amount of snugness or slack. I try to get it all put back together and inevitably it still doesn't work.

Any advice or tricks up your sleeve? The new angle drive and backside nut are in and appears ok as it spins fairly easily. But when I try to get the lower speedo cable connected on both ends it stops spinning easily. What do you suggest with the threaded connectors in that if they are a bit loose the cable can move around and if they are snug it seams like the cable won't turn.

It's not out of the question that my lambda box is knackered. Maybe I should get Hervey's long cable? I'd like to have a working speedo but I'm running out of ideas.

[Cory W]

I've been pondering the one piece cable as well, for the same reasons.

I'm currently working on my brake system, and will be focusing on making my speedo more reliable during reassembly. I've also heard that tight connections = bad.

The way I see it, the cable should be supported a short distance off the angle drive, and should then curve in such a way as to not rub against the wheel as you turn, yet not bend so much that it could bind. Connecting the lower cable to the LAMBDA box is another possible trouble area for that.

I suspect that if you removed most of the gearing inside the LAMBDA box, it would reduce drag on the cables as well....and the dash light would never be missed for most of us.

[jmpdmc]

I suspect that if you removed most of the gearing inside the LAMBDA box, it would reduce drag on the cables as well....and the dash light would never be missed for most of us.

I did this several years back when my angle drive appeared to fail and a new one from DMCH did not work either. The lower cable was binding at the Lambda box and after the gears inside the box were removed, the speedo worked fine and has for almost 8 years. Something to consider.


Jeff

[orbitron3000]

I recently replaced my angle drive system with a dust cap from DMCH, and angle drive and long cable from Hervey. Been this way only for about a month, but I've had no problems in terms of reliability or things kinking up. Totally worth it in my opinion -- the less parts of a system, the less that can go wrong...right?

[Jacko]

The angle drive has been recognized as the weak point in the speedo setup ... I've had almost as much trouble with the dust cap. Check that.

[David T]

Make sure the dust cap is not spinning between the hub and wheel rim. Make sure the square hole in the dust cap is not rounded and the square cable is fully inserted into the dust cap's square hole. You should have the bracket that supports the cable so it doesn't hang as it comes out of the angle drive. Lubricate the cable with speedometer cable lubricant. Lay the inner speedometer cables on the floor on some clean newspaper. They should lay flat in a large circle with no bends or kinks. The neds should not be frayed.
David Teitelbaum

[Jacko]

I wonder why someone hasn't made a dust cap out of metal thereby eliminating the 'rounded square hole' syndrome.

[dmc6960]

I wonder why someone hasn't made a dust cap out of metal thereby eliminating the 'rounded square hole' syndrome.

Give me 1 more year, and 'rounded square hole syndrome' will never happen again. :biggrin:

[Kenny_Z]

I wonder why someone hasn't made a dust cap out of metal thereby eliminating the 'rounded square hole' syndrome.

I thought about that but decided against it. I'd rather the dust cap round out instead of something else snagging slightly in the system and destroying something much more expensive.

[David T]

In any well designed system there is always a "weak link" that is expected to fail. Usually on purpose so it is easy to replace, not expensive, and won't damage anyone or anything when it fails. In this case I believe it is the dust cap. It works like a fuse. If a fuse keeps blowing the solution is NOT to use a bigger (stronger?) fuse. All that does is expose the next weakest link.
David Teitelbaum

[Jacko]

9485

I hadn't had 16647 long before the speedometer quit. I didn't realize at the time this was a natural occurrence with a Delorean.
That first time I tore into it and discovered the dreaded 'rounded square hole' in the dust cover (why is it called a dust cover?) I thought I could 'fix' it. As the pic attached shows I heated the tip of an awl and made four small starter holes just next to each flat side of the once square hole. I screwed a small screw in each hole and displaced the plastic enough to make the hole square again. I ground off the heads and put it back on the car and used it for thousands of miles. That particular dust cover never failed again ... it now lives on the wall. :)

[content22207]

When I contacted an independent DeLorean vendor about single piece speedometer cables, he told me they were no longer available. So I went to Autozone, bought a suitable cable for $6.99 ($7.51 with North Carolina sales tax), and simply made my own:

http://sphotos.xx.fbcdn.net/hphotos-ash4/419915_351562221555701_100001057778755_1048042_595 865964_n.jpg

Speedometer needle moves much more smoothly and holds much steadier with one cable than with two cables through a Lambda counter.

Dust caps aren't a problem -- spindle cables are. Recess in the dust cap is square deep inside, but round at the surface. Some spindle cables just aren't long enough to reach the square part of the recess.

Weakest link in the system is the cable itself. It is wound in the same direction as primary rotation. If anything binds the cable, it will simply unwind (so called "spaghetti failure").

Angle drives fail because they have several design flaws:
1) Primary rotation turns helical gear teeth into each other, creating a natural binding tendency. This can be felt by turning an angle drive manually in your hand in the direction of primary wheel rotation (binding) and backwards (unbinding). This binding causes accelerated wear on the brass bushing that holds the spindle gear in alignment, allowing it to fall away from the cable gear
2) Helical gears have unequal number of teeth (angle drive is not 1:1 rotation, but something like 1:.9). Unequal helical teeth do not turn as freely as equal teeth, also leading to accelerated wear
3) Gear teeth are very shallow and barely intermesh even when new. The actual contact area between the two gears is frightfully small. Just the slightest amount of wear, or the slightest amount of gear misalignment, severs contact altogether.

45 degree beveled gears would have been far more reliable, but would not have yielded the gear reduction that Lotus thought for some reason was necessary (why didn't Lotus simply calibrate the speedometer for 1:1 rotation? More genius engineering from Hethel...).

Bill Robertson
#5939