RobH Posted April 14, 2021 Report Share Posted April 14, 2021 I cant remember whether you have an overdrive - if so ISTR you need around 2 litres of gearbox oil. The steering box only holds a small amount. I bought 500ml of the grease and used it on two cars - and there's still a fair bit left in the bottle. You need to warm it up to get it runny enough to pour easily. I dunked the bottle in a pan of hot water. Quote Link to post Share on other sites
David Owen Posted April 14, 2021 Author Report Share Posted April 14, 2021 Just now, RobH said: I cant remember whether you have an overdrive - if so ISTR you need around 2 litres of gearbox oil. The steering box only holds a small amount. I bought 500ml of the grease and used it on two cars - and there's still a fair bit left in the bottle. You need to warm it up to get it runny enough to pour easily. I dunked the bottle in a pan of hot water. No overdrive so it's 0.8 litres. Thanks for the steering box info. Quote Link to post Share on other sites
David Owen Posted April 16, 2021 Author Report Share Posted April 16, 2021 Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 Schematic questions: 1) Is it assumed you are looking at the front or rear of a gauge, specifically the fuel gauge? 2) Does it matter which connection goes to which terminal on the fuel gauge? Quote Link to post Share on other sites
RobH Posted April 17, 2021 Report Share Posted April 17, 2021 Yes it does matter which way round the TR2/3 gauge is connected. The connections should be marked on the rear of the gauge, B for battery and T for tank. The circuit schematic is not really intended to be an accurate depiction of the gauges. The TR2/3 fuel gauge also needs an earth connection but that isn't actually shown on the schematic because it is made internally through the case rather than by a wire. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 17 minutes ago, RobH said: Yes it does matter which way round the TR2/3 gauge is connected. The connections should be marked on the rear of the gauge, B for battery and T for tank. The circuit schematic is not really intended to be an accurate depiction of the gauges. The TR2/3 fuel gauge also needs an earth connection but that isn't actually shown on the schematic because it is made internally through the case rather than by a wire. Hmm I will have to look again because I didn't see those markings. Thanks Rob. This is fun learning this! Quote Link to post Share on other sites
RobH Posted April 17, 2021 Report Share Posted April 17, 2021 (edited) This link is actually the MGA gauge but it is very similar to the TR one: http://www.mgaguru.com/mgtech/electric/fg_01.htm You can see the markings inscribed in the case below the terminals in the view of the gauge rear. Edited April 17, 2021 by RobH Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 A little bit of an oddity but my instrument cluster has the panel switch and the wiper switch reversed based on all the pictures I have seen. The panel switch is between the warning/indicator bulbs with the wiper switch located above. The holes cut out to receive the switches are dictating where each goes. What am I doing wrong? Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 1 minute ago, RobH said: This link is actually the MGA gauge but it is very similar the the TR one: http://www.mgaguru.com/mgtech/electric/fg_01.htm You can see the markings inscribed in the case below the terminals in the view of the gauge rear. Excellent. Thanks. Quote Link to post Share on other sites
RobH Posted April 17, 2021 Report Share Posted April 17, 2021 5 minutes ago, David Owen said: A little bit of an oddity but my instrument cluster has the panel switch and the wiper switch reversed My 3A has wiper switch at the top, panel rheostat in the middle, lights switch at the bottom. According to Bill Piggott's book this was changed at some point with the top two being swapped over. He says for post TS43000 models but mine is much later but still has the earlier arrangement. Quote Link to post Share on other sites
Lebro Posted April 17, 2021 Report Share Posted April 17, 2021 I think the earlier cars had the panel light switch at the top, when the switch was changed to a rehostat it move down I suspect because it would have been to tight a fit at the top. Re fuel gauge markings, I have seen one recently where the "B" & the "T" marking were on a insulating board covering the terminals. (which were the push on type. there was no stamped markings on the case. Bob. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 Thank you both. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 Let me guess....a fuel gauge from another car. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted April 17, 2021 Report Share Posted April 17, 2021 Let’s have a front view so we can work out the part numbers printed on the dial Peter W Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 29 minutes ago, BlueTR3A-5EKT said: Let’s have a front view so we can work out the part numbers printed on the dial Peter W Don't see any. I would have searched that. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 This one came as a spare part. Is there a way to tell if it is working? And is it the right one for a late 3A? Quote Link to post Share on other sites
Hamish Posted April 17, 2021 Report Share Posted April 17, 2021 19 minutes ago, David Owen said: This one came as a spare part. Is there a way to tell if it is working? And is it the right one for a late 3A? This one is the same as mine post 60k nov 1959 Quote Link to post Share on other sites
