Pete Lewis Posted March 8, 2019 Report Share Posted March 8, 2019 time to send for a heritage certificate , this will give the production build specification https://www.britishmotormuseum.co.uk/archive/heritage-certificates Pete Link to comment Share on other sites More sharing options...
dave.vitesse Posted March 9, 2019 Report Share Posted March 9, 2019 Late 1972 early 1973 was the change over to the loom wire. i. e. working though the parts. Dace Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 10, 2019 Author Report Share Posted March 10, 2019 Thanks gents, back on it tomorrow. First off will try and get the oil pressure lamp working. Need to use the sharp probe on multimeter to work along the cable and try establish any break in the positive feed as it's not reaching the bulb holder. I'd rather repair the issue and get it right than just run another feed to the holder. 1 Link to comment Share on other sites More sharing options...
Badwolf Posted March 10, 2019 Report Share Posted March 10, 2019 BF. I had a similar problem to your oil pressure light with my stop lights some time ago. No power to the switch but power all along the cable. It turned out that there was insufficient copper coming out of the wire insulation to make contact with the blade of the connector. It had worked for years, but when the foot pedal switch exploded the copper must have been pulled inside the insulation breaking the contact. Took me ages (and enquiries here) to track down as visually everything looked fine. Solution.. cut off the connector, remake, all is well. Just a few thoughts which may have no relevance but may just help. Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 11, 2019 Author Report Share Posted March 11, 2019 That's a really good point Badwolf and certainty something I'll pay attention to whilst checking the circuit today. Unless the feed has become detached or disconnected from the ignition feed or the bulb holder itself is faulty I can't see much opportunity for the wire itself to have become damaged considering where it's situated. However I'm taking nothing for granted ! Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 12, 2019 Author Report Share Posted March 12, 2019 Evening all ! Had some enjoyable time on the GT6 today and managed to make some progress. I now have a working oil pressure lamp which is illuminating and extinguishing as intended once the engine is running. I had been a little concerned in case the lamp had been purposely disconnected at some point in the past to mask low oil pressure indication, this is thankfully not the case. However the wiring on the ignition switch was not found to be as specified on the wiring diagram. The spade connection for the oil lamp live (white) was found to be detached but the terminal I think it should have been connected to was taken up with another wire. Below is a diagram of the ignition switch terminals: Specified in the factory manual, the connections should be as follows: 1: white / red wire - solenoid 2: brown wire - solenoid 3: white (x3 wires) - oil pressure lamp, ignition warning lamp and top fuse 5: white / pink wire - radio facility (then appears on diagram to lead onto heater motor. However what I actually have is as follows: 1: white/ red per spec 2: 1x brown wire (solenoid) per spec however also 1x white / pink wire should feed radio/ heater and be on terminal 5? 3 2x white wires (ignition warning lamp and fuse feed) per spec, however also the spurious blue wire to solenoid terminal shared with white and yellow coil positive side. 5 The two spade terminals were minus any wires connected and when tested were live on ignition switch position 1 as anticipated. Rather than swapping any wires around, taking into account the car starts and runs fine and most of the electrics work, I temporarily connected the oil lamp feed to terminal 5. This is fine apart from the oil lamp coming on when the ignition is is position 1 rather than 2. I guess to resolve this I should swap the white / pink wire currently connected to terminal 2 onto terminal 5? This still leaves me with the spurious blue wire which is gate crashing on terminal 3 and taking the place of the oil lamp feed. I'm not sure what the purpose of the blue wire to solenoid is! Furthermore, following Peters note on coil resistance, I'm getting 1.5 ohms across the low tension terminals, suggesting a ballasted coil still fitted. in terms of the coil and wiring, photo attached below showing white and yellow feed from solenoid, branching into a joint with some white and pink wire (looks to have been hacked about / taped over as shown in the photo) then back to white / yellow feeding the positive low tension side of the coil. My indicators and hazard flashers have sprung back into life, probably as a result of working the switches / relays which have been dormant whilst the cars been stood a while. Car starts on the button and I just have the below to sort electrically: Defective reverse lamps (will test switch and wiring when replacing transmission tunnel cover) Defective horn (removed old units and spurious wiring so a mini project to reinstate) Id like to bottom out the uncertainty over some of the ignition switch / solenoid / coil connections as described above and get the oil lamp working from position 2 on the switch rather than the current temporary "fix". Any thoughts or advice greatly appreciated! Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 13, 2019 Report Share Posted March 13, 2019 White pink to me is the resistive dropper cable should feed coil low tension when ign on running feeds 1.5 ohm coil with approx 6-8volts The white yellow takes voltage from the starter feed on the solenoid to give the coil a 12v feed when cranking The problems jere are if you are feeding a ballasted coil with 12-14v you are doubling current to the points and doubling the HT voltage This blows condensers, rotors burns points and HT will jump as its much higher than our systems are designed to cope with Sound like PO has bypassed the ballast white pink wire with a blue, but not changed the coil to a 3 ohm. This can be a misguided if electronic points have been fitted as some wont run well at a ballasted voltage If that makes any sense Pete Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 13, 2019 Author Report Share Posted March 13, 2019 Thanks Pete, In terms of the coil wiring I'm not actually sure if the white/pink is doing anything or been bypassed, hopefully the photo shows what I have left although it does look suspiciously like it's been hacked about. Could anyone with a late GT6 post an image of what the coil feed wiring should look like? I can see the different terminals on the solenoid and the corresponding wiring diagram, however I'm not certain what the different terminals are designated for. I have some reading to do! With regard to the way in which the ignition switch is wired I need to give that some consideration as to whether I change things around or leave alone, perhaps piggy backing off the ignition warning lamp feed for the oil pressure lamp rather than swapping things over on the switch. I could throw the towel in and call an auto electrician out however I'm enjoying learning about the car and gradually putting things right! Link to comment Share on other sites More sharing options...
NonMember Posted March 13, 2019 Report Share Posted March 13, 2019 2 hours ago, Pete Lewis said: White pink to me is the resistive dropper cable should feed coil low tension when ign on running feeds 1.5 ohm coil with approx 6-8volts If BF has quoted the factory manual correctly, it's an unused feed for a radio. This was intended (by the factory) to power the radio in normal running or in the AUX position (engine off) but not during cranking. Presumably a DPO has moved it to permanently power a more modern radio with battery-backed presets. I don't think that actually causes any interference, though, as terminal 2 is permanent live and you don't really want to move anything else onto it. However, it does appear to be the same colour code as the resistive one... which surely can't be right. The blue wire definitely doesn't want to be there if it connects to the white/yellow to the coil. The DPO has probably broken the resistive wire and didn't know what he was doing. What you need is a 1.5ohm ceramic resistor (or a 1.5 ohm length of resistive wire) from one of the white (ignition switched +ve) wires to the white/yellow on the coil. On earlier cars like mine this is easy as the resistor is just bolted to the coil mounting. Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 13, 2019 Author Report Share Posted March 13, 2019 Thanks for that. The white and pink from the ignition switch (component 4) terminal 5 is shown on the diagrams below feeding the radio (component 55) but also going on to the heater (components 55 / 56). Bit of a red herring as the colour is similar to the ballast wire that's applicable to my late Mk3 car. I think I could do with looking at another late GT6 to see what the original resistor wire set up looks like and then to fathom returning the ignition wiring back to standard. Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 13, 2019 Report Share Posted March 13, 2019 red herring.....i prefer haddock i was just going on wire colours not diagrams. its looking like you need the seperate ceramic or best just get a 12v 3ohm coil like lucas DLB101 and dump the ballast idea ( note there are ballast 6v coils marked as 12v ( the base car voltage ) just to make this more confusing Pete Link to comment Share on other sites More sharing options...
