52 replies to this topic

[Dan]

1.5 ohms is perfect.

[Jupitus]

1.5 ohms is perfect.

Doesn't it matter how long the ballasted wire is, though? I'm in the process of acquiring a full length of ballasted wire, but if I can join the metre or so I have inline with normal cable it might speed things up.... thanks Dan...

[Dan]

So long as the total ballast resistance is 1.5 ohms it doesn't matter at all and extending it with normal wire shouldn't alter it by that much. You'd be best having the pink bit at the coil end if you make a joint, just so that everyone can see how it's wired in the future.

Edited by Dan, 09 March 2008 - 07:13 PM.

[Jupitus]

So long as the total ballast resistance is 1.5 ohms it doesn't matter at all and extending it with normal wire shouldn't alter it by that much. You'd be best having the pink bit at the coil end if you make a joint, just so that everyone can see how it's wired in the future.

Thanks Dan

[Jupitus]

Just bumping this up as this weekend should see the final work on Huey's loom, and I am dearly hoping to have it done and in Teapot's mail next week.

Sooooo Dan.... I will use the ballasted cable I have measured - as an extra check if I hook it up to a 12V source and measure the voltage, I should get 9V for the coil input, yes?

[Teapot]

Just bumping this up as this weekend should see the final work on Huey's loom, and I am dearly hoping to have it done and in Teapot's mail next week.

[Dan]

as an extra check if I hook it up to a 12V source and measure the voltage, I should get 9V for the coil input, yes?

No. If you just drop 12v accross the resistor all you will get is a warm resistor using all the available power. It needs to be in series with the coil to work properly. The voltage you will find depends on the exact ratio between the coil primary resistance and the ballast resistance (which both change with things like the ambient temperature) and should be between 6 and 9 volts.

[Jupitus]

as an extra check if I hook it up to a 12V source and measure the voltage, I should get 9V for the coil input, yes?

No. If you just drop 12v accross the resistor all you will get is a warm resistor using all the available power. It needs to be in series with the coil to work properly. The voltage you will find depends on the exact ratio between the coil primary resistance and the ballast resistance (which both change with things like the ambient temperature) and should be between 6 and 9 volts.

Ahh ok, makes sense I guess....*tries to remember his A level physics but finds it was toooo far in the past*.... well it's exactly 1.5 ohms so it should work ok. I may wrap in a standard wire aswell for future use if teapot goes to 12v coil instead...

[Jupitus]

Just bumping this up as this weekend should see the final work on Huey's loom, and I am dearly hoping to have it done and in Teapot's mail next week.

*fingers crossed*

Hope I can do it, Teapot.... ordered another stretch of high ampage cable as I'm going to run 3 from the battery terminal on the starter, 1 to the ignition, 1 to the fusebox and 1 to the high ampage relays. I also got a high ampage big wire connector to split the heavy 60 amp wire 2 ways into the relays, and some fatter crimp terminals to re-do the connections to the fusebox as I wasn't happy with the crimping into smaller ones. I ran LOTS of the circuits last sunday and all that remains is connections to the coil and I need to design and run all the earthing runs. After that I'll do some of the main wrapping and then crimp and finish the switch connectors and the dash panel, then final wrapping, brushing some connections with a light coat of copper grease, pack it up and send it

No other plans for the weekend, so it should be done and on it's way to you

[Teapot]

all that remains is connections to the coil and I need to design and run all the earthing runs. After that I'll do some of the main wrapping and then crimp and finish the switch connectors and the dash panel, then final wrapping, brushing some connections with a light coat of copper grease, pack it up and send it

Ok, that takes you up to lunchtime tomorrow .... what will you find to do the rest of the weekend?

[Jupitus]

all that remains is connections to the coil and I need to design and run all the earthing runs. After that I'll do some of the main wrapping and then crimp and finish the switch connectors and the dash panel, then final wrapping, brushing some connections with a light coat of copper grease, pack it up and send it

Ok, that takes you up to lunchtime tomorrow .... what will you find to do the rest of the weekend?

Pffft! You know the care and attention every single crimp of this loom is getting?????

[Jupitus]

Folks!

I have been reading up on later models fitted with electric fuel pumps, and I note that they have an inertia switch, which Huey doesn't have, and also a relay. How essential is a relay, in the sense of what current is a pump likely to draw, please?

[Dan]

The fuel pump does draw a fair whack of current. The relays are used in the injected cars mainly to make the pump controllable by the ECU and alarm/imobiliser but it is a good idea to isolate it from the switch. I got a new Moss catalogue today and noticed that they have started selling an easy fit pre-wired innertia switch, you could use that or just get any innertia switch to fit. The switch should isolate the pump completely and not leave it connected to the relay.

[Jupitus]

The fuel pump does draw a fair whack of current. The relays are used in the injected cars mainly to make the pump controllable by the ECU and alarm/imobiliser but it is a good idea to isolate it from the switch. I got a new Moss catalogue today and noticed that they have started selling an easy fit pre-wired innertia switch, you could use that or just get any innertia switch to fit. The switch should isolate the pump completely and not leave it connected to the relay.

Crapola - ok... more than 11 amps, by the way?

[Jupitus]

Reet - I was thinking about this.... if the pump is to be on with the ignition on, why the need for a relay if I can take a suitable ampage from the ignition-switched live? I am thinking of taking a spur from the ignition lit side of the fuse box, 25 amp wire, running it to an inline fuse, inertia switch, and then to the pump. I am confident of the ampage feeding the fuse box on that side as it is via 50 amp wiring from the ignition switch, which is fed via it's own 50 amp from the battery terminal..... sound ok?

Also - does the inertia switch need to be mounted in a particular orientation, of can it simply be fixed to the blukhead, near the wiper motor?

Thanks, as always, for all you help!