Exhaust then I suppose today. Drive over in the Princess as normal, nothing amiss beyond the exhaust noise and I find the throttle getting gradually stiffer until I'm approaching lights and suddenly the throttle jams completely. Fortunately I was next to a bus stop so could throw the car into neutral to stop it running away and turn it off to coast to a stop. Hazards on, bonnet up, have a look. Somehow, it was earthing through the throttle cable again even though all systems were normal. I had noticed a dip in the ammeter with the headlights on, much the same as yesterday, but it was stable so just assumed the battery was a little low from lack of use. I let everything cool down and the throttle returned to normal, I then carried on to the unit with the headlights off, which I don't like doing on a drizzly day, but it was less than a mile of the journey to go and nothing untoward happened.
Wasn't particularly thrilled about this so the first job was to investigate the earth issue and we thought we'd resolved it when we noticed the headlight earth point was a bit dirty. Made a brand new earth point which improved matters, but after a while the throttle cable started to warm up again if the headlights were on (and only the headlights), so I need to find out what's going on with that. At the moment the earth points check out fine and there's nothing obvious, all I can say for certain is that something on the headlight circuit isn't routing electricity as it should and further investigation is required.
Exhaust next then, since I didn't want to chase electricals until that was sorted. Air filter box, carburettor and heat shield off first for access. I never disconnect the cables going to the carburettor because the end of the cables always fray and I can never get them back in again, so I always make use of the flat bits of the engine bay to keep the carburettor out of the way and still connected. Unconventional, perhaps, but saves me the expense and hassle of fitting a new pair of cables every time the carburettor comes off... which has been a lot lately.
20180219-01 by
Angyl Roper, on Flickr
Mike and I wanted to make the exhaust components that were leaking as clean as possible so we opted to remove the manifold rather than dropping the exhaust this time. This was also a consideration after folks on my various threads suggested the manifold casting can have flaws that cause issues with sealing, so we could deal with that too if it turned out to be the case. The exhaust downpipe flanges didn't look too bad, with the exception of some exhaust paste to remove of course, so that was something.
20180219-02 by
Angyl Roper, on Flickr
20180219-03 by
Angyl Roper, on Flickr
With everything cleaned up, which took forever, we aligned the manifold to the downpipes and immediately a problem became apparent. We moved things around a fair bit to double check and played with the clamps and dry fitting to be sure, but it looks like one of the downpipes is at the wrong angle and if you bent it to be at the correct angle, it wouldn't sit in the correct place to meet the manifold. This is probably the root cause of the exhaust blow and only a replacement exhaust is going to solve that. I was therefore okay to accept the exhaust will blow when reassembled, I cannot do anything about this at the moment.
20180219-04 by
Angyl Roper, on Flickr
After fiddling about with the clamps and the jack and the exhaust, we got a better fit than the above photograph by sort of wiggling the manifold down onto the pipe with me bracing various pieces while Mike got the clamp tightened up with a little exhaust paste. Then the chore of refitting the manifold while it was attached to the exhaust, which is about as difficult as you can imagine since it goes on with bolts rather than sitting on studs and there's a gasket to fit at the same time, so you need about 6 hands attached to two arms. It was like playing Twister, just a whole lot less fun. With it all bolted up the extras were reattached so the car could be started and here's an idea of the access available to you if you don't remove everything first.
20180219-05 by
Angyl Roper, on Flickr
20180219-06 by
Angyl Roper, on Flickr
The end result, on starting the car up, was that the driver's side clamp has sealed perfectly. The passenger side one has a little bit of a blow, it's tolerable and should go through an MoT at least and will likely quieten down a bit once the car has been through a few hot/cold cycles. Partial success at least. Annoyingly the carburettor then decided it was just going to pour fuel out of the overflow while idling and didn't want to respond to any sort of attention and the headlights are still trying to earth through the throttle cable.
So the Princess has been left in the sin bin at the unit for a bit to think about what its done while I try and find the next bit of free time to go through the electrical issues with Mike. Carburettor is probably just a stuck inside component, low oil in the dashpot or simply because SU. I hate problems like these because they take ages to find and sometimes, even worse, mysteriously fix themselves.
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After having posted the above on other fora, it seems likely that the original braided earth strap is probably to blame and is probably why this earth problem has come and gone intermittently. I'll be replacing it with a cable type instead which will either be one of my spares or, if they're not long enough, a new one of the relevant length. Hopefully that will chase out this electrical gremlin I've had for ages.
I've had enough of these shenanigans and I want to drive this wretched thing!
