Post by bedbug on Jul 2, 2014 20:50:29 GMT
The manual is very good on the carbs and if you print out a copy you can mess up and work from it then you should succeed.
I bought my parts from Southern Carburettors in Crawley they rebuild carbs / sell parts and are very helpful.
I spent ages sorting out my stromberg carbs and there were some points that are worth sharing.
1 use nitromoors or loctite gasket remover to clean out float bowls overnight. It saves wrecking any micron thick coating such as chromate or Irridite, inside the bowls.
2 when setting the needle to be flush in the piston hold a steel rule over the ledge and the slide it down until the rule sits on the piston.
3 Using a cheap digital vernier (screwfix) to check and set both float halves in the bowl is far more accurate than a steel rule and the naked eye. You can set floats accurate to 0.5mm quite easily.
3 Put the piston with needle in first, secure that and then build everything up around that. So the float bowl goes on loosely then the jet assembly in place then consistently test for the centralisation of each of these as you tighten things up.
4 The spring under the Jet is responsible for forcing the ally sealing washer up into the body. If the face in there is poor you may get fuel purging into the venturi. Putting spacers between the spring and the brass washer under the O ring can increase the spring pressure to overcome the leaking.
5 The choke assembly with the little holes in it should spring apart when you undo it and be forced back together to fit in. I thought it correct when it was seized down , see two photos.
6 The enrichment pipe between the two carb's is in fact see through and you can see bubbles of fuel go through there when the choke is on, if you use a flood lamp on it when its dark. See Pic.
7 I used colourtune in both banks simulteaneously to set up the mixture. In an effort to save my exhaust manifolds; I wanted to set it up on the weakest pots not the aggregated CO. I started on the rear cyl's but after a poor road test and checking all the plugs, it was 3 & 6. May not be the same for everyone. pulling all the plugs after a poor road test proved the point.
8 The air intake bends and gaskets, you can have a fuel bowl overflow into the venturi and not be able to see it happening.
9 The new base gaskets were not as good as the old ones, doubled up on these to stop air leaks.
farm4.staticflickr.com/3863/14559821792_280689e182_s.jpg
10 sacrifice a spanner to work on carb nuts yes, but dont choose a shiny one, it gets tooo slippery :oops: . see pic.
Carbs as fitted
175 CD-2
Metal tags that should be fitted to carbs with model numbers
3540L
3540R
Zenith Stromberg, 175 CD2S
Piston Needle, 2AY
Piston return Spring, Red, b18339
Jet Orifice, 0.100in. diameter stamped 100
Needle valve, 1,75 diameter stamped 175
Float Height, 16-17mm
175 CDS Service kit CDSK12 GRN no 311214
Base Gasket x5540 GRN no305281
I bought my parts from Southern Carburettors in Crawley they rebuild carbs / sell parts and are very helpful.
I spent ages sorting out my stromberg carbs and there were some points that are worth sharing.
1 use nitromoors or loctite gasket remover to clean out float bowls overnight. It saves wrecking any micron thick coating such as chromate or Irridite, inside the bowls.
2 when setting the needle to be flush in the piston hold a steel rule over the ledge and the slide it down until the rule sits on the piston.
3 Using a cheap digital vernier (screwfix) to check and set both float halves in the bowl is far more accurate than a steel rule and the naked eye. You can set floats accurate to 0.5mm quite easily.
3 Put the piston with needle in first, secure that and then build everything up around that. So the float bowl goes on loosely then the jet assembly in place then consistently test for the centralisation of each of these as you tighten things up.
4 The spring under the Jet is responsible for forcing the ally sealing washer up into the body. If the face in there is poor you may get fuel purging into the venturi. Putting spacers between the spring and the brass washer under the O ring can increase the spring pressure to overcome the leaking.
5 The choke assembly with the little holes in it should spring apart when you undo it and be forced back together to fit in. I thought it correct when it was seized down , see two photos.
6 The enrichment pipe between the two carb's is in fact see through and you can see bubbles of fuel go through there when the choke is on, if you use a flood lamp on it when its dark. See Pic.
7 I used colourtune in both banks simulteaneously to set up the mixture. In an effort to save my exhaust manifolds; I wanted to set it up on the weakest pots not the aggregated CO. I started on the rear cyl's but after a poor road test and checking all the plugs, it was 3 & 6. May not be the same for everyone. pulling all the plugs after a poor road test proved the point.
8 The air intake bends and gaskets, you can have a fuel bowl overflow into the venturi and not be able to see it happening.
9 The new base gaskets were not as good as the old ones, doubled up on these to stop air leaks.
farm4.staticflickr.com/3863/14559821792_280689e182_s.jpg10 sacrifice a spanner to work on carb nuts yes, but dont choose a shiny one, it gets tooo slippery :oops: . see pic.
Carbs as fitted
175 CD-2
Metal tags that should be fitted to carbs with model numbers
3540L
3540R
Zenith Stromberg, 175 CD2S
Piston Needle, 2AY
Piston return Spring, Red, b18339
Jet Orifice, 0.100in. diameter stamped 100
Needle valve, 1,75 diameter stamped 175
Float Height, 16-17mm
175 CDS Service kit CDSK12 GRN no 311214
Base Gasket x5540 GRN no305281
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