Tuesday, 27 May 2014

Carbs and Air Filters


Weekend of 14th March 2014 – Long Weekend

My everyday drive is parked behind the MG and everytime we started up the 'B, he blew black smoke onto the white paint of the car behind. Black, carbon smoke is fine - it's if it's blue(oil) or white (water) that it starts to get a bit nasty. At least with black smoke it's indicative of a too-rich mixture, which can be caused by a number of single or collective events. Thought I'd change the air filters at least and then tickle the mixture screws until I got the correct mixture, but then I thought it could well be the needles or jets in the SU carburettors. Looking at the manky state of the carbs made the decision easy to now pull them off for a rebuild.
Pulled off the air filter housings, which were in a bit of a bashed and rusted state. Ordered new air filters from the UK and after panel beating the housings back into shape, taking all the existing paint off them, they were rust primed, painted in gloss black, and clear coated as a finish. For the piece de resistance, I’d previously ordered an original set of decals of which there were two stickers to go onto the air filter housing. Pleased with the job as it turned out.

 

 

Commenced pulling the SU Carburettors off for maintenance.Needed to really have a look at this because the exhaust was spewing out quite black smoke. At least it was black and not blue or white, which would indicate quite a big problem in terms of oil burning through passing over the piston rings etc, which would be a big job. Instead, the black smoke indicates that the mixture entering the engine from the carbies is too rich. Riley and I had a quick look to see if we could adjust the mixture via the various screws and stuff around the carbies and realised it was all too filthy. Used some degreaser, but it didn’t get them clean enough so then we took the carbies off the manifold area and once they were off it became obvious how badly filthy they were and it’s no wonder there was black smoke being delivered. Right then, big job and need new parts. MGOCSpares sell a SU Rebuild kit for less than £70






 

As seen in the attached pic, we needed to totally strip the carbs down and clean each component. This was done initially with using thinners to get the majority of grease and grime off and then when we realised we couldn’t get into the nitty gritty bits, we fashioned a venturi bi-carb of soda blaster coupled to the newly acquired air compressor.Worked a treat to clean them thoroughly. Then washed them off n clean water and let them out in the sun to dry. Ordered from mgocspares a carbie renewal kit in order to change the needles and jets, gaskets and pipes, butterfly and bushes.Do it once, do it well. At the same time, we pulled the Intake manifold off and the manifold heat shield (Which has a couple of bits of crumbling asbestos attached to it and I’m not too sure of the direction I take with it yet). These all need cleaning and refurbishing with paint etc.

When the rebuild kit arrives from the UK then we’ll rebuild the carbies prior to reinstallation. Mind you, typical of most renovation projects, as soon as you renew one piece, all the rest looks desperately sad and in need of restoration too. One thing quickly begets the next. We took the existing faded red rocker cover off and briefly replaced it with the new gleaming aluminium cover. It looked like we’d just sprinkled a turd with glitter. With all the engine head looking quite rusty, the new cover looked ridiculous. So, one of the next jobs is to pull the head off and repaint it in an engine heatproof red along with the thermostat housing and then at the same time I’ll need to replace all the water hoses and fuel hoses too.

1st April 2014

Tonight I’m tackling the carbie heat shield – will sand back, prime and thinking of painting it gloss black, but in two minds about painting it silvery kind of colour. Dunno, but Riley and I will come to some decision about it.

Decided to use the same Flame Proof paint used for heat shielding on the exhaust manifold.

 
15th April 2014
 
It's taken a lot of time because I've only really managed to play around with the carbs  for a few minutes each night, but quite pleased with the end result. Unfortunately I put on new stickers and didn't line the right-hand air filter sticker up as neatly as I should've. Ah well, lessons learned and all that.
 

 

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