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Discussion in 'Vintage (thru 365 GTC4)' started by Lowell, Apr 6, 2018.
Again, what diaphragm? Where is it? What does it do?
Over and now out forever.
The diaphragm in the later Webers serves as the accelerator pump. Though, in the eralier Webers, like Lowell's, I'm pretty sure the job is done by a brass piston.
Apologies. My mistake.
I shift by the sound; I think if Lowell’s engine (and his car is beautifully maintained, btw) sounds good, it probably is good. These cars are remarkably robust in my limited experience. I wouldn’t and don’t hesitate to drive near the redline in mine.
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Late 330 GT S2s had Weber 40 DFI/2 carbs, not the DCZ/6 as in Lowell's car. I wonder if the DFI/2 used the diaphragm? The Weber 40 DFI 5 and 6 do. Service kit for DFI 2, 5 and 6 below.
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My above post should read Some late 330 GT S2s had Weber 40 DFI/2 carbs. I don't know if all the later ones had 40 DFI/2s. Damn 10 minute edit limit.
DFI 2 carbs use the diaphragm. It can definitely dry out and the early versions were subject to deterioration from ethanol.
An accelerator pump should not affect the safety of the engine at full revs.
BMW: Your statement is not correct. On many Weber carburetors, the accelerator pump jets also function as high speed fuel enrichment feeds.
There are a number of early S1 330 GTs identified on Kerry's site as having 40 DFI (not DFI/2) carbs which I believe may also have the diaphragm?
My bad. My experience is with Del'orto motorcycle carbs which simply add a charge for acceleration. I made an assumption.
Steve: The DFI model used on the Tipo 209 motor was a DFI 2. I assume some owners failed to include the suffix in describing their carburetors. As to when the DFI replaced the DCZ, that gets murky. I would say that roughly chassis number 8400 starts the DFI units on 330 engines (but the changeover was not "crisp" with DCZ's still appearing from time to time). I would suspect earlier cars that now have DFI carbs have had the original DCZ units replaced at some time in the past. The DFI was a more "modern" carburetor and was also less expensive for Weber to produce. It does not have replaceable chokes, and the diaphragm accelerator pumps provide a "quicker" squirt than the piston design.
My 330GT S/N 8855 has (I am pretty sure) 40 DCZ/6 carbs.
Bob Wallace rebuilt my 330 GT engine in the late 70s. (#9693) . I have 161000 KM on it now, and keep it tuned and valves adjusted, oil changed etc, and drive it regularly. I have hit over 6000 RPM and it makes great noise but never went past that.... why take the risk!. I am pretty sure the engines of GT and GTC are basically the same engine internally. I have 40 DFI2 carbs, and pretty sure they are original to car as the main long term owner kept records even when he changed spark plugs, for example, before or after a long trip, or after racing at the Virginia City Hill Climb and coming in 2nd. And yes 6600 RPM is the correct Max
According to the records I have, the earliest DFI/2 carbs appeared in a 330 GT was with 9667. The last 40 DCZ/6 confirmed was in 9235. These numbers are from build sheets. So somewhere in the mid 9000s was the change over, but without a build sheet, what came in each car is not certain.
Note 40 DFI (no suffix) came in the early 330 GTs, but the factory had a silent recall where the dealer was supposed to replace them with 40 DCZ/6 carbs (w/o telling the owner). They also would change out the oval air cleaner for the larger one with snorkels. Obviously, they assumed that the owner never opened his hood!
Kerry: No, the changeover occurred about 8400 per Build Sheets
I just looked at three late 330 GT build sheets (9129, 9153 and 9235) and they all specify 40 DCZ/6 carbs. The next build sheet I have is 9757 and it specified 40 DFI/2. Build sheets became sparse at 9325. When Ferrari offered build sheets for free through their website, I entered every 330 GT S/N to see if Ferrari said that a car's build sheet was available. 9325 was the last of the block of available ones, with only a few available after that S/N.
any chance you have a build sheet for mine?
No I don't. And Ferrari did not show that they had it available when I checked on all of these back in 2002. However, I do know that at least one build sheet exists that Ferrari said was not available (10019).
Kerry: The first 330 Build Sheet, that I have, with DFI carbs is 8485. Then they start fairly consistent, 8487, 8495, etc. Obviously there are DCZ cars interspersed until the factory ran out of carburetors.
Kerry's 330 GT Registry has sprinkling of data on the carburetors. Here is everything that he has starting with 8487:
8487, 8491, 8495: DFI
8537, 8601, 8607, 8617, 8637, 8643, 8657, 8709, 8715, 8741,
8755, 8779, 8845, 8855, 9001, 9109, 9119, 9129, 9153, 9235: DCZ
9667, 9693, 9727, 9757, 9763, 10165: DFI
Make of this what you will.
My car does not make a great noise at 6000 RPM, but it does make a nice roar.
I just checked the build sheets. The engine makes its maximum horsepower at 6000 RPM.
So I guess that this is where I should shift on certain occasions.
I didn't scroll up enough to notice the three cars you mentioned. Those are the only early 330 GTs with the DFI/2 carbs that I know about.
Kerry: Remember 330 GTC's went through this same carburetor switch at the same time, with early cars having DCZ and then moving over to DFI carbs. I suspect the actual story is that Weber approached Ferrari with the DFI as a "less expensive" alternative to the DCZ. Weber GAVE Ferrari some sample carbs to try. Ferrari, being a company always in financial difficulties, immediately put them on production cars and sent them on the way. There would have been some "stock" of DCZ's left, and so Ferrari used them up before paying money for more DFI's. This was the case with the Bosch and Lucas ingntions in some cars in late 1959-early 1960. These were all pieces that the suppliers GAVE to Ferrari to try, hoping to get the larger production business. Again, the factory immediately installed them on cars and sold them, as it meant a slightly larger profit on those sales.
My GTC #9411 has DCZ