Alfa Romeo Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
119 Posts
Discussion Starter #1
My Guilietta TI has got a 1750 engine en a solex C35 APAI-G carb.

Probably the carb has not been adjusted to the engine yet. I'd like to maintain
a setup with only one carb, so that I have no problems with synchronisation of
two individual carbs.

Before I'll try to adjust the Solex C35, I wonder if there is a better carb with
more capacity that I can use in a setup with one carb, to be able to bennifit
from the engine as much as possible.....with only one carb?

Advice requested!

Regards,

Joris
 

·
Registered
Joined
·
2,169 Posts
My Guilietta TI has got a 1750 engine en a solex C35 APAI-G carb.

Probably the carb has not been adjusted to the engine yet. I'd like to maintain
a setup with only one carb, so that I have no problems with synchronisation of
two individual carbs.

Before I'll try to adjust the Solex C35, I wonder if there is a better carb with
more capacity that I can use in a setup with one carb, to be able to bennifit
from the engine as much as possible.....with only one carb?

Advice requested!

Regards,

Joris
The Weber 28/36 DCD, 36/36 DCD, and 32/36 DGV are all good choices that bolt directly onto a 101 / 105 series single carb manifold. The DCD is more period correct, but harder to find. If you're looking for performance the 36/36 DCD is an interesting option, as it can be used in either progressive or synchronous mode.

I currently have a 28/36 DCD in my Giulietta spider on a 1600 engine with 1750 pistons and liners. Both types of carbs are highly tunable and jets / etc. are readily available. The DCD even has removable venturis like the DCOE, so it's very flexible.

-Jason
 

·
Registered
Joined
·
6,892 Posts
If your Solex has been sitting for a while, it will need a good cleaning and rebuild by a specialist.
Jet and venturi change also if you want more performance.
If you go with a Weber 36 the intake manifold will have to be opened up to match the bigger throats.
Look for a 36 Weber like this one to match the air filter......
 

Attachments

·
Registered
Joined
·
119 Posts
Discussion Starter #4
thanks for your advice.

Someone offered me a weber 36dcd7 R6b.

How can we establish that it is a 36/36 of something else?

the venturi's are both 24's and fuel jets are F13.
 

·
Registered
Joined
·
6,892 Posts
I think that the f13 is an emulshion tube. Main jet is on the end of it and will be something like 130.....
Normally, these are used on a 1600cc motor. Might be a bit small for a 1750 althou your fuel consumption will be very small !!
 

·
Registered
Joined
·
119 Posts
Discussion Starter #6
carb will be rejetted on a dyno.

But is a 36 dvd7 a 36/36 or 28/36...or......?

In other words: is a weber 36 dcd7 the best option in a setup with one carb?
 

·
Registered
Joined
·
6,892 Posts
Not sure of the model numbers, but a 36 DCD with 24mm venturis on both sides is caled a 36/36 by some . It is not a 28/36.
The difference in models has to do with their application........
Jets, venturis for a particular motor.
One big difference in 36 DCD models is if both throats open at the same time or if one opens first.
 

·
Registered
Joined
·
119 Posts
Discussion Starter #8
I have taken your advise into account and also got some advice from the man that has tuned up my 1750 berlina on his dyno. His advise was to choose a progressive carb for better drivability and easier to tune. He also stressed that it's best to buy a new carb instead of a used old carb that needs refurbishing.

I found a new 32/36DGV that's been sitting on a shelve for some time at a classis alfa parts dealer who wanted to get rid of it. It can not (yet?) be fitted with the stock airfilter so therefore he gave me a K&N filter I can fit to it. Im still trying to find out if the 32/36 DGV can be fitted with a dcd adapter after removing the choke, but I'm not sure I can get away with removing it?

I do know that camshaft timing with a single carb is a bit different than twincarb setups, so i've got to check that too.

Main question now is what jets to use on my (stock) 1750?
 

·
Registered
Joined
·
296 Posts
I do know that camshaft timing with a single carb is a bit different than twincarb setups, so i've got to check that too.
I have to believe camshaft timing depends on the exhaust side as much as the intake side. Are you using an early log style exhaust manifold, a later 2-piece manifold or headers?

Mike R
 

·
Registered
Joined
·
119 Posts
Discussion Starter #10
My original TI exhaust wants to be connected throug an original 4-1 exhaust manifold.

I was instructed by the man I bought the weber from.
heads with original 1 carb setup have different timing marks than heads for 2 carb setup.

With 2 carbs the timing marks are in the centre of the bolt on top and with one carb setup both marks are positioned a couple degrees to the outside.
 

·
Push hard and live
Joined
·
10,189 Posts
I used to work for BAP/Geon when we were the sole Weber distributor, and did a fair amount of work with the two-barrel types.

The DGV is an inexpensive carb, most of which were actually made by Holley in the US or elsewhere. It was intended to provide the various emission control opportunities that a carb could provide. It's an OK carb, but not nearly as flexible as the DCD types, particularly with their changeable venturies.

Given that you're going to be experimenting with a set-up that few people have done, I'd suggest the 36DCD. You need far more air than what the 28/36 DCD was designed to provide. You may find that operating in dual-mode is OK for your 1750 once you get it set up, but the primary/secondary mode will certainly give you a more gentle ride.

I wouldn't worry about the cam timing for now. That's going to have a smallish impact on the engine behavior given the very restrictive 2-barrel carb that you're choosing to stick with. As the dual Weber DCOE's give great driveability, I would still suggest them, but understand what you're trying to do.

I doubt you'll get anyone recommending a starting point for the jets, as you're doing something that few people would want to do, or have done.

Good luck!
 

·
Registered
Joined
·
119 Posts
Discussion Starter #12
progress report:

The 32/36 DGV did not fit with the original thermostat housing. After mounting a Alfetta thermostat (more compact) the DGV dit fit WITH the thick gasket on the manifold, to keep the carb cooler.

Final problem was the gaslever, but after consulting lots of companies I finally got a customized lever to fit the weber on the original linkage.

First try starting with the rough factory setting: she spinned straight away!:cool:

After warming up slowly and some tuning I took her for a short drive.
- She is suprisingly fast!
- The mixing screw had to be turned in a whole lot to get a good setting so -I probably need bigger idle jets.
- from no to full throttle the enging hesitates briefly before she dashes away. I think that means a bigger pump jet is required?
- I'm not sure how I can see if the main jets and air correctorjets are big enough?

Any tips? I don't want to get her on a dyno yet (maybe next year) because I want to do some more maintenance and updates first this winter.
 
1 - 13 of 13 Posts
Top