sj-bradley

What - Call it Diddla instead

Yes. That link you posted Ian looks more like a ballast resistor than the OP's picture which looks more like the fusible links that I have seen on my Seat near the main battery. I still think the original picture is a heavy duty fusible link though. Simon.

Yes, looks like a main 200 amp type fuse. It should have a rating on it somewhere though - perhaps underneath ? (edit - Then again it may not be stamped as this would affect the rating and probably lower it. If it's anywhere, it would be off to one side and not in the main flow path) If you can measure the width and thickness of it as accurately as possible and the length of the narrow section, I could hazard a guess at its rating for you. Or you could look for a similar sized fuse in your main car and compare it to them. But, definitely not a ballast resistor. Simon.

Is that all so far ? Come on people, this isn't eBay. I think we need a commitment to get at least 10 cars there for the stand and I don't think we can leave it to the last few seconds like ebay does I'm looking forward to this - it's not a typical car show as you can USE it for the first time here ... Simon.

Finally got round to booking this - Now looking forward to it ! Simon.

Yes, I've just got one of the SJ4000 now too. Just need to figure out the best place to mount it and upload some clips. Great bit of kit, comes with loads of mounts. Drawback is that the joints are all shiny and need some light sanding to stop them slipping. Simon.

Everyone is going to click on this now thinking it's porn. ... Oh, wait, it IS !

Nothing. No engine. No opening panels. Static model. Basically sits still and looks pretty ...

Yes, that does seem strange. But how would you install extra fire alarm wiring into an extension say as you are not allowed to do "live" wiring normally? This is only meant to isolate the system until the modifications have been made and then turned on again. That's all it's for. Now, if there WAS a fire and the alarm failed and was found to be in the OFF position, then the authorised key holder will in deep doo doo ... Simon.

If the coil gets that hot so you cannot touch it, it's likely to be even hotter inside and may have damaged the varnish / enamelled coating and created a short inside. What are the coil resistance measurements? Simon.

They seem similar to the ones machine mart sell which I have been using. Simon.

Could be the needle valve in carb has stuck open? Simon.

A basic zetec doesn't come with much. You will be looking for a shortened sump, inlet and outlet manifolds, either throttle bodies, carbs or GBS do a plenum which re-uses part of the crate engines original manifold. You will also need some ECU whether it's Emerald or some other to control the engine. Possible water rail replacement and an alternator bracket with a suitable alternator. That's for starters. I may have missed some bits. You could check my web site and see what was involved fitting a zetec to a zero. Simon.

If I had been informed earlier of a cancelled class, I *would* have been there. However, June date I CAN make ... Simon.

Yes, the IVA centre will issue the certificate on the day which you attach to the DVLA application (keep copies of EVERYTHING) DVLA require at least 6 months tax + £55 registration fee. They then issue you with tac disc and plating certificate which you use to get plates made up. Put on plates, check insurance is running and drive. Log book arrives 2+ weeks later. (or in my case a second log book also arrives for a car that never existed! You did keep copies didn't you ... ) Simon.

Oh, that's just left over junk I can remember. Seems like the more complicated the ideas in you head, the shorter the time you can remember them. Kind of like radioactive decay 1/2 life. The more active, the quicker it disappears. I mean you can remember where your cars keys are for AGES, but more complicated ideas like "whose round is it" or "Wife's anniversary" being so complex, vanish within minutes ... Simon.

Thanks. There are still some electronics components that even I am still learning about. Tunnel diodes, varactors, gyrators etc. And, yes, those are genuine names I found in electronics books. As for atomic physics, I swear that when they ran out of Greek names, they started making them up. Quarks can have spin up and down, colour, charm, strangeness. I mean Look at this I found on the net ... "There are six types of quarks, known as flavors: up, down, strange, charm, top, and bottom.[4] Up and down quarks have the lowest masses of all quarks. The heavier quarks rapidly change into up and down quarks through a process ofparticle decay: the transformation from a higher mass state to a lower mass state. Because of this, up and down quarks are generally stable and the most common in the universe, whereas strange, charm, bottom, and top quarks can only be produced in high energy collisions (such as those involving cosmic rays and in particle accelerators). For every quark flavor there is a corresponding type of antiparticle, known as an antiquark, that differs from the quark only in that some of its properties have equal magnitude but opposite sign." So a quark can have a strange charming bottom. Hmm, That could be an interesting pick up line ... Told you professors can be nutty ! Simon.

