Finishing the adaptor block.

May 11th, 2014

Today I finished the little carb to blower block. I drilled the 6mm holes to bolt it to the blower and drilled and tapped blind holes to take some 5/16 BSW to 5/16 BSF studs. These are the same as the ones that attach the mechanical fuel pump to the crankcase. I have a 5/16 tap but it’s a taper tap and not a bottoming one so I had to find a bolt to chase out the thread to the bottom of the holes. I didn’t have a 5/16 whitworth bolt but I did have a 5/16 imperial which is close. I ran a whitworth die over that to make the thread correct then cut a slot in the side of it with a Dremel and flattened the end of it on the sanding disc. I could then use it as a bottoming tap to clear the thread in the casting. I then loctited the studs in.


It all fits together well. I also made sure the block matched the outlet port of the carb and I sanded the inside of the block smooth. I have to assume the port on the blower matches it since you can’t see through it when it’s bolted on of course. I used the original gasket as a pattern so it should be good.


The other thing I noticed once I bolted the carb on was that it is possible to reverse the choke lever. As it was it was set up to pull via a cable from the left. I swapped it over so now the cable will pull from the right which will suit my car better. I still need to get a rebuild kit for the carb as well as a spring and needle. I need to order those from the UK.


4 Responses to “Finishing the adaptor block.”

  1. Duncan Says:

    I have enjoyed your blog over time and really appreciate you having a go.

  2. renaud Says:

    Hi Simon,
    Very nice job on the cast block. Well done for a first attempt really! Looks easy though I don’t think so!
    Keep doing the good work (I read here as soon as it’s written!)
    Renaud in France

  3. Dave Says:

    How do I get your blog to send me an email when it is updated. It is updated so infrequently. Reading it great while I am waiting for code to compile.

  4. admin Says:

    Is that a hint I should update more? I’ll see if there is a WordPress plugin to do that.

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