RobH Posted April 17, 2021 Report Share Posted April 17, 2021 Mine is an SG2530/63 so that spare one looks right. The internals should be very similar to the one in the MGA link so you can check that the resistances look reasonable i.e 99 Ohms from T terminal to the case, 61 Ohms between the two terminals. If those are about right you are good to go. However, if the fitted gauge was working OK why not keep it ? (unless you are going for originality of course...). That might save a bit of fiddling about as the spare will need adjustment to suit the sender. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 7 minutes ago, RobH said: Mine is an SG2530/63 so that spare one looks right. The internals should be very similar to the one in the MGA link so you can check that the resistances look reasonable i.e 99 Ohms from T terminal to the case, 61 Ohms between the two terminals. If those are about right you are good to go. However, if the fitted gauge was working OK why not keep it ? (unless you are going for originality of course...). That might save a bit of fiddling about as the spare will need adjustment to suit the sender. Going with what works but will test the spare for "experience". Thank you. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 I have some questions about the ignition switch. On the schematic it appears that the connections from the starter switch, the feed to the fuse box and the ignition warning lamp all connect to the same pole? Is this correct? It appears that the power to the light switch is the only connection on the other pole. Is this also correct? Bob mentioned I should pull the feed for the voltmeter from the ignition switch. Which pole should I use, assuming the above is correct? How should I ground the volt meter? Quote Link to post Share on other sites
Lebro Posted April 17, 2021 Report Share Posted April 17, 2021 (edited) The first fuel gauge you showed is wrong for a tr3a, it is the type which needs a voltage stabilizer, & would read "backwards" with a tr3 sender. Probably from a tr4 With this type it does not matter which way round the connections are made. Bob Edited April 17, 2021 by Lebro Quote Link to post Share on other sites
RobH Posted April 17, 2021 Report Share Posted April 17, 2021 Yes the connections to the switch are as you describe. Power comes from the battery to the lighting switch and through the brown/green wire to the input terminal on the ignition switch so that point is always 'live'. When the ignition switch is closed, power is connected to the three white wires on the output terminal. The feed to the voltmeter should come from that switched supply so that power is only applied to the meter when the ignition is on. You could take the feed from the switch itself or from the A4 terminal on the fusebox where all the green wires connect, as doing that would mean the feed was fuse protected. The voltmeter will take a low current so grounding is relatively easy. Just run a wire from the ground terminal to any convenient adjacent point where there is a screw going into metalwork - the dash support brackets are useful for that. If this is a Smiths meter don't expect it to jump up to a reading as soon as you turn the ignition on. Those use a heater coil inside to bend a bi-metallic strip so it is slow to respond as it heats up. Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 17 minutes ago, Lebro said: The first fuel gauge you showed is wrong for a tr3a, it is the type which needs a voltage stabilizer, & would read "backwards" with a tr3 sender. Probably from a tr4 With this type it does not matter which way round the connections are made, & it does not need an earth. Bob Thanks Bob. The non TR gauge was sort of working and there is a voltage stabilizer on that circuit. I don't suppose you fix gauges? 7 minutes ago, RobH said: Yes the connections to the switch are as you describe. Power comes from the battery to the lighting switch and through the brown/green wire to the input terminal on the ignition switch so that point is always 'live'. When the ignition switch is closed, power is connected to the three white wires on the output terminal. The feed to the voltmeter should come from that switched supply so that power is only applied to the meter when the ignition is on. You could take the feed from the switch itself or from the A4 terminal on the fusebox where all the green wires connect, as doing that would mean the feed was fuse protected. The voltmeter will take a low current so grounding is relatively easy. Just run a wire from the ground terminal to any convenient adjacent point where there is a screw going into metalwork - the dash support brackets are useful for that. If this is a Smiths meter don't expect it to jump up to a reading as soon as you turn the ignition on. Those use a heater coil inside to bend a bi-metallic strip so it is slow to respond as it heats up. Thanks Rob. Hence the lights will turn on without the ignition on. "Face palm emoticon" Quote Link to post Share on other sites
RobH Posted April 17, 2021 Report Share Posted April 17, 2021 7 minutes ago, David Owen said: The non TR gauge was sort of working If it is a case of working but reading incorrectly, those two holes either side of the central screw are adjustment points. There is info on how to adjust the sender and gauge here: https://www.mgexp.com/article/how-to-adjust-the-fuel-gauge-sender.140 Quote Link to post Share on other sites
David Owen Posted April 17, 2021 Author Report Share Posted April 17, 2021 48 minutes ago, RobH said: If it is a case of working but reading incorrectly, those two holes either side of the central screw are adjustment points. There is info on how to adjust the sender and gauge here: https://www.mgexp.com/article/how-to-adjust-the-fuel-gauge-sender.140 Thank you Quote Link to post Share on other sites
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