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Discussion Starter #1
I have 2 different DCO3 intakes. They are identical except for the location of the Bellcrank which is located about 45mm lower on one.
Which one is correct for a 1957 750 engine?

Why the change and what models are they for?
Ulf
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With later 101 cars, the short one was for spiders, the long one for GT's. I do not know if that is the same for the 750 cars.
 

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Discussion Starter #4
Part number on the short one is 1315.44706
The long one has no numbers cast in.
Ulf
 

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Interesting that the Parts manual gives it as 1315.44.713 and only lists the one item. The picture in the manual shows it as having the longer casting part underneath.

I can't find part #706 in the manual as yet - part #708 is the tapered tube water rail

The mystery continues

Ciao
Greig
 

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Possibly your manifold on the left is what is in this Shop Manual photo .... which might imply it is the earlier of the two.
750 Veloce 1st edition intake side Pub #637 1959-06.jpg
 

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Hi all,

#706 is a casting number I guess.


edit:

I deleted the rest of this post for double checking first the source of my statement that I made and that I can't find anymore. Sorry.

Rgds,

Thierry
 

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Part number on the short one is 1315.44706
The long one has no numbers cast in.
Ulf
That’s the same number I have on one of my manifolds, question is which is the older type and why the differences? ( edit: answered by Thierry in the previous post #7 )
B8B937ED-409D-4480-8823-68C1875E6994.jpeg
 

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Can you provide a pic of the backside of both manifolds? The period pic of the veloce engine appears touched up. Just check out the attachment point of the support rods. Heres a pic from the service manual. Again a drawing, but appears to be of the longer post.

Reed
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20200915_095839.jpg
 

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Hi Ulf and all,

After having deleted a part of my post #7 , here a, in some more conditional mode rephrased, theory from the statement that I wrote in the first place about what could have happened with the 750 Veloce inlet manifold.

Please understand that it is only a theory that still needs confirmation or disapproval . Maybe other testimonies or not published official documents are to be found and could hopefully be decisive in this matter.

My only purpose for making this statement now yet in this recent thread, is for trying to find for now, a kind of coherent and plausible answer about why there were different 750 Veloce inlet manifolds as fortunately showed here by Ulf.

If at the end it would turn out that there would be a kind of definitive indication, a sort of “ Stone of Rosetta “ showing up here, that would prove that this theory is correct or even is wrong, then I would be more than happy.

The abovementioned argument to stay prudent in this matter is important as I can’t prove the correctness of that theory by official Alfa documents , it is only a coctail from official catalog data combined with memories that I have from discussions that were held, discussions that I can’t retrace anymore, … a little dangerous, I know .

All starts with my understanding that there were former discussions held about the brand of the startmotor that was used on the 750 Veloces.

Finally, as listed in the catalogs btw, Alfa went for the Marelli as the one starter to be used on the Veloce 750 cars .
Why ?
Besides the fact that Alfa and Magneti Marelli were both Italian companies of course, this would have something to do with the Veloce being negative grounded, but maybe also with the position of the solenoid ( and so the connectors) that was more oriented downwards than the solenoid on the Lucas starter. This difference can be noticed on the next pictures from an engine with Marelli and an engine with Lucas .

1648830


1648831



Was the lower position of the connectors, and so the Marelli starter, chosen for these safety reasons: preventing the connectors from touching acidentally the horizontal rod between the acccelerator pedal lever and the bellcrank ? To my knowledge, we don’t know that from official documents.

But what I would remember from all this is that there could have been a problem with that rod, getting to close to the starter connectors.
The presumption I make now is that Alfa would have altered therefore the position of that rod to avoid accidents with that rod causing fire. The higher position of the bellcrank is perfectly noticeable on the picture in post # 1 … We know from the catalog that Alfa indeed changed the accelerator pedal lever, the bellcrank shape and the length of some of the rods. Why would they have done that if not for changing the position of that horizontal rod ? … any thoughts ?

Hence my second assumption here that Alfa changed at this occasion, and for the same reason, also the chape of the inlet manifold, bringing the bellcrank pin higher and improving that way also the traject of the rod.

Admitted, I don’t know of any evidence coming from Alfa for this up to now. Anyone ?
But the fact is that there were two different manifolds, having different bellcrank pin heights.

If this all would be correct, then Alfa ‘forgot’ to mention an altered manifold number and a new picture in the catalog.

