Morgana

No need for exactness - if it maintains the revolutions one would expect when, say, changing up a gear then it would be a way to check fuel is being delivered in sufficient quantity rather than draining the float chamber faster than it's coming in which would indicate poor fuel delivery. Just methods to logically discount what might be causing the problem without unnecessary specialist test equipment. Have you checked for Pete's dreaded rubber slivers behind the needle float valve? Mine played up no end a few months ago and I had to whip the carburettor cover off to blow through the valve half a dozen times between Bristol and Cornwall before it cleared due to some random gunk. Is there a leak at the exhaust manifold gasket? I had a problem with 'gutlessness' I put down to a lack of enough back pressure after it improved greatly when the leak here was fixed. I ended up making my own bronze nuts as the brass ones available were not keeping tension on the studs, and the bracket to hold the exhaust to the gearbox was missing allowing vibration. As Pete says, there is very little to go wrong with the Solex and my experience has been one of incremental improvement including flattening the base where it had warped from excessive tightening of the mounting nuts, allowing air past the manifold gasket, and getting an original fuel pump to reduce the wild overpressure of fuel coming in that was overwhelming the needle valve.

The capacitor prevents arcing which is a good thing all round, not just for the reduced points erosion. It means the time taken for the charge to decrease is greatly reduced, so there is a single spark rather than a drawn-out arc which not only stresses the coil but makes timing irregular. In other words, the primary current changes much faster, meaning the magnetic field in the coil collapses more quickly, which leads to the induced secondary voltage being instantaneously higher. Result? Better sparking at the plug and no arcing so erosion, burning and pitting of the points is greatly reduced. If you think of arcing as being the same process as arc welding, you can imagine what that does to the metal's surface.

Partner's MGB has a Lumenition that broke in lockdown with an intermittent fault. Testing the system out of the car with a drill to represent the rotor revealed that the sparking plug started sparking erratically after a while, which was traced to overheating in the infrared module that monitors the pulses. The Lumenition type has two infrared elements, an LED emitter and a detector, with the rotor breaking the beam between them. Instead of shelling out for a new one, it turned out to be possible to rebuild the circuit into the same mounting bracket casting, using very 1970s matrix board and through-hole rather than surface mount components for improved heat dissipation.

Does it maintain higher revs? If you keep it at 2000 for a while does it stay there? If there is a lack of fuel then the float chamber won't be topped up as quickly as it's being used and it'll choke out after a period at higher revs. Have you got the Solex? If the hose mentioned above is pliable, take the pipe out of the carburettor and see if it squirts a good volume while turning over on the starter, and doesn't tail off after the first few revolutions. Listen for air leaks. You can spray WD40 around the junctions of the carburettor to see if there are any bubbles or a change in engine note indicating air getting past a gasket. Rule out all of that, and I would think it's time to clean out all the carburettor orifices.

I have a softback one for oily hands and left in the leaky boot; a hardback for clean hands and a genuine workshop manual for desk use only. Haynes have really shot themselves in the foot with the modern manuals printed on newspaper. The photos are almost illegible from the high contrast and bleed.

I've just replaced my Desmo Boomerang glasses with convex NOS from Oxford Minor Parts. Previously as both were flat and on the wing so non-adjustable by the driver, it was like looking down a telescope and they were entirely useless so I'd never used them.

That's the spirit, Colin! Even when something works, when I know it's a bit of a bodge I am always hankering to do it properly... Next up are the acme screws that ought to be holding on the fuel tank instead of the strange collection of roofing screws the PO left me with.

@rogerguzzi It was a 1/4" starlock washer when it came off, which I still have in the 'Herald Boot Stay' bag where the original pin disappeared from. I turned the small end so it fits through the 1/4" hole in the boot bracket I welded up after it cracked, and the starlock then slides on there. I made the shoulders big enough to fit a 1/16" washer between the stay and the bracket to spread the load over more than the 1/4" hole, and will maybe put a wave/breville on as well to keep tension. I think it's the back and forth wobble, coupled with degraded packing foam between the bracket and the boot skin that causes the bracket to crack, so any way to mitigate this is to be desired.

Luckily I can borrow time on a lathe, so I turned a pin down from a bit of bar this afternoon, and it looks like it'll do the job!

Winter car too, steveo! 😉 No troubles with grip and the heater kept us toasty up to Edinburgh over new year. The wipers are pretty effective, but there are some leaks which mean more demisting than I'd like, and a gap around the seal on the passenger door front which makes a cold draft on the knees. However, with relays for the headlamps (PO running halogens through the dashboard switch with loose connections almost burned up the switch...) the lighting's better than my mother's modern car. I keep being astonished at how much room there is in a Herald for moving things around, too!

