What a difference...

[Mike914six]

I just completed rebuilding these old webers and installed them on my 911. I've had the webers for awhile and never got around to the conversion, then the CIS airbox blew up a few weeks ago forcing the issue.

I'm still messing around with them a little, but it already runs better than with the CIS, and they look great (at least I think they do). The rain shelds are new ( a very nice kit form Pelican). I got some larger venturies off eBay, and everything else was taken from my old 914-6 engine (carbs manifolds etc...). I re-did the jetting with some Jet reamers, and it's running great. I'm so excited!

[keitho64]

Nice job! I love the way webers look. Don't you love the sound of the webers with the water sheild air cleaners? What size is the motor and how do you have the carbs jetted?

[Mike914six]

Your are right, they do sound great!

Although the car is a 71 someone at some point put in a 2.7 CIS engine. It always ran well, and the low end torque of the 2.7 combined with the light weight chassis make for a very drivable car.

Here is what I went with (based on info from this board!): 32mm venturis, 135 main jets, 60 idle jets, 180 air corrector jets, and F26 Emulsion Tubes. Or as close as I could get to these values using the reamers. I'm no expert, and it was more detailed work than I usually do. I didn't even need a hammer :-) . I started out with 125 mains, and 50 idles. It also is using the tall secondary venturis from weber 46's. Not sure what the do, but the look good when the air cleaners are off.

I also had a low pressure fuel pump from the 914 that fit perfectly in the stock holder. This pump is supposed to maintain a constant 5psi or something like that, but I used one of those cheap regulators as well (set at 3.5). I'm using 2 inline filters.

There were many leaks after the first run, but a little tightening of fittings here and there got things under control. There for awhile, I was thinking that the reason people get worse gas mileage when using webers is because half of it leaks out. It is still boiling, or percolating a little fuel into the intake (puddles on top of the butterflys) right after I shut it off. I've herd that a little of this is normal, and carb insulators can help. I'm wonder, how much is normal, and do I need to worry about this? It is only doing this on one of the back barrels, and not really very much.

Here is an old before shot:

[keitho64]

Mike

I have a 2.2 motor and mine has 32mm venturis, 130 main, 60 idle, 180 air correctors and f1 tubes. I agree it takes time to tune them, but when right the throttle response is great. I went the same route as you with the fuel filters and regulator. The only thing I did different was to install a fuel filter between the tank and fuel pump to protect it.

The carb insulators will help the percolating. I have not driven mine enough yet to see if it is a problem. Is the float level to high? They may exasperate the problem. If not, I would consider some type of insulators or heat shield.

I have a friend who is in the process of putting a 2.7 in his 69. He will be running webers so I think he will be interested in your results.

Once again, nice job it sure looks leaner and cleaner with the webers.

[Mike914six]

Keith,

I actually had a hard time with the float adjustments. I think that something that requires millimeter tolerances should not be accomplished by bending metal. I'm sure I got it right, but you never know. I'll recheck the bowl connected to the tube that is giving me problems.

Thanks.

[Rich911E]

Mike:

Glad to hear that the conversion worked for you. KeithO64 finally pestered me enough to go pull the tired 2.0 liter out last weekend and I am in the process of installing the 2.7 CIS motor with webers over the next week. I have been planning this for ages (once again thanks to the other board members for their patience and advice and I apologize for the million questions about this project).

Anyhow, I contacted PMO about their suggestions for jetting for a 40IDAs on a stock 2.7 CIS motor:

Venturi = 32mm
Main Jets = 135
Idle Jets = 55-60
Air Corrector Jets = 180
Emulsion Tube = F26
Spark Plugs = NGK BP5ES
Early style exhaust system.

And here is the link to the thread: Has anyone just bolted Webers onto a 2.7 CIS engine?
I cannot believe this thread was almost two years ago. Have I been living with that POS 2.0 for that long!

Hope this helps.

Rich

[Mike914six]

Rich,
I looked at that thread before I started, it was a big help. Thanks! I think those PMO guys know what they are talking about.