Weber 40 DFI (on 330 GTC) - Spindle return springs

The Spindle Return Spring is #19. You are referring to the Choke Linkage Return Springs. Try Pierce Manifolds on the internet.

 

Weber 40 DFI/2.

 

Try Pierce Manifold, the go-to guys for Weber carb expertise and restoration.

 

How do the carbs on a 330 GTC compare with those on a 330 GT?

 

GTC/2+2: Same engines, same carb setup.

 

Gee. I thought that they were different. My 330 GT has 40-DCZ/6

So I Googled about cabs on 330 GTC, and I copy below one of the first entries that Googled up:

"Re: Carb Synching

• Quote

Post by DWR46 » Sat Oct 30, 2010 12:21 pm

Come on you guys, you all are supposed to be the experts out there, but I will take a shot at which carbs have Bypass Screws. The first Ferrari to have Bypass Screws was the 40 DFI2 equipped 330 GTC."

So, which is it?

PS: Looking more carefully, I see that the diagram of the GTC carb on post #1 above does not show a 40-DCZ/6

 

We've been here before haven't we?

 

Early 330 motors used DCZ and later engines used DFI. It was just a carb change. GTC and 2+2 used the same motors. Some early 330 motors have different water pumps and chain adjusters (like a Tipo 163 motor), but by the time of the GTC, they were all the same. The DFI is a simpler to manufacture design than the DCZ. It was also cheaper to produce.

 

Kevin: You can match up Spring #36 at your local hardware store. The other spring is more of a problem.

 

Thanks. I forgot all about this. I apologize for bring this up again.
But to say "GTC/2+2: Same engines, same carb setup." is not exactly right. That previous discussion appears to show that at least 1/2 of the 2+2 had DCZ.

 

Spring 37 looks like a torsion spring.
Try McMaster Carr.

 

Lowell: GTC and 2+2 engines are THE SAME. Some of each model had DCZ and some had DFI. Most GTC's had DFI because they came along later. All the early 2+2 engines were four mount, while all the GTC engines were two mount. The parts that make the BHP are the same in all the 330 motors. DCZ's used 27 mm chokes while DFI's used 28 mm chokes, but I have never seen any consistent difference in power on the dyno.

 

While we are on the subject, I am sure somebody will ask " Why doesn't the DFI with the 28 mm choke make more power than the DCZ with only a 27 mm choke?", so I might as well take care of that question now. If you look at my earlier post, you will see the DFI was less expensive (cheaper) to manufacturer than the DCZ. The DCZ has separate, beautifully made Choke Tubes and Auxiliary Venturis, while the DFI has both items permanently cast as part of the main carb body. It was obviously less expensive to make all these pieces in one step, but it had two downsides: 1. With the DFI, these parts are no longer removable for tuning purposes or easily adaptable for a different application. 2. And this is the major problem, the interior streamlining of the DFI is inferior to the DCZ, resulting in less air flow for the same size choke tube. That is why it takes a 28 mm choke on a DFI to produce the same power as a 27mm choke on a DCZ. DFI's also went to a "strangler" type of cold start system, instead of the DCZ fuel enrichment system. The DFI choke plates further reduce air flow capacity.