Need Help with Weber Conversion

[81Targa]

I have a 81SC 3.0 that is begging to be upgraded to Weber Carbs. There isnt a good reason to do this but I can't talk the engine out of it and this isnt the purpose of this post. What I need is:

What is required to make this conversion other than the Webers and how do you keep it so that the original CIS can be reinstalled?

Has anyone here done this conversion on a 3.0?

The only other item I am aware of is the distributor being reground.

Also, is there a resource, net or book that describes the conversion process?

I want to make sure I have all the details worked out before I start this.

Any help is appreciated. No information is to elementary.

Thanks in advance

[Formerly Steve Wilkinson]

I put PMOs on my '83SC. I don't know what the price differential is, but they're splendid pieces. If you're going to bother using carburetors, you should also change the exhaust system to headers (SSIs, typically). Otherwise, you're wasting your time fixing only one half of the "in goes the good air, out goes the bad" equation. I also had the cams reground to S specs, but they'd have to be replaced if the CIS was ever put back on the engine.

Stephan

[feelyx]

...And... when you change the cams you will have to change the pistons, otherwise you will have clearance problems.

Tim in Sac

[81Targa]

Only going to tackle CIS to Weber conversion at this point. Additional items will come later.
I have the carbs now.
What did you use as a guide to what needed to be changed. How did the manifold match up, additional parts?

All the basics

Thanks

[Lee]

I'm interested in thte same conversion. But I read somewhere that there is a potential problem with a "rotten egg" odor after converting to carbs. I have no idea what would account for it. Have you heard anything about this?

The other thing I wonder about is this: for the price of a PMO conversion, along with the SSI heat exchangers, and a cam change, couldn't a new, more efficient fuel injection system be installed that would achieve good results?

Just wondering...I obviously don't know a lot about this...

[Oldporsche]

There is a port matchup problem using the stock carb manifolds from Porsche. You might talk to PMO about this. I believe that some of their manifolds adapt to the cis intake port in the heads.

In a previous conversion we removed the heads and heli-arced the port then smoothed out the transition from the carb manifold base.

You don't have to convert anything else when converting to carbs to make the motor run.

Good luck,
David Duffield

[911pcars]

Get a parts book that shows the complete fuel system hardware on both the '81 and a 911 with Webers. Compare pieces (linkage, fuel lines, etc.), then proceed accordingly. Get a fuel pressure regulator to drop FP to 3-4 psi. Decide on air filtration system. Take notes and a lot of pictures of your present setup so you can reinstall at a later date.

Sherwood Lee

[cds72911]

"There is a port matchup problem using the stock carb manifolds from Porsche. "

Is this just for the model we're talking about or all CIS cars?

I have a '78 SC engine and webers with the stock manifold and it seems to bolt up just fine. The openings on the intake are a different shape than the manifold (out of found where the injector sat), but I understand that is not a problem.

More info please?

Thanks.