Quick carb question

Post by **ebdl** » 12 Jan 2006 09:45 pm

I want to find a spare carb for my car so that I can be sure of not being left in a pickle if I bugger one up by attempting to recondition it myself.

Is there any problem with using the post '84 (no constant CO system) or post '86 on (auto fuel cut-off system) Weber carbs in an '83 car?

Do I have to find the exact carb for my car ('83 1.4 auto)? If so, which is it?

Thanks, Ed

(PS Eurocarparts sell brand new Weber carbs and market them as being suitable for: WEBER 32DIR (VOLVO 340 1.4 B14 01/10/1980 - 01/09/1991))

Post by **340GLT** » 12 Jan 2006 10:02 pm

I know of a mk 2 1.4 auto in my local scrappy. Dont know if the carbs still in it though. Although what stopping you putting a later carb on really? If need be you could make one gud carb from 2?
Cheers Adam

Post by **pettaw** » 12 Jan 2006 10:06 pm

No prob putting a later carb on an early model. If need be you can always wire up a 12V feed to the stop valve solenoid when the ignition is on.

Post by **ebdl** » 12 Jan 2006 10:25 pm

Splendid - thanks very much chaps.

Post by **shimon340** » 12 Jan 2006 11:10 pm

pettaw...why dya need the 12v feed? the pre-83 have a solenoid also. sorry to sound dumb!

the difference ( quote volvo green book )

between pre and post 83 is that cars with Renix have different carbs to the contact breaker cars.

"In conjuction with the integrated electronic ignition system, the vacuum connector was relocated to a position under the throttle valve ( it was previously above the thottle valve ) This weber carb is not interchangable with the earlier version

Ive wondered why but maybe the vacuum is stronger for the later carbs? I thought about getting a pressure gauge and seeing what the difference is between the two... would there be way to modify a late carb vacuum with an earlier one??? mabe using something like the restrictor for the crankcase...

crankcase vacuum........

I need to check if the plastic restrictor is the same for pre and post 83 carbs. Ive only ever changed it on post 83 cars when they idle poorly ( in case it was missing and in the other it was the original rubber hose which had the restrictor built in - it had perished... so replaced with a normal hose and the plastic restrictor from volvo... about £1.50 each

maybe use something like the restrictor which is used for the crancase ventilation system.. it has a smaller diameter end facing the crankcase and a larger end towards the carb so the crankase isnt under the full vacuum of the carb....

I think at low revs the carb vacuum is needed for the crankase but at higher revs the air flow through the air filter is sufficient. the restrictor is there to provide vacuum at low revs and is restricted so it doesnt provide too much vacuum to the crankcase at higher revs....

if the crankase doesnt vent properly it causes poor idling....

extra question...

the idle solenoid opens with the ignition but a post here recently said it closes when the revs are above 1700 and the throttle is closed... how does it get this rpm input??

look forward to hearing from ya

Post by **shimon340** » 12 Jan 2006 11:20 pm

thought this might help

http://www.piercemanifolds.com/32DIR.pdf

http://www.piercemanifolds.com/32DIRpl.pdf

Post by **pettaw** » 12 Jan 2006 11:35 pm

hmm strange, cos the vacuum connector for the Renix is deffo above the throttle plates on the later cars too. Maybe they mean the PCV connector?

The restrictor is there to stop the manifold vacuum drawing in vast quantities of air and causing an air leak (manifold vacuum is highest with a closed throttle and decreases as you open it)

Maybe its the PCV system that's different with the earlier cars, with no manifold connection at all and all just plumbed in above the throttle valve so it gets vacuum as you open the throttle? So maybe you could just change the PVC system over too?

I must've misread/misunderstood the original poster cos I thought he meant the earlier carbs had no solenoid. So all good on that front!!

Post by **340GLT** » 13 Jan 2006 12:27 am

I wouldnt of thought crankcase vacuum makes a large difference TBH as my car doesnt hve any with my modified setup, it just has a breather filter on the end. AFAIK the vacuum is only there to remove the residue (Not sure if right word) produced from the heated oil? The only prob i have is that breather needs to be kept clean around once a month does it!!
Cheers Adam