Custom Throttle Cable

[ashm]

Due to having slack in the throttle cable I couldn't adjust out using the facilities at either end, I decided I'd have to remove the cable and either repair or replace it. I had the same trouble as some others trying to remove the rubber bulkhead grommet and ended up having to cut it out. Not that it matters, as once the cable was free I saw how damaged it is - not only has the inner apparently stretched nearly two inches (!) but the outer is broken in several places. The plastic clip that attaches to the pedal was also bent out of shape.

My first thought was to get a Lotus replacement, but I've decided not to, for three reasons:
1) The price is £37.65, fairly expensive for such an item.
2) The cable clearly has a problem with stretching over time and not enough adjustment to take up the slack.
3) If fitting the replacement grommet is half as hard as getting the original off, I don't even want to try.

I've designed a cable upgrade to address these issues. I'm currently working with a supplier (Venhill Engineering) on a prototype, so in a couple of weeks I should be able to supply these to anyone who wants one. However, it'd be very helpful at this point to gauge interest. Price will depend on the number ordered, but I'm aiming to keep the parts cost down to around £10 so they'll probably represent a good saving compared to the Lotus option. It also depends on whether I just order the components and make up the cables myself or have the supplier do the cutting, assembly & brazing.

If I make them up myself the soldering will be done properly, using aerospace-grade high temperature brazing alloy. If the supplier do it, well, they've been making these things for 35 years so I'm pretty confident that they know what they're doing.


Details include:
- stronger inner cable, should reduce stretching.
- high-quality conduit with teflon lining to minimize cable friction & stick-slip in throttle action.
- all-metal fixings including clevis pin assembly at the pedal end.
- all fixings and cable are zinc-plated steel, nipples are corrosion-resistant brass.
- slightly longer adjustment range than stock at the throttle end.
- additional ~12mm cable adjustment at the conduit / bulkhead fixing point.
- new bulkhead fixing hardware to replace the stock rubber grommet & plastic ferrule. This will be very easy to fit, but provide a better flexible seal and more secure attachment. It'll also be easy to remove, adjust and reuse.

As an added bonus, there'll be a choice of PVC-covered or stainless steel braided conduit for those who like their cables sparkly. The PVC conduit will come in black as standard, but there may be options for yellow, silver, red and blue - I still need to check availability with the supplier for this though.

So... any takers?

Adam

[ashm]

List time!

1) ashm (prototype!)
2) dapinky
3) rip

[Breed]

List time!

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed

[lotusgirlmarie]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM

Just a thought but would firebraid be a better option to PVC considering the heat in the engine bay? My OEM PVC is split nearly the length of the jacket.

[saska]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska

Just a thought but would firebraid be a better option to PVC considering the heat in the engine bay? My OEM PVC is split nearly the length of the jacket.

I agree with not using PVC as both of mine have cracked PVC aussi.

[dapinky]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)

and Maries question till stands:-

Just a thought but would firebraid be a better option to PVC considering the heat in the engine bay? My OEM PVC is split nearly the length of the jacket.

[alexg]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
alexg

I'm at the limit of adjustment on my cable, so this list couldn't come at a better time!

[Elanlover]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
alexg
9) elanlover (depending on cost of course)

[Monty]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
alexg
9) elanlover (depending on cost of course)
10) Monty


BTW won`t the cables on the Fedral Elan be a different length to the UK version?

[Elanlover]

BTW won`t the cables on the Fedral Elan be a different length to the UK version?

Well, I just checked and the part has numbers for LH and RH so I'm thinking you're right. Damn you Monty! Where will I get a nice, new stainless steel braided cable from now???

[Elanlover]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
8 ) alexg
9) Monty

[ailwyn]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
8 ) alexg
9) Monty
10) Ailwyn

[ashm]

BTW won`t the cables on the Fedral Elan be a different length to the UK version?

Hmm... good point. I have no idea, but I'd guess probably yes, what with the pedals being on the other side of the car. Anybody fancy measuring the length of the cable conduit on a LHD car for me?
Are the arrangements at the throttle & pedal ends the same as for the UK Elan?

Just a thought but would firebraid be a better option to PVC considering the heat in the engine bay? My OEM PVC is split nearly the length of the jacket.

I had been thinking about this idea and wondering about sleeving options. The PVC on my OE cable is full of holes and obviously melted through at one point. I'll look into it. Anyone got an opinion on good cable shielding products available in the UK?

Adam

[lotusgirlmarie]

I'll see what I can do about a quick measure when I get back.

[woody]

Count me in please.
1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
8 ) alexg
9) Monty
10) Ailwyn
11) Woody.
Cheers.

[John_W]

1) ashm (prototype!)
2) dapinky
3) rip
4) Breed
5) LGM
6) saska
7) dapinky again - (number 2!)
8 ) alexg
9) Monty
10) Ailwyn
11) Woody.
12) John_W

(Maries question "Just a thought but would firebraid be a better option to PVC considering the heat in the engine bay? My OEM PVC is split nearly the length of the jacket."
Ashm's question "Anyone got an opinion on good cable shielding products available in the UK?")

[ashm]

Update: I've found some likely heat shielding prooducts. I'll discuss with the shielding and control cable suppliers at some point today. There are various decent materials available, but the main problem is getting them in less than 50m rolls!

At the budget end I can get black fibreglass/acrylic sleeving, oil/petrol resistant and rated for 155C. This would be about £1.50 per cable.
At the other extreme, there are military/aerospace grade braided silica sleeving products rated for 1000C continuous/1650C intermittent... very expensive & overkill for the job.

I'm currently looking at two products. One is an aerospace grade, braided fibreglass/silicone sleeve that's good for 260C continuous/1650C intermittent. It's fairly flexible and very abrasion, oil & moisture resistant. It's quite thick-walled (about 14mm OD) with a red silicone rubber outer appearance and is fairly expensive (about £10 per cable).
The other product is a braided aramid fibre sleeve good for 240C continuous/310C intermittent. This is much lighter and thinner, not so impervious to oil & moisture but with good abrasion resistance. It has an off-white or olive green woven appearance, and is probably much cheaper. I'm tending towards this option at the moment, but haven't talked to the supplier yet.

Adam

[dapinky]

but the main problem is getting them in less than 50m rolls!

The way most group buys gather intensity, that isn't likely to be a huge problem

[ashm]

but the main problem is getting them in less than 50m rolls!

The way most group buys gather intensity, that isn't likely to be a huge problem

I dunno... I'd be surprised if there was demand for 50 of these cables!

[dapinky]

but the main problem is getting them in less than 50m rolls!

The way most group buys gather intensity, that isn't likely to be a huge problem

I dunno... I'd be surprised if there was demand for 50 of these cables!

Having seen the dilapidated state of most throttle cables, I'd be more surprised if there wasn't (the only thing that has put me off getting new ones has been the price and ease of fittment - both of which you have addressed )