help, can i use these carbs in my car ?

deQuincey

deQuincey

Quousque tandem...?
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hello, my car is a 3.0CS dated 1971


i just bought a couple of zeniths from a 3.0CSA

here they are:

060920073466.jpg



i kown positively they were from a CSA because i found a violet piece of tab in one of them.

here is the information of the references: in red the CSA, in green the CS


referecniascarbus.jpg


they are not major differences between these and the ones that i have actually in my car, except that these CSA carbs include a thermostat valve !!! (that incidentally is not working):

060920073468.jpg


while the carbs that are actually in my car do not include that valve,

question:

CAN I DELETE THE MENTIONED VALVE AND USE THE NEW CSA CARBS IN MY CAR CAPPING THE HOLE TO WHICH THE MENTIONED VALVE IS CONNECTED ? (see red arrow in pic)

060920073472.jpg
 
No difference to speak of

Yes and yes. You may find that you have to open the idle screw up a little more or slightly close the primary butterfly- Autos have a slightly leaner idle jet. Not a big deal.

That valve only works when the temperature is below a given setpoint and opens for a set time of several seconds. What usually happens is that there is a small conical tip on the end of the bimetallic strip that becomes dislodged on a backfire condition. I've taken them apart and placed that tip in the right orientation.

If you're going to eliminate it, perhaps an epoxy in the banjo bolt while leaving the assmbly in place. Otherwise, you're looking at a custom cap.
That cap regardless will need a sealing washer.

One last tip, the secondaries and the gap settings- I've found my mileage goes up by closing them, then only slightly opening them( just enough to feel). I place my thumb on the butterfly while watching the screw then only turn it out about an 1/8 of a turn rather than the feeler guage method in the manual. It gives a better balance on the primaries.

Bmw must have figured it out since if you compare all the manuals and the last training manual in 78- that's what it says to me.
 
Last edited:
Yes, ultrasound is fine. But first soak/ clean them to get everything off after stripping anything electrical and the injection pump/ squirter.

I still use a dremel tool and wire brush for details and stubborn deposits.
 
61porsche said:
Yes and yes. You may find that you have to open the idle screw up a little more or slightly close the primary butterfly- Autos have a slightly leaner idle jet. Not a big deal. .
Click to expand...

about this, i have found that the primary iddle jet is 100 in the CSA, while it is 80 in the CS

as i have a spare set of those "80" jets my intention is to put them instead of the "100"

is this according to your experience

regards
 
Yes, it has. I tried the 100's but it seem to not make a difference with gas here in the US.
 
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