Technical Carburetor replacement

[abacaxi]

Hi,

Just found this forum. Always great to find people outside of facebook. I'm putting a Weber 34 DMTR in my '83 1050 CL. While I've worked on these engines before I never really changed anything, just replaced with same parts, so this is more of a challenge. I need a manifold adapter and a new air filter, but there seems to be more differences. Manual choke, easy enough to install, do I just connect the two coolant tubes for the old auto choke, or plug them? How do I handle crank ventilation? High idle button can simply be disconnected? Any other advice?

/Mattias

 

[bugsymike]

Hi,

Just found this forum. Always great to find people outside of facebook. I'm putting a Weber 34 DMTR in my '83 1050 CL. While I've worked on these engines before I never really changed anything, just replaced with same parts, so this is more of a challenge. I need a manifold adapter and a new air filter, but there seems to be more differences. Manual choke, easy enough to install, do I just connect the two coolant tubes for the old auto choke, or plug them? How do I handle crank ventilation? High idle button can simply be disconnected? Any other advice?

/Mattias

So you are going from a single choke to a twin choke carb? If so the inlet manifold would need to be carefully constructed to gain any performance benefits I would have thought.
The carb would need to correctly jetted to suit, and a matching air filter.
If not for performance, what is the reason for the change?
As you say a manual choke cable can be installed.
Re the coolant pipes, I would tend to use a small tube to join them together to keep engine coolant flow as original design but minus the carb.
Crank case vent pipe would depend on whether it has a PCV valve in the system or not, depending on what air filter design and if the breather can be incorporated with it or not.
By the way does your original air cleaner draw cool air from outside the engine compartment as this has benefits.
The last Fiat 127 1050CL I worked on was a customers in the late 1980s.

 

[abacaxi]

Thank you. You've got it right. The icev carb on now does have some kind of valved crank ventilation according to the repair manual but I haven't taken everything apart yet so I'm not sure. The current air filter has a very long inlet so it's trying to get cold air for sure. I'll see if it can be modified, otherwise I'll just get one of those little "sport" filters.

 

[bugsymike]

Thank you. You've got it right. The icev carb on now does have some kind of valved crank ventilation according to the repair manual but I haven't taken everything apart yet so I'm not sure. The current air filter has a very long inlet so it's trying to get cold air for sure. I'll see if it can be modified, otherwise I'll just get one of those little "sport" filters.

The benefit of the cold air rather than the warm from engine compartment is cold air is more dense so more oxygen, which is why cars with carbs(not ecu controlled) tend to go better on a cold damp morning.