1.6 auto with Z1 34 34 carb!

[Tinkley]

Hi Should the 1.6 auto have a Z1 Solex with the 1.9 carb ie Z1 34 34 or the 'proper' 1.6 manual carb Z1 32 34?
Same XU52C engine but obviously the auto has a vac pipe for kickdown - it seems to have been blanked off...
First time the auto has had the carb off and when the vernier went on as it obviously was not the 32 34 it
showed the problem. Maybe a factory oddity? Or is this normal. Co reading was 5% on MOT but it has passed before
so usual new diaghram stuff and auto choke fiddle but that seems Ok now. Expecting reasonable Co level at next
test.

I have a Z1 32 34 should I change it over? Obviously check jet sizes etc etc.

It would appear that the carb (34 34) may have been off a 1.9 with aircon as it has the weird bracket and control screw
leading to a resraing pin linkage to stop the throttle going to low. AFAIK no 1.6 ever had aircon - is that right?
Seems someone changed it a long while back. Still the other Z1 32 34 did have a float height of 40mm.....
Now set correctly.

Anyone know where to get the internal diaghram for the autochoke - not the long metal bent rod one but the small
plastic pin one? Is it possible to make this part from a suitable polymer? It may be possible to turn the plastic and use it
through one of the other spare diaghrams in the repair/service kit. Any guesses as to the polymer - acetal (Delrin)?

[saintjamesy89]

Hey Tinkley, a couple of responses:

-The 1.6 should have the 32/34 Z1 or Weber 32/34 DMTL.

-The a/c carb bolt-on unit uses vacuum to pull a rod, which opens the throttle to raise the revs by 200rpm when the a/c compressor clutch engages - the vacuum supply is swicthed by a solenoid.

-My MK1 16 from France/Switzerland does have a/c, apart from the 14 I think it was an option for all engines.

-I'm not quite sure what [art of the autovhoke you're referring to as my early Z1 (called a CISAC i believe) had no plastic parts, if it is the below thermoplunger then I don't think it can be repaired - this is the part that extends (when heated by coolant) to gradually disengage the choke, or retracts (when coolant temp decreases) to allow the choke to gradually be engaged again.

The origianl and replacement thermoplunger for my CISAC 32/34 Z1, I can;t now remmerb whch was which but the replacement was the wrong part due to size differences, which obviously make quite a difference without having the autrochoke adjustment tool.


The innards of my choke.

[Tinkley]

Thanks St James Much appreciated info.

I'm ditching the a/c bracket on the Z1 34 34 as the car has no a/c. Maybe the other UK BX 1.6 had it but my Athena's (TRS) did not, possibly the non Meteor 1.6 auto. Looking athe pin rod from it, the control/vacuum pull you could deduce the purpose was to raise the revs for the a/c.

I think my carbs are both later as they have a black box with four screws mounting it from the left hand end of your pic centred on the axis of the roller but front rearwards. The zinc ally end you have shown is replaced by the black box and two diaghrams. There is no cable entry at all in the area as you show on the right. They are Z1 32 34 319 or later designation from 1988 to 1991.

The autochoke problem is not in the part pictured apart from one bit but the black box as would be on the left of your picture is. The repair/service kit contains only one of the two necessary diaghrams for the black box end. One has a long rod with groove and end turned at 90 deg. If there are more than one of these in any kit make sure you use the right length and groove position. There is another inside the box which has a plastic (white) pin around 3mm diameter which is about 12-15mm long. I got away with replacing the long rod with turn on a carb before but the other diaghram matters too in operating the auto choke. Thes diaghrams get pretty rigid after 15+ years of petrol and these are 30+ years. The one on this carb is porous as well as virtually rigid.

If dismantling the black box watch out for the spring and note orientation of grooves/feeds for fuel. Easy to get latter wrong on reassembly.

Thanks for the actual waxstat/thermoplunger shots. All I did before was ensure the end part actaully moved before putting it back. Your right if they have gone they are useless. Might sometimes be worth checking the temperature they operate at. I have one in my central heating wood pellet boiler.
Different body of course.

The rest of the standard repair kit for Z1 is fine but the second autochoke part which is Citroen part No 9565616 is gold dust ie unobtainium. It maybe possible to manufacture ie 3D print in a suitable material (petrol resistant) but it also has to snap onto the inside of the black box outer casing. Hence my acetal machining mention as there is also a diaghram with a hole in it (part of the kit) suitable IF you can extract the plastic pin/disc/clip prt. My previous attempt very gently with palette knife and chisel resulted in snapping a bit off. BTW the part No is for the entire black box assembly so it must have been a known issue. I have the proper 3D CAD software to model this kind of stuff easily, and access to some materials for printing. Cursory scan does not give many suitable polymers for prolonged exposure. It may be that the original pin and diaghram were ultra sonically welded together.

Replacing the rod part of the diaphragm is relatively simple.

The Haynes (blue one) says the 1.6 auto only used the Weber. Equally there is a v expensive one for sale on t'bay that also says not for use on B2C engines of which this is one.

So which one to use the Z1 32 34 or the Z1 34 34? My inclination is the Z1 32 34 but I bought it running on the Z1 34 34 and probably did 5k on it. Never saw more than 33 mpg which compared to the manual Athena at anything from 35 to 50 was pretty poor. That's trying to get economy from it too. It might get 35-40 in this warm weather with the Z1 32 34, it's also rated lower Co in the Haynes. Never beaten my old 150C with 0.15 Co at several MOTs...

[Tinkley]

Finally got a few shots of the carbs. One the 34 34 is the one the car ran on the other a 32 34 is one of a manual 1.6 but the engine/gearbox was stolen.
The former has been ultrasound cleaned and the other would spruce up OK.

It clarifies the 'black box' autochoke part of the housing.

The 32 34





The black box part dismantled and showing diaghram which needs replacing.