Gridgway

That's interesting (astonishing)! What gearbox is it? It makes no sense to cut the splines off the input shaft (if that's the right descritption) to weld different ones on presumably to suit the clutch. You couldn't do it with the input shaft in the box, so the box would have to be apart. Then for it to break sounds like bodgery of the highest order! But then I might be wrong and it be completely normal practice!

Thought I would add a question here rather than start a new thread. The master switch that I have is well dodge, so needs replacing. It's between the battery -ve and vehicle earth so will disconnect the earth and stop everything. It's just the main switch without the other connections. If the engine is running at this point, without the 3 ohm resister what is it that gets fried? I think it's the alternator. To be able to stop that (when using a cleverer master switch with the engine running), is there a way of doing it on the earth side, or do I need to wire it in the positive side as per the diagram above? I will probably be happy just having it as an isolator rather than a kill switch , just wondering what the options are.

I've not been bothered by the 6 speeder in cruising mode. (tongue a bit in cheek) there are two simple steps to remedy it. Step 1, you need ear protection anyway in a 7, so get good hearing protection and you won't notice any excess engine noise. Step 2, put some tape over the tacho so you aren't bothered by the readout. Seriously, if you need to change, you should change the diff ratio to 3.6, but I'm not sure I'd bother as the 6 speed box is fabulous in my view (YMMV).

Thanks JV, I was wondering about that approach. However, I have finally made some progress. Spinning the distributor using my electric drill I was able to reliably measure 0.1v AC - the smallest my new meter will read. So that's enough evidence for me to decide it must be the HEI module and source one of those. I'll leave it all apart so I can do the same test with the module connected and see if it works. Now just to source the right module and some computer chip paste (haven't changed a CPU in many an age so the supply is low!). Next update will be a while as next weekend is Castle Combe. As ever, thanks all for all the enthusiastic and helpful help!

#20 thanks for the info. I tried out my new multimeter that has AC volts. With the engine cranking, it doesn't register. It looks like it should be able to see down to 0.1v AC. But who knows! On looking further and squinting under the carbs I could see what looks like damage to the pickup wires. So I bit the bullet and took the dizzy out (after taking the carbs off of course). The wires have indeed been squished. Looks like somehow they got caught between the distributor and the cap somehow. Picture below. In my experience wires are pretty hardy so unlikely to be broken, but I can't tell. I can't see a way of actually checking the continuity of the wiring without cutting the outer to see and I don't really want to do that. Is there a way to check them as they are? Now the dizzy is out, I can spin it faster with my drill. I'm soon going to be changing bits! As I can't find the magnetic pickup on the internet,so I'll try changing the module in the AB14 (as that seems to be what fails). I much prefer to find the faulty bit and change it rather than changing out parts speculatively

Quick update, not much progress, but I did try a test by replacing the coil with an led. It stays off when cranking showing that there is no action from the ignition module. Next test is to see if the dizzy is producing any ac now my new multi meter has arrived. I've also worked out that your can't do static timing with this system as it requires an ac voltage to be produced for the ignition module to sync to. Rusty won't happen unless the dizzy is turning and it'll need a number of pulses to sync to. On the verge of knowing the culprit...

#17 thanks, it's very straightforward! Still unsure how the HT circuit makes a circuit!

thanks Ian. It is strange. In other transformers the +ve and -ve of each winding have to be connected to their relevant components to make a circuit. That's why I don't understand how it works with one side of the HT winding isolated unless the magnitude of the voltage changes it. An yes the earthed body of the spark plug provides the potential difference to ionise the air in the gap and make a spark, I just don't know how! Re earths I have been on an earth hunt! So far I have removed the master switch from the neg circuit which was the highest resistance (variable between 8 and 50 ohms), cleaned the connections form the battery to the body, cleaned the connections from the body to the block and cleaned the earth path from the Lucas box to the body (another 8 ohms). Having a bit of a head scratch at the moment waiting for my AC tester to arrive so I can test the reluctor in the dizzie. Part of me wants to get it working with the "period" parts, but I might just give in and get a new electronic ignition - Lumenition with the hall effect in the dizzie and suitable coil or similar. But that's all a chunky cost.

#13 that's what I understood. In my test I tried +ve to the coil and interrupting the -ve to earth and vice versa. Neither worked to make a spark. One question is that when the -ve is interrupted, this also disconnects the HT negative connection because of how the coils are wired. How does the spark happen without the -ve side of the HT circuit being connected?

had a bit of time in the garage. swapped the spare coil in, but still no sparks, suggesting the coil may not be the fault. Also checked the resistance from the case of the ign amp to earth. It was about 8 ohms. so not earthed very well. I rectified that so the case is now properly earthed. So I thought I would try and generate a spark from just 12v and the coil and the king lead. Connect the -ve on the coil to the earth. Locate the king lead end about 2mm away from the block. Switch 12v to the coil on and off. Thought I would get a spark (as the article I linked to above described). Neither coil did that so I must be doing something wrong. Also tried a different king lead I had. No different. Time for a cup of tea and a think!

