Why two oil filler caps?

I can't think of a functional reason why there are two oil fillers on the later cars. My only guess would be that the second one added later is easier to access and was added because of complaints that the front one was too difficult to fill without a funnel. Again just a guess. As far as I know someone in Italy mis-ordered too many filler necks so they used them just to consume stock; with Italy you never know.

From a usage standpoint, both use the galleys in the heads as the passages to fill the sump so there is no difference in which filler you use to add engine oil.

 

Synchronicity...
Regards, Alberto

 

I must shoot your theory down Rob....Stood with my head far down into the engine bay of a Fiat Dino yesterday with a longitudinal Dino engine also with two filler necks showing of right into your face. My thoughts were the same as the thread started, why bother? I think it is a touch of industrial design...or synchronicity as mentioned above...-

Best Peter

 

I have been asking myself the same question. Came up with this theory:
I believe it had to do with the crankcase ventilation system.

Although it is called crankcase ventilation, a fair amount of the oil fumes get trapped inside the valve covers. For this reason, the L-series was given a breather hose from the cam cover (oil filler tube) to the oil separator and intake system.
Here is what it looked like from #01132:

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This system relieved only the oil fumes in the forward cylinder bank. It is fair to assume the the rear bank generated just as many fumes, but with no place to go. A hose connection on the rear cam cover had to be added.
Instead of making a brand new part for this, I believe Ferrari simply decided to use the existing oil filler tube on the rear bank too. It already had the breather hose connection on it. Such a decision would make sense for a small manufacturer. The extra filler cap did not do any harm, and could perhaps even be considered an added convenience.

Here is the system from #02132 (approximately):

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This is all just a guess on my part, but I think it is a possible explanation for the two filler caps.

 

Lars, I think you are close. Facts ruin all good discussions...- My early L-series breath directly to the atmosphere from the forward cam cover via a hose routed to the bottom of the car...Not that many concerns back in the days. The aft cam cover does not breath at all as mentioned earlier?


Best Peter

 

Peter,

Yes, I am quite convinced it was about the crankcase ventilation. Ferrari was gradually catching up on how to treat various emissions at that time, it seems. They changed the system between every generation. Perhaps they were forced to.

And yes, as far as I can see, the rear cam covers were not vented at all in the earlier cars. Not the end of the world, of course, but not optimal either.

Lars

 

Hose or tube vented to the atmosphere is called a "road draft tube". PCV valves were mandated by law for the 1968 model year. Earlier in California.
https://en.wikipedia.org/wiki/Crankcase_ventilation_system

 

Correction: The serial number for the first change should be #01118 and nothing else. It says so right on the illustration. And of course, I meant to say the M-series. Sorry!
The L-series, at least the early ones, as Peter just pointed out, apparently had the simple device we now know is called a road draft tube.

This does not change the conclusions or assumptions about the two filler caps, but I just wanted to correct those two items for the records.

 

I think you're spot on with this Lars.
My late L-series had one filler and the ventilation tube plugged but #01118 is about 70 cars after mine.