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Carburettor mounting for small block Guzzi

I know that a number of builders are putting small block Guzzi engines in their cars using Phil's new flywheel and adaptor plate, the new plate is laser cut steel and only about 5mm thick whereas the original method was to use a thick (20mm I think) machined alloy plate and adaptors to use the existing 2cv flywheel. I found when trying to mount my carbs that the clearance between the carb and the frame upright is very tight on the nearside ( one cylinder is further back than the other), the thinner adaptor plate means that the engine being further back in the chassis, the room for carb mounting is more restricted.

I tried all sorts of ideas for carb mounting, long stubs with the carbs under the bonnet,inlet seemed a bit too long and carbs very close to brake discs, with all the rusty dust they can throw around. Eventually settling for the existing inlet stubs reversed right to left, cut and shut with welded on stub extensions, and pads welded on for take off's for carb balancing. Incidentally in the picture it shows the stubs quite long this was to give the welder something to hold, and also to enable me to hold it in the lathe chuck easily to machine a groove for the mounting rubber and to part it off, likewise the two little pads are machined with little handles for the welder to hold, they will thank you for it!

The angles were arrived at as a compromise between decent gas flow and clearing the frame, by the highly technical process of cutting the profile of the manifold out of cornflake packets and transferring the cuts to the alloy manifold. As can be seen from the pictures I did not get this entirely right, another 5 deg or so have made things much easier clearance wise, the air filters cannot be fitted direct to the carbs, so extension stubs had to be made to push the filters farther out. Even so the one for the nearside carb has had to be machined eccentrically (by eccentrically I mean offset in the chuck by about 4mm, not while dressed as napoleon!) you can see this in the picture of the stubs before plating. Even with this there is only about 4mm clearance between the stub and the frame,so there might be yet more surgery to come. The idea is to fit S&B filters on the outer ends of the stubs.

The carbs seem to be pretty close to the exhausts, so will probably wrap a short length in heat insulation, the exhausts look like they may need cutting and shutting to fit nicely along the side of the car, so that would hide the weld as well, I'm still finalising the petrol pipes, I bought a nice twin alloy fuel banjo to connect the carbs, but there is no clearance to fit it without the fuel pipes being sharply kinked, so have just ordered more petrol pipe and a tee piece.

All in all its one of those jobs that if I did it again knowing what I know now would be much easier, I would make the carb angles slightly more acute, whatever you do its going to be tight, but hopefully forewarned by my mistakes yours will go a whole lot smoother, could remake the manifolds I suppose, but it would be nice to actually finish the thing someday, and after all nothings perfect.


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