Have you tried the man, the legend Mick Dolphin?

Copper work hardening is a major issue, to the extent that it's a failure in many vehicle test codes (I don't know about the MOT specifically). Perhaps that's only a giant no-no for brake lines which are under high pressure, and you might be OK for low-pressure carburettor feed pipes as long as it's very well supported to avoid vibration. However, heating pipe at 8mm is not the same as fuel pipe at 5/16". I'd go to a reputable motor supplier and get 5/16" cupro-nickel ('kunifer'). All the malleability of copper for easy forming, but without the work-hardening, crack and then a fuel fire. I think copper needed twice as many supports as steel, which gives you some idea of the different strengths and resistance to vibration damage. Once they realised the troubles with copper, it was no longer approved and then cupro-nickel came along. From your photographs it doesn't look like there are many supports at all. Perhaps modern-style nylon would be the best like-for-like as mentioned above. If you use cupro-nickel, don't forget to put a bubble flare on the end where it joins any rubber hose (and yes, get kosher fuel hose from the club as Pete Lewis says). I don't mean a specific standard, but a half-formed double flare, just so there's a smooth bulge in the pipe at the end. Put the hose clip behind this bulge and then the rubber hose can't come off.

Thanks for the effort, Colin. It does need that shoulder since the hole in the stay is much larger than the hole in the bracket. I have the starlock bit but despite looking everywhere I can think of the pin remains elusive! I may have to do as you have done. I've got some nylon washers that might add some smoothness, as well.

Following on...I took the top pivot off too, and have now forgotten what it looks like when I'm rummaging, despite thinking I'd put everything in a carefully labelled bag. Is it a clevis pin with a starlock washer on? Any photos?

Cornwall's a good place to be - getting round bulbous SUVs in the lanes whose drivers don't know where reverse is, or where the corners are is a doddle in a Herald, and very satisfying! Pootling about and getting all the admiring looks instead of the wildly more expensive and ugly blacked out Range Rover in front is another bonus...

I have personally had problems with the brass nuts sold for this purpose as they have stripped the threads before tightening properly. Apparently bronze used to be used as it's stronger, but it's more expensive so is now very rarely available. I made my own bronze nuts from hex stock and have had no more problems, so if they're the same thread as a 1200 saloon I could make you some more.

Outer diameter can be misleading as newer wiring is 'thin wall' so there's a larger area of copper for a given diameter compared to your old loom. The only real way to ensure satisfaction is to calculate or estimate the load on each wiring element, then check the voltage drop along the wire length is not excessive. Taking the load off is also beneficial. Adding headlight relays over the front wheel arch with a new feed means the dashboard switch in the Herald is not in danger of catching fire as it was because of the previous owner's loose connections, and the headlights are brighter. You might find the attached table useful. I get wires from Auto Electric Supplies. They have a good range of colours that match the Lucas tables, and plenty of cross sectional areas available with recommendations as to their suitable uses.

Thank you both. My black bracket spacer piece has a spire clip on, so was fouling the top of the fuel tank on top of there being three different screw types in the holes! I'll make it look like Mr Lindsay's with some spires, self-tappers and a machine screw/nut combination and I think that will improve things no end.

After welding the snapped upper support bracket I'm ready to put the stay back on, and stop supporting the boot on my head. The base of the stay was held on with three completely different screws which I'm keen to return to something rather less wobbly. There was one 'J' spire nut, one nut and machine screw and one 'U' spire nut on the channel that clamps the fuel tank to the stay and the body bracket. None of the diagrams I've seen show in detail how this ought to be when it's right. I've attached some pictures of the order I think the parts should logically go in. I guess two 'J' spires on the green body bracket (to allow them to be installed from underneath without fouling the fuel tank like a 'U' would), and one (U or J?) on the separate (black) clamp piece, all held together with No.10 1/2" or 5/8" pan/flanged self-tappers? Does anyone have a picture or reference of the original fitment?

Does the pump get hot being attached to the engine? Epoxy resins like Araldite usually 'let go' around 60C. One possibility would be to thread both parts with a parallel pipe thread and fibre washer for the seal at the bottom of the recess. With the pressures involved a fuel-resistant dowty washer would likely not be necessary. A tapered thread hosetail would lock against a parallel female thread, but I would not think alloy would be suitable for that method. Depending on what the bottom of the recess looks like, perhaps an olive connection could seal there? Any mechanical method would seem better to me than a doubtful adhesive! 🤔

I haven't seen this style. Does it not have an olive and screw? It seems a problem waiting to happen with dissimilar metals otherwise!

