Carburetor compatibility question

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yellowbullet

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I recently picked up a '72 CS with 32/36 Webers. I would like to swap in some OEM carbs but all I have are '74 carbs which are different (at least part number wise). Can these be installed without too much problems?

On a different note, I am looking to purchase a carb rebuild kit and so far I have found 4 different part numbers:

13-11-1-261-402
13-11-1-261-403
13-11-1-255-741
13-11-1-255-742

Which ones do I need for a Canadian spec car?

Thanks in advance.
 
Zenith Interchange

There's no reason not to use the Zeniths from what ever the year. There were just minor mods done usually for emissions depending on destination. The jets were all the same with the exception of auto cars which had a slightly different idle jet but not enough to notice.

Carb kits- depends on one thing- secondary vac. diaphram. Kits with them or without- ( minor gasket kit.) There's a simple test- take yours off and push the rod up on the cap underneath is a small relief hole. Put your finger on it and release the rod- it stays up; your good and it's holding vacumn. If not you need the major kit.

I've found kits as cheap as $20 to $40. and as expensive as $120. Shop around. Look also for Mercedes 220 or 250 models- same carb. Mesa or Ebay.

Which ever kits- save your old gaskets, seals, O-rings, etc. for comparision. Sometimes they're not exact and you have to go to the local auto parts/ hardware store to find a better substitute. ( Nitrile o-rings)
 
Thanks for the quick response! The '72 is an automatic and I believe the '74 carbs I have are from an automatic as well. Are there any visual differences between the two? Also, are there any performance or operation differences between the '72 and '74?
 
I've just been through the rebuild process - as 61Porsche says definitely try to salvage the gaskets - the new ones are inferior and I ended up re-using the top gaskets. When you disassemble the carbs try to not tear them if possible but if you do the replacements will work but they are thinner. The mixture screws won't fit nor will the choke pull off gasket/rods - I had to get replacements from Walker that only half work (they are aware of this problem) and re-used the mix screws. Also the thick gaskets between the throttle body and float bowl compress, so after you reassemble, wait 24 hours and re-tighten these. Then wait another 24 hours and do same before installing on the manifold. The new float needle valves are also inferior, if your existing ones with the little ball bearing in the tip are still good re-use those too. Most likely you will find the kits from Walker or Royze, mine were Walker and were just ok. No experience with Royze, on eBay the Royze tend to be more expensive than the Walkers. I got my Walkers from Mesa - they are good guys. I suggest getting the major kits because they come with more than just the secondaries gaskets, notably the accell pump skirt gaskets which are vital for proper functioning and are probably stiff and leaking now.
 
carbs

Maximillian sells the kits. $146- yowser! $46 for the minors.

Visual differences-

1) Vent-90 degrees or not. ( Slightly different gasket- but every kit I've bought had both.)

2) Choke diaprahm- later ones have a cone shape vs. a flange ( esk) style.

3) heaters- aux. heating elements- a rect. cover opposite side of the manifold.

4) The very last run- had some more emission- fuel diaphram above the idle solenoids. ( Never have seen them in practice.)

Post a pic.
 
Re-building Zeniths--

My .02 cents suggest not to scrimp to save a few dollars for a kit--as when ccompleted they will not be removed in a long time. I've known the owner of Royze for many years and he is a very knowledgable BMW, VW & MBZ guy--Royze is the Distributor for the kits that are generally available from retail outlets--Mesa Performance in our part of the country--with whom I have done business for 30+ years.

BTW--John @ Royze has a service available for professional re-building of Zeniths. A call to them might be a good idea depending on your budget and desires.

Royze--800-421-2011--no relationship except as a friend of owner and customer.
Mesa Performance--800-221-8824--same as above--ask for Spence--he's the Coupe guy.
 
The Zeniths (on my '74) had separate air and fuel mixture screws.This makes setting the idle mixture somewhat difficult unless you have a CO analyzer and was one reason I switched to Webers. My car also had the mixture cut-off solenoids and cold start valves and the associated wiring and relays. So, adding the '74 carbs to a '72 car might be somewhat involved.....
 
Why not just use the Webers? I recall constantly fiddling with the Zeniths on my 72 Bavaria. One thing I did was switch to the european jetting ( per info from shop manual) using parts from a pre-emissions 2800 sedan. Bavaria ran much better. I think I have some Zeniths in the garage if you need parts (I'm in Ottawa).
 
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