French Car Forum

Hi,
Are Solex & Weber interchangeable for given engine displacement or model year?
I believe mine is Weber 30DGS ('82 1299cc GSA) - Will one drop in place of another? If so, is one better than another?
Cheers

I suspect there was no manifold change between Weber and Solex, so in theory they should interchange. But there (IIRC) may be differences in throttle and choke attachment. Some say the Weber is easier to set up, but overall difference? I doubt there is any. Only one way to find out - unless others have more experience?

Thanks - The carb guy says it'll take more than a few days to get the job done and I looked up on the German GSA spares site which has a Solex in stock. Overhaul cost is around the same as this Solex unit, but not sure if it is secondhand or overhauled....

You need to watch out for stuff labelled as 'overhauled, refurbished or reconditioned' it often just means 'rubbed down with an oily rag'
I'd guess that you could fit any make of carb with suitable adapters but whatever you use will need to be matched/tuned to the specific engine.

Among our GS's we had both Weber and Solex carburetors.

As far as I could see (and remember! it was a long time ago) they were fully interchangeable, provided you had the correct version for the engine size. EG you wouldn't want to fit a carburetor tuned for an 1220cc onto a 1299cc etc and expect it to perform right. (In theory you might be able to retune it, but that's outside my area of expertise!)

But substituting a 1299cc Weber for a 1299cc Solex or vica versa should be absolutely fine - at most you might need to swap the "hot box" underneath it if there are any variations in the mounting flange at the bottom of the carburetor. (I don't think there were though, I think all hot boxes were the same) However the horizontal pipes that join up with the hot box will match up with no problem.

The only snag you might run into is some carburetors had a stop solenoid which requires a switched live 12v from the ignition switch and some didn't have this. So you might need to run a switched live supply if your old carb didn't have this but the new one does.

Choke and throttle attachment points might vary slightly but it shouldn't be hard to get them to reach.

Gibbo2286 wrote:You need to watch out for stuff labelled as 'overhauled, refurbished or reconditioned' it often just means 'rubbed down with an oily rag'
I'd guess that you could fit any make of carb with suitable adapters but whatever you use will need to be matched/tuned to the specific engine.

cynical! but yeah you are right though, I have been burnt before... (but not with this particular vendor, just to clarify)

A lot to think about - hope it's not too complicated as working on it out in the open in the Winter doesn't appeal to me any more (getting old... ha ha)

Yes, it's the Weber that has the fuel cut off solenoid, I'm fairly sure the Solex doesn't have that (though I might be wrong!). The Hyena says that from July 1981 the 1299cc ECO engine runs a Weber 30 DGS 25/250 - Mark W115-50, prior to that the GSA Club & Pallas 1299cc ran Weber 30 DGS 16/250 Mark W96-50.
Jets are different sizes, mostly smaller in the ECO engine. Less fuel delivery, I suppose that's part of the the ECO bit! The other part of that is the "Econoscope" device fitted to GSA with manual gearboxes from July '81. A sensor unit attached to the diagnostic socket (should I go on?) monitors the throttle vacuum (read inlet manifold vacuum!) and a potentiometer then activates the yellow and orange throttle control advice lights on the instrument panel.

Well if that hasn't put you off . . . .

right - you jokers well and truly put me off....
i'll just have to soldier on til summer. it's not so after all...
cheers.