My own view on this is that any modern oil from a reputable manufacturer will be superior to anything available at the time the Fulvia was produced.
When in England I used FIAT Selenia Racing or AGIP Racing - both 10/60, but later I used a synthetic 15/50. I have had no problems despite "using" the car properly.
However, recently I have learned that a number of VSCC members are using 0W/30 oils (as specified for modern BMWs etc.) in their 1930s MGs - and for racing too without problems. I would certainly try this if it were not for the fact that every engine I build for myself seems to leak, whilst those I have built for customers do not! There is a considerable amount of oil drag in the Fulvia engine (Oh for a dry sump!) so I would expect a performance improvement.
Paul
motor oils
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Huib
running rich
They do run rich.
The ideal or stoichiometric mixture of air and fuel is 14,6kg of air per 1kg of fuel. This means there are theoretically exactly enough oxygen atoms for every atom of fuel to burn. In practice not every fuel atom is going to find its oxygen atom and vice versa. There are going to be spinster and bachelors.
If we translate the weight ratio of 14,6 to 1 to volume ratio we see that to burn 1 liter of fuel we need about 16.000 liter of air. Obviously the problem is to get the air into the engine. Getting the tiny bit of fuel per liter of air in is not the problem.
On the other hand, air comes for free (at least up till today) while for fuel we have to pay dearly.
In other words, getting the air in is a matter of engineering and getting the fuel in is a matter of money.
So it is a matter of choice.
If you want maximum power, you make sure that after all the trouble of getting the air into the engine 100% of the air is put to good use and thus add 10% or so extra fuel to the mixture to make sure no oxygen atoms go unused. This is then a rich mixture
If you want economy you make sure all the expensive fuel atoms are burned and add 10% or so of air to the mixture to make sure no fuel atoms go unburned. This is a lean mixture.
It is not advisable to change a lean burn engine to a rich burn engine or vice versa by changing the carburetor jetting as the thermal loading of the engine components is too different in both cases. In engine is either designed for rich burn or lean burn.
Since the Italians built small engines for tax reasons, it was extra difficult to get the enormous amounts of liters of air in and since they also liked power, the choice for mixing a bit of extra fuel in is obvious.
The ideal or stoichiometric mixture of air and fuel is 14,6kg of air per 1kg of fuel. This means there are theoretically exactly enough oxygen atoms for every atom of fuel to burn. In practice not every fuel atom is going to find its oxygen atom and vice versa. There are going to be spinster and bachelors.
If we translate the weight ratio of 14,6 to 1 to volume ratio we see that to burn 1 liter of fuel we need about 16.000 liter of air. Obviously the problem is to get the air into the engine. Getting the tiny bit of fuel per liter of air in is not the problem.
On the other hand, air comes for free (at least up till today) while for fuel we have to pay dearly.
In other words, getting the air in is a matter of engineering and getting the fuel in is a matter of money.
So it is a matter of choice.
If you want maximum power, you make sure that after all the trouble of getting the air into the engine 100% of the air is put to good use and thus add 10% or so extra fuel to the mixture to make sure no oxygen atoms go unused. This is then a rich mixture
If you want economy you make sure all the expensive fuel atoms are burned and add 10% or so of air to the mixture to make sure no fuel atoms go unburned. This is a lean mixture.
It is not advisable to change a lean burn engine to a rich burn engine or vice versa by changing the carburetor jetting as the thermal loading of the engine components is too different in both cases. In engine is either designed for rich burn or lean burn.
Since the Italians built small engines for tax reasons, it was extra difficult to get the enormous amounts of liters of air in and since they also liked power, the choice for mixing a bit of extra fuel in is obvious.
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Volker
Re: motor oils
My neighbour ownes a 1975 Porsche 911s Targa and asked the same question.
I read a lot and found that Porsche gives a specification for oil for every car
that was built since the 1950´s. If you find that specification on a bottle, this oil doesn´t
damage the seals of the engine.
Mercedes has a special specification for its ancient engines. The one you find in the
supermarket is only for modern engines.
I don´t know if the seals Lancia used are of the same material that Porsche and Mercedes
(they were the same) used, but the Porsche specification sounds interesting to me.
Saludos
Volker
I read a lot and found that Porsche gives a specification for oil for every car
that was built since the 1950´s. If you find that specification on a bottle, this oil doesn´t
damage the seals of the engine.
Mercedes has a special specification for its ancient engines. The one you find in the
supermarket is only for modern engines.
I don´t know if the seals Lancia used are of the same material that Porsche and Mercedes
(they were the same) used, but the Porsche specification sounds interesting to me.
Saludos
Volker