Swapping Zenith carbs for Webers

[moriarty]

Having problems with Zenith carbs on my 2.4T so considering buying Webers, are they a straight swap or what's involved? dizzy etc.??

[bjmullan]

My advice is to get your Zenith sorted. I had mine rebuild by Chris at Fenn Lane, fetuhoe on here, and they are fantastic. Car starts first and runs smoothly. And they look like brand new

[Gary71]

Agreed, rebuild what you have.

Can be sweet as anything, drove mine today and it’s just lovely.

[moriarty]

Thanks for advice guys, Gary, you are not far from me, who did you use to overhaul your carbs?
Maurice

[Gary71]

Thanks for advice guys, Gary, you are not far from me, who did you use to overhaul your carbs?
Maurice

Me

I wouldn't call them properly overhauled, just carefully cleaned (vapour blast then ultrasonic) and rebuilt.

Biggest difference for me was adding a sealed bearing at the throttle quadrant end. Mine had clear play here so would have been drawing air from all sorts of places it shouldn't have been. The other spindles were OK, although again if properly rebuilt these plain bearings would be replaced or reamed out and oversize shafts put back in.



A friend cut down the original bushes on his lathe so I still had the machined inner surface to match the carb bore. Then just a case of ensuring it's lined back up properly when you pull them back into place.


Also when putting the throttle plates back together to the spindles I spent ages ensuring the butterflies matched the bores when closed and all opened and closed together.

[moriarty]

Nice job Gary! I've been trying to contact a carb rebuild firm in newton le willows but his number comes up unrecognised.

[Gary71]

I used this place in Tarporley for the cleaning:

http://classic-custom-vapour-services.business.site/

[fetuhoe]

We have restored around 30 pairs of Zeniths 40TIN Carbs now and IMHO they are better than a 40IDA.

They have taller auxiliary venturis which is close to the size of the part used on the 46IDA.

You can individually adjust the accelerator pump volumes as they have 3 pumps rather than the single pump used on the Weber.

They also have a high speed enrichment circuit that was only fitted to the 40IDS used on the '67/'68 911S.

We make all of our own gaskets and seals as some of the parts supplied in the repair kits don't fit well.

There are few details that often need attention other than blocked progression galleries and other basic parts of the basic carb operation.

The 'cam' which operates the accelrator pumps has PTFE bearings and these aren't normally supplied as part of any repair kit and can affect the way in which the pumps perform.

Accelerator pump springs are also often in poor condition and need replacing.

You also need to check the angle joints used on the drop links as they wear which creates a backlash and makes it difficult to balance the carbs side to side.

When they are 'right' the Zenith is a great carb and performs well.

[Gary71]

Maurice, I think the answer to your question is posted just there! ^^^^

[moriarty]

fetuhoe, can you pm me your contact details please?
Maurice