#9 good point/ The system I have is ballast resistor free. I'll be taking care with the change of coil though!

#8 thanks for the info. I watched a youtube vid of the taking apart of a Lucas box, so understand that bit. Sadly my multimeter doesn't have an AC volts setting. Maybe I have some diodes left over in a box somewhere from projects in the distant past so I could make a rectifier bridge??!! Or a half wave one if I can only find one diode! Or maybe just get a new meter! I am slightly surprised that the distributor produces that much voltage on cranking. I just assumed it would be much lower. Millivolts rather than volts. I will sneal away onto the garage this evening to see if I can make any progress.

Thanks Roger, that's a good point. My plan was to use a spare coil to try and get a manual spark. Then take it from there. At the moment, I can't get anything to work! The resistance of the LT winding is around 1.2 ohms. So the current flowing is about 10A which I have measured. HT resistance is about 5k ohms. Is 1.2 ohms about right for a low resistance LT circuit?

So on with some more googling and I found a very good article, that shows in turn how to test the coil, the ignition amp and the distributor signalling. Here it is. I have tried the "manual" way of energising the coil and I didn't get a spark. So that means the coil is not working. I have a spare coil from my other crossflow before I upgraded to electronic ignition. I might just swap them and see what happens. I don't have a way of measuring the AC from the distributor. But if the coil change works, I won't need to! I do enjoy trouble-shooting!

Definitely AB14, I'll check the other number

And as I was posting, I was thinking, what would the first reply be? The obvious question about checking earths. For goodness sake, what kind of amateur do people take me for? No of course I'd not checked them. Now they all cleaned and checked. As it happens as I was doing it, I remembered problems that people had had with master switches. I measured mine and the resistance varied between about 8 and 50 ohms, moving about and depending on how I turned the key. So I have taken that out of the equation. Shame really as that's a great way of quickly isolated the battery when working on electrics. I'll get a new on I think, unless they are clean-uppable or similarly mendable.

I am slowly learning about the wiring in my 84 BDR. I'm trying to get to a point where I can see if the engine will run. But I have no sparks. It's got a Lucas ignition amp and a disti with electronic ignition (no idea of the make). Pic below. I'm simplifying the problem (I have removed what I think are the tacho wires from the coil and the rev limiter), but would like to check how the wiring should be if anyone has knowledge. The ignition amp has the red and the blue wire from the distributor. Does that just make and break a connection like points would do? Or with electronic ignition does it work differently? Then in the pic two wires in a sleeve that got to + and - on the coil. Then there is a separate 12v feed to the coil. So two connections between the ign amp and dizzy, two from the amp to the coil and a 12v feed to the coil. Is that wiring correct? Primary coil resistance is about 1.2 ohms. I can crank the motor and see no sparks from a plug which is why I think there's a fault. Also with my static timing light bulb the light seems always on. So it seems to me that either the electronic gubbins in the distributor is not doing its thing or the ignition amp is not doing its thing. Or there's something else wrong. As usual, all thoughts about what to try are very welcome!

#14, good find, that's it

Yes, it's definitely the bottom that has the +12v PM send

Thanks JK, will start my investigations proper shortly. At the moment, I am focussed on finding the electrics to get the motor running. At the moment, that's fuel pump and spark!

Interestingly as I look at the pic, I don't understand the multiple wires on both sides. I think that 12v is fed to the bottom of both. The LH fuse has three wires at the bottom. One will be the 12v feed, the other two go off unfused to their destination. Although you can see that the yellow wire goes through an inline fuse. I wonder what the other one does? I assume all 12v feeds should be fused somewhere.

Thanks Andrew, will pm for a scan if that's ok. Here's what I have:

Glad it's all ok. It's very easy to get dragged into diagnosing a non-problem, especially where oil pressure is concerned. I'd definitely want to be able to see all the gauges though without a pesky mobile phone in the way!! ETA I hope you don't mind me saying, but if your mechanical knowledge is rudimentary, please make sure you actually do know how to do those basics as getting them wrong doesn't get good outcomes.

Thanks Andrew, looks like that 81-87 wiring diagram will be the right one. I'll post a picture of my 2 fuse arrangement later, but it's not like your picture. Thanks for the link to standard wiring colours JK. I've not had to do wholescale wiring before so it's going to be a fun learning process. I can't really imagine that two fuses is properly sufficient for the whole car, but what do I know?!!

Hi Andrew, it has two fuses on the engine bay side of the scuttle upright if that makes sense?