As far as I know, the earliest parts catalog showing Veloce parts is the 11/1957 catalog 608. The picture of the manifold in there shows the manifold with the longer casting part underneath as Greig mentioned before, the same as the left manifold on Ulf’s picture in post # 1, probably making that one the earliest manifold.

Important to be noticed is that the changed rod ensemble was already listed in that early catalog, so it was already applicable earlier than 11/1957. But when ?

Unfortunately the catalog doesn’t mention when exactly the change of the rod (and maybe the manifold ) occured. If nobody shows up with new material, we only can rely on testimonies of early Veloce car owners I guess.

Once more, please don’t take the theory for granted, the last thing that I want to create is a story that, if it is repeated often enough, would be accepted as the real truth like this happened already before at other occasions. So it is only meant as a kind of first move to try to find out what happened in 1956, and for what reason.

Therefore thank you for all additional input about this matter.

Rgds,

Thierry
 

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Looks like the '59 with split case corrected the close proximity of the carb linkage to the starter.. I ran a Lucas starter in mine and it probably wouldn't have wowrked out as well with the long manifold.
 

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The 57 manual illustration has caused Thierry and I to have several discussion. Look at it closely, it appears that the bell crank pivot bolt is screwed into the side of the block instead of into the intake manifold.
 

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The 57 manual illustration has caused Thierry and I to have several discussion. Look at it closely, it appears that the bell crank pivot bolt is screwed into the side of the block instead of into the intake manifold.
Also the oil pan is an artist's interpretation.. It looks nothing like a steel one nor a cast one.
 

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1648973


There is definitely something mysterious about that 1957 picture .
It fooled us for a while indeed, but I think that, also thanks to the 'confronting' picture from Ulf, showing two different manifolds despite that there would have existed only one type according to the catalogs, we could say that that picture must show a case of very early photoshopping. The idea of the bell crank pin being screwed into the side of the crankcase is more questionable than ever now. just my opinion. Other opinions or testimonies about this ?

Thank you Divotandtralee for adding the info about your '59 car in post # 15. Am I correct that your engine- tranny combination would look very similiar to what we see on Joe's left picture in post # 13 ?

If you can imagine a Lucas starter, as pictured in post # 14, instead of the Marelli starter on the picture above, I think you would agree indeed that the solenoid of the Lucas starter would stand in the way for the rod.

Rgds,

Thierry
 

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Hi all again,

As discussed yet in former threads on AlfaBB, there were two types of 750 Veloce bell cranks.
From what we can see in all pictures and drawings that we gathered in this thread already, couldn’t we at least presume yet that the very early manifolds used the L-shaped bell crank ?
As Carl mentioned in post # 6, the left manifold on the first picture from Ulf is probably one of them .
Btw, Carl's picture in his post # 6 shows the L-shaped bell crank, on the longer support type manifold.

The second bell cranks, the ones with two levers with a spacer between them, I only found them on the manifolds with the shorter casting part underneath, like the right manifold of Ulf’s picture in post # 1 and in his post # 11.
Maybe we could conclude that the second bellcrank came with the manifold with the shorter support, making that also the second type manifold.

Just some further thoughts, to be checked.

Rgds,

Thierry
 

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View attachment 1648973

There is definitely something mysterious about that 1957 picture .
It fooled us for a while indeed, but I think that, also thanks to the 'confronting' picture from Ulf, showing two different manifolds despite that there would have existed only one type according to the catalogs, we could say that that picture must show a case of very early photoshopping. The idea of the bell crank pin being screwed into the side of the crankcase is more questionable than ever now. just my opinion. Other opinions or testimonies about this ?

Thank you Divotandtralee for adding the info about your '59 car in post # 15. Am I correct that your engine- tranny combination would look very similiar to what we see on Joe's left picture in post # 13 ?

If you can imagine a Lucas starter, as pictured in post # 14, instead of the Marelli starter on the picture above, I think you would agree indeed that the solenoid of the Lucas starter would stand in the way for the rod.

Rgds,

Thierry
Moreover the starter orientation in your picture is nothing like what ended in production. There is no flange to bolt it to the bell housing ( just a tab in the photo) and the holes to do that in the photo orient the solenoid from the top of the starter to a quadrant of like 7 0"clock, Clearly, the engineers recognized a problem developing with linkage clearances
 
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