Weber Sidedraft Mounting Interference Problem

He doesn't have the "spring thing" part on because it won't fit.

What do you expect a machine shop to do about this particular problem? The left manifold flange looks a little higher than the right, but that may be a trick of the camera. They could mill one down and get them parallel but they are still way too close. Bore out the holes to spread them apart? Then the ports won't line up. Unless the castings are total garbage and they currently don't line up.

I have a little over 6mm of space between my throttle shaft nuts. They are out of alignment in the picture because the carbs are not fastened down fully. In Mr. Dragon's picture, he has a gap on the left shaft, Presumably this will be taken up by the spring thing part. At that point the throttle shafts are still interfering with each other.

Either the manifolds need to separate, which I think will be problematic, or that throttle shaft needs to be cut down. Maybe the shaft's are not symmetrical and it's in backwards? With how low quality these carb kits seem to be it would not surprise me.

What do you expect a machine shop to do about this particular problem?

Assuming the front of the head is flat:
machine the flange surfaces as required to alter the angle of the manifold runners with respect to the front of the head so the runners are not straight 90°, or whatever they are now, but biased slightly towards the ends of the head, thus slightly spreading the centers

You could mock it up with shims between the inner flanges and the head, figure out how much to slice off. then you use a mill, something and cut a thin wedge from the flange. You remove a piece that would be .100 +/- thick on the outside end of the manifold flange, tapering to a point on the inside end of the flange. Or multiple operations as required to get the flange surfaces parallel

The extent of the job would depend on how far out of whack it is.
a common issue with these?

DbilasTDI said:

machine the flange surfaces as required to alter the angle of the manifold runners with respect to the front of the head so the runners are not straight 90°, or whatever they are now, but biased slightly towards the ends of the head, thus slightly spreading the centers

Click to expand...

That would work but I think we would end up cutting way to much off the manifolds and creating too steep of a misalignment angle. Assuming these manifolds are rough dimensions of 150mm x 100mm, if one wanted to gain an extra +10mm clearance between the two they would have to mill the head flange at ~3°. Over the 150mm of the flange that's ~7.5mm gone from the flange on the outside. How thick are these flanges? Not to mention all the fasteners are now at a ~3° angle. The design quality of these are clearly poor, I can't imagine the manufacturing quality is any good either, I would keep the flanges thick as possible. I don't think 7.5mm difference in the intake runners matter much. But I do not like that ~6° misalignment angle on the throttle shafts.

TheSamba Link said:

throttle shafts interfere so mount holes will need to be elongated and ports matched or could be suitable for other brand carbs.

Click to expand...

This is a better idea assuming there is material to play with. Now this is a big assumption, but assuming everything is straight and the ports line up favorably I would not mess with the manifolds and take my clearance from the throttle shafts. Shafts are cheaper than manifolds if you screw it up. If the manifolds are nowhere close to the ports, then by all means take out material, match them up, and shift them over if possible. The flanges are the parts that are easiest to measure, I hope, but am probably wrong, they did a half decent job lining them up.

The "other brand carbs" comment from The Samba is interesting too. Weber vs Chinese may not have exactly the same throttle shaft. Different varieties of "Weber" may not either. If we look at the 3 different carbs (mine, Dbilas, Dragon) there is clearly more shaft sticking out of Dragon's than the other two.