Numero Interno

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Numero Interno

Post by Jumprun » Tue May 06, 2014 12:58 pm

Is there anything to be learned by deciphering the Numero Interno of the 330 series engines? Has someone correlated these numbers to assembly dates? is there reference material documenting changes made in the production of the engines that the Numero Interno would indicate?

Tom in SoCal.

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Tom Wilson
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Re: Numero Interno

Post by Tom Wilson » Tue May 06, 2014 5:45 pm

Kerry would have to speak for the 330s, but there is no question that it helps to have the numbers for the 250s. For instance, since the numbers do get bigger along with the chassis numbers, we can tie engine numbers to when Carburettors were changed or when the larger valves were introduced.

Be aware, however,that the engine numbers are not completely coordinated with the chassis numbers! First of all, the lowest number I have for a GTE is in the 50s and the highest I have is in the mid 1,500's. So approximately 1,500 engine numbers for 900 cars (the four prototypes have very different numbers). As I only track GTE's, I cannot tell you if the engines used in the other 250's of the day fit into this numbering scheme, but it does seem logical. Especially when you consider the first Series I was 2043 GT and the last Series III was 4961, making 1,459 potential cars (odd numbers only) and 1,500 potential engines. Works for me.

Second, while the numbers do get larger as the the chassis numbers increase, they are still pretty mixed up. There would be no reason to require that engine #54 went with chassis #54, so I am sure they just grabbed an engine and installed it on the chassis in front of them. However, as Enzo ordered 50 bodies from Pininafarina at a time, I would assume that he ordered the factory to build 50 engines as well. If I had had enough Numero Interno's, we could probably prove that the numbers were all accounted for within that group of 50 (plus whatever other cars were included), just out of order.

It is also interesting to note that the NIs for the 330 Americas seem to be in the 1,800's, which seems to be a continuation of the numbering scheme even though it was a different type of engine.

Where knowing the numbers is most important is in spotting a renumbered engine. While I cannot guess the exact Numero Interno for a specific chassis number, I can estimate the range it should be in. If someone replaced the engine with the next one in the series, we probably would not know (though it is amazing how often people restamp the numbers in the wrong font!). However, when we see a Series I car with an NI in the 1500's, we know something has been changed.
Tom Wilson - Series III 250 GTE, SN 4247 GT
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Re: Numero Interno

Post by 330GT » Tue May 06, 2014 11:36 pm

With the numbers I have available, I can tell if it likely that an engine is or is not the original. Note the use of LIKELY.

But at Tom mentions, Ferrari did not use the engines in the same order as the chassis number. Usually the numbers are within 50 of a known engine from a car within a few serial numbers. Unless you have the build sheet or pay Ferrari for certification, there is no way of knowing if a certain engine is the original or not.

Some cars are much further off than that. One possible scenario is when a car is pushed through production quickly due to a specific customer requirement or the need for a car for a show. Then they can be a couple of hundred numbers off. There is also the case where an engine fails in testing after being assigned to a car, i.e. stamped with the chassis number, and a second engine is put in the car prior to delivery. The second engine is likely to be a much higher number than expected. Note, the build sheet will note the engine change, usually with the original number crossed out and the new one written in. An example is the build sheet for my PF coupe (1643). The original engine was 132F which has a line drawn through it and 152F is written underneath.

As far as production changes regarding engines, I doubt that they are correlated. The blocks were stamped with the numero interno after the foundary process. The person starting the engine build would just grab a block, probably the closest and easiest one at hand, not necessarily the next one in order.
Regards, Kerry 330 GT Registry 250 PF Coupe 1643GT, 330 GT 2+2 8755GT, 308 GTS 23605

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