Distributor for CIS converted to carbs engine?
 

Hey all. I've got a set of Zenith 40TIN carbs (34mm venturis) going on my 83 euro 3.0. Just wondering if the cis distributor will cut it for the carbs.

Thanks-
Craig Backer

I'm not sure what you mean... You don't need anything from the CIS to run carbs.

Do you mean the fuel pump?

I meant the ignition distributor which was and is on the cis engine - different distributors are curved differently.

You can get it recurved for use with Carbs... There are members here who do this.

They should chime in.

I know but do I need to?

Yes.

IMO... To get the most from your carbs you should get your distributor re curved.

Can you post some pics of your Zenith 40TIN carbs. I'm curious. Were did you get them?

you can run your CIS dizzy just fine, but you may be leaving a little on the table. I've been running a stock SC dizzy in this engine:

http://forums.pelicanparts.com/porsche-911-technical-forum/502996-3-0-dyno-day-pleasant-surprise.html

as you can see, it works. BUT, I will be getting a dizzy re-curved for it this season. I would leave it till one of the later things to do. sort out everything else first, it's kind of a crowning touch. FWIW

my 2.7 RS dizzy, 10deg initial/35deg total works great with 8.5:1 compression


CIS dizzy is for smog afai know

I did the same thinh Haycait911 did, just remove ALL the vacuum hoses and run mechanical advance. Mine comes full in around 3K and is a little advanced 3˚BTDC on start but you can fiddle with that after you get the thing running. Jerry West does a good job of curving for 3.0 carb engines but for now, it will work good, in fact, mine works soooo good that I don't want to chang it! But will because there is always something in there for the rear wheels. Concentrate on the carbs now.

I had mine rebuilt, recurved and vacuum advance removed by Barry Hershon. Not cheap but a GREAT job. IMHO, I'd say it was definitely worth it. If your car has 100k miles on it Id take the time to have the bushings in your distributor changed. They will def need it. 5 degrees BTDC at idle 30 Degrees at 3000 RPM is what Richard at PMO recomends for his kits.

I drove around for a while with the stock CIS distributor on my Webers, it's kind of pokey compared to re-curved distributor I have in there now. But it does work.

Zenith carbs don't have the best reputation..................however, if you install them, I suggest you either have the distributor recurved to run without vacuum or swap your 016 ignition distributor to an earlier 001 with vac advance only.

The 0 237 306 001 has a better curve because the '78-'79 SC's had no Lambda.

You also have to deal with the fuel pump.
The CIS fuel pump pressure is way too high for carbs. Switch to one with lower pressure or install a reducer of sorts.

Why are you going with Zenith carbs?
I would consider a well-maintained CIS more reliable than Zenith's.

What cams do you have?

Excellent advice!!

Stock SC distributors are quite lazy and really need the help, especially with carbs or MFI.

Craig, did you get the velocity stacks for the zeniths yet? They were shipped several days ago. For the distributor I would also suggest that you have it recurved. Im shipping mine to Rennsport Systems to be done.

I installed Zeniths with new ventures, idle and main jets on a 3.0 and it screams! With stock cams and stock dizzy. More hp's are in there but for now, it is quick enough. Getting to the limit of the suspension. cold starts are great, sound is awesome, fuel mileage is down some but thats ok. The Zeniths are a great carb if set up correctly and pull right up to redline. I'm totally happy and the cost is way cheaper than rebuilding a balky CIS system or going with Webers/PMO's. Looks great also!!
http://forums.pelicanparts.com/uploa...1263349602.jpg

how much is not cheap?

And mine...


http://forums.pelicanparts.com/uploa...1263357987.jpg

Just got her on the road today. Euro 3.0 (9.8:1 cr w/ large port heads), same carb setup as James Brown, 7.31:1, stock cis distributor and backdated exhaust. It's definitely way more of a hoot to drive than with cis! Noticeably faster and sounds great!

Barry Herschon Recurved my distributor too. I'm well pleased. It's been 5 years of great fun.

congrats fastbacker, looking good! they are a hoot to drive!

I remember the Zenith carbs in the VW Buses as a PITA.

Sounds like they may have improved?

Using carbs and a more aggressive cam-profile without re-curving the 30-year old distributor means maximum performance is not achived.

Re-curving to run without vacuum would be $400.- plus. It takes a lot of repeated dismantling and tweeking weights and springs.