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Is there any difference between the intake manifolds for dual carburetors on a 105.36 1600 and a 105.48 1750 engine? Inquiring minds want to know, thanks.
 

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The 1600 has smaller ports.
 

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Is there any difference between the intake manifolds for dual carburetors on a 105.36 1600 and a 105.48 1750 engine? Inquiring minds want to know, thanks.
Hi. You do not say what year you are talking for the 105.36 1600 but if mid to late 60s then it would be the screw in type thermostat. The 1750s had a drop in thermostat type. Search manifold variations in technical/carburetor forum.

Here's the link

https://www.alfabb.com/bb/forums/carburetors-fuel-injection-air-intake/31111-105-115-carb-manifold-variations.html

Regards

Ken
 

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Hi. You do not say what year you are talking for the 105.36 1600 but if mid to late 60s then it would be the screw in type thermostat. The 1750s had a drop in thermostat type. Search manifold variations in technical/carburetor forum.


The Giulia Supers appear to have continued to use the screw-in thermostats well into the 70's. My very original 1.3 Super from '72 surprisingly was fitted from new with the old-style threaded thermostat. The reason for this, I presume, probably had something to do with Alfa, being state owned, keeping its component supplier busy a bit longer than more profit oriented car companies would.
 

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The Giulia Supers appear to have continued to use the screw-in thermostats well into the 70's. My very original 1.3 Super from '72 surprisingly was fitted from new with the old-style threaded thermostat. The reason for this, I presume, probably had something to do with Alfa, being state owned, keeping its component supplier busy a bit longer than more profit oriented car companies would.
Yes maybe, or it has that earlier manifold for any number of other reasons, while the rest of the car remains very original. You should find evidence from other owners of similar vintage, if you haven't already.

Maybe you can take some pictures of the markings and post in the above link location if they differ from what is already posted there.

ciao

Ken
 

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Richard Jemison
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Manifolds

The 1600 and 1750 shared the same head & components. The 1600/1750 carb manifolds were both 36mm internal passage.
The 2liter manifolds were 38mm internals.

The positions of the port openings in the heads are different on these small heads compared to the 2 liter heads. This requires quite a bit of "port matching".
 

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Both the AR parts manual and the Shankle parts manual show a common part number for 1300 & 1600 intake manifolds and a different part number for 1750 & 2000 intake manifolds.
 

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mid to late 60s then it would be the screw in type thermostat. The 1750s had a drop in thermostat type.
And the water pump has to be matched to the manifold. Manifolds with the drop-in thermostat use a bypass hose (*) between the manifold and water pump. Manifolds with the screw-in thermostat have no bypass hose. In general, 1600 waterpumps don't have an outlet for the bypass, while 1750 - 2000 pumps do.

*) And to complicate life further, carburetor and Spica bypass hoses are shaped differently.
 

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Discussion Starter #9
Thanks to all for responding. The question is about a 1750 head on a 1600 block, and does the 1600 intake manifold just swap over? Sounds like the answer is yes.
 

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Thanks to all for responding. The question is about a 1750 head on a 1600 block, and does the 1600 intake manifold just swap over? Sounds like the answer is yes.
Well that's a different question.
 

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I have a drop in thermostat type 1600 intake manifold on a 2L head. The mounting holes and hose connections are the same but the ports do not match until you modify them.
 

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Manifolds

And the water pump has to be matched to the manifold. Manifolds with the drop-in thermostat use a bypass hose (*) between the manifold and water pump. Manifolds with the screw-in thermostat have no bypass hose. In general, 1600 waterpumps don't have an outlet for the bypass, while 1750 - 2000 pumps do.

*) And to complicate life further, carburetor and Spica bypass hoses are shaped differently.
Actually the outlets for the lower "Bypass" hose on both the manifold and pump can be plugged.

It`s purpose was to initially heat the water circulating early after starting to bring the temp up faster and provide the heater with hot water faster.

Those bypass hoses have a metal restrictor in them with a small 8mm hole to reduce flow.

I suspect that the mouse motors have the same port spacing, But Early 1600`s had a larger port bore???
You will rarely find that these manifolds and head ports match acceptably for a "performance" application. and should be matched reasonably in any application.
2 liter spacings were different as well. The Spica/Weber spacing, the early Bosch spacings, and the `89 & later spacings.
 
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