Technical Weber 34 DATR top-half carb gaskets oddity?

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Technical Weber 34 DATR top-half carb gaskets oddity?

RDS

Member
Joined
Apr 12, 2017
Messages
287
More queries raise their heads with this car.

I went to re-assemble the carb earlier and reached for the top-half gasket whereupon something appeared rather odd with the new one purchased a while back.

I cannot post pictures but comparing the old and new, the old gasket is “entire” over the float chambers whereas the new gasket has numerous pre-punched holes over it.

The problem is that the top of the carb has a more or less triangular open panel in the carb roof which communicates with and is directly above a float bowl. This would, if the new gaskets were used, allow direct contact between hot engine bay ambient air and fuel via the triangular panel and some of the pre-punched holes.

I am sure this cannot be right vis a vis the gasket and have looked at a few 34 DATR pictures on the internet to compare. Those carbs also have the open triangular panel so it must be correct.

Thoughts anyone? I am not willing to rebuild the carb like this but there must be a reason…

I have made some templates with the assistance of Mr Kellogg and will cut and punch them tomorrow but I would prefer to use proprietary stuff really.

Many thanks for your all assistance

RDS
 

NEG

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Sep 3, 2018
Messages
33
Pretty sure it will be ok RDS, I rebuilt my 1500 carb with one like that, I think underbonnet air temps and not a top priority, they become an issue if you delete the carb cooling fan
 
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RDS

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Joined
Apr 12, 2017
Messages
287
Cheers NEG

The problem, with the fan is that i have a good relay, new sender AND have tested the carb to be at 70deg yet the fan will not come on on its own. I do have an override switch on it now though.

As part of my continuing research into this carb; I analysed its technical drawings. I found nothing of use on the internet as to the vent or gasket.

Whilst there is no substantive mention of the matter in the notes, the drawings disclose that some models have a vertical rod (vent rod) which is attached to the carb’s secondary barrel throttle plate shaft and which, when the mechanical secondary barrel is activated, lifts the vent valve in that housing and which communicates with the area above the gasket in the float chamber and thus venting it.Mine has no rod or the valve internals and the communicating passage to the fuel bowl has a solder plug in it but the outlet to air is there. This seems a much better system though i was not able to track the missing part numbers down.

Further Citroen, who used a derivative of the carb in the CX fitted a mesh over the open trapezoidal area to minimise fuel splashing.
 
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