1974 CIS fuel distributor replacement question

[umfan866]

Hi,

I'm looking at buying a 1974 911 S. THe guy told me it
has a rebuild etc, just right now he is not driving it because
the "fuel distributor" needs to be replaced. He was quoted
around a $1,000 but that seems high based on other posts,
seem like a guy is selling the used part for $180 or something.

Doing some initial surfing here it appears that the CIS system in these cars is a little complicated. The guy was told he should while replacing this part "upgrade" to a 75 or 76 fuel distributor, is that true? I also found a thread where someone was considering replacing the CIS with Carbs.. how much is a set of Weber or PMO carbs cost (and would it run better) or sound nicer? Luckily this car does not need to be smogged being a 1974. Any pointers appreciated.

[azasadny]

Very timely post as I just converted my '74 with CIS "issues" to Webers. My fuel distributors (2) both had problems and needed to be rebuilt. Instead of going that route, I chose to follow my mechanic's recommendation (Tab Tanner at Autobahn Garage in Findlay, OH) and put Webers on the car. Webers and the associated fuel pressure regulators, manifolds, linkages, etc... will set you back about $2000, then the labor will another $1500 or so, so it will be about $3500 total for the Weber conversion.

I'm going to sell my 2 CIS setups and a brand-new CIS fuel pump to help defray the cost of the conversion and you may want to do the same. I was not willing to replace/rebuild the fuel distributor because of the past 4 years unpleasant experience with a 33 year-old Bosch K-Jetronic FI system, but others here will disagree and seem to love CIS, I don't.

The Webers get about 15mpg versus the 21mpg I was getting but I simply don't care because this car is not a daily driver. The throttle response and sound I get from the Webers make the cost and hassle all worth it. The engine compartment is significantly cleaned up and no more 90psi fuel pressures. I'm very happy with the conversion and it didn't require any modifications to the engine itself.

I'm sure others out there will disagree, but I'm happy with the CIS to Weber conversion and only wish I would have had it done 4 years ago!

[umfan866]

azasadny,

Thanks -- I think it was one of your posts that I had seen.
Wow $3,500 seems like an awful lot to sink into a '74.
Does it give a lot of extra horsepower?

So the fuel distributor is different than the fuel pump,
and you are selling your new pump, but not your
distributors, because they had to be rebuilt?

Again sorry for my ignorance. Sounds like an SC or Carrera might indeed be a better bet if the fuel system in a 74 is so complicated

[azasadny]

umfan866,
My CIS was mucked up and the fuel distributor I had was bad and the second one i got was also bad. The fuel distributor and the fuel pump are two different components. Replacing components on CIS becomes expensive very fast so you shouldn't start replaing parts until they are tested. Webers fon't add any horsepower but the throttle response makes it seem that way. The car feels completely different than it did with CIS. Get a good Porsche mechanic who knows CIS to test the car and then you'll know what you're getting yourself into. You could easily spend $3500 or more trying to fix the CIS by just buying new/rebuilt parts without troubleshooting and getting to the source of the problems. Unfortunately, the source of my problems was the fuel distributor and that's a very expensive component...

[Larry_Ratcliff]

3500 is nothing to sink into a 74 the sky is the limit!!!

[umfan866]

Wow. So book I read called "the gold-plated Porsche is really true". Amazing. My own local Porsche mechanic owns a 74 himself and has worked on 911's for years I'll get his opinion on 74's and CIS tommorow. Lets say it's just the fuel distributor itself. .how much for that part new (if its even still made) and/or how much to rebuild it alone? I'll need to find out more from the seller - but he just told me that it was running fine up until a month ago, then the fuel distributer broke and now he's avoid turning it over for fear of making the problem worse.

[pjh69911]

CIS injection runs quite well when set up properly. Rebuilt fuel distributors can be had for about $450, used ones for about $125 or so. If you have the time or inclination, there is lots of information on tuning and testing available. You mostly need a pressure tester. If not, find a reputable shop. It should be much less than $3500

[PRE-H20]

i have a used Fuel Distributor for a 1974 911 if anyone is interested......

i bought a used one but never used it as i replaced the whole engine... its just sitting waiting to be fired up again.....

if interested send me a PM.