My whole carburettor must be metric: the top cover only has the holes for the screws to go through and the female fuel pipe tube nut thread, and it's the bottom half that has the tapped holes for the M5x0.75 cover screws. The olive recess appears correct (I don't know if metric olives are made with different angles, like SAE and DIN flares), and the M12x1.25 nut is made for 1/4" pipe so I'll put the whole thing together with what I have and check for leaks. Assuming a metric nut was supplied with the carburettor when delivered new, it's not too great a leap to think it was all made for imperial pipe and fittings, but they saved machining costs by keeping the same metric internal thread for all models. Perhaps as you say it was a later alteration, so my carburettor could be a later addition. The other end of the pipe is the fuel pump's 1/2"UNF. A friend's coming over tomorrow with a flaring tool so I can make some hose-retaining bubbles on the relevant bits of pipe - yes, I'll be on the lookout for the rubber slivers! Then I'll report back.

The new (original era AC) pump is fine - it was when comparing the two I noticed the hole through the fitting into the body of the pump in the reproduction one is smaller than on the original. I've been given a new (old) pump by a local enthusiast with innumerable cars and a biplane in his wonderful workshop, as I wanted to solve the excessive spring pressure (and hopefully the oil leak around the fuel pump) once and for all. I've got a few different springs so I can see if the reproduction models can be improved with stock parts, and am making up the pipes to fit them before pressure testing. I'll try drilling out the holes in the reproduction one to 1/4" and compare. The car came with another reproduction so with the one off the car I have two to fiddle with. The new ones' springs are wildly different from the AC pump. Yes, Solex was a French concern which started in radiators before making carburettors after buying some French patents. I can only assume the designs were originally metric by nationality, and production in France only ended in 1988. The quest I had with the top cover screws shows metric is not alien (even if weird metric) to this carburettor at least, but it is interesting they seem to have made a UNF version as Colin Lindsay has. On mine the 7/16" is really sloppy though it will do up as they're almost the same TPI. The fuel pump's 1/2"-20 won't fit at all and M12x1.25 is ideal. Canley did say that this nut was not obtainable and that was why they didn't supply the fuel pipe from pump to carburettor for the 1200, so perhaps they've had the same confusing problem. Maybe it's one of those things the dogged and time-rich enthusiast can dig up that the professional cannot justify the time on. I bought all three parts Automec sell as M12x1.25, including one described as a 'Citroën carburettor' nut which looks like the original unrelieved fuel pump nuts apart from the different thread, so I'm going to try it first. They used Solexes so that fits, too. Alternatively, there is a UK and a European version of this carburettor, and at some point in the past it's been changed for reasons unknown! Though, as the previous nut threads on, despite being chewed on the head, it must have been with the carburettor and the fuel pipe been added at the same time, unless the end was not swaged and the olive could be removed. The whole assembly is cable-tied to a bracket near the water pump rather than being clipped as I believe it ought to be, so something's been done with it. That olive looks like the original ones on the steel stub pipes that were on my original pump. The new ones I have are shaped like a conical bifrustum rather than a barrel. In the reproduction fuel pump, that length of pipe cannot project as the fitting hole narrows too much, but that's how they're fitted on the original pump. The devil is in the detail, and in the archaeology!

Yes, new parts have arrived and M12 x 1.25 is the right thread for a Solex B30 PSE1. I have been fiddling with the new original fuel pump and a reproduction one. Interestingly, the original is drilled for 1/4" pipe (as expected for what's on the car) but the reproduction one is 3/16". This might be a problem as using 1/4" pipe with an olive, the pipe cannot be pushed far enough into the hole. The olive is right at the end of the pipe and in the couple of experiments I tried with new bits of 1/4" cupro-nickel pipe, compressing the fitting causes swaging of the pipe end to make a flange over the end of the olive. This is just the thing that has caused the fuel weep at the carburettor. With the stubs of steel pipe that were left in the original pump, the olive is some distance up the tube, with the part projecting beyond the olive sitting happily through the hole towards the body of the pump which avoids this problem.

There is a page in the Herald glovebox manual with a settings table for different conditions when using the heater/blower - window open slightly, distribution to windscreen, heat on with fan etc.