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SU Carburetter Conversion

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I have a number of reasons for using a SU carb, cost being perhaps the primary. If you use Phil's exhaust manifold then it is difficult to retain the Solex carburetter, you could choose to retain the not very attractive inlet-exhaust manifold but then you need adapters to attach the side pipes. I'm a fan of the simple SU and after seeing it fitted to the beautifully engineered Richard Oakes cars my mind was made up.

On to the conversion

  • The inlet/exhaust manifold was stripped off along with the oil filler, and the tubular exhaust manifold fitted.
  • A right angled bracket was made that picked up on the two oil filler tapped holes with holes on the vertical face matching those on the SU's air filter side.
  • The carb can now be temporary fixed in the middle of the engine between the oil cooler and the balance pipe of the exhaust manifold. The fitment is quite tight remember to allow for the air filter.
  • A new low profile oil filler pipe needs to be made to fit under the carb.
  • The new manifold is made using a piece of 1 ¾ inch square mild steel approx 5 inches long. The ends are drilled and counter-bored from each end to accept 1 ½ inch dia steel tube, the holes are drilled just short of the mid point allowing me to form a wall in the middle to aid fuel separation between cylinders. A further hole to match the carb was machined in the side of the block at the mid point (See Fig 1).
  • A piece of 5/16 mild steel plate was profiled to match the carbs engine side with throat and fixing holes machined.
  • This plate is now welded to the square piece and the assembly bolted on to the mounted carb.
  • Two new flanges were made to attach to the cylinder head inlet points out of ¼ inch material and fitted to the cylinders.
  • The mild steel pipe was purchased pre-bent off e-bay, two with a 90 degree bend and two with 135 degree bend, these were cut and shut to join the flanges to the square section. When happy with the fit they were tacked together and finish welded off the engine.
No information available No information available No information available Fig 1

I thing the installation looks very tidy, unfortunately I can't tell you how well it works as I'm still under construction but it ticks over fine.

Barry Hatch

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