Here is a simulation run demonstrating that circuit. The red line is the output from the coil going +- 50 volts around zero volts. The blue line which almost overlays the two high red peaks and you can just see on the zero line between these peaks is what a diode does. The green line shows that the zener does not conduct until the blue line goes above 18 volts and there is always an 18 volt difference between them. One the blue line drops below 18 volts, the zener stops conducting. (And I can hear the smirking about those humps - so stop it at the back there - Yes - YOU laddie ...) Simon.

Interesting, that is. Thanks, Simon.

The circuit you have drawn will only allow current to flow once the junction between all the diodes reaches AT LEAST 15 or 18 volts. Once that has been reached or exceeded will the voltage and current begin to rise on the Tach side. It's basically being used as a voltage limiter to stop high voltages and current surges entering the tacho and destroying it. When you switch the coil (an inductive load) you get HUGE reverse voltage spikes which this zener is protecting you from. When either coil 1 or coil 2 goes +ve (an effect from the self induction when you open the circuit), it can reach hundreds of volts. The 1n4001 diodes let this through to the junction (the other 1n4001 blocks it from going back to the coil) and the zener breaks down when 18 volts is reached allowing a small pulse through to the tacho. Once the voltage drops below that threshold again, the zener blocks it again. So this zener "leaks" once the breakdown voltage is exceeded. Simon.

Not necessarily. A gross mismatch may not move the gauge at all. Simon.

Correct about diodes letting current flow one way. Zener diodes are designed to breakdown at a certain voltage and start allowing current to flow backwards. This means that (for car applications) when you have a charging battery from 12.9 to 14 volts say, if a 12 volt zener were used, then the voltage across the zener would remain more or less constant at the 12 volts specified and it allows just enough reverse current to keep this 12 volts a constant figure. It is a cheap voltage regulator, but it has its own drawbacks that I shall not go into here. Let's just say it's a leaky diode that breaks down at a low voltage compared to the diodes you ARE looking for which have break down voltages in the hundreds of volts - even up to 1000 volts. With the correct diodes, the force is strong in them ... Simon.

Crumbs. And them's the SIMPLE circuits ... I only wanted to point out that you cannot use Zener diodes instead of ordinary ones ... Simon. Perhaps this will be simpler ... ?

I have seen several posts on here mentioning zener diodes when you really mean ordinary rectifying diodes. To be clear, I have attached a diagram on what a zener diode does. This zener is rated at 6.2 volts and as you can see the test point is at 6.4 volts from the 9 volt battery supply. But notice that there IS a current flowing at 26 mA. An ordinary diode will NOT allow current to flow in the reverse direction and you are looking for the 1n4000 1 amp series or the 1n5400 3 amp version which only allows current to flo in one direction. You want diodes that are "power rectifiers" and NOT zeners or "signal" or any other type (there are many others, all of which do different things. I hope that helps future builders. AVOID Zener diodes, they are usually NOT what you are looking for. Simon.

The single wire is a misnomer really. As you say Mick, the threads need to be in electrical contact to complete the circuit to the chassis. The one wire in is only 1/2 of the circuit and people do not realise that the body is the other 1/2 which needs to have an electrical connection to the chassis. If this sender is mounted in a T-piece with rubber hoses, it will also not work correctly. It NEEDS a solid metal path to the chassis earth connection to work. Point taken about them being colour coded - I did not know that, but I can see why. Simon.