NonMember Posted March 13, 2019 Report Share Posted March 13, 2019 3 hours ago, Bigfella70 said: Thanks for that. The white and pink from the ignition switch (component 4) terminal 5 is shown on the diagrams below feeding the radio (component 55) but also going on to the heater (components 55 / 56). Bit of a red herring as the colour is similar to the ballast wire that's applicable to my late Mk3 car. Yes, similar, but not the same. WK is primarily white with a pink tracer, while the resistor wire is supposed to be KW - primarily pink with a white tracer. How could anyone get those confused? 😮🤔😛 Link to comment Share on other sites More sharing options...
dougbgt6 Posted March 13, 2019 Report Share Posted March 13, 2019 I have late mk3 and my ballast wire is white with a pink fleck. Doug Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 13, 2019 Author Report Share Posted March 13, 2019 Thanks gents, 29 minutes ago, dougbgt6 said: I have late mk3 and my ballast wire is white with a pink fleck. Doug Doug is there any chance you could take a photo of your ballast set up and solenoid connections please? Appreciate this is a big ask, however I'm really curious as to what the factory installation should look like as compared to the image of mine in the post above. No rush at all if it's feasible? Cheers. Dave. Link to comment Share on other sites More sharing options...
dougbgt6 Posted March 13, 2019 Report Share Posted March 13, 2019 Yes, No problem, got to charge up the camera and get the bonnet up, might be too close to the passenger side garage wall! Doug 1 Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 14, 2019 Author Report Share Posted March 14, 2019 12 hours ago, dougbgt6 said: Yes, No problem, got to charge up the camera and get the bonnet up, might be too close to the passenger side garage wall! Doug Doug, thanks so much, really appreciated ! Dave. Link to comment Share on other sites More sharing options...
dougbgt6 Posted March 14, 2019 Report Share Posted March 14, 2019 Dave, Sorry, having a problem with my camera and other problems with a fuel leak. Doug Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 14, 2019 Author Report Share Posted March 14, 2019 Hi Doug, No rush at all, thanks for trying. Hope you get to the bottom of your fuel leak without too much hassle. Dave. Link to comment Share on other sites More sharing options...
Herald948 Posted March 14, 2019 Report Share Posted March 14, 2019 Something I didn't see in all this discussion bears emphasizing. Your three fuses should all be the same. Please note, though, that the "35 amps" refers to an instant-blow rating if you will, and they actually are rated at 17 amps continuous. Later original Lucas fuses were so labeled, but earlier ones weren't. If your replacement fuses are not exactly as per original, ensure that they are not actual 35 amp fuses; a typical "replacement" should be no higher than 20 amp; 15 amp might be better? I've seen my share of damage due to shorts and other problems with original configuration. I shudder to think how much worse that damage might have been if upwards of a full 35 amps were allowed to surge through those wires and components for any length of time! 😟 1 Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 14, 2019 Author Report Share Posted March 14, 2019 47 minutes ago, Herald948 said: Something I didn't see in all this discussion bears emphasizing. Your three fuses should all be the same. Please note, though, that the "35 amps" refers to an instant-blow rating if you will, and they actually are rated at 17 amps continuous. Later original Lucas fuses were so labeled, but earlier ones weren't. If your replacement fuses are not exactly as per original, ensure that they are not actual 35 amp fuses; a typical "replacement" should be no higher than 20 amp; 15 amp might be better? I've seen my share of damage due to shorts and other problems with original configuration. I shudder to think how much worse that damage might have been if upwards of a full 35 amps were allowed to surge through those wires and components for any length of time! 😟 Andy, Thanks for that and it's something I wasn't aware of! I basically replaced a lower rates fuse with a damaged cap for a Halfords supplied 35amp fuse. The others fitted are all marked 35amp hence from what you've saying this is incorrect and ought to be swapped for some 20amp rated items. Thanks for the input! Link to comment Share on other sites More sharing options...
Anglefire Posted March 15, 2019 Report Share Posted March 15, 2019 The fuses you need are GFS35 - Canley sell them as do others. Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 15, 2019 Report Share Posted March 15, 2019 yes many of the box sets and packaged fuses ,marketed with flat strip fusilbe only have a blow rating not a load and blow sadly widley avaiable and not the protection thats suitable, pete Link to comment Share on other sites More sharing options...
Bigfella70 Posted March 30, 2019 Author Report Share Posted March 30, 2019 Thanks Pete, think I will pick up a set from Canleys in lieu of upgrading to a blade type fuse box. Link to comment Share on other sites More sharing options...
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